At baseline, the disturbed-sleep group reported mainly insomnia-related symptoms, including difficulty falling asleep (43.2%), waking often at night (90.8%), restless sleep (74.2%), and waking up early (62.3%). At follow-up, improvements in the frequency of insomnia-related symptoms ranged from 0.28 to 1.25 points, and Epworth Sleepiness Scale scores fell significantly (−2.06; 95% CI, −2.64 to −1.48). Reductions in the proportion of patients with insomnia symptoms ranged from 13.1% (OR, 0.35; 95% CI, 0.20-0.59) for difficulty falling asleep to 39.0% (OR, 0.08; 95% CI, 0.04-0.14) for restless sleep, Dr. Pien and her colleagues reported.
The results “demonstrate that although symptoms improved overall among each of the three clinical phenotypes of moderate to severe OSA, patterns of treatment response … varied based on initial clinical presentation,” the authors wrote. “Our findings underscore the need to consider initial OSA phenotype when designing future trials.”
In the second study, also published in Sleep, investigators confirmed the three clinical OSA subtypes previously identified in the Icelandic Sleep Apnea Cohort. In analysis of an international sample, they also expanded these clusters to include two additional disease subtypes. One of these subtypes consisted of patients with symptoms dominated by indications of upper airway obstruction. The other new subtype, sleepiness dominant OSA, included patients who had excessive sleepiness but no symptoms of upper airway obstruction.
The study authors performed a cluster analysis using data from 972 patients from the Sleep Apnea Global Interdisciplinary Consortium with moderate to severe OSA, with 215 of these patients being from Iceland.