Reliability of the Polygraphic Home Sleep Test for OSA Determined by the Severity and Pattern Changes of Two Consecutive Examinations

Diagnosis and effective treatment of obstructive sleep apnea syndrome (OSA) in adults is an important health priority. Home respiratory polygraphy is a cost-effective alternative to polysomnography in OSA. The aim of this study was to investigate the variability of two consecutive home respiratory polygraphic examinations by comparing the severity characteristics and pattern (supine dominant, continuous, etc.) variability. We examined 100 patients with clinically suspected OSA on two consecutive nights by home respiratory polygraphy. The correlation of time in bed (TIB), apnea-hypopnea index (AHI), oxygen desaturation index (ODI), and T90 of the two examinations were compared by the Pearson test. The severity ranks and nocturnal apnea patterns of the two periods were compared using Spearman and Wilcoxon tests. Pearson's correlations represented a strong correlation of the AHI, ODI, and T90, but only moderate for TIB. The severity-specific correlation was the highest for AHI in the severe group. Out of 100 pairs of polygraphic examinations, 25 cases showed change in the severity ranking (decreased in 11, increased in 14); 15 cases showed a change in the polygraphic pattern (supine, non-supine, etc.), with severity change in 6 cases. Therapy change based on the second examination was initiated in 6 cases. Our results revealed a good intra-individual correlation between the severity grades of the two nights, with the highest value in the severe cases. In some cases, the nightly variation in the polygraphic pattern may explain the change in the severity. From a therapeutic point of view, the low number of severity changes between moderate and severe groups revealed good reliability.