According to the International Diabetes Federation (IDF), diabetes has reached epidemic proportions in many developing economies such as India which has about 77 million individuals who are diagnosed with type 2 diabetes (T2DM).1 This trend is expected to grow with population growth and ageing reaching about 134 million people with T2DM by 2045 constituting to be among the top three countries with the highest burden of diabetes.2

Obstructive sleep apnea (OSA) is a common form of disordered breathing characterized by inconsistent, partial, or total obstruction of the upper airways leading to periodic desaturation of hemoglobin oxygen during sleep and persistent agitation during sleep.3 The condition results in variations in intrathoracic pressure and intermittent decreases or stops in airflow, which can lead to hypoxia, hypercapnia, and repeated awakenings from sleep.4 Because of inadequate sleep quality, individuals with OSA encounter daytime fatigue, drowsiness, functional limitations, and a general decline in their quality of life.3 Findings from recent literature estimated that OSA impacts almost 1 billion individuals between the ages of 30-69 years worldwide.5 In India, the prevalence of OSA is based on several cross-sectional studies across various geographies and varies widely between 23.7% to 95% based on study population, methods, and criteria used for diagnosis.6 An increasing amount of research indicates a reciprocal relationship between OSA7 and T2DM, both of which are significant risk precursors for cardiovascular diseases.89 Patients with T2DM have a notably high prevalence of OSA (23%–86%).1011 Results from a recent meta-analysis reported that the prevalence of OSA in T2DM patients was 56%. Furthermore, the prevalence of both conditions increases with age, male sex, and body mass index (BMI).12 Insufficient sleep and disruptions in circadian rhythm have recently been identified as potential contributors to insulin resistance (IR) and the onset of impaired glucose tolerance and T2DM.13 Unrecognized or poorly managed OSA in individuals with T2DM is linked to an increased risk of both microvascular and macrovascular complications, such as peripheral arterial diseases, nephropathy, retinopathy, and neuropathy. Despite these risks, OSA often goes undiagnosed and untreated among T2DM patients, mainly due to a lack of awareness among both the general public and healthcare providers.1314 Guidelines from the IDF and the American Diabetes Association (ADA) recommend routine screening for OSA in all adults diagnosed with T2DM to mitigate the associated diabetes-related complications.15 Overnight polysomnography is the gold standard test used to diagnose OSA. However, this diagnostic test is costly, laborious, and time consuming which limits the use of this test specifically in resource challenged economies and specific populations such as elderly patients.16 Owing to the drawbacks of polysomnography, other easy to use and cost-efficient methods have been developed to screen patients for OSA.17 Among these, the STOP- BANG questionnaire which measures snoring, tiredness, observed apnea, high blood pressure, BMI, age, neck circumference and gender (STOP-BANG) is an easy-to-use, efficient, inexpensive, valid, and reliable alternative screening tool, for OSA.18 As there is limited data on the presence of OSA in T2DM patients, the main goal of this cross-sectional study was to estimate the risk and severity of OSA in T2DM patients using a digital mobile friendly app which included the STOP-BANG questionnaire.

The results from this study, utilizing an app-based STOP-BANG questionnaire, indicate a high OSA risk among T2DM patients, significantly influenced by elevated BMI, HbA1c, and systolic blood pressure. The frequent occurrence of comorbid conditions such as obesity, hypertension, and dyslipidemia emphasize the metabolic interplay between T2DM and OSA. Furthermore, the trend of increasing OSA risk with prolonged diabetes duration highlights the importance of sustained preventive care in T2DM management. Advanced age, particularly in patients over 50, was strongly associated with OSA risk, likely due to physiological aging effects that heighten susceptibility to sleep disturbances. These insights underscore the need for age-specific, long term screening and management strategies to enhance outcome for T2DM patients at high risk of OSA.

The findings of our study can be compared with results from other published literature. A research undertaken by Algeffari et al. in 201 T2DM patients employing the Berlin questionnaire to assess the OSA risk found that 44.3% patients were identified as having high likelihood of developing OSA.22 The study also documented that higher BMI (OR=3.9; 95% CI=1.4, 7.8, p= <0.001) and longer duration since diagnosis of diabetes (OR=3.1; 95% CI =1.3, 7.8, p= 0.837) were associated with an increased OSA risk. These results align with our findings suggesting that longer duration of diabetes and a high BMI may have a significant influence on elevating the risk of OSA in T2DM patients. Another study conducted in Iran, included a sample of 4,021 participants, with 239 diabetic patients utilized the STOP-BANG questionnaire.23 This study revealed that 78.6% of the diabetic patients were classified as high risk for developing OSA, in contrast to 35.1% of participants without diabetes. Another cross-sectional study conducted by Shnaimer et al. at the Armed Forces Hospital in Jazan involving 306 T2DM patients-revealed that the median score of the OSA risk level assessed by the STOP- BANG items was 3 on a scale of 0 to 8, of which 63.1% of the participants were classified as being at high risk of developing OSA.24 Furthermore, a meta-analysis and systematic review conducted by Fallahi et al. assessed the OSA prevalence among 2,360 Iranian patients with diabetes.25 Their analysis revealed an overall OSA prevalence of 54.5% in T2DM patients with a higher prevalence observed among females (66.22%) compared to males (63.26%). These findings are like the findings from our study. Comparisons with other published literature underscores the consistency of our findings regarding the effect of high BMI and longer diabetes duration on increasing the OSA risk in T2DM patients.

Finally, it is important to note that several studies have validated the use of the STOP-BANG score as a tool for OSA screening. For example, in a study by Chung et alwith 310 obese Canadian patients found that a STOP-Bang score of 4 had high sensitivity (87.5%) and had high negative predictive value (90.5%) for identifying severe OSA.26 In another study conducted in the Korean population, Kim et al. reported that the STOP-Bang questionnaire had high sensitivity (97% for AHI ≥ 5/h and 98% for AHI ≥ 15/h) for OSA screening in those with suspected OSA.27 These findings combined with our current results strongly support the notion that the STOP-Bang questionnaire is a useful tool for OSA screening in different populations. We would also like to emphasize that using the EQUIP app enabled us to reach a larger pool of patients, eased data collection process in outpatient clinics, and improved accuracy of data by reducing missing data as well as data entry errors.

Future efforts should focus on raising awareness among clinicians and patients about the importance of diagnosing OSA and its connection to T2DM and related complications. OSA is a significant risk factor for cardiovascular and renal disease specifically in patients with T2DM, yet many cases remain undiagnosed due to lack of symptoms. With rising age and obesity, routine screening is essential to reduce the health and economic burden of OSA. Integrating user-friendly digital OSA screening tools into routine clinical practice can enhance early detection and improve patient outcomes for T2DM patients. Future studies should focus on treatment and long-term follow-up in these patients to evaluate the benefits of diagnosing OSA.

The study's limitations encompass the absence of polysomnography, considered the gold standard confirmatory test for diagnosing OSA. Nevertheless, the STOP-BANG questionnaire's high sensitivity and specificity render it a commendable screening tool for OSA. Furthermore, due to the study's cross-sectional design, the evaluation of OSA risk's impact on diabetes control and outcomes was not explored. Also, the study did not have a control arm (i.e. participants with no T2DM) to assess the risk of OSA and was conducted in India thereby limiting the generalizability of its results to the geography. Lastly, the study did not assess hypothyroidism, a secondary cause of OSA, within the recruited sample.

This pan-India survey highlights the significant association between T2DM and OSA risk, underscoring the urgent need for early screening and intervention. Identifying at-risk individuals facilitates timely management of OSA and related comorbidities such as obesity, hypertension, and other cardiovascular disease, ultimately enhancing patient outcomes. A multidisciplinary approach that integrates sleep health assessments into diabetes care is essential for addressing the complex interplay between these conditions. Such an approach can improve the quality of life for individuals with T2DM by mitigating the adverse effects of OSA and associated health issues. In conclusion, the STOP-Bang questionnaire has demonstrated high sensitivity for OSA screening and severity assessment among diabetic patients, thereby supporting its use as a potentially important screening tool for early identification of OSA.