The economic cost of MS is largely driven by indirect costs that are linked to early and very high unemployment rates [1,2,3,4, 17, 18]. As stated earlier, this study provides a better understanding of the impact of MS on Spanish patients’ working activity, allowing for an updated estimation of the indirect costs of MS. Our study shows an employment rate of 47.2% and a mean age of retirement of 43.6 years in a clinically stable sample of 199 pwMS mostly with a low level of physical disability (median EDSS score of 2.0). Almost a quarter (22.4%) of pwMS retired early because of the condition and 7% received an incapacity benefit or pension due to MS. Ten percent of the population had sick leaves (absenteeism was seen in 90.9% of the student population and 30.9% of the employed population). Costs associated with work limitations to employed subjects were almost seven times greater than costs from professional support and 30 times greater than costs from informal caregiving. Among all costs, those with the higher value are the costs associated with premature retirement according to our sample population (women fully incorporated into working life). These results are consistent with several prior studies. Kobelt et al. found that productivity losses and informal care dramatically increased from €593 at early-stage disease to nearly €34,228 at EDSS scores > 7 [19]. Subsequently, the TRIBUNE study also showed the correlation between disability and economic impact [20]. The overall annual indirect costs associated with MS were estimated at between €207 and €440 million due to productivity losses caused by lost work hours and early retirement (27 and 33% of the total cost, respectively) [21, 22].
A high rate of unemployment also occurs at a level of disability which is typically not associated with overt physical disability [1, 17]. Less visible symptoms and difficulties including cognitive impairment, fatigue, anxiety and depression are reasons for low productivity and unemployment at low EDSS scores. Kobelt et al. also found an employment rate of 45% in a sample of 462 pwMS in Spain with an EDSS score between 0 and 3 [23]. Fatigue and cognitive complaints were found in 92 and 64% of participants, respectively. Fatigue and cognitive disturbances are much more common than mobility problems in people who are working [8, 19]. MS-related productivity loss due to presenteeism was three times that of absenteeism in a study with 740 MS employees conducted in Australia [4]. The mean total work productivity loss was 2.5 days (14.2% loss in productive time), based on an absenteeism of 0.6 days (3.4%) and a presenteeism of 1.9 days (10.8%), leading to a €4578 loss per person annually. Work productivity was determined mostly by fatigue, cognitive impairment, pain and sensory symptoms [4].
There is increasing evidence to advocate the use of more effective therapies at earlier stages of the disease [24,25,26,27]. The IMPrESS study showed that pwMS treated earlier in the course of the disease showed a trend towards lower total (€39,037 vs €42,996), indirect (€15,733 vs €18,934) and disease-modifying therapy (€19,364 vs €20,491) costs and a better health-related quality of life status (0.62 vs 0.56; p < 0.01) compared to those receiving late treatment [3]. Chen et al. found that pwMS receiving high-efficacy disease-modifying therapy reported significant increases in amount of work, work attendance and work productivity compared with those using first-generation injectable treatments [27].
Our study has several limitations. Recall bias is a common concern of studies using self-reported data. The relatively small sample size and the cross-sectional design could be additional limiting factors of this study. A salary was set based on the range indicated by the participant (mid-point). For cases where only the salary at the time of diagnosis was available, the point of the range was adjusted using the CPI for the respective year. Another limitation is not having considered the time lost due to disease for pwMS without paid work, since it was unknown during the study.