Seasonal variations of prescriptions for the major syndrome types and manifestations of upper respiratory tract infection in tradition Chinese medicine

Objective The aim of this study is to investigate the seasonal variations of prescriptions for the three most common syndrome types and the three major manifestations of upper respiratory infections (URIs) according to the theories of traditional Chinese medicine (TCM). Design This is a cross-sectional study. We examined a random sample comprising 1,000,000 beneficiaries from the National Health Insurance program in 2005. Primary diagnoses including International Classification of Diseases, Ninth Revision, Clinical Modification Codes 460–465 and 487 were regarded as URIs, for which 160,357 prescriptions of Chinese herbal medicine were analyzed. Main outcome measures We estimated the adjusted odds ratios (ORs) of three categories of Chinese herbal formulae (CHF) used to treat the three most common types of URIs and another CHF used to alleviate manifestations of URIs throughout the four seasons. Results The OR for pungent–cool CHF used to relieve external syndromes was highest in the summer (OR = 1.07). The OR for pungent–warm CHF used to relieve external syndromes was highest in the winter (OR = 1.14). The OR for CHF used to alleviate cough and reduce sputum production was highest in the spring (OR = 1.00). The OR for CHF used to alleviate nasal discharge and congestion was highest in the winter (OR = 1.19). Conclusion There are seasonal variations of prescriptions for the major syndrome types and manifestations of URIs in TCM. The results of this study may serve as a reference for TCM physicians in medical preparation and clinical practice.