Employment status of people with multiple sclerosis in relation to 10-year changes in functioning and perceived impact of the disease

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Multiple Sclerosis and Related Disorders

journal homepage: www.elsevier.com/locate/msard

Original article

Employment status of people with multiple sclerosis in relation to 10-year changes in functioning and perceived impact of the disease

David Moulaee Conradsson ^a,b,1 , Mia Forslin ^a,c,d,1 , Katharina Fink ^e,f , Ulla Johansson ^g , Lena von Koch ^h,i , Sverker Johansson ^{a,b, ⁎}

a

Department of Neurobiology, Care Sciences and Society, Division of Physiotherapy, Karolinska Institutet, Stockholm, Sweden

b

Allied Health Professionals Function, Medical Unit Occupational Therapy and Physiotherapy, Karolinska University Hospital, Stockholm, Sweden

c

Rehab Station Stockholm, Solna, Sweden

d

Physioterapy Specialist Care Hudiksvall, Region Gävleborg, Hudiksvall, Sweden

e

Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden

f

Academic Specialist Centre, Center for Neurology, SLSO, Stockholm, Sweden

g

Centre for Research & Development, Uppsala University/Region Gävleborg, Gävle, Sweden

h

Department of Neurobiology, Care Sciences and Society, Division of Primary Health Care and Family Medicine, Karolinska Institutet, Stockholm, Sweden

i

Karolinska University Hospital, Theme Neuro, Stockholm, Sweden

A R T I C L E I N F O Keywords:

activity limitation employment impairment longitudinal studies participation restriction

perceived impact of multiple sclerosis

A B S T R A C T

Background: Although it is well known that people with multiple sclerosis (PwMS) retire from work early, little is known about how long-term changes in functioning and perceived impact of multiple sclerosis (MS) interact with sustainability of employment.

Objective: To explore changes in functioning and in perceived impact of MS over 10 years, in relation to em- ployment status of PwMS.

Methods: In order to measure functioning, data on activities (walking ability, fine hand use, personal activities in daily living); participation in activities of everyday life (domestic, outdoor and leisure activities); body functions (cognitive function, fatigue, depressive symptoms); and perceived impact of MS were collected in 116 PwMS at baseline and at a 10-year follow-up. Ten-year changes were explored with the participants divided into four subgroups based on employment status at the follow-up: 1) full-time work at the 10-year follow-up; 2) part-time work at the 10-year follow-up; 3) declined from working at baseline to not working at the 10-year follow-up; and 4) not working at baseline nor at the 10-year follow-up.

Results: Patterns of change in functioning for PwMS who worked showed a more apparent deterioration over 10 years among those working part-time with regard to walking ability, fatigue and depressive symptoms. Members of the subgroups who declined from working at baseline to not working at the 10-year follow-up or who were working neither at baseline nor at the follow-up deteriorated the most in functioning. The subgroup whose employment status declined from baseline to follow-up showed a significant decrease in cognitive function and an increase in perceived physical impact of the disease. All subgroups experienced a deterioration in walking ability over the 10-year span, and in all subgroups a majority had limited fine hand use over the span of the study period.

Conclusion: The deterioration in functioning was most apparent in those PwMS whose employment status de- clined from working at baseline to not working at the 10-year follow-up. Close monitoring of work situation and frequency of activities and participation in everyday activities, as well as recurrent training of functioning, are suggested for maintaining a high level of functioning and work status, or for supporting transition to an ap- propriate number of working hours.

https://doi.org/10.1016/j.msard.2020.102519

Received 15 June 2020; Received in revised form 19 August 2020; Accepted 15 September 2020

⁎

Corresponding author at: Sverker Johansson, Karolinska Institutet, Department of Neurobiology, Care Sciences and Society, Division of Physiotherapy 23100, 14183 Huddinge, Sweden.

E-mail address: sverker.johansson@sll.se (S. Johansson).

1

David Moulaee Conradsson and Mia Forslin equally contributed as the first author.

2211-0348/ © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/BY/4.0/).

T

Introduction

Many people with multiple sclerosis (MS) retire from work rela- tively early (Berg et al., 2006, Brundin et al., 2017). It has been re- ported that 43% of people with MS (PwMS) have stopped working three years after diagnosis, and the corresponding figure after 10 years is 70%

(Jones et al., 2016). Sick leave is common (Chruzander et al., 2016), often starting before the diagnosis of MS has been made (Landfeldt et al., 2016, Murley et al., 2018). The low rate of work by PwMS results in increased costs for society (Berg et al., 2006, Brundin et al., 2017, Gyllensten et al., 2018, Kavaliunas et al., 2015) and is associated with a lower quality of life for these people (Pack et al., 2014, Krause et al., 2013).

In the International Classification of Functioning, Disability and Health (The International Classification of Functioning 2001), func- tioning comprises two components: 1) body functions/structures, and 2) activities and participation. Disability is the umbrella term for im- pairments in body functions and structures, activity limitations and/or participation restrictions. The impact of changes in functioning on employment status or on the balance between activities in working life and valued activities in everyday life except work, among PwMS, is not well understood. A work-life balance, i.e. a good balance between multiple life-roles (Haar, 2013), has been found to be positively related to work and life satisfaction (Haar et al., 2014), and it has been sug- gested to be of value for a sustainable working life (Forslin et al., 2018, Richert-Kazmierska and Stankiewicz, 2016). Nevertheless, there are indications that PwMS experience difficulties in sustaining this balance (Meide et al., 2018, Vijayasingham et al., 2017, Johnson et al., 2004).

The difficulty in finding balance might be due to the concurrent pre- sence of impairments, activity limitations and participation restrictions caused by MS (Johansson et al., 2007), of which several have been reported to be associated with a declining employment status, e.g., limited walking ability (Goldman et al., 2013), limited fine hand use (Chruzander et al., 2016), fatigue (Simmons et al., 2010, Boe Lunde et al., 2014), impaired cognition (Honan et al., 2015) and depressed moods (Boe Lunde et al., 2014). Higher perceived disability has also been reported to be associated with work-related difficulties in PwMS (Raggi et al., 2019) as well as to how MS is perceived (Karhula et al., 2019). Continuing to work at a comparable level might come at a price of not having enough energy for activities outside of work (Johnson et al., 2004). However, if and how changes over time in functioning or in the perceived impact of MS on health are associated with employment status in PwMS have, to our knowledge, not been explored.

An increased understanding of how functioning and the perceived impact of MS may interact in a sustainable working life could be used to model interventions to support a sustainable working life and to maintain quality of life for PwMS. The aim of this study, therefore, was to explore changes over a 10-year span in functioning and in the per- ceived physical and psychological impact of MS in relation to the em- ployment status of PwMS.

Methods Participants

This study was based on a cohort of PwMS recruited in 2002 at an MS Centre in Sweden for a two-year longitudinal study of functioning, perceived impact of MS and use of healthcare among PwMS (Johansson et al., 2007, Ytterberg et al., 2008). In 2012, 10 years after baseline, a follow-up was performed with those participants who had completed the original two-year study, were still alive and consented to participate in the 10-year follow-up (Forslin et al., 2018, Conradsson et al., 2018). The present study included PwMS < 55 years of age at baseline and still of working age at the 10-year follow-up, i.e.,

< 65 years, the typical age of retirement in Sweden. Written informed

consent was obtained before inclusion. The ethical review board in Stockholm approved the study, registration number 2011/2068-31/5.

Ten-year changes were explored in the present study by dividing the participants into subgroups based on employment status at the 10-year follow-up. The constituted four subgroups were: 1) full-time work at the 10-year follow-up; 2) part-time work at the 10-year follow-up; 3) de- clined from working at baseline to not working at the 10-year follow- up; and 4) not working at baseline nor at the 10-year follow-up. Other ongoing activities– parental leave, studies, or other optional reasons for not working – were categorized as not working. Participants who were not working at the 10-year follow-up were divided into subgroups 3) or 4) in view of if their employment status had changed or not compared to baseline.

Data collection

The data collection was performed by physiotherapists at the MS Centre or in the participant's home. In a few cases, the 10-year follow- up data were collected via mail and telephone interview.

Data regarding education level, employment status, type of work and living situation were collected through interviews. Sex, age, time since diagnosis, type of MS and immunomodulatory treatment were collected from medical records. Disease severity was measured using the Expanded Disability Status Scale (EDSS) (Kurtzke, 1983).

The selection of functioning measures was based on existing lit- erature and clinical experience on plausible long-term associations with employment status. Data were collected with performance-based tests or questionnaires.

Measures of activity and participation were the following: The KATZ ADL Index Extended (Asberg and Sonn, 1989, Brorsson and Asberg, 1984), an index shown to be valid and reliable in elderly (Ferretti-Rebustini et al., 2015, Reijneveld et al., 2007), was used to assess personal activities in daily living (personal ADL). The Timed 25- Foot Walk Test (Kaufman et al., 2000) and the Nine-Hole Peg Test (Mathiowetz et al., 1985) was used to assess walking ability and fine hand use, respectively, both tests are recommended for use in PwMS (Rudick et al., 2002, Solari et al., 2005). The Frenchay Activities Index, including the subdomains domestic activities, outdoor activities and leisure activities (Holbrook and Skilbeck, 1983, Wade et al., 1985) was used to measure frequency of activities and participation in everyday life except work. This index has been shown to be valid and reliable in adults (Turnbull et al., 2000) and PwMS (Kierkegaard et al., 2012).

Measures of body functions were the following: The Symbol Digit Modalities Test (Smith, 1983), recommended as a cognitive screening instrument in PwMS (Dent and Lincoln, 2000), was used to assess cognitive function. The Fatigue Severity Scale (Krupp et al., 1989), developed for PwMS (Krupp et al., 1989) and psychometrically tested (Kleinman et al., 2000, Lerdal et al., 2005), was used to assess fatigue.

The Beck Depression Inventory (Beck et al., 1961) for which validity and reliability is considered good (McDowell, 1996), was used to assess depressive symptoms.

The Multiple Sclerosis Impact Scale (Hobart et al., 2001) was used to assess perceived physical and psychological impacts of MS, the scale has been psychometrically evaluated (Riazi et al., 2002).

Analyses

To present characteristics at baseline of the study participants and of those who were lost to 10-year follow-up descriptive statistics, especially mean (standard deviation) and numbers (percent), were used.

The cut-points presented in table 1 were used for the categorization

of PwMS as having limitation/restriction or no limitation/restriction in

activities and participation measures, and impairment or no impair-

ment in measures of body functions. Then, we classified changes in

activities and participation, as well as body functions, between baseline

and the 10-year follow-up according to four categories: 1) unchanged – limitation/impairment (i.e. limitation/impairment at baseline and follow-up); 2) declined activity/body function (i.e. limitation/impair- ment at follow-up but not at baseline); 3) unchanged - no limitation/

impairment (i.e. no limitation/impairment at baseline and follow-up);

and 4) improved activity/body function (i.e. limitation/impairment at baseline but not at follow-up). These categorical outcomes, reflecting the patterns of change between baseline and follow-up, were presented descriptively as percentages for each subgroup based on employment status.

Thereafter, within-group differences regarding changes in median and interquartile range of the studied variables – variables representing activities and participation, body functions and perceived physical and psychological impacts of MS – between baseline and follow-up for the subgroups were analysed. The Wilcoxon signed-rank test was used, as data were not normally distributed. Level of significance was set to

≤0.01 to decrease the risk of Type 1 error related to the multiple sta- tistical tests performed.

All statistical analyses were carried out using IBM SPSS, version 26.0 (SPSS Inc., Chicago, Illinois, USA).

Results

Characteristics of the sample

A total of 219 PwMS were enrolled in the study in 2002, 154 of them were < 55 years of age at baseline. Of them 38 PwMS were lost to the 10-year follow-up, either they declined participation (n=27) or were deceased (n=11). Thus, 116 PwMS < 55 years of age at baseline were included in the present study. Of them 28% and 23% worked full- and part-time at the 10-year follow-up, respectively, 24% declined in employment status from working to not working, and 25% were not working at baseline nor follow-up.

The participants’ baseline characteristics are presented in table 2.

Across the whole sample, the mean age was 41 years, about two-thirds were women, and had relapsing-remitting and mild MS (EDSS 0-3.5).

The majority of PwMS who worked full-time at the 10-year follow-up had, at baseline, mild MS, a high education level and sedentary work, whereas the corresponding numbers were lower in the other subgroups.

The subgroups working full-time or part-time at the follow-up had close to 10 years since diagnosis at baseline, about five years shorter com- pared to those not working.

Baseline characteristics of 38 PwMS < 55 years of age lost to follow-up are presented in Table 2. Mean age, sex and education level proportions among the PwMS lost to follow-up were similar to the participants completing the study. A majority of those lost to follow-up

were not working and about 40% had moderate or severe disease se- verity and/or progressive MS.

Changes in activities and participation

The patterns of change, as depicted in figure 1, showed that a ma- jority in the full-time and part-time working groups (≥80%) were classified as having no limitation in frequency of activities and parti- cipation in everyday life and in personal ADL at baseline and at the 10- year follow-up. The corresponding proportion for no limitation was around 50% for the declining working group and 30% for the not working group. The vast majority (≥90%) of those working full-time had no limitation in walking ability at baseline and at follow-up, whereas the corresponding proportion for the part-time working group was around 60%, for the declining working group 45%, and for the not working group around 10%. Irrespective of employment status, a ma- jority of PwMS was classified as being limited in fine hand use at baseline and at follow-up.

Frequency of activities and participation in everyday life decreased significantly in the subgroup working full-time, and in the subgroup declining from working to not working (see Table 3). There was a significant decrease in participation in outdoor activities in the part- time and declining subgroups. The declining subgroup also showed a significant decrease in participation in domestic activities. There was a significant decrease in personal ADL in all subgroups except in the part- time working group. Walking ability decreased significantly in all subgroups. The subgroups not working at the 10-year follow-up also demonstrated a significant decrease in fine hand use, while fine hand use in the working subgroups remained stable.

Changes in body functions

The patterns of change, as depicted in Figure 2, showed that a majority in the full-time working group showed no impairment at baseline or at follow-up in cognitive function (100%), with no fatigue (69%) and no depressive symptoms (81%). A majority (85%) in the part time working group demonstrated no impairment in cognitive function, while the corresponding proportions for no fatigue or no depressive symptoms were lower (33% and 33%, respectively). In the declining and the not working subgroups, about 50% of PwMS showed no im- pairment in cognitive function at baseline or at follow-up, while the corresponding proportions for fatigue and depressive symptoms were even lower (15% to 21%).

The only statistically significant change found in body functions was a decrease in cognitive function in the subgroup that had declined from working to not working during the 10-year span (see Table 3).

Table 1

Variables, instruments and criteria used for categorization of the independent variables.

Variables and instruments Criteria for categorization

Activities and participation

Personal ADL: KATZ ADL Index Extended (Asberg and Sonn, 1989, Brorsson and

Asberg, 1984) dependent in one or more items/independent

Walking ability: Timed 25-Foot Walk Test

^a

(Kaufman et al., 2000) limited ambulator (0−1.2m/s)/community ambulator (≥1.2m/s) (Fritz and Lusardi, 2009)

Fine hand use: Nine-Hole Peg Test

^a

(Mathiowetz et al., 1985) limitation (<0.5 pegs/sec)/no limitation (≥0.5 pegs/sec) (Kierkegaard et al., 2012)

Frequency of activities and participation in everyday life: Frenchay Activities Index

^b

(Holbrook and Skilbeck, 1983, Wade et al., 1985) restrictions (≤15)/no restrictions (≥15 points) (Turnbull et al., 2000) Body functions

Cognition: Symbol Digit Modalities Test

^b

(Smith, 1983) impairment (32<correct responses)/no impairment (32≥ correct responses) (Kierkegaard et al., 2012)

Energy (fatigue): Fatigue Severity Scale (Krupp et al., 1989) fatigue (≥5 points)/ no fatigue (<5 points) (Bakshi et al., 2000) Mood: Beck Depression Inventory (Beck et al., 1961) depressive symptoms (≥13)/no depressive symptoms (<13)

(Goldman Consensus, 2005)

a

Speed calculation/result was set to 0 for PwMS unable to perform the test.

b

The index consists of 15 items (score 0 – 3), and the item concerning work was excluded in the analyses. Therefore, the minimum-maximum score was 0 – 42.

Table 2

Baseline characteristics for all study participants (n=116) and by subgroups of employment status

^a

at the 10-year follow-up. In the table is also included the baseline characteristics of the participants < 55 years of age included at baseline but lost to 10-year follow-up (n=38).

Baseline characteristics All, n=116

n (%), mean (SD)

^b

Full-time work at follow-up, n=32

n (%), mean (SD)

^b

Part-time work at follow-up, n=27

n (%), mean (SD)

^b

Declined to no work at follow-up, n=28

n (%), mean (SD)

^b

No work at baseline and follow-up, n=29

n (%), mean (SD)

^b

Lost to follow- up, n=38

n (%), mean (SD)

^b

Women 78 (67) 20 (63) 21 (78) 18 (64) 19 (66) 26 (68)

Age, years 20-34 35-44 45-54

41 (9)

^b

26 (22) 46 (40) 44 (38)

39 (8)

^b

7 (22) 19 (59) 6 (19)

36 (10)

^b

12 (44) 8 (30) 7 (26)

45 ()

^b

2 (7) 10 (36) 16 (57)

43 (8)

^b

5 (17) 9 (31) 15 (52)

40 (8)

^b

12 (32) 13 (34) 13 (34) Education level

^c

Elementary school High School University

25 (21) 46 (40) 45 (39)

2 (6) 10 (31) 20 (63)

4 (15) 13 (48) 10 (37)

7 (25) 10 (36) 11 (39)

12 (41) 13 (45) 4 (14)

6 (18) 15 (44) 13 (38) Employment status

Full-time work Part-time work No work

49 (42) 32 (28) 35 (30)

26 (81) 2 (6) 4 (13)

15 (56) 10 (37) 2 (7)

8 (29) 20 (71) 0 (0)

0 (0) 0 (0) 29 (100)

9 (24) 9 (24) 20 (52)

Sedentary work

^d

66 (57) 22 (69) 14 (52) 19 (68) 11 (38) 14 (44)

Living alone 29 (25) 9 (28) 8 (30) 7 (25) 6 (21) 16 (42)

Living with

children <18 years 51 (44) 15 (47) 9 (33) 14 (50) 13 (45) 12 (32)

Yeas since diagnosis 0-10 11-20 21-30 31-40

12 (9)

^b

67 (58) 30 (26) 13 (11) 6 (5)

9 (8)

^b

21 (66) 9 (28) 0 (0) 2 (6)

9 (7)

^b

21 (77) 5 (19) 0 (0) 1 (4)

13 (10)

^b

14 (50) 7 (25) 5 (18) 2 (7)

15 (10)

^b

11 (38) 9 (31) 8 (28) 1 (3)

11 (7)

^b

19 (50) 15 (39) 4 (11) 0 (0) Type of MS

Relapsing remitting

Progressive 85 (73)

31 (27) 31 (97)

1 (3) 24 (89)

3 (11) 17 (61)

11 (39) 12 (41)

17 (59) 22 (58)

16 (42) Disease severity

Mild, EDSS 0-3.5 Moderate, EDSS 4-6.5 Severe, EDSS 7-9.5

81 (70) 24 (21) 11 (10)

31 (97) 1 (3) 0 (0)

23 (85) 4 (15) 0 (0)

17 (61) 8 (28) 3 (11)

10 (34) 11 (38) 8 (28)

22 (58) 5 (13) 11 (29)

Immunomodulatory treatment 100 (86) 27 (84) 23 (85) 25 (89) 25 (86) 25 (66)

a

Subgroups which at the 10-year follow-up worked; full-time, part-time, had declined from working at baseline to not working at 10 years, or were not working at baseline nor at the 10-year follow-up.

b

mean (SD)

c

Education level: for those lost to follow-up the information is based on n=34

d

Sedentary work, data collected partly two years after baseline. For those lost to follow-up the information is based on n=32

Figure 1. Classification reflecting patterns of change in frequency of activities and partici- pation in everyday life except work between baseline and the 10-year follow-up according to four categories: 1) unchanged limitation/

restriction at baseline and follow-up), 2) de- clined activity/participation, i.e., limitation/

impairment at follow-up but not at baseline 3)

unchanged no limitation/restriction at baseline

and follow-up, and 4) improved activity/par-

ticipation, i.e., limitation/impairment at base-

line but not at follow-up). These categorical

outcomes reflecting the patterns of change

between baseline and the 10-year follow-up

were presented descriptively as percentages for

each subgroup.

Table 3 Functioning and perceived impact of MS at baseline and at the 10-year follow-up in subgroups of employment status

a

. Data is presented as median and interquartile range.

Variables Full time work Part time work Declined work status Not working

Baseline 10-year follow-up

P-value

Baseline 10-year follow-up

P-value

Baseline 10-year follow-up

P-value

Baseline 10-year follow-up

P-value Activities and participation

Personal ADL (0-6) 6.0 (6.0−6.0) 6.0 (6.0−6.0)

.014

6.0 (6.0−6.0) 6.0 (6.0−6.0)

.025

6.0 (6.0−6.0) 6.0 (3.0−6.0) .003 6.0 (5.0−6.0) 3.0 (1.0−6.0) .001 T25FW

b

(m/s)

1.90 (1.75−2.16) 1.73 (1.52−1.97)

<.001

1.73 (1.56−1.98)

1.38 (0.97−1.72) <.001

1.52 (0.96−1.70) 0.88 (0.31−1.46)

<.001

0.97 (0.37−1.22) 0.14 (0.00−1.00)

<.001 NHPT

b

(pegs/s)

0.46 (0.40−0.53) 0.46 (0.38−0.52)

.458

0.44 (0.39−0.49)

0.41 (0.35−0.50) .375

0.37 (0.28−0.43) 0.30 (0.08−0.42)

<.001

0.33 (0.21−0.37) 0.22 (0.10−0.32)

<.001 FAI

c

(0-42)

36.0 (32.2−38.0) 34.0 (30.0−36.0)

.012

35.0 (29.0−36.0) 30.0 (24.0−38.0)

.071

29.0 (20.5−33.0) 18.0 (7.0−28.7)

.001

17.0 (11.0−27.5) 13.5 (5.5−19.0) .064

FAI subdomains

Domestic activities* (0-15)

13.0 (12.0−14.0) 12.5 (10.2−14.7)

.023

14.0 (11.0−15.0)

12.0 (11.0−14.0) .391

11.0 (6.5−13.0) 8.0 (3.0−13.0)

.006

9.0 (2.0−12.0) 3.0 (0.0−10.5) .041 Outdoor activities* (0-15)

12.0 (11.0−14.0) 11.0 (9.0−12.0)

.019

11.0 (10.0−12.0) 9.0 (7.0−11.0)

.008

8.0 (6.2−10.7) 3.5 (1.0−9.0)

.002

5.0 (3.0−9.5) 3.0 (0.0−7.0)

.017 Leisure activities* (0-12)

7.5 (6.0−8.7) 7.0 (5.0−9.7)

.611

8.0 (5.0−10.0) 7.0 (5.0−9.0)

.759

6.0 (4.0−8.0) 5.0 (4.0−6.0)

.116

5.0 (1.5−7.5) 5.0 (3.0−7.5) .321

Body functions

SDMT (correct responses/s)

0.56 (0.47−0.62) 0.57 (0.42−0.63)

.861

0.52 (0.42−0.61)

0.54 (0.40−0.66) .485

0.39 (0.29−0.50) 0.40 (0.26−0.45)

.012

0.34 (0.19−0.43) 0.29 (0.26−0.45)

.175 FSS (0-7)

3.4 (2.2−4.6) 2.9 (2.2−4.3)

.739

5.0 (3.8−6.0) 5.0 (3.9−6.1)

.809

5.3 (4.7−5.8) 5.7 (4.0−6.3)

.136

6.1 (4.7−6.4) 5.8 (3.6−6.6)

.259 BDI (0-63)

6.0 (2.0−8.0) 5.0 (1.0−6.7)

.181

8.0 (6.0−17.0) 7.0 (4.0−12.0)

.710

9.0 (5.0−11.0) 8.0 (6.0−10.7)

.819

14.0 (7.7−21.2) 9.0 (5.0−17.5)

.115

Perceived impact

MSIS

phys (0-100) 6.5 (2.0−21.0) 6.0 (2.0−15.0)

.914

22.0 (12.0−42.0)

27.0 (11.0−51.0) .809

42.0 (22.7−52.5) 46.5 (25.5−65.0)

.006

51.5 (32.7−66.7) 58.0 (38.0−81.0)

.211 MSIS

psychol (0-100) 19.0 (8.0−38.0) 19.0 (2.0−25.0)

.029

33.0 (19.0−58.0) 36.0 (8.0−47.0)

.330

38.0 (22.0−56.5) 26.0 (11.5−50.7)

.127

50.0 (19.7−63.0) 47.0 (25.0−69.0)

.602 Abbreviations: ADL: Activities of Daily Living; BDI: Beck Depression Inventory; FAI: Frenchay Activities Index; FSS: Fatigue Severity Scale; KATZ: Personal ADL: Katz ADL Index Extended; MSIS phys: Multiple Sclerosis Impact Scale, physical subscale; MSIS psychol: Multiple Sclerosis Impact Scale, psychological subscale; NHPT: Nine-Hole Peg Test; SDMT: Symbol Digit Modalities Test; T25FW: Timed 25 Foot Walk.

a

Subgroups which at the 10-year follow-up worked; full-time, part-time, had declined from working at baseline to not working at 10 years, or were not working at baseline nor at the 10-year follow-up.

b

No ability to perform the the Timed 25-Foot Walk Test or the 9-Hole Peg Test was reported as 0.

c

FAI: Self-report questionnaire, with a summed score 0-42 points. A higher score indicates higher frequency of social/lifestyle activities. The index consists of 15 items (score 0-3), and the item concerning work was excluded in the analyses. Therefore, the minimum-maximum score was 0-42.

Changes in perceived impact of MS

The declining subgroup showed a significant increase in perceived physical impact. No other significant changes in physical or psycholo- gical impact were found (see Table 3).

Discussion

In this study, changes in functioning – activities and participation, and body functions – and in perceived impact of MS, over a 10-year span, were explored in PwMS of different employment status. Our study showed that the patterns of change in functioning were more pro- nounced overall for PwMS who worked part-time than for PwMS working full-time. Further, the subgroups not working after 10 years deteriorated the most in functioning and in perceived physical impact, particularly the subgroup declining from working to not working. All subgroups experienced a significant decrease in walking ability across the 10-year span. Further, in all subgroups a majority had limited fine hand use during the study period, even if a decrease in fine hand use was significant only in the groups that were not working.

Our study disclosed that the patterns of change or significant de- crease over the 10-year span in functioning did not necessarily imply

that working life had ended. However, our results showed different patterns of change in the subgroups working full-time and part-time after 10 years; in particular, the subgroup working part-time presented large proportions of its members (43-52%) with limitation in walking ability and of experiencing fatigue and symptoms of depression at the follow-up. Our results confirm findings in previous studies (Goldman et al., 2013, Simmons et al., 2010, Boe Lunde et al., 2014) emphasizing the influence of these disabilities on working ability.

Further, they place a focus on the concurrent presence of various lim- itations and impairments that need to be considered when planning for the amount of work that is possible for each individual and also for how a good balance between multiple life-roles can be obtained. These findings are in accordance with qualitative studies where difficulties in sustaining work-life balance in PwMS were described (Meide et al., 2018, Vijayasingham et al., 2017, Johnson et al., 2004). In the working subgroups, the within-group changes were few. The group working full- time showed a significant decrease in frequency of activities and par- ticipation in everyday life except work and in personal ADL. In the participation subdomains, the part-time subgroup showed a significant decrease in outdoor activities, and the full-time subgroup showed a tendency to decrease in both outdoor and domestic activities. These results reflect challenges in work-life balance among PwMS still working either full-time or part-time; valued everyday activities might be given a lower priority to save energy for work.

In line with studies reporting associations between disability and employment status in PwMS (Chruzander et al., 2016, Boe Lunde et al., 2014, Busche et al., 2003), we found a more evident pattern of change over time in functioning in PwMS not working after 10 years compared to PwMS working full- or part-time. The subgroup declining from working to not working demonstrated a significant decrease in cogni- tive function, in line with previous research (Chruzander et al., 2016, Honan et al., 2015) that has shown that cognitive impairment has a strong impact on sustaining work life for PwMS. The declining sub- group and the subgroup that worked neither at baseline nor at the 10- year follow-up showed a significant decrease in outdoor activities. It has previously been reported that cognitive impairment is associated with restriction in outdoor activities, which also seemed to be relevant to the declining subgroup in the present study (Ben Ari Shevil et al., 2014). In addition, the declining group demonstrated over time a sig- nificant decrease in domestic activities and a significant higher per- ceived physical impact, which illuminates the progression of disability in this group. The results address the importance from a rehabilitative perspective of recurrent assessments of cognitive function and per- ceived impact, in order to assist the individual PwMS to develop or to start using available strategies for management of cognitive changes and higher perceived physical impact in relation to work. Such strate- gies for management of upcoming disabilities are likely to be important also with regard to participation in other valued everyday life activities.

Walking ability was the only variable that decreased significantly over 10 years in all subgroups, in line with previous research (Simmons et al., 2010). Walking speed has been reported as a predictor of sustained participation (Johansson et al., 2019) and as a predictor of sustainability of employment status in PwMS (Chruzander et al., 2016).

There could be multiple reasons for how walking can impact employ- ment status. Accessibility is one, where society and employers have a great responsibility to enable and not hinder employment when walking ability is limited. Attitudes are another, both in terms of the attitudes of the individual regarding asking for help and using appro- priate walking aids and/or wheelchairs, as well as physical and social attitudes expressed through their environment. On the other hand, the increased walking limitation was not related to declining employment status in all PwMS, which implies that PwMS might be able to com- pensate and continue working despite the presence of walking limita- tions. This might be a result of the content of working tasks where it is difficult for PwMS to continue with more physical demanding jobs.

Another explanation might be that changed working tasks make it Figure 2. Classification reflecting patterns of change in body functions between

baseline and the 10-year follow-up according to four categories: 1) unchanged

impairment at baseline and follow-up), 2) declined function, i.e., impairment at

follow-up but not at baseline 3) unchanged no impairment at baseline and

follow-up, and 4) improved function, i.e., impairment at baseline but not at

follow-up). These categorical outcomes reflecting the patterns of change be-

tween baseline and the 10-year follow-up were presented descriptively as

percentages for each subgroup.

possible to continue working.

A previous Swedish study reported that limited fine hand use was associated with future full-time disability pensions (Chruzander et al., 2016). In the present study, limited fine hand use decreased sig- nificantly in the subgroups not working across the study period. Limited fine hand use seems to impact largely on possibilities for working.

During the present study period, however, fine hand use was limited also in the subgroups working full-time or part-time, implying that other factors – other functioning or personal and/or environmental factors – might have contributed and enabled the possibility of con- tinuing to work despite limited fine hand use. The results call for further intervention studies targeting compensation for limited fine hand use in working life.

Fatigue did not change significantly across the study period in any subgroup; however, as depicted in Figure 2, the presence of and pat- terns of change of fatigue differed between the subgroup working full- time and the other subgroups. Our results may indicate that those working full-time had a disease course with a lower level of fatigue compared to the other subgroups. This is in line with previous studies where fatigue was identified as a contributor to decreased work ability (Kobelt et al., 2019) and a main driver for decreasing working hours in MS (Coyne et al., 2015). Depressive symptoms showed a similar pattern as fatigue, which also highlights how important it is for health care to monitor and treat mood disorders/disturbances in PwMS in order to support their working life.

The lower level of the perceived physical impact of MS in PwMS working that was elucidated in our cohort is in line with existing re- search, where PwMS who are working describe better perceived health compared to those not working (Krause et al., 2013, Haar et al., 2014).

Working is known to provide opportunities for social interaction, a sense of identity and financial security (Krause et al., 2013). There may be several reasons for the higher levels of perceived physical as well as psychological impacts in PwMS in the declining work and not working subgroups. The decrease and the lower levels of functioning in these subgroups compared to those still working may have an impact, as disabilities are reported to have a high impact on perceived health, e.g.

limited walking ability, fatigue and depression (Barin et al., 2018).

Clinical implications and further research

Based on our results, deterioration in functioning and increased perceived impact of MS were related to declining employment status or inability to work. Close monitoring of work situations and the fre- quency of activity and participation in everyday life except work, and recurrent training of various body functions and activities, are sug- gested for maintaining a high level of functioning and work or a tran- sition to an appropriate level. When disease progression has already caused decreased functioning, its consequences need to be addressed to not become barriers to a continued working life. The workplace needs to be accessible so as to not hinder people with walking difficulties. To promote continued work life, adapting work conditions (e.g. allowing for a slower pace) may also be beneficial for PwMS with disabilities such as limited fine hand use and impaired cognition. It is also possible that decreasing work earlier, or receiving more help to conserve energy, may prolong one's work life. Additional studies are required to enhance knowledge of early signs among PwMS of problems with work-life balance and how it can be best handled. Studies targeting compensation for limited fine hand use in the MS population are needed.

Methodological considerations

Strengths of this study were the long-term follow-up and the divi- sion of the sample into subgroups based on employment status, which made it possible to identify aspects of working life in PwMS not possible to identify when analysing the sample as a single group. However, the division of the sample into subgroups results in the statistical analyses

being less robust. To decrease the risk of Type 1 error related to the multiple statistical tests performed in the analyses, the level of sig- nificance was adjusted. Furthermore, the classification in subgroups in the present study was based on employment status at 10-year follow-up and did not include other activities (e.g. parental leave, studies), and other reasons for decrease in working hours (e.g., sick-leave). The led up to a pragmatic classification of four subgroups representing different work trajectories across the study period. Still, we acknowledge the importance and the need of further studies on reasons for change in employment status over 10 years in more detail. Another strength of this study was that the data was collected in a variety of modes: self- rated, performance-based, and complex measures such as frequency of activity and participation. A limitation of the study was that the content of the work that the participants did over the 10-year span, as well a description of the environments they worked in, was missing.

Our results reflect a Swedish MS cohort in which about 50% of the participants were working at the 10-year follow-up, despite an average MS duration of >20 years. This rate of employment is higher than previous studies, which report that 70% of PwMS retire from work about 10 years after diagnosis (Jones et al., 2016) and might be ex- plained by the support system in Sweden making part-time work pos- sible for people with disabilities.

Conclusion

There was a more apparent deterioration over 10 years in func- tioning in PwMS who worked part-time compared to those working full- time. However, the deterioration was most apparent in those PwMS whose employment status declined from working to not working, and they also showed significant changes in cognitive function and in per- ceived physical impact. All subgroups deteriorated in walking ability, and fine hand use was generally limited over the study period. Close monitoring of work situations and the frequency of activities and par- ticipation in everyday activities, and recurrent training of functioning, are suggested for maintaining a high level of functioning and main- taining work status, or for supporting a transition to an appropriate number of working hours.

Funding

This work was supported by the Doctoral School in Health Care Sciences at Karolinska Institutet, the Norrbacka-Eugenia Foundation, and Neuro Sweden.

CRediT authorship contribution statement

David Moulaee Conradsson: Data curation, Writing - original draft. Mia Forslin: Conceptualization, Data curation, Methodology, Writing - original draft. Katharina Fink: Conceptualization, Methodology, Writing - original draft. Ulla Johansson:

Conceptualization, Writing - original draft. Lena von Koch:

Conceptualization, Data curation, Methodology, Formal analysis, Writing - original draft. Sverker Johansson: Conceptualization, Data curation, Methodology, Formal analysis, Writing - original draft.

Competing interests

The authors report no declarations of interest.

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