Improving medication adherence and helping patients make lifestyle changes.

Abstract

To minimize the possibility of misclassification of those who had taken and then, for safety reasons, ceased ACEI/ARB therapy prior to the first erythropoiesis-stimulating agent (ESA) prescription as nonusers, we redefined the nonusers (the referent group) as those who have not ever been treated with an ACEI/ARB up to 3 months and 6 months before commencing ESA therapy, respectively. Our data showed that the adjusted hazard ratios (95% CIs) of chronic dialysis in ACEI/ARB users were 0.94 (0.91-0.97) and 0.95 (0.92-0.98), respectively, and of dialysis or death, 0.94 (0.91-0.96) and 0.95 (0.92-0.98), respectively. Similar results could also be observed in the multivariable models further adjusted for the propensity score. The serial sensitivity analyses suggest our previously published data 1 that the hazard ratio of long-term dialysis or death for the ACEI or ARB users was 0.94 compared with nonusers was an unbiased estimate. We acknowledge the “new user” design 2 is a good method for pharmaco-epidemiological research. However, it may not be applicable to our study. In fact, the number of new ACEI or ARB users who had never used an ACEI or ARB at least 6 months prior to the first ESA prescription was only 1159 (8.2% of total ACEI or ARB users 1 ) in our cohort. The sample size was too small to secure a sufficient statistical power for the study. Few patients with advanced chronic kidney disease were also recognized to improve their renal function by stopping ACEI or ARB therapy in our study, 1 and it has been mentioned in the smallscale observational study by Ahmed et al. 3 However, our study and the study by Ahmed et al 3 are not comparable and have differences in case number (28 497 vs 52), median follow-up period (7 vs 30 months) and study outcomes (70.7% dialysis