Observational studies link poor sleep and insomnia with worse cardiometabolic health. Few studies have examined the effect of insomnia treatment on cardiometabolic health. This systematic review of randomized controlled trials (RCTs) aims to assess the effectiveness of Cognitive Behavioral Therapy for Insomnia (CBT-I) on cardiometabolic health. Medline, EMBASE, PsycINFO, and Cochrane CENTRAL databases were searched using relevant terms and articles were screened by two independent reviewers. Eligibility criteria were adult population, the delivery of CBT-I, reporting of ≥1 cardiometabolic health marker, and peer-review. Standardized mean differences (Cohen’s d) in outcomes between groups post-intervention were calculated. Studies were appraised for quality by two independent raters using the Cochrane Risk of Bias 2.0 tool. After screening 1290 articles, 13 unique studies (15 publications) met inclusion criteria. Markers of inflammation (CRP, IL-6, TNF-α) , systolic and diastolic blood pressure (SBP, DBP) , and glycemic regulation (HbA1c) were reported most frequently, in ≥3 studies each. Most studies that examined HbA1c and CRP found reductions in the CBT-I group compared to the control group and effect sizes ranged from small (d = -0.27) to medium (d = -0.66) . Effects varied widely for IL-6, TNF-α, SBP, and DBP, with most studies finding null results. Two studies were judged as having low risk of bias and the remaining as moderate to high risk of bias. CBT-I was most consistently associated with improvements in HbA1c and CRP, which are relatively temporally stable, suggesting that CBT-I may influence enduring habits rather than short term behavior changes. Interpretation of studies is limited by high risk of bias (e.g., baseline differences between groups despite randomization, lack of prespecified analytic plan) . High quality studies are needed to better understand and quantitatively synthesize effects.
K.L.Savin: None. T.Clark: None. P.Perez-ramirez: None. M.Tristăo parra: None. L.Gallo: None.