On October 23rd, virology blog published the third installment of David Tuller’s investigative report about the PACE study of treatments for ME/CFS. In the post, Dr. Tuller demonstrated that the key finding of an economic analysis of the PACE trial, published in PLoS One in 2012, was almost certainly false. The finding–that cognitive behavior therapy and graded exercise therapy were cost-effective treatments–relied on an inaccuracy in the paper about whether the results of sensitivity analyses were “robust.”
Since the publication of the virology blog series, the PACE study has come under sustained and blistering public criticism for its many flaws. The PLoS One paper is currently the center of attention as a result of the researchers’ insulting response to Dr. James Coyne, a well-known psychologist and PLoS blogger. Dr. Coyne requested data to verify the results from the PLoS One paper, and was told that his request was “vexatious.” The researchers have called patients “vexatious” for years, of course, but the effort to use this strategy against a respected researcher has caused an uproar. Several colleagues and I, including Dr. Tuller, cited this rejection recently in our own request for a different set of PACE-related data.
Because of the open data policies of the PLoS journals, requesting data on that basis was a smart move by Dr. Coyne, and he has done a brilliant job of rousing support for the larger issue of access to data in scientific research. The PACE authors must recognize by now that at some point they will have to release all of their data.
The PLoS One study reported that cognitive behavior therapy and graded exercise therapy, the two treatments long favored by the main investigators, were more cost-effective than other approaches. The investigators have routinely cited these findings in promoting use of the two treatments. The truth or falseness of these claims from the PLoS One study are at the heart of the current controversy
In fact, it is already clear that the claim is highly unlikely to withstand serious scrutiny, based on the public record. In the October 23rd post, Dr. Tuller demonstrated that subsequent public comments of the lead author contradicted a critical statement in the paper about the PLoS One study’s sensitivity analyses..
The relevant excerpt from virology blog is below:
In another finding, the PLoS One paper argued that the graded exercise and cognitive behavior therapies were the most cost-effective treatments from a societal perspective. In reaching this conclusion, the investigators valued so-called “informal” care—unpaid care provided by family and friends–at the replacement cost of a homecare worker. The PACE statistical analysis plan (approved in 2010 but not published until 2013) had included two additional, lower-cost assumptions. The first valued informal care at minimum wage, the second at zero compensation.
The PLoS One paper itself did not provide these additional findings, noting only that “sensitivity analyses revealed that the results were robust for alternative assumptions.” Commenters on the PLoS One website, including Tom Kindlon, challenged the claim that the findings would be “robust” under the alternative assumptions for informal care. In fact, they pointed out, the lower-cost conditions would reduce or fully eliminate the reported societal cost-benefit advantages of the cognitive behavior and graded exercise therapies.
In a posted response, the paper’s lead author, Paul McCrone, conceded that the commenters were right about the impact that the lower-cost, alternative assumptions would have on the findings. However, McCrone did not explain or even mention the apparently erroneous sensitivity analyses he had cited in the paper, which had found the societal cost-benefit advantages for graded exercise therapy and cognitive behavior therapy to be “robust” under all assumptions. Instead, he argued that the two lower-cost approaches were unfair to caregivers because families deserved more economic consideration for their labor.
“In our opinion, the time spent by families caring for people with CFS/ME has a real value and so to give it a zero cost is controversial,” McCrone wrote. “Likewise, to assume it only has the value of the minimum wage is also very restrictive.”
In a subsequent comment, Kindlon chided McCrone, pointing out that he had still not explained the paper’s claim that the sensitivity analyses showed the findings were “robust” for all assumptions. Kindlon also noted that the alternative, lower-cost assumptions were included in PACE’s own statistical plan.
“Remember it was the investigators themselves that chose the alternative assumptions,” wrote Kindlon. “If it’s ‘controversial’ now to value informal care at zero value, it was similarly ‘controversial’ when they decided before the data was looked at, to analyse the data in this way. There is not much point in publishing a statistical plan if inconvenient results are not reported on and/or findings for them misrepresented.”