However, confounding by indication bias cannot be ruled out [48].
However, we could be faced with an inherent indication bias in such a setting.
The current discussion about colloids, especially on the safety of HES, might have caused significant indication bias by some investigators.
This tool allows us to group subjects according to their propensity to be in a particular treatment group and, in so doing, to account for the indication bias.
Second, this analysis refutes prior studies that support a protective effect of in-hospital ongoing statin therapy probably due to indication bias.
Indication bias is a further conceivable limitation if elite athletes had more easy access to health care.
Although indication bias cannot be excluded, attempts to increase ultrafiltration by the long term use of hypertonic bags [46] seem to be no guarantee for achieving sustained euvolemia.
This probably reflects indication bias.
Therefore, results would have suffered from an indication bias.
First, indication bias and residual confounding could account for some of the observed associations.
Indication bias is controlled best by an RCT, however randomization and control is not always feasible.
