Association Of Obstructive Sleep Apnea and Type 2 Diabetes

The association of obstructive sleep apnea and type 2 diabetes may be bidirectional, and patients with type 2 diabetes may have a higher risk of developing obstructive sleep apnea (OSA);  what should you look out for?

OSA is a disease state that is highly underdiagnosed. OSA often coexists with other diseases and can lead to compilations, including death. While patients may not know when they are presenting with symptoms, it is important for healthcare professionals to be assessing for symptoms. In certain disease states, OSA has been described as a modifiable risk factor with proper diagnosis and treatment. Previous studies have found OSA to be a risk factor for the development of type 2 diabetes. In contrast, fewer studies have examined type 2 diabetes as a risk factor of OSA.

The study had 2 aims: the primary, to assess type 2 diabetes as a risk factor for incident OSA, OSA preceding diabetes diagnosis. Secondly, in patients with type 2 diabetes, determine predictors of incident OSA. A retrospective cohort study was performed, controlling for age, sex, and BMI. Data was taken from a U.K. database, The Health Improvement Network (THIN). The exposed group consisted of 360,250 patients with type 2 diabetes, and the unexposed group of patients without type 2 diabetes, 1,296,489. There was a 1:4 ratio between the exposed and unexposed groups: for every 1 patient with type 2 diabetes used in the exposed, 4 patients without type 2 diabetes were used in the unexposed. The study ran from 2005 through 2017, with a 15-month follow-up period.

Two Poisson regressions were used, one comparing the incidence of OSA in both cohorts, and the second, in patients only with type 2 diabetes, to assess for risk factors (20 were considered in this study). An exploratory analysis was performed in subgroups (age, sex, BMI) to compare the occurrence of OSA between patients with and without type 2 diabetes. From the analyses, two -sided P values were recorded.

OSA was developed in 3,110 patients with type 2 diabetes (0.88%), whereas only 5,968 of the control group developed OSA (0.46%). The calculated crude incidence rate ratio (IRR) of OSA in patients with or without type 2 diabetes was 1.76 (P < 0.001). Even after adjustment for confounders, the data was still considered statistically significant with an aIRR of 1.48 (P < 0.001). In the subgroups, from the exploratory analysis, patients with type 2 diabetes showed a significant increase in OSA incidence in all age groups, except those 16-29 years old. Furthermore, women showed a stronger association between diabetes and OSA aIRR [95% CI 1.62-1.91] compared to men aIRR 1.76 [1.32-1.46].

In patients with type 2 diabetes, of the 20 risk factors that were measured in the study, 11 were statistically foretelling of incident OSA with a P-value of < 0.05. These risk factors being:  male sex, overweight, or obese, previous smoker, diabetes-related foot disease, heart failure, ischemia heart disease, atrial fibrillation, hypertension, depression, and insulin therapy. Interestingly, in the patients with newly diagnosed type 2 diabetes, a sensitivity analysis was performed, with similar results in terms of risk factors, except being a previous smoker, atrial fibrillation, and insulin treatment were nonsignificant, but hypoglycemic event became statistically significant aIRR 2.06 (P = 0.004).

Based on the data obtained from the study, the authors determined, patients with type 2 diabetes, not including confounders, are at an increased risk of developing OSA by almost 50%. Those most at risk are the same as mentioned in the previous paragraph. These higher risk patients should be considered for OSA testing. This study was performed on a large sample size where the authors felt it was generalizable to the U.K. population. The 15-month follow-up period was done to decrease the chance of undiagnosed OSA, but the authors discussed this possibility cannot be completely ruled out, due to not being able to examine OSA at baseline. Knowing from previous studies that OSA is a risk factor for type 2 diabetes, this study gives further evidence to the bidirectional relationship. It is important to determine the effect of OSA treatment on diabetes-related outcomes, so future randomized controlled trials would be necessary.

Practice Pearls:

• The association between OSA and type 2 diabetes is proving to be bidirectional.
• Patients might not know if they are presenting with symptoms of OSA; symptoms should be checked for at visits specifically in patients with type 2 diabetes.
• OSA testing should be considered in patients with type 2 diabetes, also presenting with these risk factors: male sex, high BMI, diabetes-related foot disease, cardiovascular disease, hypertension, depression and insulin therapy.

Subramanian, Anuradhaa, et al. Risk of Incident Obstructive Sleep Apnea Among Patients With Type 2 Diabetes. Diabetes Care. 2019 May 1.

Emma Kammerer, L|E|C|O|M Bradenton School of Pharmacy, PharmD Candidate