Objective

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To systematically analyze the outcome indicators used in randomized controlled trials （RCTs） of traditional Chinese medicine （TCM） for postinfectious cough （PIC）， and to provide references for study design.

Methods

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Eight Chinese and English databases were searched to identify RCTs of TCM for PIC. Information including sample size， ethical approval， syndrome type， intervention measures， treatment duration and follow-up， and outcome indicators was extracted. The risk of bias and study quality were also assessed.

Results

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A total of 208 RCTs were included， with sample sizes ranging from 20 to 480 cases. Among them， 59 studies （28.37%） mentioned ethical approval. The most common intervention and control measures were oral Chinese medicine and conventional Western medicine. Wind evil invading the lung syndrome was the most common syndrome type. Treatment duration was mainly 7–14 days （88.94%）， and 24 RCTs （11.54%） reported follow-up. A total of 146 outcome indicators were reported across the 208 RCTs. According to their functional attributes， the indicators were categorized into symptoms and signs （50.00%）， physical and chemical examinations （24.65%）， safety indicators （10.65%）， TCM disease and syndrome indicators （9.13%）， quality-of-life indicators （3.85%）， and long-term prognosis indicators （1.72%）. The most common type of outcome indicator was symptoms and signs alone （23.08%）， followed by safety indicators combined with symptoms and signs （16.83%）.

Conclusion

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RCTs of TCM for PIC have several deficiencies in outcome indicator design， including insufficient application of TCM-specific outcome indicators， unclear distinction between primary and secondary outcome indicators， nonstandardized use of composite outcome indicators， and insufficient attention to long-term outcome indicators and quality-of-life indicators