Underpowered Study?
Further results showed nonsignificant trends for increased T2 lesion volume and white matter fraction and decreased brain volume, gray matter fraction, and cortical gray matter volume at baseline and at 12 months in the depressed group.
The researchers note that study limitations include the unavailability of information on treatment compliance for depression or date of depression onset.
Feng added that because this was an observational study, other missing data included depression status for some patients at year 1 and some MRI metrics.
“So this may have been underpowered to detect some of the results. The power may have been inadequate to detect all changes,” she said.
The investigators write that future research should assess larger sample sizes with longer follow-ups and should use more advanced MRI measures, such as diffusion tensor imaging or functional MRI.
In addition, they will continue examining data from MS-PATHS. “With the newest data cut, we have new patients that we can analyze. So perhaps that can provide sufficient power to detect [more MRI] changes,” Feng said.
Unusual, Intriguing Findings
Commenting on the study for Medscape Medical News, Mark Freedman, MD, professor of neurology at the University of Ottawa and director of the Multiple Sclerosis Research Clinic at the Ottawa Hospital Research Institute, noted that he wasn’t terribly surprised” by the overall findings.
“We’ve known for years that patients who are depressed don’t do as well on our performance methods,” said Freedman, who was not involved with the research.
However, the current investigators “took a huge number of patients in this multicenter study and started using some of the statistical methods we’ve seen in the use of real-world evidence,” he noted.
“So you’re looking at some outcome measures and you have to ask yourself, ‘Why would it influence that?’ and ‘Did it happen by chance or not?’ And you ask why it is that depressed people might actually have more lesions on their MRI, which is something that is unusual,” Freedman said.
“When you start to look at this, even when you’re trying to standardize things for the differences that we know of, there are some stuff that comes out as intriguing. In general, I think those depressed patients did worse on several outcome measures that one would say, ‘That’s somewhat surprising.’ That’s why this group was very careful to not conclude absolutely that depression drives this disease. But it was consistently trending in the direction that it looks like there was more inflammatory activity in these people,” he said.
He echoed the investigators’ note that drug adherence and which depression treatment was used wasn’t controlled for; and he added that depression in the study was not based on receiving a diagnosis of clinical depression but on self-report.
Still, the patients classified as depressed “did worse. They didn’t walk as fast, which was interesting; and we know that cognitive performance is often damped because of poor concentration. But how do you get worse MRIs? This study is raising a question and [the researchers] conclude that it may be that depression might be an independent factor” for that outcome, Freedman said.
“It might be that you could get more out of a particular [MS] medicine if you pay attention to depression; and if that’s the investigators’ conclusion, and I think it is, then I certainly agree with it.”
Freedman noted that, instead of a blanket recommendation that all patients with MS should be screened for depression, he thinks clinicians, especially those at smaller centers, should focus on what’s best for treating all aspects of an individual patient.
“Don’t try to manage them if you’re not going to manage the entire picture. Looking at depression and mood and other things is very important. And if you have the capacity for an official screening, I think it’s wonderful; but not everybody does,” he said.
Feng and Freedman have disclosed no relevant financial relationships. Freedman is currently a member of the Medscape Neurology Advisory Board.
This article appeared on Medscape.com.