Sleep Characteristics and Glycemic Control in Type 2 Diabetes

Background: The interrelation between sleep quality and diabetes mellitus (DM) is a double-edged sword, as on one hand DM adversely affects the sleep quality, and on the other hand prolonged periods of sleep disturbance significantly increase the risk of developing insulin resistance and thus increasing the prevalence of diabetes. Alteration in either sleep quality or quantity results in an increased prevalence of obesity, metabolic disorders, DM, cardiovascular diseases, and hypertension. Both shorter duration of sleep, that is <6 h, as well as longer duration of sleep, that is > 9 h, have been adversely related to increased insulin resistance in an individual. Aim: The aim of this study was to study the effect of sleep characteristics on glycemic control in type 2 diabetes. Materials and Methods: This is a cross-sectional study conducted at a tertiary care center. This study included 200 type 2 DM (T2DM) patients between age >18 year and <60 year. Hemoglobin A1c (HbA1c) was used to assess the glycemic control. The quality and quantity of sleep were assessed using the Pittsburgh Sleep Quality Index (PSQI) and daytime sleepiness by the Epworth Sleepiness Scale (ESS). Results: The study showed the prevalence of poor sleep quality with a PSQI score >5 is 81.5%, and for daytime sleepiness with an ESS score >10 is 63%. The HbA1c (%) ranged from 6.6 to 13 and mean HbA1c (%) was 8.68 (±1.26). Out of 200 T2DM, 36 (18.0%) of the participants had HbA1c <7.5, and 164 (82.0%) of the participants had HbA1c ≥7.5. There was a positive association between HbA1c and PSQI and ESS score. There is a statistically significant ( P ≤ 0.001) strong association between HbA1c and total PSQI with cut off of HbA1c (%) as ≥7.5% and PSQI score cut off >5 shows a sensitivity of 100%, and a specificity of 97% and with ESS cutoff >10 shows a sensitivity of 96%, and a specificity of 42% which indicate superiority of PSQI over ESS for assessing sleep quality in diabetes. Conclusion: A positive association is present between sleep quality and quantity with HbA1c level. So, these easily available, less time-consuming, bedside questionnaires can be used to assess sleep characteristics and help us to take timely measures for better glycemic control and delaying of diabetes related complication, which are potentially preventable by improving sleep patterns, which in turn improve quality of life.