Antibiotic use and risk of ischemic stroke in the elderly.
OBJECTIVE
To determine whether treating infections with antibiotics that have antichlamydial activity decreases the risk of ischemic stroke in the elderly.


METHODS
We analyzed data from 199 553 subjects 65 years and older in a health care claims database who had continuous health and pharmacy coverage for at least 2 years between January 1, 1991, and September 30, 1997. Using proportional hazards models with time-dependent covariates for prior antibiotic prescription and adjusting for cardiovascular risk factors, we determined the associations between antibiotic use and first claim for ischemic stroke (n = 7,335) during the observation period.


RESULTS
Rates of stroke (per 1,000 person-years) were 6.64 for macrolides, 9.27 for quinolones, 7.49 for tetracyclines, 6.88 for penicillins, 7.97 for cephalosporins, 8.58 for trimethoprim-sulfamethoxazole, and 7.29 for subjects with no antibiotic claims. The adjusted hazard ratios (HR) were 0.94 (95% confidence interval [CI]: 0.87 to 1.01) for macrolides, 1.04 (95% CI: 0.91 to 1.18) for tetracyclines, 1.02 (95% CI: 0.95 to 1.08) for penicillins, and 1.00 (95% CI: 0.82 to 1.22) for trimethoprim-sulfamethoxazole. Subjects with claims for quinolone antibiotics (HR = 1.17; 95% CI: 1.09 to 1.26) and cephalosporins (HR = 1.09; 95% CI: 1.02 to 1.16) had a slightly higher risk of stroke.


CONCLUSIONS
Exposures to short courses of antibiotics are not associated with lower risk of ischemic stroke in patients aged 65 years and older.
Luchsinger
J A
JA
Division of General Medicine, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
Pablos-Mendez
A
A
Knirsch
C
C
Rabinowitz
D
D
Shea
S
S
D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002545:Brain Ischemia / Q000453:epidemiology* / Q000517:prevention & control; D002690:Chlamydia Infections / Q000188:drug therapy; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D016016:Proportional Hazards Models; D012307:Risk Factors
D000900:Anti-Bacterial Agents