Severe major depressive disorder readmissions: A national United States population study

National population data are scarce on readmission following hospitalization for severe major depressive disorder (SMDD) in the United States (U.S.). We aim to describe the rates, characteristics, and reasons for readmissions for adults hospitalized for SMDD in the U.S.

We analyzed the 2018 Nationwide Readmissions Database (NRD). We included index hospitalizations for all adult patients (≥18 years) with a "principal" diagnosis of SMDD using (ICD)-10 codes. We excluded elective readmissions. Chi-square tests were used to compare baseline characteristics between readmissions and index hospitalizations. The 10 most common reasons for readmission were highlighted.

A total of 236,284, 185,737, 120,218, and 21,645 index hospitalizations with a principal diagnosis of SMDD discharged alive, were included in the 30-, 90-180- and 330-day readmission analysis. Among these, 27,443 (11.6 %), 36,844 (19.8 %), 32,269 (26.8 %) and 7915 (36.6 %) were readmitted within 30, 90, 180 and 330 days, respectively. 90-day readmissions were older, had more males, greater hospital costs, fewer patients with private insurance, higher comorbidity burden, more patients from lower-income households, present to metropolitan hospitals, and leave against medical advice compared to index admissions.

Limitations of our study include possible coding errors, lack of data on race/ethnicity, age of disease onset, duration of illness, medication use, and adherence.

About 1 in 3 patients admitted for SMDD are readmitted within 11 months. Readmissions constitute a significant economic burden and differ from index admissions. SMDD and other psychiatric disorders are common reasons for readmission. Interventions to reduce readmissions are needed.