Differential roles of comorbidity burden and functional status in elderly and non-elderly patients with infections in general wards

Background: Differential roles of comorbidity burden, functional status and severity of illness in elderly and non-elderly patients admitted to general wards with infections in terms of short-term and long-term mortality remain poorly understood and worth further investigation. Methods: From 2011 to 2013, patients admitted to general wards with a main diagnosis of infections were included and their Barthel index, Charlson comorbidity index and Pitt bacteremia score were collected to evaluate their association with in-hospital and 1-year outcomes of the study cohort. Age stratification was applied for all outcome analysis. Results: A total of 2481 patients were identified, with main diagnoses of pneumonia (57%), urinary tract infection (28%) and intra-abdominal infection (18%). In-hospital mortality occurred in 291 (12%) of the population and was independently predicted by Barthel index ≤50 (odds ratio [OR] 5.67 and 2.73, respectively) and Charlson comorbidity index >2 (OR 1.49 and 2.87, respectively) in both elderly and non-elderly patients. Among 2190 hospital survivors, Barthel index ≤50 (hazard ratio [HR] 1.38) and Charlson comorbidity index >2 (HR 1.96) were associated with a higher hazard of 1-year mortality in elderly patients. However, only Charlson comorbidity index >2 (HR 2.87) was a significant characteristic of non-elderly patients to be correlated with higher 1-year mortality. Conclusion: This study found that functional status on admission was predictive of in-hospital mortality of general patients with infections irrespective of age groups; however, it played a differential role in 1-year mortality in between elderly and non-elderly patients, emphasizing the importance of functional assessment among the elderly. Keywords: Age, Comorbidity, Functional status, Infection, Outcome