Prevalence of undiagnosed stage 3 chronic kidney disease in the Tabari Cohort: a population-based study

Chronic kidney disease (CKD) is a well-established public health concern worldwide. Considering the asymptomatic nature of early-stage CKD and its importance, we aimed to investigate the prevalence of undiagnosed stage 3 CKD in a large-scale, population-based cohort study.

In this cross-sectional study, data collected during the enrollment phase of the Tabari Cohort Study (TCS) were utilized. Between June 2015 and November 2017, 10,255 men and women aged 35-70 years were enrolled. CKD was determined based on the estimated glomerular filtration rate (eGFR). The Modification of Diet in Renal Disease (MDRD) equation, utilizing serum creatinine, was used to calculate eGFR. In the present study, participants with 30 ≤ GFR < 60 mL/min/1.73 m² were considered to have stage 3 CKD, and undiagnosed stage 3 CKD was defined as those unaware of CKD at enrollment but had an eGFR between 30 and 60 mL/min/1.73 m². Chi-square tests and univariate and multivariate logistic regression analyses were used to analyze the data.

Out of 10,255 TCS participants, 25.6% (N = 2,630) had stage 3 CKD (30 ≤ eGFR < 60 mL/min/1.73 m²), with 98.1% (N = 2,579) being unaware of their disease. Multivariate logistic regression results showed that the risk of undiagnosed stage 3 CKD was significantly lower in mountainous residents (OR: 0.30, 95% CI: 0.13-0.73, P = 0.008) and participants with hypertension (OR: 0.35, 95% CI: 0.18-0.66, P = 0.001), diabetes (OR: 0.52, 95% CI: 0.29-0.95, P = 0.032), and cardiovascular disease (OR: 0.44, 95% CI: 0.23-0.82, P = 0.010) compared to urban residents and those without hypertension, diabetes, and cardiovascular diseases, respectively.

The present study demonstrated a substantially high prevalence of undiagnosed stage 3 CKD. Urban residency and the absence of medical history of hypertension, diabetes, or cardiovascular disease were predictive factors of undiagnosed stage 3 CKD.