Most studies of an association of visit-to-visit variability of blood pressure with increased risk of future adverse cardiovascular events are of short duration and rarely include a placebo group. Using data from the double-blind, placebo-controlled Systolic Hypertension in the Elderly Program, the authors examined mortality from cardiovascular causes up to 17 years of follow-up using the National Death Index. Visit-to-visit blood pressure variability was associated with cardiovascular death after adjustment for sex, age, serum creatinine, diabetes, body mass index, smoking status, left ventricular failure, and high-density lipoprotein cholesterol. The relationship was significantly stronger in the active treatment group compared with the placebo group. Although this could be the result of an effect of the medications used unrelated to visit-to-visit variability, the data are compatible with the hypothesis that inconsistent adherence leading to missing active medication doses may be an additional explanation for the relationship of visit-to-visit variability with cardiovascular death.