Abstract
RATIONALE & OBJECTIVE: The use of renin-angiotensin system (RAS) inhibitors is standard of care in people with early to moderate chronic kidney disease (CKD). Less is known regarding the efficacy of RAS inhibitors in very advanced CKD. In this study, we describe patterns of use of RAS inhibitors and associations of these patterns of use with risk for CKD progression and mortality in patients with advanced CKD. STUDY DESIGN: Propensity-matched cohort study. SETTINGS & PARTICIPANTS: We identified 678 participants who were enrolled in the multicenter Chronic Renal Insufficiency Cohort (CRIC) Study with estimated glomerular filtration rates (eGFRs) < 30 mL/min/1.73 m(2) at the baseline visit. EXPOSURE: Use of RAS inhibitors within the first year after the baseline visit, characterized by 4 patterns of use: never users, always users, dynamic users, and new users. OUTCOMES: Progression to end-stage renal disease (ESRD) and all-cause mortality. ANALYTICAL APPROACH: We generated propensity scores and matched participants in the always users group with a 1:1 ratio with a participant from the other 3 groups, matching by age, sex, race, diabetes, hypertension, systolic blood pressure, eGFR, urinary protein-creatinine ratio, and serum potassium level. Cox models were used to test the association of patterns of RAS inhibitor use with risk for kidney failure and death. RESULTS: Of the 678 participants with eGFRs < 30 mL/min/1.73 m(2), 57% were identified as always users of RAS inhibitors during the 1 year, 23% as never users, 13% as dynamic users, and 7% as new users. We found no differences in risk for ESRD across patterns of RAS inhibitor use (never users [HR, 1.09; 95% CI, 0.71-1.67], dynamic users [HR, 1.46; 95% CI, 0.83-2.55], new users [HR, 0.78; 95% CI, 0.33-1.84] vs the always users reference group). Similarly, there was no association of patterns of RAS inhibitor use with death (never users [HR, 1.02; CI, 0.74-1.40], dynamic users [HR, 1.23; 95% CI, 0.80-1.90], new users [HR, 1.10; 95% CI, 0.63-1.92] vs always users). LIMITATIONS: Observational study. CONCLUSIONS: Use of RAS inhibitors in patients with eGFRs < 30 mL/min/1.73 m(2) is heterogeneous.(.)We found no difference in risk for progression to ESRD or mortality across patterns of RAS inhibitor use. Further research is required to identify optimal prescribing strategies of RAS inhibitors during advanced stages of CKD.