No dose-response relationship of clarithromycin utilization on cardiovascular outcomes in patients with stable coronary heart disease: Analysis of Taiwan's national health insurance claims data.

Background: Clarithromycin is widely used to treat various bacterial infections and has been reported to have potential cardiovascular risk. However, it is uncertain whether this association was dose dependent and confounded by indication bias in patients with stable coronary heart disease (CHD). Methods: This cohort study retrospectively analyzed a national health insurance claims data from Taiwan's 2005 Longitudinal Generation Tracking Database. We used a new-user design and 1:1 propensity score matching. A total of 9,631 eligible clarithromycin users and 9,631 non-users in 2004-2015 were subject to final analysis. All patients were followed-up after receiving clarithromycin or on the matched corresponding date until occurrence of cardiovascular morbidity in the presence of competing mortality, all-cause and cause-specific mortality, or through the end of 2015. The effect of cumulative dose, exposure duration, and indications of clarithromycin on cardiovascular outcomes were also addressed. Results: Clarithromycin use, compared with non-use, was associated with higher risk for all-cause [adjusted hazard ratios (aHR), 1.43; 95% confidence interval, 1.29-1.58], cardiovascular (1.35; 1.09-1.67), and non-cardiovascular (1.45; 1.29-1.63) mortality, but not for overall cardiovascular morbidity. Further analysis of individual cardiovascular morbidity demonstrated major risk for heart events (1.25; 1.04-1.51) in clarithromycin users than non-users. However, there was no relationship of cumulative dose, exposure duration, and indications of clarithromycin on cardiovascular outcomes. Analyses of the effects over time showed that clarithromycin increased cardiovascular morbidity (1.21; 1.01-1.45), especially heart events (1.39; 1.10-1.45), all-cause (1.57; 1.38-1.80), cardiovascular (1.58; 1.20-2.08), and non-cardiovascular (1.57; 1.35-1.83) mortality during the first 3 years. Thereafter, clarithromycin effect on all outcomes almost dissipated. Conclusion: Clarithromycin use was associated with increased risk for short-term cardiovascular morbidity (especially, heart events) and mortality without a dose-response relationship in patients with stable CHD, which was not dose dependent and confounded by indications. Hence, patients with stable CHD while receiving clarithromycin should watch for these short-term potential risks.