However, these findings could be attributed to multiple comparisons or unmeasured confounders.
In this study, a few associations with better control were observed, but they may be artifacts of multiple comparisons or unmeasured confounders.
However, we argue that it is more likely to reflect residual confounding by unmeasured confounders.
In addition, non-randomized studies are subject to possible residual confounding bias by unmeasured confounders.
We used a flowchart to illustrate the best practice recommendation which was driven by 2 critical components: (1) availability of information on the unmeasured confounders; and (2) goals of the unmeasured confounding assessment.
Finally, our relatively low event rate for early kidney damage did not allow adjustment for multiple covariates, or more granular analyses of income levels; and unmeasured confounders, particularly of the association of income and early kidney disease, are likely.
Observational epidemiological studies often suffer from confounding bias due to measured and unmeasured confounders.
Third, although propensity score matching is an elegant way to adjust for multiple baseline differences between the investigational groups, bias can occur as a result of unmeasured confounders.
Second, models used in this study assumed that there were no unmeasured confounders related to health status, and it is possible that residual confounding existed from unmeasured effects.
