Comparative effectiveness research accounts for only around one third of published drug studies in leading medical journals, and only 2% of these studies include cost-effectiveness analyses, a new analysis has found.

More rigorous assessments of drug value are gaining traction worldwide, while the US Obama administration has committed US$1.1 billion to comparative effectiveness research under the American Recovery and Reinvestment Act.

Against this backdrop, Dr Michael Hochman and Dr Danny McCormick from Cambridge and Harvard Medical School, Boston and the Keck School of Medicine, Los Angeles looked at 328 randomised trials, observational studies and meta-analyses involving pharmaceuticals and published in the six general and internal medicine journals with the highest impact factor between 1 June 2008 and 30 September 2009. Their findings were published in the Journal of the American Medical Association (JAMA).

Just 104 or 32% of the studies compared the effectiveness of existing therapies. Among the published comparative effectiveness (CE) studies, 45 or 43% compared different medicines; 11 (11%) compared medicines with non-pharmacologic interventions; 32 (31%) compared different pharmacologic strategies; and 16 (15%) compared different medication dosing schedules.

A total of 20 (19%) CE studies focused on safety while only two (2%) included cost-effectiveness analyses. Not surprisingly, comparative effectiveness studies were much less likely than non-CE studies to have been exclusively funded by commercial sponsors (13% and 45% of the total respectively).

Of the 21 randomised trials evaluated by Hochman and McCormick, 97 or 46% used an active comparator and the rest an inactive control. Active comparator trials were less likely than those with inactive controls (44% versus 66%) to report positive results, the authors noted.

Hochman and McCormick want to see more government funding for CE research. They also recommend that the US Food and Drug Administration should require pharmaceutical companies to compare medicines with other existing treatments whenever there are alternatives for that condition.