Costs and Quality of Life in Multiple Sclerosis A Cross-Sectional Study in the USA

SUMMARY Treatment of multiple sclerosis (MS) has changed substantially during the past decade, as new biological disease-modifying treatments have been introduced in a field where only symptomatic pharmacological treatment had been available. The new treatments come at a high cost, between $ 8-12,000 per patient and year. Consequently, it must be expected that the part of total costs represented by drugs has increased, from essentially a very minor part in the nineties (2-5%) to a much larger proportion. However, no studies investigating this development from a societal perspective have so far been published. Objective The objective of this study was to investigate the current cost structure in MS and the effect of disease severity on costs and quality of life (utility) for patients treated with the new disease modifying drugs (DMDs) in the US. Methods The study follows closely the methodology used in three previous observational studies in Sweden, the United Kingdom and Germany. It is a descriptive bottom-up prevalence-based cost of illness study. The analysis was performed from the societal perspective and did not investigate costs for different payers. Costs were calculated as mean annual cost per patient in the sample, and mean costs for patients using a given resource. All unit costs are for 2004, or were inflated to 2004 using the CPI. Demographic variables, information on disease severity and disease activity, resource utilization and utility were collected directly from a sub-sample of ~24,000 patients taking part in a regular follow-up since up to 8 years, the North American Committee on Multiple Sclerosis (NARCOMS) Patient Registry. A questionnaire was mailed to a 4,000 randomly selected sample and the target answer rate was 50%. Results 1,989 (49.7%) of patients contacted returned the questionnaire, but 80 of them were returned empty and had to be excluded. This left a sample of 1,909 (47.7%) for analysis. The mean age of the sample was 49 years and three quarters were women. Their age at first symptoms was 30 years, and time since diagnosis was 13 years. 10.5% of patients had primary progressive, 47.6% relapsing-remitting and 33.3% secondary progressive disease. Less than 1% of patients did not answer the question, but 7.6% were unsure. 28.8% of patients indicated to have experienced a relapse during the past 3 months. 34.8% had mild, 42.7% had moderate and 22.1% had severe disease. Slightly less than one third (31.4%) was in early retirement due to MS. Total costs are estimated at $ 47,215 per patient and year. The largest proportions of costs are indirect costs ($ 17,581 or 37.2%) and drugs ($ 18,628 or 39.5%). Of the latter, disease modifying drugs accounted for 86% of total drug cost and 34% of total costs ($ 16,050), while OTC medication amounted to $ 122. Informal care represented 9.8% ($ 4614) and services and investments, which were to a large extent paid for by patients themselves, amounted to $ 2707 per patient (5.7%). Using the new (unpublished) US health status system, the mean utility in the sample was 0.698, with women having higher utility than men (0.709 versus 0.667). Patients who had experienced a relapse in the past 3 months had a utility of 0.648, compared to 0.742 for those who did not. On the absence of published gender and age specific population values in the US, the UK tariff has been used to estimate the age and gender specific utility loss of MS patients compared to the normal population. The loss of quality-adjusted life years (QALYs) was estimated at 0.255 QALY/patient. Using a willingness to pay for a QALY of $ 60000, intangible costs were estimated at $ 15,315. Costs increased and utility decreased with decreasing functional capacity. Patients with mild disease had a cost of $ 32,297 and a utility of 0.824; figures for patients with moderate MS were $ 50,293 and 0.679, and for patients with severe MS $ 64,492 and 0.533. The proportion of bed-ridden patients in the sample (EDSS 8.0 or more) was small compared to the expected prevalence. When the proportion was increased to 4%, costs for patients in the severe group increased slightly to $ 65,173 and utility decreased to 0.479. Thus, it appears that the effect of very severe disease is more pronounced on patients’ quality of life than on costs. Conclusions The objective of this study was to investigate the overall costs for patients treated with the new MS therapies, and cost distribution among different resources after the introduction of the new MS treatments. In view of the high cost of these treatments, our results are not surprising, with MS drugs representing 34% of total costs. When the use of disease modifying drugs is adjusted to the estimated national average (52%), the share of costs represented by these drugs is 21%. The findings are consistent with previous studies into the cost of MS: costs and utilities are significantly correlated with functional capacity (EDSS). This study does not investigate the value of the investment in these treatments. Rather it provides the necessary input into a disease model where costs and utility are linked to disease progression, without treatment, or with different treatments.