Dossabhoy, Neville R

Key Points Genetic testing in CKD showed diagnostic and clinical utility in the year following reporting of test results. Genetic testing was helpful for or changed management in 86% of patients with a positive finding and 42% with a negative finding. Clinical utility was seen across 12 clinical cohorts, including CKD of unknown etiology and hypertension or diabetes-related nephropathy. Background CKD is a significant public health burden, affecting >800 million people worldwide with significant cost to the health care system. CKD is a disease process with substantial genetic and phenotypic heterogeneity that can obscure a definitive diagnosis, resulting in suboptimal management. Recent guidelines support greater adoption of genetic testing in CKD. We assessed the diagnostic and clinical utility in the year following broad-panel CKD genetic testing. Methods The Renasight Clinical Application, Review, and Evaluation (RenaCARE) study (NCT05846113) was a single-arm, interventional, prospective, multicenter study evaluating the utility of genetic testing with a 385-gene panel on the diagnosis and management of CKD. Clinical history was collected before testing, and nephrologists responded to questionnaires at both 1 month and 1 year after testing. The impact of genetic testing on CKD diagnosis and management were assessed in active study patients at the 1-year time point. Results In a cohort of 1388 CKD patients with 13 pretest clinical categories of CKD, 335 (24%) patients had a positive genetic finding; 1174 had a questionnaire completed at 1 year and were included in the analysis. Genetic testing was reported helpful for clinical management and/or led to a change in management in 86% of patients with a positive test finding and 42% of patients with a negative test finding. In addition, genetic testing resulted in a change in the physician estimation of the 5-year prognosis for 55% of patients with a positive test finding and 18% of those with a negative test finding. Conclusions Supporting the previous results of the RenaCARE study at 1 month, this report demonstrated that genetic testing was helpful in the clinical management and estimated prognosis of patients with CKD. Clinical Trial registry name and registration number: ClinicalTrials.gov, NCT05846113.

Key Points Using multiple markers may improve GFR estimation especially in settings where creatinine and cystatin C are known to be limited. Panel eGFR is a novel multimarker eGFR equation consisting of age, sex, cystatin C, and nuclear magnetic resonance–measured creatinine, valine, and myo-inositol. eGFR-Cr and eGFR-Cr-CysC may underestimate measured GFR, while panel eGFR was unbiased among younger Black male individuals. Background Using multiple markers may improve accuracy in GFR estimation. We sought to externally validate and compare the performance of a novel multimarker eGFR (panel eGFR) equation among Black and White persons using the Genetic Epidemiology Network of Arteriopathy cohort. Methods We included 224 sex, race/ethnicity, and measured GFR (mGFR) category–matched persons, with GFR measured using urinary clearance of iothalamate. We calculated panel eGFR using serum creatinine, valine, myo-inositol, cystatin C, age, and sex. We compared its reliability with current eGFR equations (2021 CKD Epidemiology Collaboration creatinine [eGFR-Cr] and creatinine with cystatin C [eGFR-Cr-CysC]) using median bias, precision, and accuracy metrics. We evaluated each equation's performance in age, sex, and race subgroups. Results In the overall cohort, 49% were Black individuals, and mean mGFR was 79 ml/min per 1.73 m 2 . Panel eGFR overestimated mGFR (bias: −2.4 ml/min per 1.73 m 2 ; 95% confidence interval [CI], −4.4 to −0.7), eGFR-Cr-CysC underestimated mGFR (bias: 4.8 ml/min per 1.73 m 2 ; 95% CI, 2.1 to 6.7), while eGFR-Cr was unbiased (bias: 2.0 ml/min per 1.73 m 2 ; 95% CI, −1.1 to 4.6). All equations had comparable accuracy. Among Black male individuals younger than 65 years, both eGFR-Cr (bias: 17.0 ml/min per 1.73 m 2 ; 95% CI, 8.6 to 23.5) and eGFR-Cr-CysC (bias: 14.5 ml/min per 1.73 m 2 ; 95% CI, 6.0 to 19.7) underestimated mGFR, whereas panel eGFR was unbiased (bias: 1.7 ml/min per 1.73 m 2 ; 95% CI, −3.4 to 10.0). Metrics of accuracy for all eGFRs were acceptable in all subgroups except for panel eGFR in Black female individuals younger than 65 years (P30: 73.3%). Conclusions Panel eGFR can be used to estimate mGFR and may have utility among Black male individuals younger than 65 years where current CKD Epidemiology Collaboration equations are biased.