Objective

2

To clarify the graded quantitative diagnostic characteristics of lung

qi

deficiency syndrome in chronic obstructive pulmonary disease （COPD） based on latent class analysis combined with a hidden structure model.

Methods

2

Clinical data， including the four diagnostic methods of traditional Chinese medicine （TCM）， were collected from 745 COPD patients with lung

qi

deficiency syndrome. Latent class modeling was performed using R 4.1.2 software， and each patient was classified into one of three severity categories （mild， moderate， or severe） based on probabilist

ic parameterization， parameter estimation， and model fitting. A database was established for different severity levels of lung

qi

deficiency syndrome. Based on this， Lantern 5.0 software was used to construct hidden structure models for mild， moderate， and severe lung

qi

deficiency syndrome， and syndrome differentiation rules were developed through comprehensive clustering.

Results

2

A latent class model was constructed using 28 symptoms and signs with a frequency greater than 10%. Considering TCM theory and model simplicity， the optimal model was determined when the number of latent classes was three， categorizing lung

qi

deficiency syndrome into mild （298 cases）， moderate （164 cases）， and severe （283 cases）. Hidden structure models were separately developed for each severity level， and syndrome differentiation rules were established. A comparison of common symptoms in the syndrome differentiation rules for mild and moderate lung

qi

deficiency syndrome showed no statistically significant differences in diagnostic values and weights （

P

＞0.05）， leading to their combined analysis and the development of a unified syndrome differentiation rule. Value and weight of quantitative diagnosis of mild-to-moderate lung

qi

deficiency syndrome were as followed： shortness of breath （diagnostic value 9.3， diagnostic weight 86.92%）， dyspnea on exertion （8.2， 76.64%）， low voice and reluctance to speak （6.7， 62.62%）， poor appetite （4.0， 37.38%）， loose stools （4.0， 37.38%）， weak cough sound （2.9， 27.10%）， wheezing （2.3， 21.50%）， fatigue （1.8， 16.82%）， spontaneous sweating （1.7， 15.89%）， susceptibility to colds （1.6， 14.95%）， swollen tongue （1.4， 13.08%）， teeth marks on the tongue edge （1.2， 11.21%）， deep pulse （1.6， 14.95%）， with a diagnostic threshold of 10.3. Value and weight of quantitative diagnosis of severe lung

qi

deficiency syndrome were as followed： weak cough sound （15.1， 61.13%

）， soreness and weakness of the waist and knees （12.6， 51.01%）， shortness of breath （11.1， 44.94%）， low voice and reluctance to speak （8.3， 33.60%）， frequent nocturia （6.1， 24.70%）， spontaneous sweating （3.7， 14.98%）， susceptibility to colds （3.5， 14.17%）， teeth marks on the tongue edge （7.8， 31.58%）， pale tongue body （1.9， 7.69%）， white tongue coating （5.5， 22.27%）， thin pulse （1.5， 6.07%）， with a diagnostic threshold of 23.7.

Conclusion

2

The combination of latent class analysis and a hideen structure model effectively clarified the graded quantitative diagnostic characteristics of lung

qi

deficiency syndrome， providing a reference for the quantitative diagnosis of other fundamental syndromes in TCM.