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Quantifying Adverse Drug Events – Are Systematic Reviews the Answer? PDF Print E-mail
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Wednesday, 01 September 2004 00:00
“The direct medical costs associated with ADEs have been estimated to be in the range of $US30 billion to $US130 billion annually in the US alone. These estimates are even more meaningful when compared with other high cost conditions or diseases, such as diabetes mellitus ($US45.2 billion), obesity ($US70 billion), and cardiovascular disease ($US199.5 billion). Drug-related mortality has been estimated to claim 218,000 lives annually.”

“The importance of quantifying ADEs is particularly apparent in the case of drug treatment for children, women of child-bearing age, and the elderly. Because these population groups are exposed to medications almost entirely in the postmarketing phase of drug use, there is no systematic examination of the outcomes of medication use as would exist if the medication were given as part of the clinical trial.”

“Federal government agencies in North America (the US FDA and Health Canada) have voluntary ADE reporting systems for healthcare professionals and mandatory reporting systems for pharmaceutical companies. It is unclear what proportion of ADEs are reported by practicing clinicians directly to the FDA, but it is believed to be less than the proportion reported through the pharmaceutical industry. Between mid-1997 and mid-1998, physicians reported 2083 ADEs to the FDA. If one assumes that 1997 is a typical reporting year, US physicians report an ADE to the FDA once every 336 years, based on the number of licensed physicians in the US. During the same reporting period, pharmacists in the US reported 7406 ADEs to the FDA. US pharmacists fare a bit better in the frequency analysis, reporting an ADE to the FDA once every 26 years, based on the number of licensed pharmacists in the US. Health-related accreditation bodies estimate that as many as 95% of all ADEs are not reported, supporting the need to stimulate reporting on a large-scale basis.”

“National public health agencies are in a unique position to conduct systematic revies of ADEs. These agencies have access to published and unpublished ADE data, which will strengthen the validity of such reviews.”

“Although ADE data collected from RCTs [Randomized Controlled Trials] may not reflect ADEs that may be seen in a real clinical setting (as clinical trials are conducted in a more controlled setting), randomization and blinding in these studies usually alleviate biases and confounding that may exist in observational pharmacovigilance studies.”

“Recently, clinicians and scientists have come to realize that systemic reviews of RCTs can be a valuable tool for combining both efficacy and toxicity data in RCTs. However, the majority of published systematic reviews are those of efficacy data and the number of published reviews on ADEs is small. We conducted a Medline search (from 1966 until September 2003) using the terms ‘adverse drug events’, ‘adverse drug reactions’, ‘drug toxicity’, and combining them with ‘meta-analysis’ or ‘systematic reviews’. Our search only resulted in 21 systematic reviews of ADEs.”

“One solution may be for the US National Library of Medicine to systematically index ADEs in clinical trials where these events are reported in the publication.”

“One approach in overcoming this problem is to develop strict criteria for reporting ADEs in clinical trials. Such criteria must concentrate on an active organ system-based reporting of ADEs. Some of these criteria have been developed, but are still not widely used.”

“Systematic reviews of ADEs have the potential to be a valuable resource to clinicians. However, poor quality of ADE reporting in RCTs has made it difficult to use systematic reviews as an effective and efficient tool in quantifying ADEs. Stricter guidelines on the reporting of ADEs in clinical trials will enable future clinical scientists to use systematic reviews of ADEs in their clinical decision-making process.”


Mahyar Etminan, Bruce Carleton, Paula A. Rochon, "Quantifying Adverse Drug Events – Are Systematic Reviews the Answer?", Drug Safety, September 1, 2004, Vol. 27, Num. 11, pp. 757-761

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Last Updated on Wednesday, 24 June 2009 12:52