Apnea-hypopnea index during rapid eye movement (REM) sleep is independently associated with diabetic retinopathy in patients with type 2 diabetes (T2D), according to study results published in The Journal of Clinical Endocrinology & Metabolism.
To evaluate the association between diabetic retinopathy and apnea-hypopnea index during REM sleep, researchers conducted a study in which 131 patients with T2D (average age, 57.5 ± 11.8 years) underwent in-hospital, all-night polysomnography with at least 30 minutes of REM sleep. Participants, required to be free of heart failure, active lung disease, and prior treatment for obstructive sleep apnea, were categorized into 1 of 4 groups according to quartiles of apnea-hypopnea index during REM sleep.
Median apnea-hypopnea index scores during REM sleep for Q1 to Q4 were, respectively, 13.9, 28.9, 45.8, and 63.2. There were significant differences between quartiles in several measurements, including diabetic retinopathy, body mass index, apnea-hypopnea index, and arterial oxyhemoglobin saturation.
Adjusting for factors such as age, sex, smoking status, T2D duration, and use of sleep pills, the researchers discovered that 3 variables were significantly and independently associated with diabetic retinopathy: quartile of apnea-hypopnea index during REM sleep (P =.024), T2D duration (odds ratio, 7.232; P <.001), and mean blood pressure (odds ratio, 1.043; P =.028).
Compared with Q1, each successive quartile of apnea-hypopnea index during REM had significantly higher odds of diabetic retinopathy (odds ratios: Q2, 3.887; Q3, 9.467; Q4, 12.898). There was not, however, an association between diabetic retinopathy and quartile of apnea-hypopnea index during non-REM sleep (P =.119).
Furthermore, after controlling for common risk factors, the researchers discovered that continuous apnea-hypopnea index was independently associated with diabetic retinopathy (P =.043).
Several limitations were noted for this study, including its cross-sectional nature and small sample size.
Summarizing their findings, the researchers concluded that evaluation of apnea-hypopnea index during REM sleep or lowest arterial oxyhemoglobin saturation, rather than categorical apnea-hypopnea index, may be necessary to understand the effects of obstructive sleep apnea on diabetic retinopathy.
Nishimura A, Kasai T, Kikuno S, et al. Apnea hypopnea index during rapid eye movement sleep with diabetic retinopathy in patients with type 2 diabetes [published online January 11, 2019]. J Clin Endocrinol Metab. doi:10.1210/jc.2018-00946