The findings suggest that the benefits of CPAP adherence may translate beyond improving obstructive sleep apnea in older adults with mild cognitive impairment.
Kathy Richards, PhD, RN
Adherence to continuous positive airway pressure (CPAP) is associated with a significant improvement in cognitive function in older adults with mild cognitive impairment (MCI) and obstructive sleep apnea (OSA), according to results of the Memories 1 clinical trial.
Findings from the prospective study were presented at SLEEP 2019, June 8-12, in San Antonio, Texas.
Investigators led by Kathy Richards, PhD, RN, of the University of Texas at Austin, sought to determine whether CPAP adherence is predictive of cognitive and everyday function at 1 year in older adults with MCI. Notably, the trial (NCT01482351) was originally designed as a 6-month, double-blind, randomized, controlled pilot clinical trial evaluating active CPAP versus placebo, followed by a 6-month open-label period; however, after initial participant recruitment, no subjects consented to randomization.
Given that CPAP must be used with consistency for at least 4 hours per night for a therapeutic response, the investigators adjusted the trial design to evaluate 2 comparison groups: those with MCI, OSA, and who were CPAP-compliant, and those with MCI, OSA, and who were not CPAP-compliant.
Ultimately, 54 participants with MCI and OSA were included in the final analysis: CPAP-compliant (n=29) and CPAP non-compliant (n=25). Participants were aged 55 to 89, and had a apnea-hypopnea index of ≥10. Primary outcome measures included change from baseline to 6 months and 1 year on the Hopkins Verbal Learning Test-Revised, Digit Symbol Subtest, Mini Mental State Evaluation Exam, Stroop Color and Word Test, Psychomotor Vigilance Task, and Epworth Sleepiness Scale.
The investigators reported a significant improvement in the Digit Symbol Subtest in the MCI CPAP-compliant group versus the MCI CPAP non-compliant group after adjusting for age, race, and marital status (PE 1.68; SE 0.47; 95% CI, 0.73-2.62) with effect sizes of 0.46 and 1.25 at 6 months and 1 year, respectively. They also reported small to moderate effect sizes and a beneficial pattern of improvement across other domains of cognitive function, though these were not statistically significant. The investigators noted that statistical significance was likely not reached due to the small sample size and nature of the study.
“To our knowledge, Memories 1 is the first prospective clinical trial to show that CPAP adherence in older adults with MCI and apnea significantly improves cognitive function,” they concluded.
Given the positive results, the investigators have initiated Memories 2, a larger and more adequately powered study to both confirm and further extend the findings from the initial cohort.
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Richards K, Gooneratne N, DiCicco B, et al. Effect of CPAP adherence on cognition in older adults with mild cognitive impairment and obstructive sleep apnea. Presented at: SLEEP 2019. June 8-12, 2019; San Antonio, TX. Abstract 0538.