Strengths and Limitations
cancer, HCC
CANCER
This study has several strengths. By using a nationally registered data set with a 99% coverage of the Taiwanese population, this large-scale cohort study has national representativeness and low potential for selection bias. Furthermore, we adjusted for a range of potential confounders and took into consideration the potential induction periods of antidepressants, the timing of antidepressant use (before and after HCC diagnosis), and types of mortality (overall and cancer specific). In our analysis of antidepressant use after HCC diagnosis, we used time-varying exposure to minimize immortal time bias. Therefore, this study yielded robust results on the association between mortality and postdiagnosis antidepressant use in patients with HCC.Several limitations may affect the results and interpretations of this study. First, information on some potential confounders was not available in the NHIRD, including adherence to antidepressant use, smoking status, body mass index, nutritional status, other health-related factors, and laboratory test results, and we thus could not include and adjust for them in our statistical models. Second, our study may have misclassification bias because some participants may not have adhered to antidepressant medication. However, such misclassification usually results in an underestimation of the effect of interest