How patients with diabetes perceive their risk for major complications.

CONTEXT To educate patients with diabetes about their illness and to motivate these patients to pursue intensive treatment, physicians often inform them about their risk for serious complications. However, little is known about patient perceptions of these risks. OBJECTIVE To compare patient perceptions of risk for major complications of diabetes with actual risk for these complications. DESIGN Structured interviews were done to obtain the patient's estimate of their risk for complications. To generate estimates of actual risk for each patient, we used a simulation model based on the Diabetes Control and Complications Trial (DCCT). SETTING Four university-affiliated diabetes clinics in the midwestern United States. PATIENTS 139 patients with type 1 diabetes mellitus. MAIN OUTCOME MEASURES Probability of blindness, end-stage renal disease (ESRD), and lower-leg amputation over 20 years. RESULTS Participants were young (mean age, 30 years) and reported having had diabetes for an average of 15 years. Seventy-nine percent reported their current diabetic therapy to be "intensive." Ninety-eight percent had completed high school, and 51% were college graduates. The patients' estimates of their risks far exceeded the DCCT estimates for all three complications. The mean patient estimate of the risk for blindness was 31.6% (DCCT estimate, 17.0%), of the risk for ESRD was 33.7% (DCCT estimate, 8.7%), and of the risk for amputation was 25.1% (DCCT estimate, 1.9%). Similarly, patients overestimated the benefit of intensive therapy. They estimated, on average, that intensive therapy would result in a 17.0% absolute risk reduction for blindness (DCCT estimate, 12.2%), an 18.1% risk reduction for ESRD (DCCT estimate, 7.0%), and a 14.2% risk reduction for amputation (DCCT estimate, 1.2%). CONCLUSION Patients with diabetes overestimated their risk for major complications and the benefits of intensive treatment.