High-Normal Protein Intake Is Not Associated With Faster Renal Function Deterioration in Patients With Type 2 Diabetes: A Prospective Analysis in the DIALECT Cohort

OBJECTIVE To study the prospective association between dietary protein intake and renal function deterioration in patients with type 2 diabetes (T2D). RESEARCH DESIGN AND METHODS Prospective analyses were performed in data of 382 patients of the Diabetes and Lifestyle Cohort Twente (DIALECT) study. Dietary protein intake was determined by the Maroni equation from 24-h urinary urea excretion. Renal function deterioration was defined as need for renal replacement therapy or a persistent increase of ≥50% in serum creatinine. Cox proportional hazards models were used to calculate hazard ratios (HRs) for the association between dietary protein intake and renal function deterioration. Threshold levels represent the dietary protein intake at which there was a significantly increased and reduced hazard of renal function deterioration. RESULTS Renal function deterioration occurred in 53 patients (14%), with a median follow-up duration of 6 (interquartile range 5–9) years. Mean dietary protein intake was 91 ± 27 g/day (1.22 ± 0.33 g/kg ideal body weight/day). Dietary protein intake was inversely associated with renal function deterioration (HR 0.62 [95% CI 0.44–0.90]). Patients with an intake 163 g/day had a decreased hazard for renal function deterioration (HR 0.42 [95% CI 0.18–1.00]). Regarding dietary protein intake per kilogram body weight, patients with an intake