Host – Dan Keller
Hello, and welcome to Episode Eighty-nine of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m Dan Keller.
Today's interview features Dr. Charity Evans, assistant professor of pharmacy at the University of Saskatchewan in Saskatoon, Canada. After a drug is on the market, systematically evaluating hospital admissions and the reasons for them can add new evidence for its effectiveness or adverse effects. By using clinical data from the British Columbia MS database and linking it to health system databases for MS patients, Dr. Evans evaluated the effect of beta-interferon on hospital event rates compared to those not on beta-interferon. She tells us what led up to this study.
Interviewee – Charity Evans
This was part of a larger study that was looking at long-term effects of beta-interferons, and we wanted to see if there was any impact of the interferons on hospitalization rates.
Interviewer – Dan Keller
And what did you do to look at it?
So we used data from two different sources in British Columbia. We had a clinical data set that has collected clinical data on patients since 1980, and then we linked that with health administrative data in BC; so we were able to get information on individual’s hospitalizations as well as the drugs that they were taking, and we used that to see if there was any effect of the beta-interferons on their hospitalization rates.
And this was per patient per month or year, some time frame?
Yup. We actually looked at each individual patient in this study on a monthly basis; and so we each month said did you have any hospitalizations this month, yes or no, or how many did you have? And then we looked at their drug exposure, and we did that in two different ways; so we looked at were you on drug at that time that we were measuring you – so monthly – and we were looking at cumulative drug exposure, so how much drug had you been exposed to prior to that time, as well.
We actually found that there wasn’t any differences between the people who had been exposed to beta-interferon either currently or cumulatively compared to those who had no exposure to beta-interferon on the hospitalization rates.
But what about any individual outcomes?
So with a secondary analysis, we also looked at specific reasons for hospitalizations, and we did find that there did seem to be a beneficial effect of the beta-interferons on hospitalizations related to respiratory diseases; so those individuals who had a higher cumulative exposure to beta-interferon over time actually had less hospitalizations for respiratory diseases.
Does that take into account both infectious diseases as well as anything respiratory, like COPD or any other things that would affect the lungs?
Yup, that includes all of them. We did look at kind of the specific diagnosis for these patients and the majority were respiratory infections, so things like pneumonia or influenza.
Do you have any idea what might account for that?
We have two thoughts. The first one is because the majority of hospitalizations were due to infections, we know that the beta-interferons have antiviral activity, so we thought is it this kind of an antimicrobial or immunoregulatory effect that the interferons were resulting in these lower hospitalization rates. And then the second one is a far less scientific thought, but we also wondered if people who are on drug, are they seen by healthcare professionals more regularly than someone who isn’t, and if that’s the case are they receiving more messages about preventative strategies for these types of infections; so when it’s flu season, are these people hearing more about the flu shots and getting a flu shot more than someone who maybe doesn’t see a healthcare professional as much?
Could the interferon, because it’s working on their MS, have any beneficial effect in terms of neuromuscular function of respiratory muscles?
That one I wouldn’t be able to comment on specifically yet.
Can you sort of dissect this by looking at patients on other disease-modifying therapies, which if they had the same reduction in respiratory might say that it’s not a direct antiviral effect but could be neurologic or healthcare access?
Yeah, that would definitely be the way to do it. This study specifically looked at the interferons; again, that was how the study was designed, but for sure if you included glatiramer acetate, as well, or some of the newer agents. At the time of this study for sure we didn’t have enough long-term data on the newer agents to be able to include them, but that’s certainly something that we’d be looking at in the future.
So where do you take this in the future?
So we are, as you suggest, wanting to look at the newer agents and seeing if there is any impact of that, as well, so that would probably be the next step that we would do.
If it were a direct antiviral effect, wouldn’t you expect to see it on other viral diseases? But I guess they’re much less common so events might be less.
And this might just be a complete chance finding, as well. Respiratory infections are more common in MS to begin with, so we didn’t notice it with other types of infections. But this is a secondary outcome so we weren’t looking specifically for this, so it might be something that if we tease out a study that that was a primary endpoint we might find differences, as well.
If there was no overall effect on hospitalizations but there was a lower level of hospitalization for respiratory problems, was there an increase in other things that accounted for this zeroing out?
We didn’t see any statistically significant increases in any of the other areas.
Sort of the difference between mortality and all-cause mortality, I’m sort of thinking, in the same way that you don’t want to prevent one and raise the other.
Right, yeah. You know, our findings did kind of coincide with right around the time where the 21-year followup of the initial pivotal trials of the beta-interferons came out where they did show a lower mortality related to respiratory infections, as well. Our findings kind of fit with that, as well, but as for the specific reason why I can’t say for sure.
Can you reach any conclusions or recommendations?
Well, we didn’t see a beneficial effect of the interferons on hospitalizations, but I think it was also reassuring in that we didn’t see a spike in any kind of hospitalizations, or we didn’t see one particular type of hospitalization occurring. And so I think that is a good sign that there don’t seem to be any serious long-term effects or adverse effects that are happening with the interferons. So this is just kind of another, I guess, support for that, that these seem like they’re pretty safe drugs over the long term.
Very good, thanks.
Thank you for listening to Episode Eighty-nine of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Carol Cruzan Morton. Msdiscovery.org is part of the nonprofit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is Vice President of Scientific Operations.
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For Multiple Sclerosis Discovery, I'm Dan Keller.