Effect of intensive therapy on early macrovascular disease in young individuals with type 1 diabetes - A systematic review and meta-analysis

OBJECTIVE - We conducted a systematic review of randomized controlled trial s (RCTs) of intensive insulin therapy (IIT) in type 1 diabetes to determine the effect on macrovascular complications, RESEARCH DESIGN AND METHODS - MEDLINE (1966-1996), Citation Index, referenc e lists, and personal files were used to identify RCTs of >2 years' duratio n comparing IIT to conventional therapy (CT) in type 1 diabetes. Two indepe ndent reviewers applied selection criteria and identified 11 studies; 5 wer e subsequently excluded because no data were available for macrovascular co mplications. Data were extracted on macrovascular disease and cardiovascula r risk factors, Macrovascular disease was defined as angina, myocardial inf arction, angioplasty, coronary artery bypass graft, stroke, claudication, o r peripheral bypass, The first event of each type was counted. RESULTS - IIT decreased the number of macrovascular events (odds ratio [OR] 0.55, [95% CI 0.35-0.88], P = 0.015) but had no significant effect on the number of patients developing macrovascular disease (OR 0.72, [95% CI 0.44- 1.17],P = 0.22) or on macrovascular mortality (OR 0.91, [95% CI 0.31-2.65], P = 0.93). CONCLUSIONS - IIT decreases the extent of early macrovascular disease in yo ung individuals with type 1 diabetes but has no effect on the number of pat ients affected or on macrovascular mortality. These data suggest that IIT m ay stabilize macrovascular disease or prevent progression in those at risk.