Modified scoring criteria to improve the accuracy of the home sleep apnea test

The Home Sleep Apnea Test (HSAT) has good diagnostic performance for patients with a high pretest probability of moderate to severe obstructive sleep apnea (OSA). However, the false negative rate has been reported as high as 17%. Therefore, the American Academy of Sleep Medicine (AASM) recommends polysomnography (PSG) after a nondiagnostic HSAT (apnea-hypopnea index (AHI) < 5/hr). Our objective was to improve the accuracy of HSATs by using hyperpneas as a surrogate for arousals.

A retrospective analysis was conducted on patients with non-diagnostic Type 3 HSATs with subsequent PSG. HSATs were re-scored using the AASM recommended hypopnea scoring including using post-hypopnea hyperpneas without relative desaturations as a surrogate for cortical arousals. The new AHI was then compared with the gold-standard PSG.

We identified 68 patients (80.9% male) with a non-diagnostic HSAT and subsequent PSG. 38 patients (55.9%) had an AHI ≥ 5 on PSG. By applying our modified HSAT criteria, 41 (60.2%) of the previously non-diagnostic HSATs had an AHI ≥ 5. The mean difference in AHI between the modified HSAT criteria and PSG was 3.7/hr, compared to 5.9/hr between the original HSAT and PSG. The overall concordance between the modified HSAT criteria and PSG for OSA diagnosis was 89.7% compared to only 44.1% of the original HSATs.

Incorporating a surrogate indicator of a cortical arousal such as a hyperpnea can improve the diagnostic accuracy of the HSAT. Our modified HSAT scoring criteria improved AHI concordance with PSG with fewer false negatives (5%), thereby decreasing the need for repeat testing and saving costs.