Prevalence of Traditional East Asian Medicine Patterns among Older Adults with Frailty: a systematic review of observational studies.

Frailty is a common geriatric syndrome that increases vulnerability to adverse health outcomes. Traditional East Asian medicine (TEAM) provides a distinct framework for understanding frailty through syndrome differentiation; however, the prevalence and distribution of TEAM patterns in frail populations remain unclear. This review aimed to systematically evaluate and meta-analyze the prevalence of TEAM patterns in frail older adults. A comprehensive search of five electronic databases was conducted through May 2025. Observational studies reporting TEAM patterns in adults aged ≥ 60 years with validated frailty diagnoses were included. Two independent reviewers screened studies, extracted data, and assessed methodological quality using the Newcastle-Ottawa Scale. Random-effects meta-analysis was used to pool prevalence estimates. Eleven observational studies involving 3,345 participants met the inclusion criteria. All studies were conducted in China; no eligible studies from Korea or Japan were identified. Methodological quality was generally low, and no study was rated as high quality. Deficiency-related TEAM patterns predominated. The most frequently reported patterns were qi-blood deficiency (exploratory pooled prevalence: 24.0%) and kidney essence deficiency (24.0%), followed by spleen deficiency with phlegm-dampness (23.0%). Liver-kidney yin deficiency had a pooled prevalence of 26.0%, based on two studies. Substantial heterogeneity was observed across studies (I2 > 80%), and overall methodological limitations reduce the precision and generalizability of these findings. Syndrome differentiation was conducted by TEAM practitioners using the four diagnostic methods, consistently incorporating tongue and pulse examination; however, diagnostic criteria varied among studies. Age, comorbidities, and nutritional markers were associated with frailty. Exploratory analysis suggests frail older adults predominantly exhibit deficiency-related patterns, particularly qi-blood deficiency, kidney essence deficiency, and spleen deficiency with phlegm-dampness. However, the low methodological quality, substantial heterogeneity, and restriction to Chinese populations indicate that these findings should be considered preliminary and require confirmation through rigorously designed studies.