PURPOSE: The International Classification of Sleep Disorders 2nd Edition (ICSD-2) defines obstructive sleep apnea (OSA) based on scoreable respiratory events which included apneas, hypopneas, and respiratory effort related arousals (RERAS) while Center for Medicare and Medicaid (CMS) uses apneas plus hypopneas. We hypothesize that CMS criteria may underdiagnose OSA because of exclusion of RERAS. We compared the impact of ICSD-2 versus CMS criteria on the diagnosis of OSA.
METHODS: We retrospectively compared the effect of using the ICSD-2 (RDI ≥ 15, AHI < 10) vs. CMS criteria (AHI between 15-30) to diagnose significant OSA on polysomnography (PSG) parameters, Epworth Sleepiness Scales (ESS), Pittsburgh Sleep Quality Index (PSQI), Fatigue Severity Scale (FSS) and prevalence of co-morbidities (hypertension, diabetes mellitus and depression) using Mann-Whitney U statistical method.
RESULTS: 100 consecutive patients with suspected OSA undergoing PSG, were analyzed. Comparison of patient groups (ICSD-2 vs. CMS group) did not reveal any significant difference in associated sleep efficiency, Stages I &II, Stage Delta, Stage REM or spontaneous arousals, suggesting comparable sleep disruption. The use of AHI was associated with a significantly lower mean SaO2 (83% AHI vs. 87% RDI). No significant difference was noted in the subjective measures of daytime functioning. Prevalence of hypertension was higher using the RDI (54% RDI vs. 27% in the AHI).
CONCLUSION: Inclusion of RERAs in the ICSD-2 criteria impacts classification of the severity of SDB. The AHI criteria, which exclude RERAS, tend to select patients with significantly worse nocturnal hypoxemia.
CLINICAL IMPLICATIONS: The CMS criteria for the diagnosis of OSA may underdiagnose patients with SDB and related co-morbidities, i.e., hypertension.
DISCLOSURE: Asif Anwar, No Financial Disclosure Information; No Product/Research Disclosure Information