Multiple sclerosis (MS) is a chronic, disabling, and progressive illness, representing one of the most common causes of neurological disability in young and middle-aged adults. There is not a definitive treatment for MS yet. However, disease-modifying drugs (DMDs) for MS, which include interferon-beta and copolymer-1 have shown to be effective in reducing the frequency and severity of relapses and the progression of disability. The clinical efficacy of such therapies has been well documented in the medical literature. Instead, the factors underlying the decision to start the pharmacological treatment, to continue it or to drop out, have not been studied so far. Adverse drug effects, as well as patients’ emotional states, therapeutic expectations, the need to assume the medicines very often, and lack of communication with medical staff, are some of the elements affecting patients’ adherence to the therapy. Data from medical records of 567 MS patients referred to the MS Centre of the IRCCS Centro Studi Neurolesi (Messina) between the years 2001-2008 have been retrospectively analyzed in a first phase. Factors influencing patient decision to start a pharmacological treatment with DMDs, in agreement with the neurologist suggestion, have been evaluated by applying a multinomial logit model. The second phase of the study was cross-sectional and analyzed the data obtained through a questionnaire administered to consecutive outpatients referred to Centro Studi Neurolesi within March and May 2009 (n = 143). The probability to proceed in the treatment or to drop out was estimated through a probit model. The present research constitutes a novelty among the existing economic and medical literature: in fact, there are no, so far, studies evaluating factors underlying MS patients’ decision to undergo a pharmacological treatment and to proceed it according to medical protocols. Moreover, a significant expenditure for health care systems is associated to MS treatment, both for patients who undergo the treatment (cost of medicines, productivity losses for patients who experience severe side effects, etc.) and for those who do not take the medicine or take it discontinuously. Given the documented evidence of augmenting costs (direct and indirect) with increasing disease severity, the ability of the DMDs to reduce relapse rates and slow the progression of MS may help to offset the cost of these therapies. Conversely, delayed treatment or poor compliance can dramatically increase costs and reduce benefits.
