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STATISTICAL BRIEF #153


April 2013


Readmissions to U.S. Hospitals by Diagnosis, 2010


Anne Elixhauser, Ph.D. and Claudia Steiner, M.D., M.P.H.



Introduction

The problem of readmissions to the hospital is receiving increased attention as a potential way to address problems in quality of care, cost of care, and care transitions.1,2 Medicare reports 30-day hospital readmissions for acute myocardial infarction, congestive failure, and pneumonia for individual hospitals across the country.3 Interventions are underway to reduce hospital readmissions at the state and national level.4,5

Prior research reports have focused on readmissions for specific conditions such as congestive heart failure, pneumonia, chronic obstructive pulmonary disease (COPD), and psychoses.6,7,8 This Statistical Brief provides an overview of 30-day all-payer, all-cause readmissions to U.S. hospitals for a range of conditions in 2010, thereby presenting the most comprehensive national estimates on readmissions by condition.

In this Statistical Brief, readmission was defined as a subsequent hospital admission within 30 days following an original admission (or index stay) that occurred from January through November 2010. All-cause readmissions were examined; thus, readmissions may or may not include conditions that were listed as the principal diagnosis during the index stay. Readmissions were tracked across the same or different hospitals. Some readmissions may be planned or unavoidable-no attempt was made to remove these types of readmissions from the analysis.

Readmission rates using Healthcare Cost and Utilization Project (HCUP) data are presented for the most frequently treated conditions in U.S. hospitals during 2010 and for the conditions with the highest readmission rates. All estimates were taken from HCUPnet, the online query system that provides free access to information from HCUP.9 For a subset of conditions, readmission rates are presented by age group and expected payer (insurance status). Patients younger than 1 year were excluded from this analysis. Readmission rates were calculated without risk adjustment.

Appendix A provides detailed information on readmission rates for most conditions treated in U.S. hospitals in 2010. The table provides information on the number of index stays for each condition, the number of all-cause readmissions within 30 days, and the percentage of index stays that were followed by a readmission within 30 days for any cause. Excluded were nonspecific conditions and any conditions with fewer than 5,000 index stays or fewer than 500 readmissions. Conditions are organized by etiology or body system.
Highlights
  • For several of the most frequently treated conditions in U.S. hospitals, at least one in five cases resulted in a readmission within 30 days: congestive heart failure (24.7 percent), schizophrenia (22.3 percent), and acute and unspecified renal failure (21.7 percent).


  • For several conditions, over one in four patients were readmitted: sickle cell anemia (31.9 percent), gangrene (31.6 percent), hepatitis (30.9 percent), diseases of the white blood cells (30.9 percent), and chronic renal failure (27.4 percent).


  • For conditions with both large numbers of stays and high readmission rates, Medicare and especially Medicaid patients were more likely to be readmitted than privately insured or uninsured patients. For example, congestive heart failure readmission rates were 30.1 percent for Medicaid, 25.0 percent for Medicare, 19.5 percent for privately insured, and 17.1 for uninsured patients.


  • For the same selected conditions, children and adolescents had the highest readmission rates only for complications of devices, implants or grafts (25.5 percent), compared to 19.2 percent for patients aged 65 years and older.
Findings

Readmission rates for the most frequently treated conditions
Table 1 lists the 30 most frequently treated conditions in U.S. hospitals, with their 30-day readmission rates. The most frequent conditions and their readmission rates were pneumonia (15.7 percent), mood disorders (14.8 percent), osteoarthritis (4.8 percent), congestive heart failure (24.7 percent), and cardiac dysrhythmias (14.8 percent).

Among these most frequent conditions, the highest readmission rates were seen for congestive heart failure (24.7 percent), schizophrenia (22.3 percent), and acute and unspecified renal failure (21.7 percent). In other words, for these conditions over one in five patients were readmitted to the hospital within 30 days.

The lowest readmission rates were for childbirth-related procedures (trauma to perineum and vulva during childbirth, 0.8 percent; C-section, 1.5 percent), osteoarthritis (4.8 percent), and appendicitis (4.9 percent).

Conditions with the highest readmission rates
Table 2 lists conditions ranked by the highest readmission rates. Because cancer readmissions are often planned, cancer is excluded from this table (although cancer-related conditions are included in the Appendix).

The five conditions with the highest readmission rates were sickle cell anemia (31.9 percent), gangrene (31.6 percent), hepatitis (30.9 percent), diseases of the white blood cells (30.9 percent), and chronic renal failure (27.4 percent). In other words, over one in four patients were readmitted to the hospital within 30 days for these conditions.

Readmission rates by age and insurance status for selected conditions
Figures 1-5 provide details on 30-day all-cause readmission rates for the five conditions from Table 2 that involved more than 300,000 index stays and had overall readmission rates of at least 20 percent.10


Table 1. All-cause 30-day readmissions ranked by the most frequently treated conditions* in U.S. hospitals, 2010
Rank Principal diagnosis for index hospital stay ** Number of index stays 30-day all-cause readmissions
Number of readmissions Percent readmitted
1 Pneumonia 924,160 144,894 15.7
2 Mood disorders 883,245 131,125 14.8
3 Osteoarthritis 872,661 42,241 4.8
4 Congestive heart failure, nonhypertensive 847,073 209,017 24.7
5 Cardiac dysrhythmias 705,616 104,607 14.8
6 Septicemia (except in labor) 696,122 145,896 21.0
7 Coronary atherosclerosis 666,897 90,147 13.5
8 Trauma to perineum and vulva due to childbirth 610,073 5,046 0.8
9 Chronic obstructive pulmonary disease and bronchiectasis 606,186 126,443 20.9
10 Nonspecific chest pain 601,899 61,465 10.2
11 Complication of device, implant or graft 596,062 121,036 20.3
12 Spondylosis, intervertebral disc disorders, other back problems 579,103 47,774 8.2
13 Skin and subcutaneous tissue infections 576,902 64,680 11.2
14 Urinary tract infections 522,921 84,858 16.2
15 Acute myocardial infarction 520,901 85,932 16.5
16 Acute cerebrovascular disease 520,793 71,174 13.7
17 Diabetes mellitus with complications 480,958 97,784 20.3
18 Previous C-section 462,378 7,046 1.5
19 Complications of surgical procedures or medical care 453,266 81,353 17.9
20 Biliary tract disease 430,988 48,062 11.2
21 Schizophrenia and other psychotic disorders 397,166 88,629 22.3
22 Fluid and electrolyte disorders 396,551 73,721 18.6
23 Asthma 347,404 41,320 11.9
24 Acute and unspecified renal failure 326,586 70,756 21.7
25 Gastrointestinal hemorrhage 320,613 54,154 16.9
26 Intestinal obstruction without hernia 315,128 51,135 16.2
27 Fracture of neck of femur (hip) 291,847 38,668 13.2
28 Diverticulosis and diverticulitis 289,097 35,461 12.3
29 Pancreatic disorders (not diabetes) 282,159 49,936 17.7
30 Appendicitis and other appendiceal conditions 262,024 12,875 4.9
Source: Weighted national estimates from a readmissions analysis file derived from the Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases (SID), 2010, Agency for Healthcare Research and Quality (AHRQ).
* Information is provided for diagnoses with 5,000 or more weighted index stays and 500 or more weighted readmissions. See text and Definitions for details on methods for calculating readmissions.
** Clinical Classification Software (CCS) label. Excludes cancers and nonspecific CCS categories.


Table 2. All-cause 30-day readmissions ranked by conditions with the highest readmission rates,* U.S. hospitals, 2010
Rank Principal diagnosis for index hospital stay ** Number of index stays 30-day all-cause readmissions
Number of readmissions Percent readmitted
1 Sickle cell anemia 87,326 27,837 31.9
2 Gangrene 33,786 10,693 31.6
3 Hepatitis 37,480 11,593 30.9
4 Disease of white blood cells 54,861 16,771 30.6
5 Chronic renal failure 17,394 4,766 27.4
6 Systemic lupus erythematosus and connective tissue disorders 18,850 5,123 27.2
7 Mycoses 23,026 6,222 27.0
8 HIV infection 34,958 9,230 26.4
9 Screening and history of mental health and substance abuse 60,417 15,695 26.0
10 Peritonitis and intestinal abscess 25,219 6,315 25.0
11 Congestive heart failure, nonhypertensive 847,073 209,017 24.7
12 Personality disorders 5,436 1,316 24.2
13 Nutritional deficiencies 9,845 2,355 23.9
14 Coagulation and hemorrhagic disorders 33,397 7,920 23.7
15 Respiratory failure, insufficiency, arrest (adult) 260,781 59,842 22.9
16 Nausea and vomiting 51,833 11,854 22.9
17 Schizophrenia and other psychotic disorders 397,166 88,629 22.3
18 Acute and unspecified renal failure 326,586 70,756 21.7
19 Aspiration pneumonitis, food/vomitus 147,837 31,772 21.5
20 Hypertension with complications and secondary hypertension 211,243 45,309 21.4
21 Chronic ulcer of skin 50,845 10,823 21.3
22 Pleurisy, pneumothorax, pulmonary collapse 101,298 21,485 21.2
23 Early or threatened labor 179,175 37,797 21.1
24 Septicemia 696,122 145,896 21.0
25 Anemia 203,098 42,374 20.9
26 Chronic obstructive pulmonary disease and bronchiectasis 606,186 126,443 20.9
27 Aortic and peripheral arterial embolism or thrombosis 26,104 5,381 20.6
28 Heart valve disorders 100,327 20,613 20.5
29 Diabetes mellitus with complications 480,958 97,784 20.3
30 Complication of device, implant or graft 596,062 121,036 20.3
Source: Weighted national estimates from a readmissions analysis file derived from Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases (SID), 2010, Agency for Healthcare Research and Quality (AHRQ).
* Information is provided for diagnoses with 5,000 or more weighted index stays and 500 or more weighted readmissions. See text and Definitions for details on methods for calculating readmissions.
** Clinical Classification Software (CCS) label. Excludes cancers and nonspecific CCS categories.


Figure 1 shows that readmission rates for congestive heart failure were relatively uniform across age groups, ranging from 24.2 percent to 26.1 percent. The highest readmission rate was seen for patients with an expected payer of Medicaid (30.1 percent) compared to 25.0 percent for Medicare-covered patients, 19.5 percent for privately insured patients, and 17.1 percent for the uninsured.


Figure 1 is a bar chart illustrating. percent readmitted by age in years and by expected payer for congestive heart failure by age and insurance status, United States hospitals in 2010.

Figure 1. All-cause 30-day readmission rates for congestive heart failure by age and insurance status, U.S. hospitals, 2010. This is a bar chart showing percent readmitted by age in years and by expected payer. Ages 1 through 17, too few cases to report. Ages 18 through 44, 26.1 percent. Ages 45 through 64, 25.7 percent. Ages 65 and older, 24.2 percent. Medicare payer, 25.0 percent. Medicaid payer, 30.1 percent. Privately insured, 19.5 percent. Uninsured, 17.1 percent. Source: Weighted national estimates from a readmissions analysis file derived from the Healthcare Cost and Utilization Project State Inpatient Databases, 2010, Agency for Healthcare Research and Quality.



Readmission rates for schizophrenia are shown in figure 2. The highest readmission rates were seen for patients aged 18-44 years (22.6 percent) and 45-64 years (23.4 percent). Readmission rates for patients with an expected payer of Medicare (23.7 percent) and Medicaid (24.0 percent) were about 50 percent higher than for other patients (15.1-16.1 percent).


Figure 2 is a bar chart illustrating percent readmitted by age in years and by expected payer for schizophrenia and other psychotic conditions by age and insurance status, United States hospitals in 2010.

Figure 2. All-cause 30-day readmission rates for schizophrenia and other psychotic conditions by age and insurance status, U.S. hospitals, 2010. This is a bar chart showing percent readmitted by age in years and by expected payer. Ages 1 through 17, 12.4 percent. Ages 18 through 44, 22.6 percent. Ages 45 through 64, 23.4 percent. Ages 65 and older, 18.8 percent. Medicare payer, 23.7 percent. Medicaid payer, 24.0 percent. Privately insured, 16.1 percent. Uninsured, 15.1 percent. Source: Weighted national estimates from a readmissions analysis file derived from the Healthcare Cost and Utilization Project State Inpatient Databases, 2010, Agency for Healthcare Research and Quality.



Readmission rates for acute and unspecified renal failure are depicted in figure 3. Readmission rates were similar for all adult age groups (19.0-22.1 percent), but again were substantially higher for patients with an expected payer of Medicare (22.7 percent) or covered by Medicaid (25.0 percent) than for other patients (13.3-17.0 percent).


Figure 3 is a bar chart illustrating percent readmitted by age in years and by expected payer for acute and unspecified renal failure by age and insurance status.

Figure 3. All-cause 30-day readmission rates for acute and unspecified renal failure by age and insurance status, U.S. hospitals, 2010. This is a bar chart showing percent readmitted by age in years and by expected payer. Ages 1 through 17, too few cases to report. Ages 18 through 44, 19.0 percent. Ages 45 through 64, 21.5 percent. Ages 65 and older, 22.1 percent. Medicare payer, 22.7 percent. Medicaid payer, 25.0 percent. Privately insured, 17.0 percent. Uninsured, 13.3 percent. Source: Weighted national estimates from a readmissions analysis file derived from the Healthcare Cost and Utilization Project State Inpatient Databases, 2010, Agency for Healthcare Research and Quality.



Figure 4 shows readmission rates for diabetes mellitus with complications. The highest readmission rate was for patients aged 18-44 years (22.6 percent), followed closely by patients aged 65 years and older (20.6 percent) and 45-64 years (19.9 percent). Readmission rates were nearly identical for patients covered by Medicare (23.6 percent) and Medicaid (23.5 percent); these rates were about 70 percent higher than rates for the privately insured and uninsured (13.6-14.1 percent).


Figure 4 is a bar chart illustrating percent readmitted by age in years and by expected payer for diabetes with complications by age and insurance status, United States hospitals in 2010

Figure 4. All-cause 30-day readmission rates for diabetes with complications by age and insurance status, U.S. hospitals, 2010. This is a bar chart showing percent readmitted by age in years and by expected payer. Ages 1 through 17, 7.2 percent. Ages 18 through 44, 22.6 percent. Ages 45 through 64, 19.9 percent. Ages 65 and older, 20.6 percent. Medicare payer, 23.6 percent. Medicaid payer, 23.5 percent. Privately insured, 13.6 percent. Uninsured, 14.1 percent. Source: Weighted national estimates from a readmissions analysis file derived from the Healthcare Cost and Utilization Project State Inpatient Databases, 2010, Agency for Healthcare Research and Quality.



Finally, figure 5 depicts readmission rates for patients with an index stay during which their principal diagnosis was complication of device, implant, or graft. The highest readmission rate was for children aged 1-17 years (25.5 percent). Similarly, the readmission rate for Medicaid-covered patients was 25.4 percent; this rate was nearly 20 percent higher than rates for Medicare (21.4 percent) and over 60 percent higher than those for privately insured and uninsured patients (15.6-15.7 percent).


Figure 5 is a bar chart illustrating percent readmitted by age in years and by expected payer for complication of device, implant, or graft by age and insurance status, United States hospitals in 2010.

Figure 5. All-cause 30-day readmission rates for complication of device, implant, or graft by age and insurance status, U.S. hospitals, 2010. This is a bar chart showing percent readmitted by age in years and by expected payer. Ages 1 through 17, 25.5 percent. Ages 18 through 44, 23.4 percent. Ages 45 through 64, 19.9 percent. Ages 65 and older, 19.2 percent. Medicare payer, 21.4 percent. Medicaid payer, 25.4 percent. Privately insured, 15.7 percent. Uninsured, 15.6 percent. Source: Weighted national estimates from a readmissions analysis file derived from the Healthcare Cost and Utilization Project State Inpatient Databases, 2010, Agency for Healthcare Research and Quality.





44
Appendix. All-cause 30-day readmissions and costs for selected diagnoses,* U.S. hospitals, 2010
Principal diagnosis for index hospital stay (Clinical Classification Software [CCS] diagnosis category number and label) Number of index stays 30-day all-cause readmissions
Number of readmissions Percent readmitted
Infectious and Parasitic Diseases
1 Tuberculosis 5,064 653 12.9
2 Septicemia (except in labor) 696,122 145,896 21.0
3 Bacterial infection, unspecified site 5,654 721 12.8
4 Mycoses 23,026 6,222 27.0
5 HIV infection 34,958 9,230 26.4
6 Hepatitis 37,480 11,593 30.9
7 Viral infections 56,477 5,849 10.4
10 Immunizations and screening for infectious diseases 7,128 1,034 14.5
Neoplasms
11 Cancer of head and neck 28,530 6,020 21.1
12 Cancer of esophagus 11,054 3,170 28.7
13 Cancer of stomach 19,528 5,111 26.2
14 Cancer of colon 89,183 14,388 16.1
15 Cancer of rectum and anus 39,395 8,090 20.5
16 Cancer of liver and intrahepatic bile duct 17,980 5,077 28.2
17 Cancer of pancreas 31,054 8,512 27.4
18 Cancer of other GI organs, peritoneum 18,461 4,379 23.7
19 Cancer of bronchus, lung 117,172 24,893 21.2
21 Cancer of bone and connective tissue 12,242 3,307 27.0
24 Cancer of breast 76,838 6,120 8.0
25 Cancer of uterus 35,278 3,923 11.1
26 Cancer of cervix 16,090 2,457 15.3
27 Cancer of ovary 22,064 4,753 21.5
28 Cancer of other female genital organs 6,132 1,025 16.7
29 Cancer of prostate 82,794 5,016 6.1
32 Cancer of bladder 30,244 6,465 21.4
33 Cancer of kidney and renal pelvis 42,028 5,074 12.1
35 Cancer of brain and nervous system 32,382 6,649 20.5
36 Cancer of thyroid 22,335 1,494 6.7
38 Non-Hodgkin's lymphoma 34,769 12,712 36.6
39 Leukemias 31,157 13,008 41.8
40 Multiple myeloma 15,427 4,381 28.4
41 Cancer, other primary 6,146 1,781 29.0
42 Secondary malignancies 177,796 44,647 25.1
43 Malignant neoplasm without specification of site 6,636 1,670 25.2
Neoplasms of unspecified nature or uncertain behavior 42,002 9,551 22.7
45 Maintenance chemotherapy, radiotherapy 126,113 82,601 65.5
46 Benign neoplasm of uterus 156,836 6,186 3.9
Endocrine, Nutritional, and Metabolic Diseases and Immunity Disorders
48 Thyroid disorders 40,936 3,072 7.5
49 Diabetes mellitus without complication 20,776 1,776 8.5
50 Diabetes mellitus with complications 480,958 97,784 20.3
52 Nutritional deficiencies 9,845 2,355 23.9
54 Gout and other crystal arthropathies 17,506 2,710 15.5
55 Fluid and electrolyte disorders 396,551 73,721 18.6
56 Cystic fibrosis 10,518 1,366 13.0
Diseases of Blood and Blood-Forming Organs
59 Anemia 203,098 42,374 20.9
60 Acute posthemorrhagic anemia 27,199 5,239 19.3
61 Sickle cell anemia 87,326 27,837 31.9
62 Coagulation and hemorrhagic disorders 33,397 7,920 23.7
63 Disease of white blood cells 54,861 16,771 30.6
Mental Disorders
650 Adjustment disorders 49,073 3,980 8.1
651 Anxiety disorders 45,102 5,519 12.2
652 Attention-deficit, conduct, and disruptive behavior disorders 18,218 1,692 9.3
653 Delirium, dementia, and amnestic and other cognitive disorders 131,003 21,566 16.5
655 Disorders diagnosed in infancy, childhood, or adolescence 5,613 753 13.4
656 Impulse control disorders, NEC 12,204 1,652 13.5
657 Mood disorders 883,245 131,125 14.8
658 Personality disorders 5,436 1,316 24.2
659 Schizophrenia and other psychotic disorders 397,166 88,629 22.3
660 Alcohol-related disorders 245,289 45,033 18.4
661 Substance-related disorders 212,612 32,050 15.1
663 Screening and history of mental health and substance abuse 60,417 15,695 26.0
670 Miscellaneous mental disorders 43,193 4,189 9.7
Diseases of Nervous System and Sense Organs
76 Meningitis 32,909 2,565 7.8
77 Encephalitis 8,487 1,219 14.4
79 Parkinson's disease 13,089 2,118 16.2
80 Multiple sclerosis 21,708 2,529 11.6
82 Paralysis 7,394 987 13.3
83 Epilepsy, convulsions 252,200 31,965 12.7
84 Headache, including migraine 70,782 7,373 10.4
85 Coma, stupor, and brain damage 16,823 2,740 16.3
89 Blindness and vision defects 5,364 521 9.7
90 Inflammation, infection of eye 15,984 1,201 7.5
92 Otitis media and related conditions 9,855 738 7.5
93 Conditions associated with dizziness or vertigo 69,022 4,964 7.2
Diseases of the Circulatory System
96 Heart valve disorders 100,327 20,613 20.5
97 Peri-, endo-, and myocarditis, cardiomyopathy 66,648 11,986 18.0
98 Essential hypertension 72,930 7,721 10.6
99 Hypertension with complications and secondary hypertension 211,243 45,309 21.4
100 Acute myocardial infarction 520,901 85,932 16.5
101 Coronary atherosclerosis 666,897 90,147 13.5
102 Nonspecific chest pain 601,899 61,465 10.2
103 Pulmonary heart disease 162,269 25,599 15.8
105 Conduction disorders 58,074 6,386 11.0
106 Cardiac dysrhythmias 705,616 104,607 14.8
107 Cardiac arrest and ventricular fibrillation 8,063 1,398 17.3
108 Congestive heart failure, nonhypertensive 847,073 209,017 24.7
109 Acute cerebrovascular disease 520,793 71,174 13.7
110 Occlusion or stenosis of precerebral arteries 111,833 11,877 10.6
112 Transient cerebral ischemia 166,904 16,436 9.8
113 Late effects of cerebrovascular disease 18,829 2,981 15.8
114 Peripheral and visceral atherosclerosis 162,792 28,031 17.2
115 Aortic, peripheral, and visceral artery aneurysms 73,143 11,247 15.4
116 Aortic and peripheral arterial embolism or thrombosis 26,104 5,381 20.6
118 Phlebitis, thrombophlebitis and thromboembolism 154,023 23,640 15.3
120 Hemorrhoids 30,467 4,003 13.1
Diseases of the Respiratory System
122 Pneumonia 924,160 144,894 15.7
123 Influenza 10,284 776 7.5
124 Acute and chronic tonsillitis 31,874 1,097 3.4
125 Acute bronchitis 78,848 7,461 9.5
127 Chronic obstructive pulmonary disease and bronchiectasis 606,186 126,443 20.9
128 Asthma 347,404 41,320 11.9
129 Aspiration pneumonitis, food/vomitus 147,837 31,772 21.5
130 Pleurisy, pneumothorax, pulmonary collapse 101,298 21,485 21.2
131 Respiratory failure, insufficiency, arrest (adult) 260,781 59,842 22.9
132 Lung disease due to external agents 5,477 966 17.6
Diseases of the Digestive System
135 Intestinal infection 207,083 36,451 17.6
136 Disorders of teeth and jaw 25,722 1,621 6.3
137 Disease of mouth, excluding dental 19,009 1,966 10.3
138 Esophageal disorders 125,280 16,921 13.5
139 Gastroduodenal ulcer (except hemorrhage) 42,462 6,170 14.5
140 Gastritis and duodenitis 99,130 15,355 15.5
142 Appendicitis and other appendiceal conditions 262,024 12,875 4.9
143 Abdominal hernia 174,459 19,885 11.4
144 Regional enteritis and ulcerative colitis 94,732 17,579 18.6
145 Intestinal obstruction without hernia 315,128 51,135 16.2
146 Diverticulosis and diverticulitis 289,097 35,461 12.3
147 Anal and rectal conditions 47,035 5,326 11.3
148 Peritonitis and intestinal abscess 25,219 6,315 25.0
149 Biliary tract disease 430,988 48,062 11.2
152 Pancreatic disorders (not diabetes) 282,159 49,936 17.7
153 Gastrointestinal hemorrhage 320,613 54,154 16.9
154 Noninfectious gastroenteritis 144,507 17,262 11.9
Diseases of the Genitourinary System
156 Nephritis, nephrosis, renal sclerosis 7,561 1,473 19.5
157 Acute and unspecified renal failure 326,586 70,756 21.7
158 Chronic renal failure 17,394 4,766 27.4
159 Urinary tract infections 522,921 84,858 16.2
160 Calculus of urinary tract 154,073 15,938 10.3
163 Genitourinary symptoms and ill-defined conditions 32,102 5,711 17.8
164 Hyperplasia of prostate 55,298 5,505 10.0
165 Inflammatory conditions of male genital organs 23,662 2,344 9.9
167 Nonmalignant breast conditions 19,482 1,668 8.6
168 Inflammatory disease of female pelvic organs 38,989 3,225 8.3
169 Endometriosis 33,918 1,621 4.8
170 Prolapse of female genital organs 105,048 2,847 2.7
171 Menstrual disorders 87,633 4,311 4.9
172 Ovarian cyst 36,491 2,374 6.5
173 Menopausal disorders 9,602 654 6.8
Complications of Pregnancy, Childbirth, and the Puerperium
180 Ectopic pregnancy 20,948 784 3.7
182 Hemorrhage during pregnancy, abruptio placenta, placenta previa 46,191 6,847 14.8
183 Hypertension complicating pregnancy, childbirth and the puerperium 230,927 22,091 9.6
184 Early or threatened labor 179,175 37,797 21.1
185 Prolonged pregnancy 250,122 3,591 1.4
186 Diabetes or abnormal glucose tolerance complicating pregnancy 84,725 5,384 6.4
187 Malposition, malpresentation 132,312 2,918 2.2
188 Fetopelvic disproportion, obstruction 65,609 1,255 1.9
189 Previous C-section 462,378 7,046 1.5
190 Fetal distress and abnormal forces of labor 170,752 3,893 2.3
191 Polyhydramnios and other problems of amniotic cavity 179,406 7,028 3.9
192 Umbilical cord complication 161,112 1,284 0.8
193 Trauma to perineum and vulva 610,073 5,046 0.8
196 Normal pregnancy and/or delivery 208,463 1,559 0.7
Diseases of the Skin and Subcutaneous Tissue
197 Skin and subcutaneous tissue infections 576,902 64,680 11.2
199 Chronic ulcer of skin 50,845 10,823 21.3
Diseases of the Musculoskeletal System and Connective Tissue
201 Infective arthritis and osteomyelitis 70,424 12,199 17.3
202 Rheumatoid arthritis and related disease 14,836 1,587 10.7
203 Osteoarthritis 872,661 42,241 4.8
205 Spondylosis, intervertebral disc disorders, other back problems 579,103 47,774 8.2
207 Pathological fracture 59,946 11,781 19.7
210 Systemic lupus erythematosus and connective tissue disorders 18,850 5,123 27.2
Congenital Anomalies
213 Cardiac and circulatory congenital anomalies 23,824 2,610 11.0
214 Digestive congenital anomalies 6,100 626 10.3
215 Genitourinary congenital anomalies 7,480 729 9.7
Injury and Poisoning
225 Joint disorders and dislocations, trauma-related 31,027 2,222 7.2
226 Fracture of neck of femur (hip) 291,847 38,668 13.2
227 Spinal cord injury 13,188 1,609 12.2
228 Skull and face fractures 45,409 3,164 7.0
229 Fracture of upper limb 136,326 10,895 8.0
230 Fracture of lower limb 234,607 23,540 10.0
232 Sprains and strains 29,538 2,356 8.0
233 Intracranial injury 162,589 18,304 11.3
234 Crushing injury or internal injury 85,422 7,744 9.1
235 Open wounds of head, neck, and trunk 29,547 2,028 6.9
236 Open wounds of extremities 38,921 2,847 7.3
237 Complication of device, implant or graft 596,062 121,036 20.3
238 Complications of surgical procedures or medical care 453,266 81,353 17.9
239 Superficial injury, contusion 40,973 4,975 12.1
240 Burns 34,452 3,431 10.0
241 Poisoning by psychotropic agents 60,590 6,496 10.7
242 Poisoning by other medications and drugs 107,558 13,426 12.5
243 Poisoning by nonmedicinal substances 15,356 1,121 7.3
Symptoms, Signs, and Ill-Defined Conditions
245 Syncope 235,483 24,686 10.5
246 Fever of unknown origin 53,785 9,322 17.3
247 Lymphadenitis 13,632 1,242 9.1
248 Gangrene 33,786 10,693 31.6
250 Nausea and vomiting 51,833 11,854 22.9
251 Abdominal pain 166,071 26,993 16.3
252 Malaise and fatigue 33,141 6,054 18.3
253 Allergic reactions 23,860 2,482 10.4
254 Rehabilitation care, fitting of prostheses, adjustment of devices 47,035 5,008 10.6
Source: Weighted national estimates from a readmissions analysis file derived from the Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases (SID), 2010, Agency for Healthcare Research and Quality (AHRQ).
* Information is provided for diagnoses with 5,000 or more weighted index stays and 500 or more weighted readmissions. See text and Definitions for details on methods for calculating readmissions.


Data Source

The estimates in this Statistical Brief are based on a readmissions analysis file that was created with the Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases (SID). These databases include reliable, verified synthetic patient identifiers that can be used to track a person across hospitals within a State. Estimates were taken from HCUPnet, the online query system that provides free access to information from HCUP: https://datatools.ahrq.gov/hcupnet. HCUPnet provides access to health statistics and information on hospital inpatient and emergency department utilization, and it includes analytic tables using the readmissions analysis file. HCUPnet provides additional detailed results and sortable tables that provide instant information on readmissions to the hospital within 30 days of discharge.

For 2010, readmissions data were available from 18 States: Alaska, Arkansas, California, Florida, Georgia, Hawaii, Louisiana, Massachusetts, Mississippi, Missouri, Nebraska, New Mexico, New York, South Carolina, Tennessee, Utah, Virginia, and Washington. These 18 States are geographically dispersed and accounted for 46 percent of the total U.S. resident population and 45 percent of the total U.S. hospitalizations. The readmissions analysis file included 14.0 million unweighted discharges.

The study population in this readmissions analysis file included discharges from community, non-rehabilitation, non-specialty hospitals. Weights for national estimates were developed using poststratification on hospital characteristics (Census region, urban-rural location, teaching capabilities, bed size, and control/ownership) and patient age groups.

Definitions

Diagnoses, ICD-9-CM, and Clinical Classifications Software (CCS)
For the index stay, the diagnoses examined in this Statistical Brief are based on the CCS for the principal diagnosis. The principal diagnosis is that condition established after study to be chiefly responsible for the patient's admission to the hospital.

ICD-9-CM is the International Classification of Diseases, Ninth Revision, Clinical Modification, which assigns numeric codes to diagnoses. There are approximately 14,000 ICD-9-CM diagnosis codes.

CCS categorizes ICD-9-CM diagnoses into a manageable number of clinically meaningful categories.11 This "clinical grouper" makes it easier to quickly understand patterns of diagnoses. CCS categories identified as "Other" typically are not reported; these categories include miscellaneous, otherwise unclassifiable diagnoses that may be difficult to interpret as a group.

Readmissions
The 30-day readmission rate is defined as the number of admissions for each condition for which there was at least one subsequent hospital admission within 30 days divided by the total number of admissions from January through November 2010. That is, when patients are discharged from the hospital, they are followed for 30 days in the data. If any readmission to the same or different hospital occurs during this time period, the admission is counted as a readmission. No more than one readmission is counted within the 30-day period, because the outcome measure assessed here is "percentage of admissions who are readmitted." If a patient was transferred to a different hospital on the same day or was transferred within the same hospital, the two events were combined as a single stay and the second event was not counted as a readmission; that is, transfers were not considered a readmission. In the case of admissions for which there was more than one readmission in the 30-day period, the data presented in this Statistical Brief reflect the characteristics and costs of the first readmission.

Every qualifying hospital stay is counted as a separate index (starting point) admission. Thus, a single patient can be counted multiple times during the course of the January through November observation period. In addition, index admissions do not require a prior "clean period" with no hospitalizations; that is, a hospital stay may be a readmission for a prior stay and the index admission for a subsequent readmission. Admissions were disqualified from the analysis as index admissions if they could not be followed for 30 days for one of the following reasons: (1) admissions in which the patient died in the hospital, (2) admissions missing information on length of stay, and (3) admissions discharged in December 2010.

Types of hospitals included in HCUP
HCUP is based on data from community hospitals, which are defined as short-term, non-Federal, general, and other hospitals, excluding hospital units of other institutions (e.g., prisons). HCUP data include obstetrics and gynecology, otolaryngology, orthopedic, cancer, pediatric, public, and academic medical hospitals. Excluded are long-term care, rehabilitation, psychiatric, and alcoholism and chemical dependency hospitals.

Payer (Insurance Status)
Payer is the expected payer for the hospital stay. To make coding uniform across all HCUP data sources, payer combines detailed categories into more general groups:
  • Medicare: includes patients covered by fee-for-service and managed care Medicare
  • Medicaid: includes patients covered by fee-for-service and managed care Medicaid. Patients covered by the State Children's Health Insurance Program (SCHIP) may be included here. Because most State data do not identify SCHIP patients specifically, it is not possible to present this information separately.
  • Private Insurance: includes Blue Cross, commercial carriers, and private health maintenance organizations (HMOs) and preferred provider organizations (PPOs)
  • Other: includes Worker's Compensation, TRICARE/CHAMPUS, CHAMPVA, Title V, and other government programs
  • Uninsured: includes an insurance status of "self-pay" and "no charge."
For this Statistical Brief, a hierarchy was used to assign the payer category based on the primary and secondary expected payer:
  • If the primary or secondary expected payer indicates Medicare, then the payer category is assigned to Medicare. This categorization includes patients who are dually eligible for Medicare and Medicaid under Medicare.
  • If not Medicare and the primary or secondary expected payer indicates Medicaid, then the payer category is Medicaid.
  • If not Medicare or Medicaid and the primary or secondary expected payer indicates private insurance, then the payer category is private.
  • If not Medicare, Medicaid, or private and the primary expected payer indicates self-pay or no charge, then the payer category is uninsured.
  • Stays for other types of payers are not reported in this Statistical Brief because this is a mixed payer group and small numbers.
For this Statistical Brief, categorization of the readmission counts by expected payer was based on the index stay.

About HCUP

HCUP is a family of powerful healthcare databases, software tools, and products for advancing research. Sponsored by the Agency for Healthcare Research and Quality (AHRQ), HCUP includes the largest all-payer encounter-level collection of longitudinal healthcare data (inpatient, ambulatory surgery, and emergency department) in the United States, beginning in 1988. HCUP is a Federal-State-Industry Partnership that brings together the data collection efforts of many organizations—such as State data organizations, hospital associations, private data organizations, and the Federal government—to create a national information resource.

HCUP would not be possible without the contributions of the following data collection Partners from across the United States:

Alaska State Hospital and Nursing Home Association
Arizona Department of Health Services
Arkansas Department of Health
California Office of Statewide Health Planning and Development
Colorado Hospital Association
Connecticut Hospital Association
Florida Agency for Health Care Administration
Georgia Hospital Association
Hawaii Health Information Corporation
Illinois Department of Public Health
Indiana Hospital Association
Iowa Hospital Association
Kansas Hospital Association
Kentucky Cabinet for Health and Family Services
Louisiana Department of Health and Hospitals
Maine Health Data Organization
Maryland Health Services Cost Review Commission
Massachusetts Center for Health Information and Analysis
Michigan Health & Hospital Association
Minnesota Hospital Association
Mississippi Department of Health
Missouri Hospital Industry Data Institute
Montana MHA - An Association of Montana Health Care Providers
Nebraska Hospital Association
Nevada Department of Health and Human Services
New Hampshire Department of Health & Human Services
New Jersey Department of Health
New Mexico Department of Health
New York State Department of Health
North Carolina Department of Health and Human Services
North Dakota (data provided by the Minnesota Hospital Association)
Ohio Hospital Association
Oklahoma State Department of Health
Oregon Association of Hospitals and Health Systems
Oregon Health Policy and Research
Pennsylvania Health Care Cost Containment Council
Rhode Island Department of Health
South Carolina Budget & Control Board
South Dakota Association of Healthcare Organizations
Tennessee Hospital Association
Texas Department of State Health Services
Utah Department of Health
Vermont Association of Hospitals and Health Systems
Virginia Health Information
Washington State Department of Health
West Virginia Health Care Authority
Wisconsin Department of Health Services
Wyoming Hospital Association

About the SID

The HCUP State Inpatient Databases (SID) are hospital inpatient databases from data organizations participating in HCUP. The SID contain the universe of the inpatient discharge abstracts in the participating HCUP States, translated into a uniform format to facilitate multistate comparisons and analyses. Together, the SID encompass more than 95 of all U.S. community hospital discharges in 2010. The SID can be used to investigate questions unique to one State, to compare data from two or more States, to conduct market area variation analyses, and to identify State-specific trends in inpatient care utilization, access, charges, and outcomes.

About HCUPnet

HCUPnet is an online query system that offers instant access to the largest set of all-payer healthcare databases publicly available. HCUPnet has an easy step-by-step query system, allowing for tables and graphs to be generated on national and regional statistics as well as trends for community hospitals in the United States. HCUPnet generates statistics using data from HCUP's Nationwide Inpatient Sample (NIS), the Kids' Inpatient Database (KID), the Nationwide Emergency Department Sample (NEDS), the State Inpatient Databases (SID), and the State Emergency Department Databases (SEDD).

For More Information

For more information about HCUP, visit http://www.hcup-us.ahrq.gov/.

For additional HCUP statistics, visit HCUPnet, our interactive query system, at https://datatools.ahrq.gov/hcupnet. HCUPnet provides ready-to-use tables on readmission rates by condition and procedure (using Clinical Classification Software categories), diagnosis related groups (DRGs), and major diagnostic categories (MDCs).

Suggested Citation

Elixhauser A (AHRQ), Steiner C (AHRQ). Readmissions to U.S. Hospitals by Diagnosis, 2010. HCUP Statistical Brief #153. April 2013. Agency for Healthcare Research and Quality, Rockville, MD. http://www.hcup-us.ahrq.gov/reports/statbriefs/sb153.pdf.

Acknowledgements

The authors would like to acknowledge the contributions of Marguerite Barrett and Minya Sheng for work on programming.

***

AHRQ welcomes questions and comments from readers of this publication who are interested in obtaining more information about access, cost, use, financing, and quality of healthcare in the United States. We also invite you to tell us how you are using this Statistical Brief and other HCUP data and tools, and to share suggestions on how HCUP products might be enhanced to further meet your needs. Please e-mail us at hcup@ahrq.gov or send a letter to the address below:

Irene Fraser, Ph.D., Director
Center for Delivery, Organization, and Markets
Agency for Healthcare Research and Quality
540 Gaither Road
Rockville, MD 20850



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2 3M Health Information Systems. Potentially Preventable Readmissions Classification System, Methodology Overview, Document number GRP-139, May, 2008. http://www.illinois.gov/hfs/SiteCollectionDocuments/3MPotentiallyPreventableReadmissions.pdf. Exit DisclaimerAccessed March 21, 2013.
3 Hospital Compare. Medicare website. https://www.medicare.gov/hospitalcompare/search.html. Accessed November 8, 2017.
4 Boutwell AE, Johnson MB, Rutherford P, Watson SR, Vecchioni N, Auerbach BS, Griswold P, Noga P, Wagner C. An early look at a four-state initiative to reduce avoidable hospital readmissions. Health Aff (Millwood). 2011 Jul;30(7):1272-80.
5 Partnership for Patients: Better Care, Lower Costs. April, 2011. http://www.healthcare.gov/news/factsheets/2011/04/partnership04122011a.html. Accessed March 21, 2013.
6 Jencks SF, Williams MV, Coleman EA. Rehospitalizations among patients in the Medicare fee-for-service program. N Engl J Med 2009;360:1418-28.
7 Stranges E, Barrett ML, Wier LM, Andrews RM. Readmissions for Heart Attack, 2009. HCUP Statistical Brief #140. August 2012. Agency for Healthcare Research and Quality, Rockville, MD. http://www.hcup-us.ahrq.gov/reports/statbriefs/sb140.pdf. Accessed March 21, 2013.
8 Elixhauser A, Au D, Podulka J. Readmissions for Chronic Obstructive Pulmonary Disease, 2008. HCUP Statistical Brief #121. September, 2011. Agency for Healthcare Research and Quality, Rockville, MD. http://www.hcup-us.ahrq.gov/reports/statbriefs/sb121.pdf. Accessed March 21, 2013.
9 https://datatools.ahrq.gov/hcupnet
10 Two additional conditions met these criteria; however, these conditions are the subject of separate HCUP Statistical Briefs. (Chronic obstructive pulmonary disease: http://www.hcup-us.ahrq.gov/reports/statbriefs/sb121.jsp and Septicemia: forthcoming in 2013).
11 HCUP Clinical Classifications Software (CCS). Healthcare Cost and Utilization Project (HCUP). U.S. Agency for Healthcare Research and Quality, Rockville, MD. Updated March 2013. http://www.hcup-us.ahrq.gov/toolssoftware/ccs/ccs.jsp. Accessed March 21, 2013.

Internet Citation: Statistical Brief #153. Healthcare Cost and Utilization Project (HCUP). May 2016. Agency for Healthcare Research and Quality, Rockville, MD. www.hcup-us.ahrq.gov/reports/statbriefs/sb153.jsp.
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