Prolonged hospitalization in Brazil: clinical need or systemic failure?

BACKGROUND: Prolonged hospitalization increases the risk of adverse events and resource overuse. In dual public-private systems like Brazil's, it is unclear how much hospital length of stay reflects clinical needs versus systemic delays. OBJECTIVE: The aim of the study was to quantify clinical and non-clinical contributions to length of stay in medical inpatients and compare patterns between public (Unified Health System [SUS]) and privately insured patients. METHODS: We conducted a prospective multicenter cohort study including 5,423 adults admitted via the emergency department to internal medicine wards in three Brazilian hospitals (2009-2022). Physicians recorded daily whether ongoing hospitalization was clinically necessary or due to delays (e.g., tests, specialist input, administrative or social issues). Statistical analyses included multivariate models adjusted for comorbidities and frailty. RESULTS: The mean length of stay was 11.8±5.2 days, but only 38% (4.5±2.6 days) were clinically justified. The remainder resulted from non-clinical delays, particularly in diagnostics (2.9±3.1 days) and specialist input (1.9±1.5 days). SUS patients had longer stays than those privately insured (13.2 vs. 10.1 days; p<0.001), despite similar clinical complexity. These differences remained significant after adjustment. SUS patients were more likely to stay ≥12 days (OR 1.76), wait ≥3 days for tests (OR 1.89), and ≥2 days for specialist evaluations (OR 1.67). CONCLUSION: Most hospital days were not due to clinical needs. Diagnostic and specialist delays, especially in the public system, were key contributors to prolonged length of stay, highlighting structural inefficiencies and the need for system-wide reforms.