Prognosis in diabetic nephropathy.

OBJECTIVE: To assess the effect of long term antihypertensive treatment on prognosis in diabetic nephropathy. DESIGN: Prospective study of all insulin dependent diabetic patients aged under 50 with onset of diabetes before the age of 31 who developed diabetic nephropathy between 1974 and 1978 at Steno Memorial Hospital. SETTING: Outpatient diabetic clinic in tertiary referral centre. PATIENTS: Forty five patients (20 women) with a mean age of 30 (SD 7) years and a mean duration of diabetes of 18 (7) years at onset of persistent proteinuria were followed until death or for at least 10 years. INTERVENTIONS: Antihypertensive treatment was started a median of three (0-13) years after onset of nephropathy. Four patients (9%) received no treatment, and 9 (20%), 13 (29%), and 19 (42%) were treated with one, two, or three drugs, respectively. The median follow up was 12 (4-15) years. MAIN OUTCOME MEASURES: Arterial blood pressure and death. RESULTS: Mean blood pressure at start of antihypertensive treatment was 148/95 (15/50) mm Hg. Systolic blood pressure remained almost unchanged (slope -0.01 (95% confidence interval -0.39 to 0.37) mm Hg a year) while diastolic blood pressure decreased significantly (0.87 (0.65 to 1.10) mm Hg a year) during antihypertensive treatment. The cumulative death rate was 18% (8 to 32%) 10 years after onset of nephropathy, in contrast to previous reports of 50% to 77% 10 years after onset of nephropathy. As in previous studies, uraemia was the main cause of death (9 patients; 64%). CONCLUSIONS: The prognosis of diabetic nephropathy has improved during the past decade largely because of effective antihypertensive treatment.