Risk factors for pneumonia in the elderly.

PURPOSE: To investigate the prevalence of certain chronic conditions among the elderly and to estimate the relative risk for pneumonia associated with each condition. PATIENTS AND METHODS: Medical records of all inhabitants aged 60 years or more (4,175 persons) in one township (population 24,716) in Finland were reviewed, seeking 15 chronic conditions. Which patients had pneumonia in the same population was prospectively ascertained over a period of 3 years (185 patients).
RESULTS: Hypertension was the most frequent chronic condition (36.4%) in the study population. Other common conditions were heart disease (23.7%, with chronic compensated heart failure in 96.3% of these), other cardiovascular disease (13.1%), and diabetes (13.1%). The prevalence of any other condition was less than 5%. The following conditions were significantly more common among pneumonia patients than among control subjects: heart disease (38.4% versus 23.0%), lung disease (13.0% versus 3.8%), bronchial asthma (11.9% versus 3.1%), immunosuppressive therapy (2.7% versus 0.8%), alcoholism (2.2% versus 0.3%), and institutionalization (8.6% versus 3.9%). By multivariate logistic regression analysis, independent risk factors for pneumonia were alcoholism (relative risk [RR] = 9.0, confidence interval [CI] = 5.1 to 16.2), bronchial asthma (RR = 4.2, CI = 3.3 to 5.4), immunosuppressive therapy (RR = 3.1, CI = 1.9 to 5.1), lung disease (RR = 3.0, CI = 2.3 to 3.9), heart disease (RR = 1.9, CI = 1.7 to 2.3), institutionalization (RR = 1.8, CI = 1.4 to 2.4), and age (70 years or more versus 60 to 69 years; RR = 1.5, CI = 1.3 to 1.7). One third of the study population and 57% of the pneumonia patients had one or more of these risk factors. Diabetes, chronic pyelonephritis, and malignancies of sites other than the lungs were not associated with increased risk for pneumonia.
CONCLUSION: We found which elderly persons have an increased risk for pneumonia. Although the highest relative risk was associated with alcoholism, that condition was rare in this elderly population. Chronic obstructive lung diseases were more common and were also associated with a high relative risk. Heart disease had the highest public health impact because it was very common among the elderly and increased the risk of contracting pneumonia almost twofold; it also increased the risk of pneumonia-related death. These population-based data confirm and extend previous findings derived from selected patient groups and are useful for designing cost-effective pneumonia prevention programs.