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Beyond randomized controlled trials: A critical comparison of trials with nonrandomized studies
Author(s) -
Sørensen Henrik Toft,
Lash Timothy L.,
Rothman Kenneth J.
Publication year - 2006
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.21404
Subject(s) - medicine , randomized controlled trial , clinical trial , intensive care medicine
Observational analogs of randomized clinical trials (RCTs) are well accepted in the study of disease risk factors, diagnosis, and prognosis. There is controversy about observational studies when the focus is on the intended benefit due to lack of blinding and poor control for unmeasured confounding. Well‐designed randomized clinical trials are costly both in time and money. Therefore, existing databases are used increasingly and are often the only feasible source with which to examine delayed health effects. We reviewed the reasons for possible discrepancies between RCTs and observational studies. There can be different patient populations, differences in therapeutic regimen, control of confounding, follow‐up, measuring outcome, and differences arising from the intention‐to‐treat analysis. Observational studies cannot replace trials, nor do trials make observational studies unnecessary. Both designs are susceptible to particular bias, so neither provides perfect information. (H EPATOLOGY 2006;44:1075–1082.)