EARLY-PREGNANCY PROTEINURIA IN DIABETES-RELATED TO PREECLAMPSIA

Objective. To test the hypothesis that the risk of preeclampsia in dia betic mothers is increased with incipient diabetic nephropathy as well as with overt nephropathy. Methods: Pregnancy outcome was studied in 311 women with class B-RF diabetes from two institutions. Using 104 wo men without chronic hypertension followed at the University of Califor nia, San Francisco, we constructed a receiver-operating characteristic curve relating 24-hour urinary total protein before 20 weeks' gestati on to the subsequent development of preeclampsia. From the curve, a pr edictive cutoff level of proteinuria was selected and tested in two va lidation groups not used to construct the curve: 158 women without chr onic hypertension followed at the University of Cincinnati and 49 wome n with chronic hypertension from both institutions. Results: The recei ver-operating characteristic curve showed an increased risk of preecla mpsia with early-pregnancy proteinuria of 190 mg/day or more. In the C incinnati validation group, the rate of preeclampsia was 7% in women w ith early-pregnancy proteinuria of less than 190 mg/day, 31% with prot einuria of 190-499 mg/day, and 38% with proteinuria of 500 mg/day or m ore. In the chronic-hypertension validation group, the rates were 0, 5 0, and 58%, respectively. By multiple logistic regression, the increas ed risk of preeclampsia with proteinuria above 190 mg/day persisted af ter controlling for the effects of parity, chronic hypertension, retin opathy, and glycemic control. Conclusions: Diabetic gravidas with earl y-pregnancy proteinuria of 190-499 mg/day are at increased risk for pr eeclampsia. The risk is comparable to that in women with overt diabeti c nephropathy and is independent of chronic hypertension. We speculate that diabetic women with proteinuria in this range have incipient or subclinical diabetic nephropathy.