Outcomes within 30 days after co-prescription of clarithromycin or azithromycin with a statin not metabolized by CYP3A4
| Outcome | No. of events (%)* | Absolute risk difference (95% CI), % | Relative risk (95% CI) | ||
|---|---|---|---|---|---|
| Clarithromycin n = 51 523 | Azithromycin† n = 52 518 | Unadjusted | Adjusted‡ | ||
| Hospital admission with rhabdomyolysis | 13 (0.03) | 6 (0.01) | 0.02 (−0.03 to 0.03) | 2.21 (0.84 to 5.81) | 2.27 (0.86 to 5.96) |
| Hospital admission with acute kidney injury | 175 (0.34) | 122 (0.23) | 0.11 (0.04 to 0.17) | 1.46 (1.16 to 1.84) | 1.65 (1.31 to 2.09) |
| Hospital admission with hyperkalemia | 33 (0.06) | 18 (0.03) | 0.03 (0.00 to 0.06) | 1.87 (1.05 to 3.32) | 2.17 (1.22 to 3.86) |
| All-cause mortality | 200 (0.39) | 155 (0.30) | 0.09 (0.02 to 0.16) | 1.32 (1.07 to 1.62) | 1.43 (1.15 to 1.76) |
Note: CI = confidence interval, CYP3A4 = cytochrome P450 3A4.
↵* The number of events (and the proportion of patients who experienced an event) for all outcomes except all-cause mortality were assessed with the use of hospital diagnostic codes. This underestimates the true event rate, because these codes have high specificity but low sensitivity.
↵† Patients prescribed azithromycin served as the referent group.
↵‡ Adjusted for 15 covariates (age, sex, year of cohort entry; baseline evidence of chronic kidney disease, stroke or transient ischemic attack, peripheral vascular disease, coronary artery disease, congestive heart failure, major cancer and diabetes; baseline use, in the 120 days before the index date, of β-blockers, calcium-channel blockers, diuretics, angiotensin-converting-enzyme inhibitors or angiotensin II receptor blockers, and nonsteroidal anti-inflammatory drugs) using logistic regression model (see Methods section). To reduce concerns about model over-fitting, we repeated the analysis adjusting for only age and sex; the results did not differ.