SSE/EFI Working Paper Series in Economics and Finance
Costs and Quality of Life in Multiple Sclerosis A Cross-Sectional Study in the USA
(), Jenny Berg
(), Debbie Atherley, Olympia Hadjimichael and Bengt Jönsson
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.
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.
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%.
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.
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.
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.
Keywords: Costs; Quality of Life; Multiple Sclerosis; (follow links to similar papers)
JEL-Codes: I10; I12; (follow links to similar papers)
76 pages, March 31, 2005
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