Abstract Introduction Obstructive sleep apnea (OSA) prevalence approaches 60% in older adults with mild cognitive impairment (MCI). The primary aim of this quasi-experimental clinical trial, “Changing the Trajectory of Mild Cognitive Impairment with CPAP Treatment of Obstructive Sleep Apnea”, was to determine the effect of CPAP adherence on cognitive function over 1 year. Methods Study inclusion criteria: Age 55-85, and amnestic MCI based on established testing criteria. Those who chose to try CPAP received a tailored telehealth CPAP adherence intervention and those who chose not to try CPAP received a telehealth attention control intervention. Participants were divided into a CPAP-adherent group ( = 4 hours use per night) or a CPAP-non-adherent group ( 4 hours use per night). The pre-specified primary cognitive outcome was psychomotor/cognitive processing speed as measured by the Digit Symbol Coding (DSC) test. Percent change at 6 and 12 months from baseline were compared. The CPAP adherent and non-adherent groups were compared using propensity score-weighted linear regression analysis. Results At 12 months, 116 (63.0%) were CPAP adherent and 68 (37.0%) were not. Mean age was 67.3 years (sd. 7.5); 55.4% were male; 71.2% were White persons, and 7.1% were of Hispanic ethnicity. Mean AHI was 33.4 (sd. 20.7). At 6 months, the percent change from baseline in psychomotor/cognitive processing speed in the CPAP adherent group was 7.83% greater than the CPAP non-adherent group (95% C.I.: 2.50, 13.16, p=0.004). At 12 months, group differences were not statistically significant. Adherent participants with less cognitive impairment Clinical Dementia Rating (CDR) score = 0) at baseline had a 15.7% improvement in DSC at 6 months relative to the CPAP non-adherent group (p .05). Adherent participants with a baseline CDR = 0.5 (indicative of greater cognitive impairment) had a 7.75% improvement in psychomotor/cognitive processing speed relative to the CPAP non-adherent group (p 0.05). Conclusion In older adults with MCI and moderate-severe OSA, the CPAP adherent group, compared to CPAP non-adherent group, had significantly better psychomotor/cognitive processing speed at 6 months, but not at one year. Participants with less severe baseline cognitive impairment demonstrated the largest gains in cognitive performance. Support (if any) R01AG054435
Gooneratne et al. (Fri,) studied this question.