Changes in disability in people with multiple sclerosis: a 10-year prospective study

Journal of Neurology https://doi.org/10.1007/s00415-017-8676-8 ORIGINAL COMMUNICATION Changes in disability in people with multiple sclerosis: a 10‑year prospective study David Conradsson1,2 · Charlotte Ytterberg1,2 · Lena von Koch3,4 · Sverker Johansson1,2 Received: 4 September 2017 / Revised: 7 November 2017 / Accepted: 8 November 2017 © The Author(s) 2017. This article is an open access publication Abstract Background Little is known about the long-term course of disability in relation with disease severity in people with multiple sclerosis (PwMS). Objective To explore changes in a broad spectrum of disability over 10 years in relation with disease severity in PwMS. Methods We conducted a longitudinal study of 155 PwMS who attended the MS Centre at Karolinska University Hospital, Stockholm. Disease severity was determined by the use of the Expanded Disability Status Scale (EDSS) and classified as mild MS (EDSS score 0–3.5) or moderate/severe MS (EDSS score 4–9.5). Ten-year changes in perceived physical and psychological impacts of MS, walking, cognition, manual dexterity, participation in social/lifestyle activities, and signs of depression were compared between PwMS with mild and moderate/severe MS at baseline. Results Although walking, manual dexterity, and cognition declined in both groups, only the moderate/severe group demonstrated that long-term increased physical impact of MS, increased wheel-chair dependency, and reduced participation in social/lifestyle activities. Perceived psychological impact of MS declined in both groups, while signs of depression were experienced by fewer in the mild group and remained unaltered in the moderate/severe group. Conclusion We found a more pronounced increase in disability across 10 years in individuals with moderate/severe MS compared to mild MS. These findings accentuate the importance of developing a variety of interventions that can be applied across the spectrum of disease severity. Keywords Disease progression · Epidemiology · Functioning · Longitudinal study · Mobility · Participation Introduction The progressive disability course of Multiple Sclerosis (MS) is leading to significant individual and societal burdens [1]. As MS typically is diagnosed between the ages of 20 and * David Conradsson 1 Division of Physiotherapy, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, 23100, Huddinge, 141 83 Stockholm, Sweden 2 Allied Health Professionals Function, Function Area Occupational Therapy and Physiotherapy, Karolinska University Hospital, Stockholm, Sweden 3 Division of Occupational Therapy, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden 4 Department of Neurology, Karolinska University Hospital, Stockholm, Sweden 40, most people with MS (PwMS) will likely experience disability across different areas of functioning for decades [2]. Therefore, understanding the course across a wide spectrum of disability is required to prioritize and optimize health services for PwMS. In line with the progressiveness of MS, the previous longitudinal studies have demonstrated increased EDSS scores over time [3–5] and a decline in the physical aspects of quality of life [4, 6, 7]. In contrast, psychological domains of quality of life have been shown to remain stable [7, 8] or even improve [6]. Similarly, although fatigue and signs of depression are common among PwMS, most studies have found unchanged levels over time [7, 9, 10]. Notably, a majority of these studies included a follow-up period of 4–6 years [4, 6, 8, 10], whereas few studies have monitored long-term disability for a decade or more. Although the aforementioned studies have provided significant information about the course of disability for PwMS, there are important limitations to the existing body 13 Vol.:(0123456789) Journal of Neurology of research. First, few studies have addressed the long-term course of disability in different groups of disease severity. In a study by Wynia et al. [8], the authors compared changes in self-reported disability across 5 years between PwMS with different severity levels of MS. While this study found a more prominent increase in disability for individuals with mild MS, a higher mortality rate was observed in the severe disease group [8]. These findings need to be confirmed and self-reported disability complemented with performancebased tests of functioning. Second, cross-sectional studies have demonstrated that disability in walking, manual dexterity, and cognition is associated with increased activity limitations [11, 12], or a decreased quality of life in PwMS [2]. However, few long-term studies have conducted a detailed assessment to evaluate the progression of disability in relation with activities of daily living (ADL) and participation. Finally, although immunomodulatory treatment has shown promising impact on the course of the disease severity in PwMS [13], the previous long-term studies have evaluated cohorts, where a minority have received immunomodulatory treatment (15–40%) [3, 5, 9]. In this explorative study, we aimed to investigate changes in a broad spectrum of disability over 10 years in a cohort of PwMS who, to a large extent, received immunomodulatory treatment. More specifically, we aimed to compare changes concerning disease severity, perceived physical and psychological impacts of MS, walking ability, cognition, manual dexterity, fatigue, signs of depression, ADL, and participation in social/lifestyle activities between individuals with mild MS and with moderate/severe MS at baseline. Materials and methods Study design and participants This study was a 10-year prospective study in PwMS, and details of the baseline and short-term follow-ups of this cohort have been published elsewhere [2, 14]. Briefly, during the period between February 2002 and June 2002, consecutive PwMS who were scheduled for an outpatient appointment with a neurologist at the MS Centre of Karolinska University Hospital, Stockholm, Sweden were considered for enrolment in this study. Of the 255 eligible PwMS diagnosed according to Poser criteria [15], 219 agreed to participate. Participants were re-assessed in 2004 and 2012 for a 2- and 10-year follow-up. All participants were contacted and received information about the aim and procedures of the present study, and thereafter, written informed consent was obtained. This study was approved by the regional board of ethics in Stockholm, registration numbers 449/01 and 2011/2068-31/5, and was conducted in accordance with 13 the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. Data collection Data collection comprised standardized face-to-face interviews, self-reported questionnaires, and performance-based tests [2]. The 10-year follow-up occurred at the MS Centre or in the participant’s home. Demographic data (age and sex), disease duration (years), symptomatic pharmacolog (...truncated)