Body mass index modifies the effect of urinary protein-to-creatinine ratio on chronic kidney disease progression

This study aimed to determine the association between the urinary protein-to-creatinine ratio (UPCR) and chronic kidney disease (CKD) progression in a cohort study, and to determine whether body mass index (BMI) modifies this association.

The study population consisted of 856 hypertensive patients with CKD stages 2–5, enrolled between 2010 and 2011 in Japan. Generalized linear models with a logit link were used to evaluate the independent and combined effects of the UPCR and BMI on CKD progression

During a median follow-up of 25 months, 242 patients developed CKD progression during follow-up. A notably higher risk of CKD progression was found in participants in tertiles 2 [odds ratio (OR): 5.46, 95% confidence interval (95% CI): 2.49–11.99] and 3 (OR 27.74, 95% CI 12.34–62.38) comparing with tertiles 1 for UPCR levels. Moreover, an interaction was found between UPCR and BMI on CKD progression (P for interaction = 0.006). Participants in both the highest tertile of UPCR and overweight (UPCR ≥ 248.9 mg/mmol and BMI ≥ 25 kg/m²) had a 45.59-times higher risk of CKD progression compared with those in the lowest tertile of UPCR and nonoverweight (UPCR < 36.2 mg/mmol and BMI < 25 kg/m²)

The present study demonstrates that the combination of elevated UPCR and BMI may contribute to an increased risk of CKD progression.