Observed association between antidepressant use and pneumonia risk was confounded by comorbidity measures

Abstract

Objective-A prior study suggested that antidepressants might increase the risk of hospitalization for pneumonia in the elderly. This study sought to confirm or refute this hypothesis.Study Design and Setting-Case-control study of persons age 65 and above nested in the UK General Practice Research Database.Results-We identified 12,044 cases of the hospitalization for pneumonia (the primary outcome) and 48,176 controls. The odds ratio (OR) for any antidepressant use, adjusting for age, sex, and calendar year was 1.61 (95% confidence interval 1.46 to 1.78). After further adjustment for comorbidity measures, the OR was 0.89 (0.79 to 1.00). We also identified 159 cases of hospitalization for aspiration pneumonia (the secondary outcome) and 636 controls. The OR for any antidepressant use, adjusted for age, sex, and calendar year was 1.45 (0.65 to 3.24). After further adjustment for comorbidity measures, the OR was 0.63 (0.23 to 1.71).Conclusion-These findings refute the prior hypothesis that use of antidepressants by elderly patients increases the risk of hospitalization for pneumonia or for aspiration pneumonia. Decisions regarding use of antidepressants in elderly persons should not be affected by concern about pneumonia risk. Data-derived hypotheses should be independently confirmed before being acted upon.

Risk factors for community-acquired pneumonia in adults in Europe: a literature review

“…Other neurological or psychiatric conditions were also associated with an increased risk of CAP in some studies (epilepsy, crude ORs: 2.81 (1.83 to 4.30) and 2.83 (1.11 to 7.21)21 38; Parkinson's disease, crude ORs: 1.82 (1.52 to 2.19) and 1.87 (1.60 to 2.19)14 46; multiple sclerosis, crude OR 3.20 (2.40 to 4.26)46). Crude ORs for CAP in patients with depression or bipolar disorder ranged from 1.75 (1.65 to 1.86) to 2.54 (1.03 to 6.26) 14 21 23. However, the association with depression may have been confounded by other factors, as other studies reported an adjusted OR of 1.13 (0.99 to 1.28)19 or an adjusted RR of 1.30 (1.19 to 1.40) 42…”

“…The association between comorbidities and the risk of CAP was investigated in 14 case-control studies (Denmark (n=1),48 Germany (n=1),44 The Netherlands (n=1),23 Spain (n=2)12 38 and the UK (n=9)14 19–22 42 46 47 49 (see online supplementary table S4).…”

“…A history of pneumonia increased the risk of a subsequent episode (crude ORs: 2.39 to 6.25 (1.83 to 21.40)22 38 44). Patients with chronic respiratory diseases, including COPD, bronchitis or asthma, had a twofold to fourfold increase in the risk of CAP (crude ORs: 2.17 (1.99 to 2.37) to 3.92 (3.67 to 4.18)12 14 21–23 38 44 46 47). Additional data also support this association.…”

“…Cerebrovascular disease/stroke and dementia approximately doubled the risk of CAP (for cerebrovascular disease/stroke, crude ORs: 1.86 (1.74 to 1.99) to 2.37 (2.19 to 2.57),14 21 46 49 adjusted ORs: 1.08 (0.93 to 1.26)19 and 1.68 (1.58 to 1.77),20 adjusted RR: 1.42 (1.25 to 1.61)42 for dementia, crude ORs: 2.12 (0.91 to 4.94) to 2.41 (2.11 to 2.75),14 38 46 adjusted ORs: 2.64 (1.86 to 3.75)19 and 2.68 (2.42 to 2.97)20). Other neurological or psychiatric conditions were also associated with an increased risk of CAP in some studies (epilepsy, crude ORs: 2.81 (1.83 to 4.30) and 2.83 (1.11 to 7.21)21 38; Parkinson's disease, crude ORs: 1.82 (1.52 to 2.19) and 1.87 (1.60 to 2.19)14 46; multiple sclerosis, crude OR 3.20 (2.40 to 4.26)46).…”

“…A large database study in patients aged ≥65 years reported a crude OR of 2.10 (1.85 to 2.38),14 whereas a small study in patients aged ≥70 years reported a crude OR of 16.3 (4.57 to 58.2) and an adjusted OR of 11.9 (3.03 to 46.9) 12…”