TORONTO, CANADA--(Marketwired - Oct. 29, 2013) - The author of a new article published by the Canadian Health Policy Institute (CHPI) questions the validity of statistics about fatal Adverse Drug Reactions (ADRs) that are commonly cited by those who advocate for increased regulation of new drugs in Canada. It is frequently claimed that 100,000 or more hospitalized patients in the United States die each year from adverse drug reactions. Since the population of Canada is about one-tenth the size of the United States' population, advocates of increased drug regulation in Canada have argued that 10,000 hospitalized Canadian patients also probably die from adverse drug reactions annually. The CHPI article critically reviewed the analyses on which these statistics are based, and examined the factual evidence for the rate of fatal ADRs from studies of hospital records in Canada.
The study, Adverse drug reactions in Canada: facts v. urban myths, was authored by pharmacoepidemiologist Dr. Nigel SB Rawson (Ph.D.). It was published in Canadian Health Policy, the online journal of Canadian Health Policy Institute (CHPI).
Dr. Rawson observed that the original source of the American statistic on deaths due to ADRs was a meta-analysis. This is a method originally designed for the synthesis of randomized clinical trials, which are often sufficiently similar to allow them to be aggregated. However, the meta-analysis used observational studies which can vary widely so that they are frequently too different to combine. Moreover, 75% of the studies on which the statistic is based were published between 1964 and 1976, which challenges the relevancy of the findings because the practice of medicine has changed markedly since that time. More importantly, the incidence of fatal ADRs reported in the studies decreased steeply between 1964 and 1995 so that the estimated number of deaths due to ADRs in hospitalized patients in the United States based only on studies published after 1987 is 13,250. An analysis of actual hospital discharge and mortality data from Ontario for 1992/93 to 1996/97 found that an ADR (fatal or not) was recorded in 1.2% of the hospitalizations and only 0.05% of the hospitalizations had a fatal outcome. Assuming these rates were the same in other provinces, approximately 33,500 hospitalizations involve an ADR annually in Canada and 1,400 of these lead to death. The Canadian Adverse Events Study reviewed patient charts from admissions in 2000 to four randomly selected hospitals in five provinces and found that 3.1% of hospitalized patients experienced any type of ADR from which one can estimate that the number of deaths due to an ADR in hospital is 3,600.
The study concludes that the frequency of fatal ADRs should be accurately monitored and even low rates of occurrence deserve serious attention. However, public discussion of drug safety and regulatory policies to address drug safety should be informed only by rigorous analyses of empirical evidence.
The study is available for free download from Canadian Health Policy, the online journal of the Canadian Health Policy Institute (CHPI) and can be accessed at the following web link: www.canadianhealthpolicy.com.
Canadian Health Policy Institute (CHPI) is a non-profit think-tank funded by independent research grants and unrestricted operating grants from public sector, private sector and non-profit sector sources. CHPI is dedicated to conducting, publishing and communicating evidence-based socio-economic research on health system performance and health policy issues that are important to Canadians.