Identification and classification of traditional Chinese medicine syndrome types among senior patients with vascular mild cognitive impairment using latent tree analysis

OBJECTIVE： To treat patients with vascular mild cognitive impairment （VMCI） using traditional Chinese medicine （TCM）, it is necessary to classify the patients into TCM syndrome types and to apply different treatments to different types. In this paper, we investigate how to properly carry out the classification for patients with VMCI aged 50 or above using a novel data-driven method known as latent tree analysis （LTA）. METHOD： A cross-sectional survey on VMCI was carried out in several regions in Northern China between February 2008 and February 2012 which resulted in a data set that involves 803 patients and 93 symptoms. LTA was performed on the data to reveal symptom co-occurrence patterns, and the patients were partitioned into clusters in multiple ways based on the patterns. The patient clusters were matched up with syndrome types, and population statistics of the clusters are used to quantify the syndrome types and to establish classification rules. RESULTS： Eight syndrome types are identified： Qi deficiency, Qi stagnation, Blood deficiency, Blood stasis, Phlegm-dampness, Fire-heat, Yang deficiency, and Yin deficiency. The prevalence and symptom occurrence characteristics of each syndrome type are determined. Quantitative classification rules are established for determining whether a patient belongs to each of the syndrome types. CONCLUSION： A solution for the TCM syndrome classification problem for patients with VMCI and aged 50 or above is established based on the LTA of unlabeled symptom survey data. The results can be used as a reference in clinic practice to improve the quality of syndrome differentiation and to reduce diagnosis variances across physicians. They can also be used for patient selection in research projects aimed at finding biomarkers for the syndrome types and in randomized control trials aimed at determining the efficacy of TCM treatments of VMCI.

Applying latent tree analysis to classify Traditional Chinese Medicine syndromes(Zheng)in patients with psoriasis vulgaris

OBJECTIVE:To treat patients with psoriasis vulgaris using Traditional Chinese Medicine(TCM),one must stratify patients into subtypes(known as TCM syndromes or Zheng)and apply appropriate TCM treatments to different subtypes.However,no unified symptom-based classification scheme of subtypes(Zheng)exists for psoriasis vulgaris.The present paper aims to classify patients with psoriasis vulgaris into different subtypes via the analysis of clinical TCM symptom and sign data.METHODS:A cross-sectional survey was carried out in Beijing from 2005-2008,collecting clinical TCM symptom and sign data from 2764 patients with psoriasis vulgaris.Roughly 108 symptoms and signs were initially analyzed using latent tree analysis,with a selection of the resulting latent variables then used as features to cluster patients into subtypes.RESULTS:The initial latent tree analysis yielded a model with 43 latent variables.The second phase of the analysis divided patients into three subtype groups with clear TCM Zheng connotations:'blood deficiency and wind dryness';'blood heat';and'blood stasis'.CONCLUSIONS:Via two-phase analysis of clinic symptom and sign data,three different Zheng subtypes were identified for psoriasis vulgaris.Statistical characteristics of the three subtypes are presented.This constitutes an evidence-based solution to the syndromedifferentiation problem that exists with psoriasis vulgaris.

A data-driven method for syndrome type identification and classification in traditional Chinese medicine

The efficacy of traditional Chinese medicine （TCM） treatments for Western medicine （WM） diseases relies heavily on the proper classification of patients into TCM syndrome types. The authors developed a data-driven method for solving the classification problem, where syndrome types were identified and quantified based on statistical patterns detected in unlabeled symptom survey data. The new method is a generalization of latent class analysis （LCA）, which has been widely applied in WM research to solve a similar problem, i.e., to identify subtypes of a patient population in the absence of a gold standard. A well-known weakness of LCA is that it makes an unrealistically strong independence assumption. The authors relaxed the assumption by first detecting symptom co-occurrence patterns from survey data and used those statistical patterns instead of the symptoms as features for LCA. This new method consists of six steps： data collection, symptom co-occurrence pattern discovery, statistical pattern interpretation, syndrome identification, syndrome type identification and syndrome type classification. A software package called Lantern has been developed to support the application of the method. The method was illustrated using a data set on vascular mild cognitive impairment.