PERFORMANCE OF SIX SCREENING SCORES FOR OBSTRUCTIVE SLEEP APNOEA IN AN AFRICAN POPULATION

Abstract

Introduction: A screening tool for obstructive sleep apnoea (OSA) is useful in low-income countries where it may be difficult to access sleep recordings. The objective of this study was to assess the performance of six screening scores compared with objective sleep recording in an African population sample.

Methods: This analysis is based on the "Benin Sleep and Society" (BeSAS) populational study in which respiratory polygraphy (PG) was performed using a type III device and OSA screening questionnaires (STOP, STOP-Bang, Berlin, NOSAS [≥ 8 and ≥ 5), No-Apnea, GOAL) were administered to participants. PG-defined OSA severity categories were defined according to the apnoea-hypopnoea index (AHI): mild (AHI 5 to <15/h), moderate (AHI 15 to <30/h) or severe (AHI≥30/h), and these were compared to score findings.

Results: A total of 1810 subjects (mean age 45.4±14.6 years; 57.3% women) were included. For moderate to severe OSA, the area under the receiving operating characteristic (ROC) curve was greatest for GOAL and No-Apnea (0.70), followed by NoSAS5 (0.69). The highest sensitivity values were for NoSAS5 (0.73), No-Apnea (0.72), and GOAL (0.69), while NoSAS8 had the highest specificity (0.91), followed by Berlin (0.88) and GOAL (0.71). All scores performed poorly with respect to the positive predictive value (PPV), which was highest with NoSAS8 (0.38). Conclusion: This study provides the first comparison of the performance of screening scores for OSA in an African population. Although still low, PPV was highest with NoSAS8. Hence, NoSAS8 would be the screening method of choice for OSA in resource-constrained settings where formal sleep recordings are not accessible.

Keywords: Africa; Diagnosis; Obstructive sleep apnoea; Sleep questionnaire; sleep-disordered breathing.