Diagnostic efficacy of urine dipstick in detecting chronic kidney disease

ABSTRACT

Background: Proponents of routine urine dipstick screening to identify patients at risk for ESRD in the primary care setting have argued that urine dipsticks are inexpensive, low risk, acceptable to patients, and now, more accurate. Proponents believe that urine dipstick screening has the potential to improve outcomes for people with early disease and increase awareness of CKD. Most primary care physicians agree that populations who are at high risk for CKD should be tested and appropriately treated to decrease complications of ESRD. However, proponents of mass screening may not appreciate the challenges, limitations, and potential harms of screening. Urine dipstick testing does not meet all of the criteria for a good screening test. The aim of the study To elucidate the diagnostic efficacy of the urine dipstick in detecting chronic kidney disease by assessing its validity as a screening test for detecting CKD. Materials and methods: A community-based cross-sectional study was conducted among 287 subjects aged 20 years and above residing in the P.K. Garden area of Chennai during November 2018 to January 2019. Subjects were interviewed with a questionnaire and blood samples were collected to estimate serum creatinine and a urine sample was collected to estimate the proteinuria using urine S. Thirumavalavan, Noormohamed, Balaji S.M., R Vijaya Kumar. Diagnostic efficacy of urine dipstick in detecting chronic kidney disease. IAIM, 2019; 6(3) 137-142. Page 138 dipstick. eGFR was calculated using CKD – EPI equation and CKD was diagnosed using KDOQI CKD guidelines. Results: The prevalence of Chronic Kidney Disease (<60 ml/min eGFR) in the study group was 10.45%. The Area under Curve (AUC) of the ROC curve for urine dipstick in detecting CKD was 0.948 (0.900 – 0.996) and the 2+ proteinuria was closest to the ideal test point. When proteinuria criteria set at dipstick 2+ or more, the sensitivity was 83.33% and specificity was 98.36%, positive predictive value was 83.33% and κ coefficient of agreement of proteinuria with CKD was 0.81. Conclusion: The urine dipstick test can be used as an effective screening tool in detecting CKD in primary care level. Non Communicable Diseases screening at primary health care level should include the screening of proteinuria using urine dipstick especially for people with risk factors like Diabetes and Hypertension.