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Background and Objective: Generalizability of clinical predictors for mortality from lower respiratory infection (LRI) in nursing home residents has not been assessed for residents with dementia., Study Design and Setting: In prospective cohort studies of LRI in 61 nursing homes in the Netherlands (n = 541) and 36 nursing homes in Missouri, USA (n = 564), we examined 14-day and 1- and 3-month mortality in residents with dementia who were treated with antibiotics., Results: A logistic model predicting 14-day mortality derived from Dutch data included eating dependency, elevated pulse, decreased alertness, respiratory difficulty, insufficient fluid intake, high respiratory rate, male gender, and pressure sores. After adjusting coefficients with the heuristic shrinkage factor, the 14-day model showed good discrimination and calibration in both datasets. The apparent c-statistic for the original Dutch model was 0.80 (after correction for optimism, it was 0.75); the c-statistic was 0.74 in the U.S. validation population. The models predicting 1- and 3-month mortality showed moderate performance. A scoring system for estimating 14-day mortality performed equally well as the original model., Conclusion: We identified a set of credible clinical predictors that are easily assessed and demonstrated validity in identifying residents at low risk of dying from LRI across different nursing home populations. This tool should inform decision-making for families and doctors.

Abstract: Objective: In some nursing home populations, antibiotic treatment may not reduce mortality following lower respiratory infection (LRI). To better inform treatment decisions, we determined influences on mortality following LRI among antibiotic-treated and non–antibiotic-treated residents in 2 populations. Design: Observational, prospective, cohort studies. Setting: Ninety-seven nursing homes (36 US, 61 Netherlands). Participants: Residents (1044 US, 513 Netherlands) who met a standardized study definition for LRI. Measurements: Demographics, symptoms and physical findings of LRI, functional status, major illness diagnoses, dementia status, treatments, and date of death within 6 months after diagnosis. Methods: We estimated a 2-period (0–14/15–90 days) weighted proportional hazards model of mortality for antibiotic-treated (n = 1280) and non–antibiotic-treated (n = 277) residents; both weights and regressors provide “doubly robust” risk adjustment—for LRI (illness) severity using a prognostic score and for nonrandom receipt of antibiotic treatment using a propensity score. Results: In both the United States and the Netherlands, 14-day mortality was associated with three factors—LRI severity, water intake at diagnosis, and antibiotic use (not directly by severe dementia)—that accounted for 82% or, sequentially, 39%, 42%, and 1% of the cross-national mortality difference. The LRI Severity Score (based only on at-diagnosis eating dependency, pulse rate, decreased alertness, and breathing difficulty, with adequate discrimination [c ≥ 0.74] and calibration, and cross-indexed to commonly used LRI mortality measures) was related to mortality through 90 days, regardless of treatment. With sufficient water intake at diagnosis, 14-day mortality was unrelated to not receiving antibiotic treatment (adjusted hazard ratio [AHR], 1.20; 95% confidence interval, 0.70–2.04); insufficient water intake was related to increased 14-day mortality with antibiotics (AHR, 1.90; 1.38–2.60) or without (AHR, 7.12; 4.83–10.5). After 14 days, relative mortality worsened for antibiotic-treated residents with insufficient water intake. Inadequate water intake was related to increased eating dependence at onset of the LRI (OR, 4.2; 3.0–5.8). Conclusion: LRI severity, water intake, and antibiotic use explain mortality in both studies and reconcile cross-study Dutch/US 14-day mortality differences. LRI severity, derived at 14 days, is related to mortality through 90 days, regardless of treatment, and is key to risk adjustment. With adequate hydration, the survival benefit from antibiotic use is nonsignificant. Conversely, hydration, even without antibiotic treatment, appears central to curative treatment. In LRI guidelines, treatment, and research, the relative benefits of antibiotics and hydration for curative treatment should be addressed. [Copyright &y& Elsevier]