Statins and Renovascular Disease in the Elderly
Statins and Renovascular Disease in the Elderly
Aims More than 90% of cases of renovascular disease (RVD) are caused by atherosclerosis; thus patients with this condition are at high risk for vascular events. We examined the association of statins with prognosis in patients with RVD.
Methods and results We performed a population-based cohort study in 4040 patients with RVD older than 65 years using province-wide health data in Ontario, Canada. The primary outcome was time to first cardiorenal event, specifically myocardial infarction, stroke, heart failure, acute renal failure, dialysis or death; the primary analysis used a time-dependent covariate for statin exposure. Despite having a greater burden of cardiovascular and renal comorbidity, the risk of the primary outcome was significantly lower in statin users than in non-users [unadjusted hazard ratio (HR) 0.51, 95% confidence interval (CI) 0.47–0.57; P < 0.0001]. This association was materially unchanged after adjusting for demographic characteristics, cardiovascular risk factors, other comorbidities, measures of health-care utilization, screening, and concomitant medications (adjusted HR 0.51, 95% CI 0.46–0.57). An analysis using the same endpoint in a propensity-matched cohort without time-dependent statin exposure revealed a lower risk of the primary outcome in statin-treated patients but with a substantially more conservative point estimate (HR 0.82, 95% CI 0.71–0.95).
Conclusion These data suggest that statins are associated with improved prognosis in elderly patients with RVD.
Atherosclerotic renovascular disease (RVD) is a highly prevalent vascular condition, particularly among the elderly, with nearly 7% of community dwelling persons 65 years or older demonstrating RVD on duplex sonography. In addition, patients with RVD incur high rates of cardiovascular and renal events. In the recent Angioplasty and Stenting for Renal Artery Lesions (ASTRAL) trial, 37% of participants suffered a major cardiovascular event and 15% suffered a major renal event over a median follow-up of 34 months. Among elderly patients with RVD captured in US Medicare data, annual rates of stroke, acute coronary syndrome, heart failure, and death were 18, 30, 19, and 17%, respectively.
Randomized trials in RVD have typically focused on the role of revascularization in the management of this condition; remarkably few trials have assessed the effects of medical therapy on prognosis. Because >90% of RVD is caused by atherosclerosis, most experts recommend statin therapy for affected patients, although no statin trial has been conducted in this setting. Patients with RVD are on an average sicker, older and more likely to have renal impairment than the typical participant recruited to a statin 'mega-trial'; RVD might therefore complicate the risk-benefit ratio of statins. Alternatively, since RVD is often a marker of diffuse multisystem atherosclerosis, affected patients might have more to gain from adding a statin to their regimen.
We conducted a retrospective, population-based cohort study to evaluate the association between statins and cardiorenal outcomes in a defined sample of patients with RVD. Because non-adherence is common in statin users, we performed our analyses using time-dependent covariates to model statin exposure throughout follow-up. In a sensitivity analysis, we also matched statin users to controls using propensity-based matching, which accounts for the likelihood of being prescribed a statin according to measured baseline characteristics. Finally, because statins seem to exert beneficial effects across disparate vascular beds, we assessed a spectrum of major cardiac, cerebral, and renal events in the primary analysis, while also testing these outcomes separately in secondary analyses.
Abstract and Introduction
Abstract
Aims More than 90% of cases of renovascular disease (RVD) are caused by atherosclerosis; thus patients with this condition are at high risk for vascular events. We examined the association of statins with prognosis in patients with RVD.
Methods and results We performed a population-based cohort study in 4040 patients with RVD older than 65 years using province-wide health data in Ontario, Canada. The primary outcome was time to first cardiorenal event, specifically myocardial infarction, stroke, heart failure, acute renal failure, dialysis or death; the primary analysis used a time-dependent covariate for statin exposure. Despite having a greater burden of cardiovascular and renal comorbidity, the risk of the primary outcome was significantly lower in statin users than in non-users [unadjusted hazard ratio (HR) 0.51, 95% confidence interval (CI) 0.47–0.57; P < 0.0001]. This association was materially unchanged after adjusting for demographic characteristics, cardiovascular risk factors, other comorbidities, measures of health-care utilization, screening, and concomitant medications (adjusted HR 0.51, 95% CI 0.46–0.57). An analysis using the same endpoint in a propensity-matched cohort without time-dependent statin exposure revealed a lower risk of the primary outcome in statin-treated patients but with a substantially more conservative point estimate (HR 0.82, 95% CI 0.71–0.95).
Conclusion These data suggest that statins are associated with improved prognosis in elderly patients with RVD.
Introduction
Atherosclerotic renovascular disease (RVD) is a highly prevalent vascular condition, particularly among the elderly, with nearly 7% of community dwelling persons 65 years or older demonstrating RVD on duplex sonography. In addition, patients with RVD incur high rates of cardiovascular and renal events. In the recent Angioplasty and Stenting for Renal Artery Lesions (ASTRAL) trial, 37% of participants suffered a major cardiovascular event and 15% suffered a major renal event over a median follow-up of 34 months. Among elderly patients with RVD captured in US Medicare data, annual rates of stroke, acute coronary syndrome, heart failure, and death were 18, 30, 19, and 17%, respectively.
Randomized trials in RVD have typically focused on the role of revascularization in the management of this condition; remarkably few trials have assessed the effects of medical therapy on prognosis. Because >90% of RVD is caused by atherosclerosis, most experts recommend statin therapy for affected patients, although no statin trial has been conducted in this setting. Patients with RVD are on an average sicker, older and more likely to have renal impairment than the typical participant recruited to a statin 'mega-trial'; RVD might therefore complicate the risk-benefit ratio of statins. Alternatively, since RVD is often a marker of diffuse multisystem atherosclerosis, affected patients might have more to gain from adding a statin to their regimen.
We conducted a retrospective, population-based cohort study to evaluate the association between statins and cardiorenal outcomes in a defined sample of patients with RVD. Because non-adherence is common in statin users, we performed our analyses using time-dependent covariates to model statin exposure throughout follow-up. In a sensitivity analysis, we also matched statin users to controls using propensity-based matching, which accounts for the likelihood of being prescribed a statin according to measured baseline characteristics. Finally, because statins seem to exert beneficial effects across disparate vascular beds, we assessed a spectrum of major cardiac, cerebral, and renal events in the primary analysis, while also testing these outcomes separately in secondary analyses.
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