Prognostic factors for serious morbidity and mortality from community-acquired lower respiratory tract infections among the elderly in primary care

Background. Uncertainty about the prognosis of lower respiratory tract infections (LRTI) hinders optimal management in primary care. Objective. We determined prognostic factors for a severe complicated course of LRTI among elderly patients in primary care. Methods. In a retrospective clinical database study we examined 455 patients with a first LRTI episode; 226 with physician-diagnosed acute bronchitis or lung exacerbations and 229 with pneumonia. Multivariate logistic regression analysis was used to assess independent associations of the potential predictors with the endpoint. Results. Occurrence of the combined endpoint 30-day home-treated complications from LRTI (4.4%) or hospitalisation (4.6%), or all-cause mortality (5.3%) was 14.3%. In a logistic regression model, increasing age [odds ratio (OR) 1.04; 95% confidence interval (95% CI) 1.00-1.08], male sex (OR 3.12; 95% CI 1.66-5.87), heart failure (OR 5.14; 95% CI 2.33-11.34), stroke or dementia (OR 3.36; 95% CI 1.18-9.58), use of antidepressants or benzodiazepines (OR 1.89; 95% CI 1.02-3.52) and a diagnosis of pneumonia (OR 4.24; 95% CI 2.17-8.28) were independent predictors. Conclusion. GPs need to be aware of readily available prognostic factors that can be used in primary care to complement physical examination and laboratory data in LRTI to guide preventive and therapeutic management decisions.