[intro music]   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?   Dr. Evans 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.   MSDF And this was per patient per month or year, some time frame?   Dr. Evans 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.   MSDF But what about any individual outcomes?   Dr. Evans 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.   MSDF Does that take into account both infectious diseases as well as anything respiratory, like COPD or any other things that would affect the lungs?   Dr. Evans 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.   MSDF Do you have any idea what might account for that?   Dr. Evans 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