Does outcome reporting bias "cause" cancer? Risks associated with hidden data on Angiotensin receptor blockers.

Conflicting reports have been published regarding the influence of angiotensin receptor blockers (ARBs) on the incidence of cancer. One meta-analysis reported a 1% absolute increase in the incidence of cancer associated with ARBs over 4 years. Contrasting findings were reported in an industry-sponsored meta-analysis and in another meta-analysis, both of which showed no difference in the incidence of cancer in ARB treatment groups relative to control groups. The US Food and Drug Administration has recently asserted that evidence does not support an association between ARBs and the development of cancer. The current review compares the 3 published meta-analyses assessing the association between ARBs and cancer and shows that outcome reporting bias contributed to the conflicting results. Given the prevalence of this form of bias in the scientific literature, the processes for systematic reviews and meta-analyses are under siege, and there is an important role for health care regulators to play. If all outcome data from clinical trials were to be reported in the public domain, independent analyses could be performed and the results of industry-sponsored trials verified. Furthermore, if regulators were to mandate the publication, in the public domain, of all clinical outcomes collected in clinical trials, outcome reporting bias could be eliminated.