Improved prognosis in type 1 diabetic patients with nephropathy: a prospective follow-up study

BACKGROUND: In early studies, a median survival time of 5 to 7 years from onset of diabetic nephropathy was observed. Furthermore, end-stage renal disease (ESRD) was the main cause of death. We prospectively assessed the impact of reno- and cardiovascular protective treatment on prognosis in type 1 diabetic patients with diabetic nephropathy.

METHODS: We prospectively followed 199 type 1 diabetic patients with diabetic nephropathy and 192 patients with normoalbuminuria for 10 years. Aggressive antihypertensive treatment was initiated in patients with diabetic nephropathy in mid 1980s, whereas statins and aspirin were not prescribed routinely until April 2002. The primary end point was cardiovascular mortality and morbidity. Secondary end points were all-cause mortality and ESRD.

RESULTS: During follow-up, 79 patients (40%) with nephropathy reached the primary end point versus 19 (10%) of normoalbuminuric patients, log rank test P < 0.0001. Predictors of the primary end point were: nephropathy (hazard ratio 3.26; 95% confidence interval 1.89 to 5.62), previous event (3.19; 2.04 to 4.97), age (1.27; 1.04 to 1.55), and systolic blood pressure (1.13; 1.03 to 1.24). In the nephropathy group, 60 patients (30%) died; hereof, 25 deaths (42%) were ascribed to cardiovascular causes while 30 patients (50%) with nephropathy died with ESRD. The estimate of median survival time from onset of diabetic nephropathy was 21.7 years, SE 3.3 years.

CONCLUSION: The survival of patients with diabetic nephropathy has improved most likely due to aggressive antihypertensive treatment and improved glycaemic control.