The utility of various predictive equations in patients with severe Obstructive Sleep Apnea: a clinical practice viewpoint in settings with limited resources

The continuous positive airway pressure (CPAP) needed for the treatment of obstructive sleep apnea (OSA) can be determined after a manual titration study which is often expensive and time consuming. Hence, different predictive equations were suggested to simplify the treatment of OSA. The purpose of this work was to compare the CPAP identified with manual titration with that calculated using various equations in a cohort of patients with severe OSA. This work was conducted on patients diagnosed with severe OSA. Data collected included full medical history, demographic and anthropometric measures, polysomnography results, and the CPAP pressure obtained after manual titration which was further compared to 15 predictive equations retrieved from the literature. A total of 166 patients [137 (82.5%) males and 29 (17.5%) females] with severe OSA were recruited in the study. Their mean age was 55.91 ± 12.64, and their baseline diagnostic apnea hypopnea index was 71.75 ± 23.70. The mean CPAP manual titration pressure was 11.31 ± 2.9 cmH2O. Non-significant statistical difference was found (p > 0.05) when the mean titration pressure was calculated by Eqs. 2 (11.36 ± 2), 3 (11.55 ± 1.68), 10 (11.51 ± 2.29), 11 (11.14 ± 2.04), and 14 (11.71 ± 2.06), whereas the mean titration pressure calculated by Eqs. 1, 4, 5, 6, 7, 8, 9, 12, 13, and 15 differed significantly from the manual titration pressure (p < 0.05). Predictive equations suggested to calculate CPAP pressure, albeit simple and easy to apply, yielded variable results and should be investigated carefully before their use into clinical practice.