Depression is independently associated with increased length of stay and readmissions in multimorbid inpatients.

BACKGROUND: Little is known about the impact of depression across a broad range of multimorbid patients hospitalized for reasons other than depression. The objective of the study was to investigate in a large sample of multimorbid inpatients whether ancillary depression is associated with increased length of stay (LOS) and readmissions, two important clinical outcomes with implications for healthcare utilization and costs. METHODS: We retrospectively analyzed a cohort of 253,009 multimorbid inpatients aged ≥18 at an academic medical center, 8/2009-8/2017. PRIMARY OUTCOME: LOS. SECONDARY OUTCOMES: LOS related to different main diagnoses, readmissions within 1, 3, 6, 12, and 24-months after discharge. RESULTS: Multivariable linear regression showed 24% longer LOS in patients with ancillary depression (1.24; 95% confidence interval [CI]: 1.22, 1.25). Females stayed 22% longer (1.22; 95% CI: 1.20, 1.25), males 24% (1.24; 95% CI: 1.22, 1.27). We identified 16 main diagnosis clusters in which ancillary depression was associated with significant LOS increases, with associations being strongest for "Failure and rejection of transplanted organs and tissues", "Other noninfective gastroenteritis and colitis", and "Other soft tissue disorders, not elsewhere classified". Multivariable logistic and Poisson regression showed independent associations of ancillary depression with increased readmission odds and frequencies at 1, 3, 6, 12, and 24 months. CONCLUSIONS: Ancillary depression was independently associated with increased LOS and more readmissions across a broad range of multimorbid inpatients.