Comparison of evidence on harms of medical interventions in randomized and nonrandomized studies

Safety of neuraminidase inhibitors for influenza

Neuraminidase inhibitors, oseltamivir and zanamivir, are used for the treatment of, and protection from, influenza. The safety of these compounds has been assessed in systematic reviews. However, the data presented are somewhat limited by the paucity of good quality adverse event data available. The majority of safety outcomes are based on evidence from just one or two randomised controlled trials. The results of the systematic reviews suggest that neuraminidase inhibitors have a reasonable side effect and adverse effect profile if they are to be used to treat or protect patients against a life-threatening disease. However, if these compounds are to be prescribed in situations in which avoidance of inconvenience or minor discomfort is hoped for, then the balance of harms to benefits will be more difficult to judge.

A survey of inclusion of the time element when reporting adverse effects in randomised controlled trials of cyclo-oxygenase-2 and tumour necrosis factor alpha inhibitors

BACKGROUND

The adequacy of reporting the time element in adverse effects in articles on randomised clinical trials of cyclo-oxygenase-2 and tumour necrosis factor (TNF)alpha antagonists was surveyed.

METHODS

Prominent rheumatology and general/internal medicine journals were searched for all randomised controlled trials published about cyclo-oxygenase-2 and TNFalpha inhibitor use in rheumatological diseases up to November 2005. Reporting of time to the occurrence of the adverse effects, the use of patient years as the time frame of the reported adverse effects and the use of annual standard incidence ratios based on the surveillance, epidemiology and end-results (SEER) programme when reporting neoplasms as potential adverse effects of TNFalpha antagonists were specifically tabulated.

RESULTS

Only 23 of 70 (33%) of all articles gave the specific time of onset of an adverse effect. Nine studies used patient years to report the adverse effects and six studies used annual standard incidence ratios, using SEER, as the comparator.

CONCLUSION

In reporting of adverse effects in randomised clinical trials, a particularly neglected issue is the reporting of the time dimension of adverse effects.