With a continuing increase in OSA prevalence and limited access to PSG examination it is important to prioritize patients with a higher risk for the severe form of the disorder. Multiple scales and questionnaires have been created to screen patients for OSA and refer them for PSG examination. Two of the most popular tools include the STOP-BANG questionnaire [12
] and the recently developed NoSAS score [8
]. However, both scales include either numerous parameters, 8 in the STOP-BANG questionnaire and multiple scoring levels for parameters in NoSAS. Newly created BOAH scale is one of the simplest tools available with only 4 variables and only BMI with 2 different levels of scoring. Additionally, 3 remaining variables: observed apneas, age over 50, and history of hypertension are collectible at history taking, allowing for the calculation of BOAH score in a short time, making the tool more practical and convenient.
BOAH scale had greater diagnostic value compared to the STOP-BANG questionnaire in the meta-analysis, which at the optimal cutoff point of 5 for severe OSA had both specificity and sensitivity of 66% [13
]. This study is the second one to investigate the usefulness of the BOAH scale among sleep clinic patients. Previously, it was studied among 1135 patients, who underwent PSG examination in Sleep and Respiratory Disorders Centre (Lodz, Poland). In that study, the BOAH scale presented greater predictive values than the STOP-BANG questionnaire at the optimal cut-off points [9
]. As the aforementioned center deals exclusively with OSA patients, in the present study, the scale was evaluated in a center attending to various sleep disorders to verify its potential diagnostic value on a more heterogeneous patient group. The BOAH scale disclosed the highest AUC (0.78) for severe OSA, at a cutoff level of 4, high specificity (89%), PPV (75%), and NPV (78%). The BOAH scale has had similar AUC results to NoSAS for clinically significant OSA (compared to both: the original and validating cohort, 0.74 and 0.81, respectively) [8
], while having simpler scoring criteria suggesting it can be used as a robust tool for prioritizing patients with a high risk of severe OSA, for PSG examination. Furthermore, STOP-BANG meta-analysis [13
] shows that PPV of 97% for mild and 88% for moderate OSA is achieved for a score of 7 in this questionnaire, which directly corresponds to the predictive values obtained for the BOAH score of 4. This shows that BOAH scale has the same diagnostic values as STOP in mild and moderate OSA diagnoses. Additionally, with 99% sensitivity, BOAH score of 1 has 97% NPV for severe OSA with only one false negative, allowing for quick prioritization of patients for PSG examination, while the STOP-BANG for the same severity and sensitivity has NPV of 89% at the cutoff point of 2. The primary limitation of the study is the lack of direct comparison between STOP-BANG and BOAH scores in the study group. Unfortunately, less than 10% of individuals included in the analysis had information regarding their neck circumference, which is mandatory for STOP-BANG. This shows that a limited number of parameters in the scale are advantageous as it is more likely that necessary data will be collected. In this manner, it may be more friendly to use GPs assessing OSA risk before referral. Yet, in general, neck circumference is recorded for most patients while they are admitted to the sleep clinic, which might make this missing data a negligible problem. The relatively small size of the study group could be also considered as a limitation to the study. Nevertheless, obtained results for the BOAH scale were comparable to the original study on a larger group of patients [9
], which suggests that the examined group was representative.
BOAH scale is a valuable tool in OSA diagnosis and assessment of the risk of the disorder. It offers similar predictive values to other available tools while being shorter and easier in use. Therefore, it should be considered as a useful tool in clinical practice.