Genetic Testing to Understand and Address Renal Disease Disparities Across the United States

Overview

GUARDD-US is a prospective, multicenter, unblinded, two arm randomized pragmatic clinical trial. Participants will be randomized in a 1:1 ratio to immediate APOL1 gene testing and return of results (ROR) to participant and provider (Intervention arm) versus delayed APOL1 gene testing and ROR to participant and provider (Control arm). The main study will compare outcomes between APOL1 positive participants in the Intervention arm (i.e., early knowledge of APOL1 status) to APOL1 positive participants in the Control arm (i.e., delayed knowledge of APOL1 status). Participants that are APOL1 negative in the Intervention and Control groups will not be included in the main study analyses. GUARDD-US also includes a substudy to determine the effect of knowledge of genetic test results that predict efficacy of various antihypertensive medications on change in SBP from baseline to 3 months in APOL1 negative individuals at participating sites. This substudy is listed separately on clinicaltrials.gov as NCT06748040 and Unique Protocol ID - PRO00102997\_A

High-risk variants in the APOL1 gene explain approximately 70% of the excess prevalence of CKD in African Americans (AAs), conferring a 5 times higher risk for hypertensive CKD and a 10 times higher risk for ESRD. A pilot study (GUARDD), showed that returning APOL1 gene test results had a statistically significant improvement in SBP at 3 months when comparing APOL1 positives to APOL1 negatives who received their genetic testing results and when comparing APOL1 positives that received their results early to overall controls who did not receive their results until after the 3 month visit. GUARDD was not however powered to evaluate the effects of having and knowing a positive APOL1 status on outcomes for those with high risk of developing CKD (i.e., comparing outcomes for APOL1 positive patients who know their genetic risk to APOL1 positive patients who do not know their genetic risk). A broader trial is needed to better determine the importance of APOL1 gene testing for improving the testing, diagnosis, and treatment of individuals at risk of CKD. The primary aim is to determine the effect of participant and provider knowledge of a positive APOL1 status and accompanying guideline based clinical decision support (CDS) on blood pressure management on change in systolic blood pressure (SBP) from baseline to 3 months after randomization among the APOL1 positive participants. Secondary aims are to: 1. Determine the effect of participant and provider knowledge of a positive APOL1 status on the probability of documented CKD diagnosis. 2. Determine the effect of participant and provider knowledge of a positive APOL1 status on the probability of receiving a urine microalbumin/creatinine testing and ACE-I/ARB prescription based on results of the urine microalbumin level. 3. Explore cost effectiveness, mediators, moderators, psychobehavioral impact of results disclosure on participants, and effects of participant and provider knowledge of APOL1 status on provider treatment recommendations. Approximately 6,750 participants of African ancestry age 18-70 with hypertension that either: 1) do not have diabetes and do not have CKD, or 2) have CKD. Participants with diabetes may be included as long as they also have CKD. Population for Main Study: Participants from Randomized Population (above) who test positive for APOL1 Main Study Analyses: * To determine the effect of participant and provider knowledge of a positive APOL1 status on SBP, we will compare the change in SBP from baseline to 3 months of the Intervention - APOL1 positive group to the change in SBP from baseline to 3 months of the Control - APOL1 positive group using a two sided t-test, as appropriate, with an overall two-sided type I error of 0.05. * The effect of knowledge of a positive APOL1 status on all secondary endpoints will be compared between Intervention - APOL1 positives to Control - APOL1 positives with the proportion difference test. * Additional analyses will include analysis of time trends in SBP, subset analyses, and exploratory analyses of cost effectiveness, mediators, moderators, psychobehavioral impact of results disclosure on participants, and effects of knowledge of APOL1 status on provider treatment recommendations.