Statin use and risk of community acquired pneumonia in older people: population based case-control study

Objective To test the hypothesis that hydroxymethyl glutaryl coenzyme A reductase inhibitors (statin s) may decrease the risk of community acquired pneumonia. Design Population based case-control study. Setting Group Health, a large integrated healthcare delivery system. Population Immunocompetent, community dwelling Group Health members aged 65 to 94; two matched controls for each case with pneumonia. Information on comorbid illnesses and functional and cognitive status, potential confounders of the association between statin use and risk of pneumonia, came from medical record review and computerised pharmacy data. Main outcome measure Adjusted estimates of risk of pneumonia in relation to current statin use. Results 1125 validated cases of pneumonia and 2235 matched controls were identified. Compared with controls, cases were more likely to have chronic lung and heart disease, especially severe disease, and functional or cognitive impairment. Current statin use was present in 16.1% (181/1125) of cases and 14.6% (327/2235) of controls (adjusted odds ratio 1.26, 95% confidence interval 1.01 to 1.56). Among cases admitted to hospital and matched controls, current statin use was present in 17.2% (68/395) of cases and 14.2% (112/788) of controls (adjusted odds ratio 1.61, 1.08 to 2.39, compared with non-use). In people in whom statins were indicated for secondary prevention, the adjusted odds ratio for risk of pneumonia in relation to current statin use was 1.25 (0.94 to 1.67); in those with no such indication, it was 0.81 (0.46 to 1.42). Conclusions Statin use was not associated with decreased risk of pneumonia among immunocompetent, community dwelling older people. Findings of previous studies may reflect healthy user bias.