‘WORST PAPER OF 2022 COMPETITION’ Entry No 5: “Chinese Herbal Medicine … Improves the Survival Rate of Patients with Ischemic Heart Disease”

Ischemic heart disease (IHD) related to cardiovascular or cerebrovascular disease is the leading cause of mortality and an important issue of public health worldwide. The cost of long-term healthcare for IHD patients may result in a huge financial burden. This study analyzed the medical expenditure incurred for and survival of IHD patients treated with Chinese herbal medicine (CHM) and Western medicine.

Subjects were randomly selected from the National Health Insurance Research Database in Taiwan. The Cox proportional hazards regression model, Kaplan–Meier estimator, logrank test, chi-square test, and analysis of variance were applied. Landmark analysis was used to assess the cumulative incidence of death in IHD patients.

A total of 11,527 users were identified as CHM combined with Western medicine and 11,527 non-CHM users. CHM users incurred a higher medical expenditure for outpatient care within 1 (24,529 NTD versus 18,464 NTD,  value <0.0001) and 5 years (95,345 NTD versus 60,367 NTD,  value <0.0001). However, CHM users had shorter hospitalizations and lower inpatient medical expenditure (7 days/43,394 NTD in 1 year; 11 days/83,141 NTD in 5 years) than non-CHM users (11 days/72,939 NTD in 1 year; 14 days/107,436 NTD in 5 years).

The CHM group’s adjusted hazard ratio for mortality was 0.41 lower than that of the non-CHM group by Cox proportional hazard models with time-dependent exposure covariates. Danshen, Huang qi, Niu xi, Da huang, and Fu zi were the most commonly prescribed Chinese single herbs; Zhi-Gan-Cao-Tang, Xue-Fu-Zhu-Yu-Tang, Tian-Wang-Bu-Xin-Dan, Sheng-Mai-San, and Yang-Xin-Tang were the five most frequently prescribed herbal formulas in Taiwan.

The authors concluded that combining Chinese and Western medicine can reduce hospital expenditure and improve survival for IHD patients.

Why, you will ask, do I think that this study deserves to be in the ‘worst paper cometition’?

It is not so bad!

It is an epidemiological case-control study with a large sample size that generates interesting findings.

Agreed!

But, as a case-control study, it cannot establish a causal link between CHM and the outcomes. You might argue that the conclusions avoid doing this – “can … improve survival” is not the same as “does improve survival”. This may be true, yet the title of the article leaves little doubt about the interpretation of the authors:

Chinese Herbal Medicine as an Adjunctive Therapy Improves the Survival Rate of Patients with Ischemic Heart Disease: A Nationwide Population-Based Cohort Study

I find it difficult not to view this as a deliberate attempt of the authors, editors, and reviewers to mislead the public.

Looking at the details of the study, it is easy to see that the two groups were different in a whole range of parameters that were measured. More importantly, they most likely differ in a range of variables that were not measured and had significant influence on IHD survival. It stands to reason, for instance, that patients who elected to use CHM in addition to their standard care were more health conscious. They would thus have followed a healthier diet and lifestyle. It would be foolish to claim that such factors do not influence IHD survival.

The fact that the authors fail even to mention this possibility, interpret an association as a causal link, and thus try to mislead us all makes this paper, in my view, a strong contender for my

WORST PAPER OF 2022 COMPETITION