Characteristics Related to Poor Glycemic Control in NIDDM Patients in Community Practice

OBJECTIVE To identify clinical characteristics related to poor glycemic control in patients with NIDDM cared for by Michigan primary care physicians.

RESEARCH DESIGN AND METHODS This study was a cross-sectional secondary analysis of data from 393 NIDDM patients (mean age, 63 ± 11 years; 54% female; 92% white) in the 1990–1991 Michigan Diabetes in Communities II Study. We evaluated patient demographic, clinical, and physiological characteristics, attitudes toward diabetes, and self-care ability. Logistic regression was used for multivariate evaluation of the characteristics of those patients whose glycosylated hemoglobin (normal GHb 4–8%) was in the upper 25% of the study sample (GHb > 11.6%).

RESULTS A high meal-stimulated plasma C-peptide was associated with a lower likelihood of poor control (odds ratio [OR] for highest quartile vs. all others = 0.37; 95% CI 0.23-0.58). Longer time since diagnosis (OR for each 5 years duration = 1.28; 95% CI 1.07-1.53), poor self-care ability (OR = 1.85; 95% CI 1.27-2.71), and perceived absence of dietary recommendations (OR = 2.37; 95% CI 1.11–5.08) were also independently associated with presence in the highest GHb quartile. Characteristics that were not significantly related to poor glycemic control included sex, age, obesity, educational level, exercise, self-rated health status, and pharmacological treatment.

CONCLUSIONS 1) Poor glycemic control may reflect progressive failure of islet function, although the independent relationships of C-peptide level and time since diagnosis are consistent with concepts of heterogeneous mechanisms underlying NIDDM. 2) Despite the important relationships of biological characteristics of NIDDM to glycemic control, patient attitudes and self-care ability may be useful targets for designing management strategies for certain poorly controlled patients.