Because of the problem of bias by indication, simply making treatment a time-dependent variable is more likely to introduce bias than adjust for it [ 56].
Without effectively addressing the problem of bias by indication, ICS/LABA combinations can appear to increase the risk of asthma and COPD exacerbations in the general populations, when in fact the treatment is simply acting as a marker for more severe disease.
Second is the issue of bias by indication.
Although this study had a patient selection bias of a surgical indication for liver metastases, cases that received a survival benefit from surgical resection for primary tumor and liver metastasis exist, as in our case.
Lachin further suggested that the glargine-treated patients receiving higher insulin doses were likely to have had the allocation bias of confounding by indication or of imbalances in other important factors, suggesting an issue with cohort selection bias.
Evaluations of treatment effects were prone to bias by indication, as most of the centres treated the least sick patients with supportive care only, sicker patients with plasmapheresis, and the sickest with eculizumab.
It removes the effects of fixed cofounders and largely removes the effect of indication bias, although it could still be susceptible to ascertainment bias.
These analytic methods will be oriented toward reduction of indication bias.
To reduce the effect of indication bias, we calculated the score only for patients applicable for all six measures.
The lack of association of agent number and optimal control may be as a result of indication bias, as many older patients have multiple co-morbidities.
By using a newly diagnosed group of diabetic patients, we minimized the risk of indication bias that may have affected the results of other studies.
