The definition of N_DISC_U differs by HCUP database:

• For the NIS prior to 2012, N_DISC_U contains the total number of inpatient discharges in the universe of AHA community excluding, non-rehabilitation hospitals for the stratum.
• For the NIS beginning in 2012, N_DISC_U contains the total number of inpatient discharges in the universe of AHA community excluding non-rehabilitation and long-term acute care (LTAC) hospitals for the stratum.
• For the NRD, N_DISC_U contains the total number of inpatient discharges in the universe of AHA community excluding non-rehabilitation and LTAC hospitals for the stratum.
• For the NEDS, N_DISC_U contains the total number of ED visits in the universe of AHA hospital-based emergency departments for the stratum.
• For the NASS, N_DISC_U contains the total number of major ambulatory surgery encounters in the universe of hospital-owned facilities for the stratum.