Disease-modifying drugs and immune modulators are supposed to influence the course of multiple sclerosis positively. They can reduce in case of the relapsing-remitting form exacerbations and the formation of new CNS lesions, as well as the progression of the disease. The success of these treatments is considered moderate. One of the main problems of the treatment: to keep patients motivated for long-term therapy, since adherence to treatment is poor and many patients stop treatment completely, it has repeatedly been shown, and was additionally indicated by a recent study in Ontario of 682 Canadian patients with relapsing-remitting MS. About half of these patients discontinued treatment with β-interferon or glatiramer acetate within the first two years after having started therapy. In only 3.4 percent to 6.5 percent of cases was a change of treatment involved.
High discontinuation rates are documented in Germany as well. The MS-register, initiated by the German Multiple Sclerosis Society (DSMG) in 2001, provides statistics from 2009. In it the data from nearly 8700 patients was analysed. Frequency of discontinuity in treatment due to cessation or change of treatment were revealed, varyingly among the differing MS-types, of almost 40 up to more than 60 percent. More than 60 percent of patients with secondary progressive MS (SPMS) interrupted the treatment at any point in time.
Lack of adherence to therapy in MS – few studies on the causes
High discontinuation rates are not only specific to MS patients, other chronically-ill patients are also often part of this picture. Nevertheless, MS patients have a particularly high risk, say Jared Bruce and Sharon Lynch of the University of Missouri-Kansas City and the University of Kansas. The psychologist and the neurologist discuss in a review article the possible causes for the particularly frequently low treatment compliance with MS patients. There would of course be, in deriving numbers on patient retention, delays in the the start of therapy, irregular dosing and administration of medication to be taken into account. Errors in surveys are to be expected, because self-reports are not reliable and certain people would, in investigations undertaken to establish the degree of treatment compliance, not participate at all in the first place.
In the Canadian study by Wong et al. all classes of disease-modifying drugs involving injection had in common a comparably low level of treatment compliance. One of the reasons, according to the review report: fear of injections and related disorders. Oral medications may be a solution here but would not solve the problem completely. Telephone support and advice proved to be helpful. The treatment of depression also improved treatment compliance according to the results of one study. Further factors that contribute to improvements include education, open doctor-patient communication and the reduction of barriers to care. Significant research is needed regarding social, clinical and emotional factors that influence treatment compliance.
Cost-benefit analysis puts therapy in question
The costs of the therapy for Canadian patients were apparently not the cause of the lack of adherence to therapy and are in Germany also not as high as in, for instance, the USA. One U.S. study on cost effectiveness by epidemiologists from the University of Rochester in New York on the basis of long-term data recently showed that the treatment there is implausibly expensive, the payoff in terms of quality of life in relation to it turns out rather modest. The ten-year administration of disease-modifying medication was associated with only moderate health gains. One Quality Adjusted Year of Life (QALY) – the indicator term used for assessing the cost of care within a year, viewed in relation to health benefits – showed an annual cost of $US 800,000.
Patients undertaking interferon β-1a treatment, when compared to patients without this treatment, over the course of ten years with this disease-modifying therapy gained only two months QUALY. Patients using interferon-β-1b had an average of six out of ten years relapse-free, for patients without disease-modifying treatment however the figure was also a comparable five years. This data, of course, says nothing about the possible individual health benefits of the treatment, which can be quite substantial. The cost-effectiveness ratio for treatment in the U.S. could be reduced most suitably by a drop in costs of these very expensive medications.
The lack of individually identifiable benefits of MS treatment may also be in Germany one reason for lack of adherence to treatment. Exploring the underlying factors of loss in motivation toward treatment would be important, for the possibilities of influencing the disease are limited but still available; the World Health Organization (WHO) suggests that improved treatment adherence would have a greater benefit to society and health than the development of new drugs.