Recruitment, Randomization, and Baseline Characteristics of the Treatment Groups

The general and ophthalmologic eligibility criteria were applied in the course of formal screening of selected members of clinic populations at the six treatment centers between August 1980 and November 1981. Patients eligible on the grounds of the history and general physical examination underwent a detailed ophthalmologic examination and determination of C-peptide status. Initial rates of recruitment were slow, which occasioned modifications of the eligibility criteria and a prolongation of the recruitment phase. All six clinics approached their goal of at least six patients in each of the continuous subcutaneous insulin infusion (CSII) and conventional insulin treatment (CIT) groups, with a final total of 70 randomized subjects. The method of paired randomization was acceptable, but led to some delay during periods of slow recruitment activity. Data from two patients who chose to drop out of the study shortly after randomization are included in the baseline characteristics. There was no difference between treatment groups with respect to age or duration of known diabetes, body weight, systolic blood pressure, proportion of cigarette smokers, retinopathy level as assigned by analysis of stereofundus photographs, or microaneurysm counts performed on fluorescein angiograms. A trend toward milder retinopathy in the CIT group proved to be statistically insignificant. Subsequent assessment of stereofundus photographs at the Fundus Photograph Reading Center indicated that six patients were misclassified by treatment center ophthalmologists with respect to ophthalmologic eligibility. We conclude that recruitment goals were met and randomization was successful.