Meta-analysis: Drug trials too simplistic for the general population

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More than one in four Americans suffer from at least two chronic health conditions and, among the elderly, this number rises to two out of three. Yet a recent research letter in the Journal of the American Medical Association suggests that the overwhelming majority of randomized clinical drug trials ignore the specific needs of this large population: Very few of these trials actually analyze the effects of a given medication on patients with more than one chronic condition.

Recently, researchers from the University Health Network in Toronto assessed all randomized controlled studies of treatments for long-lasting diseases or conditions that were published in five major medical journals and six specialized chronic condition journals in 1995, 2000, 2005, and 2010. Out of the 284 studies that fulfilled the researchers criteria for inclusion, only six specifically included patients who had more than one chronic condition. And this tiny fraction (2.1 percent) effectively did not budge between 1995 and 2010. In fact, 179 of the studies explicitly excluded patients with multiple conditions.

The authors fear that this failure to include patients with multiple chronic conditions may lead to inappropriate generalizations about drug trial results. Given the possible drug-to-drug, drug-to-disease, and disease-to-disease interactions that remain unexamined, most of the evidence gathered to date [from these randomized controlled trials], they assert, is of limited value to guide decisions.

ACSH's Dr. Gilbert Ross, too, notes that this is a serious problem; the people who take these drugs often will have multiple conditions, and they are not the ones who are targeted in the clinical trials.

But ACSH's Dr. Josh Bloom is concerned about the authors suggestion to include in clinical trials subgroups of patients who have multiple chronic conditions. To add more complex trials involving specialized groups of patients would make clinical trials nearly impossible. It s hard enough now, he says. And while the current system is not perfect, these new requirements would result in even fewer clinical trials and thus fewer new drugs to warn anyone about. Instead, perhaps a more productive change would be to require more stringent phase IV (post-marketing) surveillance, where adverse effects not seen prior to approval can be detected in a larger and more diverse population.