Community Detection of CKD Markers and Evaluation of Point-of-Care Creatinine Testing in Kazakhstan

Abstract

Background: Evidence on chronic kidney disease (CKD) in Central Asia remains limited, particularly for community-based detection using both kidney function and albuminuria. This study assessed the frequency of CKD markers among adults in three cities of Kazakhstan and examined whether point-of-care (POC) creatinine testing could support community screening. Methods: Adults were recruited through community screening events in Astana, Ust-Kamenogorsk, and Turkestan. Laboratory serum creatinine was used to calculate eGFR with the CKD-EPI 2021 equation, and urine albumin-to-creatinine ratio (ACR) was measured to identify albuminuria. Participants were classified as having screening-detected CKD markers if eGFR was <60 mL/min/1.73 m² and/or ACR was ≥30 mg/g on a single assessment. Multivariable logistic regression was used to examine associated factors. Capillary POC creatinine was compared with laboratory creatinine, and its diagnostic performance for identifying eGFR <60 mL/min/1.73 m² was evaluated. Results: Of 1,022 participants with complete laboratory kidney measurements, 100 (9.8%; 95% CI 8.1–11.8) had screening-detected CKD markers. Albuminuria was identified in 7.7%, while reduced eGFR was present in 3.4%. Among participants with CKD markers, 52.0% reported no previous awareness of abnormal kidney findings. Hypertension was associated with approximately twice the adjusted odds of CKD markers (aOR 2.05, 95% CI 1.24–3.41). POC and laboratory creatinine were available for 987 participants. POC creatinine exceeded laboratory values by an average of 18.5 µmol/L, with wide limits of agreement. For identifying laboratory-defined reduced eGFR, POC-derived eGFR had 84.4% sensitivity, 83.4% specificity, 14.5% positive predictive value, 99.4% negative predictive value, and an AUC of 0.919. Conclusions: CKD markers were detected in roughly one in ten screened adults, and albuminuria accounted for a substantial proportion of identified abnormalities. The high proportion of previously unrecognized findings supports greater use of combined eGFR and ACR assessment in CKD case-finding. POC creatinine may be useful for triage because of its strong rule-out performance, but positive findings should be confirmed with standardized laboratory testing.