Introduction:
Hospital length of stay (LoS) and hospital readmissions are metrics of healthcare performance. We examined the association between these two metrics in older patients hospitalized with decompensated heart failure (HF).

Material and methods:
Eight thousand and forty-nine patients hospitalized for HF in 106 U.S. hospitals had a median LoS of 5 days; among them, 3777 had a LoS > 5 days. Using propensity scores for LoS > 5 days, we assembled 2723 pairs of patients with LoS 1–5 vs. > 5 days. The matched cohort of 5446 patients was balanced on 40 baseline characteristics. We repeated the above process in 7045 patients after excluding those with LoS > 10 days, thus assembling a second matched cohort of 2399 pairs of patients with LoS 1–5 vs. 6–10 days. Hazard ratios (HR) and 95% confidence intervals (CI) for outcomes associated with longer LoS were estimated in matched cohorts.

Results:
In the primary matched cohort (n = 5446), LoS > 5 days was associated with a higher risk of all-cause readmission at 30 days (HR = 1.16; 95% CI: 1.04–1.31; p = 0.010), but not during longer follow-up. A longer LoS was also associated with a higher risk of mortality during 8.8 years of follow-up (HR = 1.13; 95% CI: 1.06–1.21; p < 0.001). LoS had no association with HF readmission. Similar associations were observed among the matched sensitivity cohort (n = 4798) that excluded patients with LoS > 10 days.

Conclusions:
In propensity score-matched balanced cohorts of patients with HF, a longer LoS was independently associated with poor outcomes, which persisted when LoS > 10 days were excluded.