Screening for CKD in undiagnosed populations with diabetes and hypertension: lessons from the SEARCH study

Abstract

INTRODUCTION: Despite advances in chronic kidney disease (CKD) management, early diagnosis and risk stratification remain major challenges. This study analyzed national data derived from a Brazilian CKD screening campaign, targeting high-risk individuals unaware of their condition, to estimate CKD prevalence and evaluate longitudinal trends in estimated glomerular filtration rate (eGFR). METHODS: This cross-sectional, observational study evaluated adults with diabetes mellitus (DM) and/or arterial hypertension, previously undiagnosed with CKD, who participated in a CKD screening campaign. Demographic, clinical, and laboratory data-including serum creatinine and albumin-to-creatinine ratio (ACR)-were collected. CKD staging followed Kidney Disease: Improving Global Outcomes (KDIGO) criteria, and eGFR was calculated using the CKD-EPI 2021 equation. Mixed effect models were used to assess eGFR trajectories and logistic regression was used to examine CKD risk factors. RESULTS: Among 14,239 high-risk participants (mean age 54 years; 84% hypertensive; 37% diabetic), CKD was newly identified in 19.6%, with 11.3% showing eGFR <60 mL/min and 11.1% ACR >30 mg/g. Despite abnormal ACR results, testing remained uncommon: <5% prior to the campaign and <7% afterward. eGFR decline was steeper among diabetics (+40%), hypertensive individuals (+17%), those >65 years of age (+17%), and individuals with body mass index (BMI) >25 kg/m2 (+60%). Logistic regression models of risk projected ~169,000 kidney failure cases in 2 years and ~500,000 in 5 years, excluding competing mortality risk. CONCLUSION: A high prevalence of previously undiagnosed CKD was found in this high-risk population. Despite universal access to testing in Brazil, albuminuria remains markedly underused, representing a missed opportunity for early detection and implementation of nephroprotective interventions.