The use of traditional Chinese medicine diagnostic methods in heart failure – an evidence map

Introduction Heart failure (HF) is a significant global health issue. There is an ongoing need for early detection and monitoring of its severity, which remains a critical and unmet requirement. Inspection diagnosis in traditional Chinese Medicine (TCM) is a method of assessing the condition of the internal zang-fu organs by observing the body's external manifestations, offering a promising approach to this issue. In this study, we aimed to systematically evaluate the existing research on the correlation between TCM diagnostic inspection and HF, using an evidence map to uncover potential research directions in this domain. Methods A comprehensive literature search was conducted across several databases, including the China National Knowledge Infrastructure (CNKI), Wanfang Database, Chinese Scientific Journal Database (VIP), PubMed, and Web of Science. The search screened clinical studies, systematic reviews, guidelines, and clinical pathways relevant to diagnostic inspection and HF. The collected data were analyzed using graphical and textual representations to delineate the distribution and characteristics of the evidence. Results Overall, 33 studies, comprising 14 cross-sectional, 8 cohort, and 11 case-control studies, were included in the analysis. The clinical research output showed consistent growth between 1992 and 2024, with 70% of the investigations enrolling ≤300 participants. The primary focus of these studies was chronic HF (10 studies, 30.3%). Regarding diagnostic approaches, 26.47% used visual assessment and 61.76% used device-based methods. Inspection diagnosis played several roles in HF management, predominantly facilitating disease risk prediction (15 studies, 45.45%) and disease severity evaluation (14 studies, 42.42%). Conclusion Observational evidence from TCM inspection diagnoses, especially regarding retinal/fundus and tongue manifestations, indicates that it may be of possible prognostic use. However, this needs to be confirmed through high-quality prospective studies, which should also validate the auxiliary role of inspection diagnoses in preventing and treating HF.