Objective

2

To explore the syndrome distribution of cough cases in ancient Chinese medical books.

Method

2

A total of 9 323 cough cases in the database of lung diseases in ancient Chinese medical books were extracted. Lantern 5.0 was used to construct the latent structure model for the 100 manifest variables based on the first 50 symptoms and 50 Chinese herbal medicines， and different latent nodes were interpreted. The syndrome differentiation patterns of syndromes with symptoms and Chinese herbal medicine （formula） were quantitatively revealed by the comprehensive clustering weights of latent structure. The correlation of diseases with syndromes was fitted through the binary Logistic regression analysis.

Result

2

There were 204 syndromes involved in 9 323 cough cases with 18 syndromes showing a frequency higher than 100. As demonstrated by the model established on the first 50 symptoms and 50 Chinese herbal medicines， 35 latent variables， 98 latent classes， and 10 comprehensive clustering models were obtained， where

Z

5

was the highest in the threshold value （6.7），

Z

6 in the information coverage of productive cough （52%）， and

Z

7 in the score （19）. The binary Logistic regression model fitted the correlation between different disease types and five syndromes， where the dominance ratio of external wind to the syndrome of wind-heat invading lung reaching up to 88.919， those of syndrome of phlegm-heat accumulating in lung to diseased heat and sputum 51.594 and 15.861， and those of the syndrome of phlegm-dampness obstructing lung to dampness， phlegm， and fluid retention 31.415， 34.370， and 4.936， respectively.

Conclusion

2

The newly discovered cough syndromes included lung heat and yin deficiency， external cold and internal fluid retention， weakness of spleen and stomach， and phlegm and blood stasis in lung. In most cases， multiple syndromes were observed clinically， such as syndrome of deficiency of both Qi and Yin in lung combined with yin deficiency in lung and kidney. Since differentiation of traditional Chinese medicine （TCM） syndrome is subjective， the weight can indicate the difference in the contributions of different symptoms to the syndrome， which is of guiding significance for syndrome inference. The latent structure model combined with Logistic regression analysis can solve the problem of quantification in TCM syndrome differentiation and can be used to explore the syndrome distribution of diseases.