The Effect of Insomnia on Mild Cognitive Impairment in Patients with Cardiovascular Risk Factors: Results of a Three-Year Longitudinal Study

Objective. To assess the dynamics of sleep parameters based on analysis of three items on the Hamilton Rating Scale (HDRS-17) designed to measure the severity of insomnia and their relationship with measures of the cognitive phenotype over a 36-month observation period in patients with cardiovascular risk factors (CVRF). Materials and methods. This longitudinal study included 51 patients (mean age 57.7 ± 6.2 years, 19 (37.3%) men) who met the inclusion criteria. All participants underwent general clinical examination with assessment of CVRF and neuropsychological testing using the Montreal Cognitive Assessment Scale (MoCA) and HDRS-17 at baseline and 36 months. During the study, patients received stable baseline therapy to control modifiable CVRF. Hypnotics were taken sporadically when there were complaints of problems falling asleep. Results. During the 36-month study, vascular cognitive impairment (CI) progressed from 23.7 ± 2.6 to 22.1 ± 2.4 MoCA points (p = 0.01), mainly due to decreases in attention (p = 0.01), executive functions (EF) (p = 0.01), memory (p = 0.02), and speech (p = 0.02), while an increase in sleep disturbances was noted (item 4: from 0.8 ± 0.02 to 1.9 ± 0.1 points, p = 0.01; point 5: from 0.6 ± 0.02 to 1.7 ± 0.1 points, p = 0.01), along with an increase in depression (from 7.5 ± 0.5 to 13.7 ± 3.0 points, p = 0.01) in patients with CVRF. A strong inverse correlation was found between values on items 4, 5, and 6 of the HDRS-17 and mean MoCA-total scores (r = –0.85; r = –0.87; r = –0.8 (p < 0.05 )), memory index (r = –0.8; r = –0.75; r = –0.81 (p < 0.05)), attention index (r = –0.88; r = –0.86 ; r = –0.83 (p < 0.05)), and index of EF (r = –0.87; r = –0.85; r = –0.8 (p < 0.05)) respectively. Conclusions. Progression of CI in patients with CVRF is associated with increases in insomnia disorders and depression.