A Method to Detect Residual Confounding in Spatial and Other Observational Studies

Residual confounding in observational studies.

To the Editor:—I read the study by Fellahi JL et al. titled “Perioperative use of dobutamine in cardiac surgery and adverse cardiac outcome” with great interest. This study showed that the use of dobutamine was associated with adverse outcomes in adult cardiac surgery, and the authors concluded that these results suggest that dobutamine should only be administered when the benefit is judged to ...

Residual Confounding in Observational Studies

To the Editor:—I read the study by Fellahi JL et al. titled “Perioperative use of dobutamine in cardiac surgery and adverse cardiac outcome” with great interest. This study showed that the use of dobutamine was associated with adverse outcomes in adult cardiac surgery, and the authors concluded that these results suggest that dobutamine should only be administered when the benefit is judged to ...

Confounding in Observational Studies Explained

Practical and ethical constraints mean that many clinical and/or epidemiological questions cannot be answered through the implementation of a randomized controlled trial. Under these circumstances, observational studies are often required to assess relationships between certain exposures and disease outcomes. Unfortunately, observational studies are notoriously vulnerable to the effect of diffe...

Confounding Equivalence in Observational Studies

[Confounding bias due to indication and severity in observational studies].

Observational studies are subject to biases that may lead to misinterpretation of the results. This study aimed to determine the influence of omeprazole treatment on the duration of sick leave in patients with ankle sprains treated with non-steroidal anti-inflammatory drugs. We used the Ibermutuamur database. Contrary to our expectations, sick leave was longer in patients who received omeprazol...