LaFleur, Kelley

Abstract Introduction Sleep disturbance and circadian rhythm disruptions are common among adults with chronic heart failure (HF), and are related to cognitive impairment. Although light levels are known to influence sleep quality, cognition, and the circadian system, little is known about the role of light among adults with HF. The purpose of this study is to investigate the association between light exposure and sleep, diurnal rest-activity rhythms (RAR), and cognitive function among adults with HF. Methods We retrospectively analyzed baseline data from a randomized controlled trial of cognitive behavioral therapy for insomnia for adults with HF and insomnia. We measured light levels and sleep with 24-hour wrist actigraphy and computed the circadian quotient, inter-daily stability, and intra-daily variability (strength of the RAR) using cosinor and non-parametric methods. We computed time above threshold (TAT) (100, 500, and 1000 lux), ratio of light exposure in daytime to evening (AUC ratio), and light regularity index (LRI) (20, 50, and 100 lux) to assess the intensity and consistency of light exposure patterns. Lapses in performance on the Psychomotor Vigilance Task (PVT lapse) measured cognitive function. Multiple linear regressions tested if the light exposure metrics could predict the RAR, sleep efficiency, and PVT lapses after adjusting for age, sex, and comorbidities. Results The sample included 167 participants (M age=63.8 (SD =12.9) years; 45.5%female). The AUC ratio and TAT500 were associated with a stronger circadian quotient in males (0.339 ± 0.095, p=.0005; 0.296 ± 0.085, p=.0006) compared to females (0.058 ± 0.106, p=.5800; -0.061 ± 0.128, p=.6364), after controlling for age and comorbidities. TAT500 was associated with better inter-daily stability (0.221 ± 0.077, p=.0044) than the other thresholds. Higher light exposure intensity (TAT100) (0.129 ± 0.065, p=.0492) and a greater circadian quotient (0.267±0.076, p=.0006) were associated with improved sleep efficiency. TAT100 was associated with fewer PVT lapses (-0.229 ± 0.082, p=.0061), after controlling for total sleep time, circadian quotient, and demographics. Conclusion Light exposure, particularly at certain intensities and regularity, predicted RARs, sleep efficiency, and cognitive function in adults with HF. Future tailored light interventions with varying intensities and regularity may improve HF outcomes. Support (if any)

Abstract Introduction Sleep disordered breathing (SDB: obstructive & central sleep apnea) and insomnia are common in heart failure (HF). However, most studies have not addressed the presence of combined SDB and insomnia (COMISA). The purposes of this study were to (1) describe COMISA among adults with stable chronic HF; (2) compare the clinical and demographic characteristics between groups with COMISA, insomnia, SDB, and normal sleep; and (3) examine the risk of COMISA in the presence of normal sleep, insomnia, SDB and other clinical and demographic characteristics. Methods Secondary analysis of an observational study of sleep among adults with stable HF. COMISA was defined as an apnea hypopnea index (AHI) > 15 with difficulty initiating or maintaining sleep or waking too early in the morning (Insomnia). We measured self-reported (Pittsburgh Sleep Quality Index) and objective sleep characteristics (polysomnography – PSG), symptoms (depression, sleepiness); used chi-square and ANOVA; and calculated the risks of COMISA for normal sleepers and with insomnia or SDB under different conditions (depression, poor sleep quality, left ventricular ejection fraction, age, race, and sex). Results The sample included 170 [(M age = 60.3 ± 16.8 years; n = 60 (35%] female. They had normal sleep (n = 37/22%); insomnia only (n = 48/28%): SDB only (n = 46/27%); and COMISA (n = 39/23%). Those with COMISA were significantly more likely to be obese (32.1%) compared to others [13.6% -29.6%, p = 0.0128]. They had the shortest total sleep time (TST) (mean = 291 ± 109 mins) and poorest sleep efficiency (M = 65.8 ± 20.5%) (p = .05). Women with insomnia were less likely to have COMISA than men (36% vs. 51%), while 74% of adults with SDB who were depressed had COMISA, compared with 41% of those with insomnia. Conclusion Risk of COMISA is associated with depression and poor sleep among adults with stable HF and SDB. Future study is needed to better understand the risks of COMISA among adults with chronic HF outcomes and to address the need for intervention that addresses it beyond a focus on only SDB or insomnia. Support (if any)