Effect of Kami Guibi-tang (KGT) in elderly subjects with insomnia: a study protocol from a single center, randomized, double-blind, placebo-controlled trial

BACKGROUND: The incidence of insomnia increases with age and is related to cognitive function in older adults; therefore, it is important to manage it actively. In this study, we report a protocol for the evaluation of the efficacy and safety of Kami Guibi-tang (KGT), a herbal prescription that has been widely used in East Asia for insomnia, forgetfulness, and depression, in older adults with insomnia. METHODS: In this single-center, double-blind, randomized controlled trial, 60 older adults with insomnia and subjective cognitive decline will be recruited and randomly assigned to the KGT or placebo group. The KGT group will take KGT granules thrice a day for 12 weeks, whereas the control group will take placebo granules in the same manner. Participants will be assessed for sleep, cognitive function, quality of life, and depression using the Pittsburgh Sleep Quality Index-Korean (PSQI-K), Insomnia Severity Index-Korean (ISI-K), Seoul Neuropsychological Screening Battery–Dement (SNSB-D), 36-item MOS Short Form Survey (SF-36) and Short version of the Geriatric Depression Scale (S-GDS) before and at the end of administration of the investigational product. The PSQI-K, ISI-K, and SF-36 will be further assessed 12 weeks after the end of medication to determine whether the effects on sleep and quality of life are sustained. The PSQI-K total score difference between the two groups at 12 and 24 weeks will be the primary outcome; all other endpoints will be secondary. Safety will be assessed by performing blood tests and electrocardiograms before taking the investigational drug, 6 weeks after taking the drug, and 12 weeks after taking the drug; any adverse events will be observed throughout the study. DISCUSSION: The protocol will provide a detailed process for a clinical trial to evaluate the efficacy and safety of KGT in elderly patients with insomnia. We will also investigate if changes in cognitive function correlated with improvements in insomnia. TRIAL REGISTRATION: This trial was registered at CRIS (Clinical Research Information Service) on April 27, 2023 (KCT0008391, version 2.0). https://cris.nih.go.kr/cris/search/detailSearch.do?seq=24811&search_page=L. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12906-023-04199-y.