Wednesday, 9 March 2016

ResearchSpeak: how comorbidities affect prescribing of DMTs

Did you know if you have MS and are depressed you are more likely to be prescribed a DMT? #ResearchSpeak #MSBlog #MSResearch

"Have you heard of the term 'in silico'? It means doing research using computer modeling or analysing data without the need for any lab work on data collection. The in silico study below on the impact of comorbidity on DMT use in MS is fascinating. It shows that if you have MS and have a comorbidity, in particular anxiety and ischemic heart disease, you are less likely to start a DMT. Why? Is this a negative bias of the healthcare system against these MSers? Or could MSers with comorbidities be less likely to go onto a DMT for personal reasons? In other words they are refuseniks. Answering these questions is clearly important to see if something needs to be done to address this problem. If there is prescriber bias we may be disadvantaging these MSers; if they are refuseniks we need better education about DMTs. Interestingly, MSers with comorbid depression were more likely to start a DMT than MSers without depression. I wonder of this is linked to disease severity? The more severe your disease is the more likely you are to be depressed and hence your healthcare professional is more likely to suggest, and start, a DMT. It is interesting what is possible with big data. More reasons for us to invest in these in silico studies."

Epub: Zhang et al. CIHR Team in the Epidemiology and Impact of Comorbidity on Multiple Sclerosis. Examining the effects of comorbidities on disease-modifying therapy use in multiple sclerosis. Neurology. 2016 Mar 4. pii: 10.1212/WNL.0000000000002543.

OBJECTIVE: Comorbidities are common in multiple sclerosis (MS) and adversely affect health outcomes. However, the effect of comorbidity on treatment decisions in MS remains unknown. We aimed to examine the effects of comorbidity on initiation of injectable disease-modifying therapies (DMTs) and on the choice of the initial DMT in MS.

METHODS: We conducted a retrospective observational analysis using population-based health administrative and linked clinical databases in 3 Canadian provinces. MS cases were defined as any individual with ≥3 diagnostic codes for MS. Cohort entry (index date) was the first recorded demyelinating disease-related claim. The outcomes included choice of initial first-line DMTs and time to initiating a DMT. Logistic and Cox regression models were used to examine the association between comorbidity status and study outcomes, adjusting for sex, age, year of index date, and socioeconomic status. Meta-analysis was used to estimate overall effects across the 3 provinces.

RESULTS: We identified 10,698 persons with incident MS, half of whom had ≥1 comorbidities. As the total number of comorbidities increased, the likelihood of initiating a DMT decreased. Comorbid anxiety and ischemic heart disease were associated with reduced initiation of a DMT. However, patients with depression were 13% more likely to initiate a DMT compared to those without depression at the index date (adjusted hazard ratio 1.13; 95% confidence interval 1.00-1.27).

CONCLUSIONS: Comorbidities are associated with treatment decisions regarding DMTs in MS. A better understanding of the effects of comorbidity on effectiveness and safety of DMTs is needed.


  1. Re "Interestingly, MSers with comorbid depression were more likely to start a DMT than MSers without depression"
    It's somewhat of a sick ironic joke that you can be not suffering from depression and the DMT you get prescribed has depression as a side effect. I had no depression but Interferon Beta-1A gave me very bad depression - which all but disappeared within one week of stopping the drug. No - I'm not exaggerating - just one week to start feeling a whole heap better and rapidly heading back towards normal again.

  2. Prof G, you're too drug-happy. You doctors have abused drug prescription privileges and it's ruining society. Kids are being prescribed anti-depressives without recourse and now antibiotics have been rendered inefficient due to the fact you've over prescribed them. It's a mess and doctors are to be blamed.

    Be more holistic and take health seriously.

    1. So true. I think these new DMTs do more harm than good.

    2. It was on the BBC news a teenager suffering from depression was given by a GP antidepressants and some phone numbers. He felt suicidal. No counselling or psychotherapy. This is what he said could of really helped him. It was ridiculous he was not offered this. The waiting lists are long for NHS talking therapy referrals. The NHS mental healthcare system is a mess.

      I was suffering from severe anxiety some years ago. The GP just offered me pills, no self help ideas or asking why I was anxious, no offer of referral to psychotherapy. Anxiety pills are short term, psychotherapy can help someone longer term.

    3. Re: the teenager suffering from depression. Antidepressants take two weeks to work so the teenager would need other forms of help/support during this time, then needs to be monitored. Being handed a list of phone numbers is not enough.

  3. Anon on March 9 at 12.12pm
    That's going a bit over the top! You can't blame Prof G for the bad or poor prescribing practices of a proportion of the millions of doctors worldwide. And prescribing practices vary. Yes - there are impacts from time-poor doctors just handing out scripts in over-burdened health services everywhere. But patients are also to blame to some extent on the antibiotic front - way too many people go to the Doc and expect to be handed a prescription. They don't like being told to go home, spend a couple of days in bed, drink plenty of fluids etc. If they don't get given a pill to take they think that the Doc has not done their job.

    Anon at 7.42pm - without doubt patients' perspectives on the new DMTs will vary depending on how active and damaging their MS is. If someone is having frequent bad relapses with poor recovery and are facing a faster rate of disability accumulation then their viewpoint is likely to be somewhat different to that of someone who is more stable. I am not on any DMT but it is not my right or place to judge the decisions of others who may choose to take some of the risks attached to some of the newer DMTs. I'm not walking in their shoes (nor they in mine) and each person has to weight up all of the factors involved in their own circumstances to arrive at a decision which is right for them. Where things do have potential to go astray is if patients are not provided with sufficient knowledge to enable them to make informed decisions. (and that's a topic which has been addressed before on this blog).

  4. There are so many posts on this website with people angry that they cannot get DMTs. Now it seems the complaint is overprescribing. No one is forced to take anything in the UK other than in exceptional circumstances. If one has access to this blog, then they have access to the patient information leaflets online along with the side effects. It can also be discussed with a GP. As athletes know, they are responsible for what goes into their body, we are no different.


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