Statin use and the risk of herpes zoster: a nested case–control study using primary care data from the U.K. Clinical Research Practice Datalink

BACKGROUND Statins are commonly prescribed worldwide and recent evidence suggests that they may increase the risk of herpes zoster (HZ). OBJECTIVES To quantify the effect of statin exposure on the risk of HZ in the U.K. METHODS A matched case-control study was conducted using data from U.K. primary care and hospital records. Patients > 18 years with an incident diagnosis of HZ were matched to up to four controls for age, sex and general practice. Patients were included in the statin exposure group if they had ever used a statin, and the daily dosage of the most recent statin prescription and the time since the most recent statin prescription were also recorded. The primary outcome was an incident diagnosis of HZ. Odds ratios (ORs) were estimated from conditional logistic regression and adjusted for potential confounders. RESULTS A total of 144 959 incident cases of HZ were matched to 549 336 controls. Adjusted analysis suggested strong evidence for an increase in the risk of HZ related to statin exposure (OR 1·13, 95% confidence interval 1·11-1·15). There was also an increased risk when dosages were increased for patients who were currently or had recently been receiving statin treatment (Ptrend < 0·001), and we found an attenuation of the increased risk of HZ in previous statin users as the time since last statin exposure increased (Ptrend < 0·001). CONCLUSIONS These findings are consistent with the hypothesis that statin therapy leads to an increase in the risk of HZ.