Factors Associated with 30-Day Non-Return to Pre-Hospital Residence in Older Patients Hospitalized with Pneumonia or Lower Respiratory Tract Infection: The Role of Serum Albumin and Early Treatment Failure

Background/Objectives: Return to the pre-hospital residence is a meaningful patient-centered outcome after hospitalization for pneumonia or lower respiratory tract infection (LRTI). We examined factors associated with 30-day non-return, including prespecified baseline characteristics, the initial empirical antimicrobial therapy pattern, and initial treatment failure within 7 days. Methods: This retrospective observational study included 126 consecutive patients aged ≥65 years admitted with pneumonia or LRTI to a community-based general hospital in Japan. Patients who died within 48 h were excluded. Three multivariable logistic regression models were fitted: Model 1 evaluated prespecified baseline characteristics; Models 2 and 3 added the initial empirical antimicrobial therapy pattern and initial treatment failure within 7 days, respectively. Initial treatment failure was treated as a post-baseline marker of an unfavorable early clinical course. Results: The median age was 89.0 years, and 56 patients (44.4%) returned to their pre-hospital residence within 30 days. Higher serum albumin was associated with lower adjusted odds of non-return across all models (OR range, 0.365–0.407 per 1 g/dL increase). Initial treatment failure was associated with higher adjusted odds of non-return (OR, 3.296; 95% CI, 1.095–9.923), whereas the initial empirical antimicrobial therapy pattern showed no statistically significant overall association (global p = 0.859). The principal findings were materially unchanged in sensitivity analyses addressing early deaths and the treatment-failure definition. However, in other supportive analyses, the associations remained directionally consistent but were attenuated and no longer statistically significant in the analysis restricted to 30-day survivors; in addition, the serum albumin association in Model 3 did not retain statistical significance in some leave-one-out analyses. Conclusions: Higher serum albumin at admission was associated with lower odds of 30-day non-return, whereas initial treatment failure was associated with higher odds. Initial treatment failure should be interpreted as a post-baseline marker of an unfavorable early clinical course rather than as an independent baseline predictor. No statistically significant association with the initial empirical antimicrobial therapy pattern was detected. These findings do not establish causality.