Prospective follow-up study of the renal function in type 2 diabetic patients

Type 2 diabetes mellitus is the main cause of increase in patients sufferin g from end-stage renal failure in France. We performed an observational stu dy of the change in renal function of type 2 diabetic patients, attending o ur diabetology clinic. Clinical and biological data were regularly entered in an informatic database (Penelope, Poitiers University Hospital). We pros pectively followed 351 type 2 diabetic patients (age at diagnosis: 40 to 75 years), for 32 months (extremes: 1-120). Renal function was graded in 4 st ages according to plasma creatinine and urinary albumin excretion (UAE) det ermined by nephelometry on random urinary sample: absent (UAE<20 mg/L et cr eatinine< 150 mu mol/L), incipiens (UAE 20 to 200 mg/L and creatinine <150 <mu>mol/L), established (UAE=200 mg/L et creatinine <150 <mu>mol/L) advance d (creatinine=150 mu mol/L). Glycated haemoglobin (HbA1c) was determined by HPLC. Systolic/Diastolic Blood Pressure (SBP/DBP) was measured with a merc ury sphygmomanometer. We defined renal events as the change from one stage of nephropathy to a higher one. A total of 351 type 2 diabetic subjects wer e studied: 194 men/157 women mean age 63 +/- 11 years, mean diabetes durati on 10 +/- 9 yr. At baseline, 206 patients had no nephropathy, 98 incipient nephropathy, 28 established nephropathy and 19-advanced nephropathy. Baseli ne stage of nephropathy was related to SBP (p<0.0001), DBP (p=0,0002), diab etes duration (p=0.0064) but not HbA1c (p=0.2182) or sex (p=0.4794). Among those 332 subjects without baseline advanced nephropathy, 134 progressed in nephropathy. Progression of nephropathy was not related to the presence of hypertension (SBP/DBP <greater than or equal to> 160/95 mmHg) (log-rank=0. 22; p=0.6377). Conversely, patients with a poor glycaemic control (HbA1c gr eater than or equal to 10%) had a worse renal-event free survival (log-rank =4.89; p=0.0269). Glycaemic control is a risk factor for the progression in nephropathy of type 2 diabetic patients.