B-Vitamin Therapy for Diabetic Nephropathy—Reply

In Reply: Dr Drion questions generalizability because of the number of exclusions and the method of diabetic nephropathy diagnosis. The number 4175 represents all patients in the participating nephrology clinics whose charts were reviewed for potential enrollment in the DIVINe study. Many of these patients were not diabetic and hence were not eligible. Data on other exclusions or refusals are not available in the database, so we are not able to analyze whether those patients were systematically different from participants. Those with diabetes were scrutinized more thoroughly, some requiring additional blood and urine testing to determine eligibility. The criteria for diabetic nephropathy were as stringent, if not more so, than those of landmark trials of angiotensin receptor antagonists in diabetic nephropathy.^1- 2 Before screening, the clinical diagnosis had been made in all instances by a nephrologist, sometimes by renal biopsy when the diagnosis was in doubt. The Collaborative Study Group, using entry criteria similar to ours, found that 94% of patients with type 2 diabetes and nephropathy had diabetic glomerulosclerosis on biopsy.³