This study examined whether individuals with insomnia and objective short sleep duration <6h, a subgroup with greater risks of adverse health outcomes, differ in their response to cognitive behavioral therapy for insomnia (CBT-I) when compared to individuals with insomnia and normal sleep duration >6h.Secondary analyses of a randomized, clinical trial with 60 adults participants (n=31 women) from a single academic medical center. Outpatient treatment lasted 8 weeks, with a final follow-up conducted at 6 months. Mixed-effects models controlling for age, sex, CBT-I treatment group assignment, and treatment provider examined sleep parameters gathered via actigraphy, sleep diaries, and an Insomnia Symptom Questionnaire (ISQ) across the treatment and follow-up period.Six months post-CBT-I treatment, individuals with insomnia and normal sleep duration >6h fared significantly better on clinical improvement milestones than did those with insomnia and short sleep duration <6h. Specifically, individuals with insomnia and normal sleep duration had significantly higher insomnia remission [ISQ<36.5; X2(1, N=60) =44.72, P<.0001], more normative sleep efficiency on actigraphy [SE>80%; X2(1, N=60) =21, P<.0001], normal level of MWASO <31 minutes [X2(1, N=60) =37.85, P<.0001], and a >50% decline in MWASO [X2(1, N=60) =60, P<.0001] compared to individuals with insomnia and short sleep duration. Additionally, those with insomnia and normal sleep duration had more success decreasing their TWT at the 6-month follow-up compared to those with insomnia and short sleep duration [X2(2, N=60) =44.1, P<.0001]. Receiver operating characteristic curve analysis found that using a 6-h cutoff with actigraphy provided a 95.7% sensitivity and 91.9% specificity for determining insomnia remission, with the area under the curve = 0.986.Findings suggest that individuals with insomnia and objective short sleep duration <6h are significantly less responsive to CBT-I than those with insomnia and normal sleep duration >6h. Using an actigraphy TST cutoff of 6 hours to classify sleep duration groups was highly accurate and provided good discriminant value for determining insomnia remission.

Study objectives

To examine the relationship between hypertension prevalence in individuals with insomnia who have short total sleep duration < 6 h or sleep duration ≥ 6 h, using both objective and subjective measures of total sleep duration.

Methods

Using a cross-sectional, observational design, 255 adult volunteers (n = 165 women; 64.7%) meeting current diagnostic criteria for insomnia disorder (MAge = 46.2 y, SDAge = 13.7 y) participated in this study at two large university medical centers. Two nights of polysomnography, 2 w of sleep diaries, questionnaires focused on sleep, medical, psychological, and health history, including presence/absence of hypertension were collected. Logistic regressions assessed the odds ratios of hypertension among persons with insomnia with short sleep duration < 6 h compared to persons with insomnia with a sleep duration ≥ 6 h, measured both objectively and subjectively.

Results

Consistent with previous studies using objective total sleep duration, individuals with insomnia and short sleep duration < 6 h were associated with a 3.59 increased risk of reporting hypertension as a current medical problem as compared to individuals with insomnia with sleep duration ≥ 6 h. Increased risk for hypertension was independent of major confounding factors frequently associated with insomnia or hypertension. No significant risk was observed using subjectively determined total sleep time groups. Receiver operating characteristic curve analysis found that the best balance of sensitivity and specificity using subjective total sleep time was at a 6-h cutoff, but the area under the receiver operating characteristic curve showed low accuracy and did not have good discriminant value.

Conclusions

Objectively measured short sleep duration increased the odds of reporting hypertension more than threefold after adjusting for potential confounders; this relationship was not significant for subjectively measured sleep duration. This research supports emerging evidence that insomnia with objective short sleep duration is associated with an increased risk of comorbid hypertension.