Risk of stroke following antivenom use after venomous snakebite: correspondence

We read with great interest the epidemiological study by Hunget al.1 on the risk of stroke with antivenom use after venomous snakebite in Taiwan. According to the national medical claims data, the authors provide us with useful information and disclose that venomous snakebite is associated with an increased risk of hemorrhagic stroke after the use of antivenom after using the matching propensity score in relevant measurable covariates. We strongly agree with the comments by Yehet al.2 on the unmeasured confounders associated with stroke in the present study. Furthermore, we are concerned that other residual confounders related to the occurrence of stroke were not mentioned in the cohort study. Excess alcohol use, air pollution, childhood health and fitness, high-risk diet and poor nutrition, physical inactivity, obesity, variability in blood pressure, sleep-disordered breathing, migraine, hormonal contraception or hormone replacement therapy, psychosocial stress, depression, work load, long working hours, etc.3 have been reported to be associated with stroke, which can have a substantial impact on study results. The limited availability of secondary data in the Taiwan National Health Insurance Research Database cannot fully smooth out their potential confounder effects.4 Therefore, we would like to draw the readers ’ attention to the consequential effect of other unmeasured confounders on the outcome of the study when reading the findings of the article.
Source: QJM - Category: Internal Medicine Source Type: research