Interpreting, Integrating, and Individualizing Evidence about the Prevention of Diabetic Nephropathy

Policy-relevant research for the care of patients with diabetes mellitus is in high demand, given the prevalence, morbidity, and costs associated with this condition. Randomized trials, meta-analyses, and economic studies have evaluated myriad management strategies directed at the diagnosis, prevention, and treatment of the macrovascular and microvascular sequelae of diabetes. Accordingly, diabetes mellitus is an ideal condition for evidence-based disease management (1, 2).

A decision analysis reported in this issue focuses on prevention of diabetic nephropathy [3]. Golan and colleagues address this question: In patients with newly diagnosed type 2 diabetes mellitus, what is the relative impact on quality-adjusted life expectancy and costs associated with 1) treating all patients with angiotensin-converting enzyme [ACE] inhibitors, 2) screening for microalbuminuria and treating with ACE inhibitors when it develops, or 3) screening and treating only for gross proteinuria?

Where should we look for evidence to answer such questions? Increasingly, randomized trials are furnishing information on the consequences of different screening strategies for such conditions as hypertension, hypercholesterolemia, and breast cancer (4). A randomized trial in which patients are assigned to one of these three strategies would tell us what does happen under each alternative. If follow-up is complete, the trial is more likely to be unbiased; if the sample is large, its estimates will be more precise. If adherence of caregivers and patients with the protocol is high, the results will apply under “ideal conditions.” If adherence is low, the results may better reflect “real world conditions.” However, …