Longitudinal study of a diabetes education and care intervention: predictors of improved glycemic control.

BACKGROUND This study prospectively identifies those characteristics of office patients with diabetes that predict subsequent improvement in glycemic control in response to an educational intervention. METHODS Data on demographic factors, disease characteristics, and glycemic control were obtained on a consecutive series of patients referred by their primary physician to a 4-day outpatient diabetes education and care program. Follow-up measurement of glycosylated hemoglobin (HbA1C) was obtained from the same laboratory 2 months later. Analysis using logistic response models identified baseline characteristics associated with improved HbA1C. RESULTS Among the 169 study subjects, 74 (44 percent) had at least a 20 percent improvement in HbA1C levels 2 months after the program. Among these subjects, mean HbA1C level was 10.6 percent before and 7.4 percent 2 months after the program. Factors associated with improvement in HbA1C values in bivariate and multivariate logistic models included duration of diabetes less than 2 years (risk ratio = 1.90, 95 percent confidence interval (CI) 1.30-2.76) and initial HbA1C level greater than 10 percent (risk ratio = 2.75, 95 percent CI 2.08-4.01). Baseline functional status, health locus of control, social support, knowledge of diabetes self-care, age, weight as percentage of ideal body weight, age at diagnosis, race, sex, family history of diabetes, type of diabetes, and mode of treatment were not significant predictors of improved HbA1C. CONCLUSIONS Patients with shorter duration of diabetes and poor baseline glycemic control were most likely to have clinically significant glycemic responses to this program. Severity of disease and regression to the mean were unable to account for this association, leaving unanswered the question of the mechanism of this association. The data also identified a group of patients who do not respond well to this educational approach and for whom novel approaches to behavior change should be considered.