The association between rest-activity parameters and hemoglobin A1c in patients with prediabetes.

Circadian abnormalities can adversely affect glucose metabolism. This study determined whether behavioral circadian parameters, as assessed by rest-activity rhythm, were predictors of glycemic control in patients with prediabetes. Seventy-nine patients with prediabetes participated. Nonparametric rest-activity rhythm parameters, sleep duration and efficiency were obtained from 7-d actigraphy recordings. Sleep-disordered breathing severity was assessed using a home sleep apnea test. Hemoglobin A1c (HbA1c) was obtained to evaluate glycemic control. The results revealed that shorter sleep duration, lower relative amplitude and higher L5 (average activity of the least active 5-h period) were associated with higher HbA1c, while other sleep variables were not related to HbA1c. Multiple stepwise regression analysis adjusting for age, sex, body mass index and sleep duration revealed that lower relative amplitude, but not L5, was independently associated with higher HbA1c (B = -0.027, p = 0.031). In summary, among patients with prediabetes, an abnormal circadian rhythm was associated with higher HbA1c, implying a greater risk of developing diabetes. These results support the role of circadian rhythmicity in glucose control among those with prediabetes.