Factors related to nephrotic-range proteinuria in late-stage chronic kidney disease patients with diabetes mellitus.

PURPOSE: Diabetic nephropathy and proteinuria are important risk factors for both end-stage renal disease and cardiovascular events. The present study aimed to identify the factors associated with nephrotic-range proteinuria in patients with advanced diabetic nephropathy. METHODS: This cross-sectional study enrolled 386 diabetic patients with chronic kidney disease (CKD) stages 3-5, from our outpatient Department of Nephrology. Urinary protein-to-creatinine ratio was recorded. Additionally, other laboratory parameters, body mass index, blood pressure, comorbidities, and medications were also reviewed. RESULTS: The mean age of the patients was 65.1 ± 11.6 years. Among patients with CKD stage 3 and 4, the odds ratio (OR) for nephrotic-range proteinuria in relation with systolic blood pressure significantly increased starting from 121 mmHg (OR 7.04 and 11.79 for systolic blood pressure of 121-140 and ≥141 mmHg, respectively, in comparison with systolic blood pressure below 121 mmHg). In addition, serum phosphorus ≥4.7 mg/dl was associated with significantly higher risk (OR 15.45) for severe proteinuria, compared with a phosphorus level ≤2.6 mg/dl. Finally, hypertriglyceridemia ≥241 mg/dl was also associated with higher OR for severe proteinuria, compared with a triglyceride level ≤200 mg/dl. Similar associations were found in patients with CKD stage 5. CONCLUSIONS: Higher systolic blood pressure, serum phosphorus, and triglyceride levels are associated with nephrotic-range proteinuria in patients with diabetic nephropathy and CKD stage 3-5. Further studies should clarify whether a reduction in serum phosphorus would lead to a decrease in proteinuria in these patients.

Hyperphosphatemia is associated with overt proteinuria in non-diabetic patients with late-stage chronic kidney disease: a cross-sectional study.

PURPOSE: Proteinuria plays an important role in the progression of chronic kidney disease (CKD), as well as a powerful predictor of cardiovascular morbidity and mortality. The aim of our study was to investigate the potential determinants associated with overt proteinuria in non-diabetic patients with late-stage CKD. METHODS: Between January 2006 and September 2011, a total of 418 non-diabetic patients with CKD stage 3-5 were enrolled from the outpatient department of nephrology. Urinary protein-to-creatinine ratio and serum phosphorus were determined. Other laboratory parameters, associated comorbidities, medication use, body mass index, and blood pressure were also assessed. RESULTS: The mean age of the patients was 66.7 ± 14.0 years. In multiple logistic regression analysis and adjusting for established risk factors, the odds ratios for overt proteinuria were 3.96 (95 % confidence interval, 1.80-8.76; p = 0.001) for higher serum phosphorus level (≥4.3 mg/dl) and 3.56 (95 % confidence interval, 1.47-8.63; p = 0.005) for hypercholesterolemia (≥217 mg/dl), compared to subjects with serum phosphorus <3.3 mg/dl and cholesterol level 158-184 mg/dl. The similar significant findings remained robust in individuals not receiving phosphate binder. CONCLUSIONS: Hyperphosphatemia and high serum cholesterol are associated with overt proteinuria in non-diabetic patients with late-stage CKD. Further studies should clarify whether this relation is causal and whether serum phosphorus level should be a new therapeutic target for proteinuria reduction.