Risk factors for development of incipient and overt diabetic nephropathy in patients with non-insulin dependent diabetes mellitus: prospective, observational study

Abstract

Objective: To evaluate putative risk factors for the development of incipient diabetic nephropathy (persistent microalbuminuria) and overt diabetic nephropathy (persistent macroalbuminuria) in patients with non-insulin dependent diabetes. Design: Prospective, observational study of a cohort of white, non-insulin dependent diabetic patients followed for a median period of 5.8 years. Setting: Outpatient clinic in tertiary referral centre. Subjects: 191 patients aged under 66 years with non-insulin dependent diabetes and normoalbuminuria (urinary albumin excretion rateMain outcome measures: Incipient and overt diabetic nephropathy. Results: Fifteen patients were lost to follow up. Thirty six of the 176 remaining developed persistent microalbuminuria (30-299 mg/24 h in two out of three consecutive 24 hour urine collections) and five developed persistent macroalbuminuria (≥300 mg/24 h in two out of three consecutive collections) during follow up. The five year cumulative incidence of incipient diabetic nephropathy was 23% (95% confidence interval 17% to 30%). Cox's multiple stepwise regression analysis revealed the following risk factors for the development of incipient or overt diabetic nephropathy: increased baseline log urinary albumin excretion rate (relative risk 11.1 (3.4 to 35.9); PConclusion: Several potentially modifiable risk factors predict the development of incipient and overt diabetic nephropathy in normoalbuminuric patients with non-insulin dependent diabetes.