Kido R, et al. - Researchers here aimed at assessing whether the use of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers individually or as a combination confer a survival benefit in hemodialysis patients. Unlike ACEI use, ARB use was associated with greater survival than non-use among hemodialysis patients with secondary hyperparathyroidism. However, combination use seemed correlated with greater mortality.

Methods

• Researchers conducted a case-cohort study using data from the Mineral and Bone Disorder Outcomes Study for Japanese CKD stage 5D patients (MBD-5D)(a 3-year multicenter prospective case-cohort study that included 8,229 hemodialysis patients registered from 86 facilities in Japan).
• They identified that all patients had secondary hyperparathyroidism (a condition defined as a parathyroid hormone level ≥180 pg/mL) and/or were receiving vitamin D receptor activators.
• They performed comparison of all-cause mortality rates between those receiving ACEI, ARB, and their combination and non-users with interaction testing.
• They utilized marginal structural Poisson regression (causal model) to assess the causal effect and interaction adjusted for possible time-dependent confounding.  
• They also determined cardiovascular mortality.

Results

• Patients taking ACEI, ARB, and their combination at baseline accounted for 4.0, 31.6, and 3.8%, respectively, among 3,762 randomly sampled subcohort patients.
• Researchers noticed 1,226 all-cause and 462 cardiovascular deaths over 3 years.
• In comparison to non-users, a lower all-cause mortality rate was observed among ARB-alone users (adjusted incident rate ratio [aIRR] 0.62, 95% CI 0.50–0.76), whereas ACEI-alone users showed a statistically similar rate (aIRR 1.01, 95% CI 0.57–1.77).
• However, a greater mortality rate was observed among combination users (aIRR 2.56, 95% CI 1.22–5.37), indicating significant interaction (p=0.03).
• Similar results were observed in analysis for cardiovascular mortality.