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

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:

• Determine the effect of participant and provider knowledge of a positive APOL1 status on the probability of documented CKD diagnosis.
• 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.
• 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.

Inclusion criteria

• Self reported African ancestry
• English Speaking
• Age 18-70 years
• Have diagnosis of hypertension: Diagnosis of hypertension is defined by either:

• ICD10 diagnosis codes (i.e., I10; I11.x; I12.x; I13.x; I16.x) OR
• On active antihypertensive therapy for indication of hypertension OR
• Having systolic blood pressure of 140 mm Hg or greater in at least 2 of the last 3 consecutive recorded values in the EHR OR
• Having hypertension in the patient's medical record problem list
• Have been seen at ≥1 time in past year at a participating primary care site
• 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.

CKD is defined by either: A) ICD10 codes (i.e., N18.x; E08.22; E09.22; E10.22; E11.22;E13.22 (exclude Z94.0; N18.6; Z99.2)) OR B) Microalbumin/proteinuria level >30 mg/g for 2 time periods ≥ 3 months. Values taken within 12 months of enrollment, unless 2 values are unavailable, then review within 24 months of enrollment. OR C) 15 ≤ eGFR ≤ 60 ml/min for 2 time periods ≥ 3 months. GFRs are taken within 12 months of enrollment, unless 2 values are unavailable, then review within 24 months.

Diabetes is defined by: HbA1c ≥ 6.5 at least one time in the last year OR ICD10 diagnosis codes OR Having diabetes in the patient's medical record problem list.

Exclusion criteria

• Have diabetes, but no CKD.
• Are currently on dialysis (ICD 10 codes N18.6, Z99.2 and Z94.0)
• Have ESRD (eGFR<15 ml/min)
• Have a left ventricular assist device (LVAD)
• Have a terminal illness
• Have patient-reported known pregnancy at time of enrollment
• Have had a liver, kidney, or allogeneic bone marrow transplant
• Too cognitively impaired to provide informed consent and/or complete the study protocol
• Institutionalized or too ill to participate (i.e. incarcerated, psychiatric or nursing home facility)
• Plan to move out of the area within 6 months of enrollment
• Not a current patient seeing a provider who cares for their hypertension (i.e., family medicine, internal medicine, nephrology, HIV provider, cardiology, hypertension specialists) at a participating site
• Previously participated in the GUARDD pilot study OR have previously undergone APOL1 testing