Screening tools for obstructive sleep apnea in patients with systemic lupus erythematosus

Obstructive sleep apnea (OSA) seems to be an important comorbidity in systemic lupus erythematosus (SLE) but studies on prevalence have inconsistent results. Moreover, uncertainty exists as to the reliability of questionnaires that could predict who should be considered for sleep testing. We aimed to determine the prevalence OSA in SLE patients and in healthy controls, and to evaluate the performance of two widely used OSA screening tools (STOP-Bang; NoSAS). Selected patients underwent a home sleep apnea testing (HSAT), or type III polysomnography, using a portable ApneaLinkTM Air device (ResMed®), Martinsried, Germany. OSA was defined as apnea-hypopnea index ≥5 events/h. The probability of OSA was evaluated with two questionnaires: STOP-Bang and NoSAS. The ability of these questionnaries to diagnose apnea in SLE patients was analyzed with ROC curves, determining the area under the ROC curve (AUC-ROC) and the respective 95% confidence intervals. The final sample included 19 SLE patients (women: 89.5%; mean age: 35.6 ± 10.3 years; mean BMI: 27.87 ± 6.87 kg/m2) and 20 controls. The prevalence of OSA was 26.4% for SLE patients and 35% for controls (p = 0.360). OSA patients had higher BMI (p = 0.043). STOP-Bang scores were higher for patients with OSA than for patients without OSA (3 [2; 3] vs. 1 [0; 2], p = 0.001). The same was observed for NoSAS scores (7 [7; 9] vs. 2 [0; 3], p < 0.005). The area under the ROC curve (AUC) was greater for NoSAS than for STOP-Bang (0.957, 95%CI: 0.710–1.000, p = 0.003) vs. (0.914, 95%CI 0.786–1.000, p = 0.003), respectively. SLE patients and controls had a similar frequency of OSA in this study. Both OSA screening tools (NoSAS and STOP-Bang scores) detected OSA with reasonable accuracy in this population but at cut-offs lower than the usual.