Background/Purpose:  The prevalence of multimorbidity (≥ 2 chronic morbidities in 1 person), is increasingly common also in patients at working age. Musculoskeletal diseases (MSKD) are among the most frequently occurring chronic diseases and comorbidities. However, little is known about the association of multimorbidity with official work disability and even less about its association with economic unemployment or dependence on living allowances (LA). Also, the additional influence of MSKD as comorbidity is unclear. We aimed to explore 1) whether an increasing number of morbidities is associated with increased odds to be work disabled (WD), unemployed or depending on LA & 2) whether presence of MSKD is associated with these outcomes or has an important additional contribution when combined with other morbidities.

Methods: In a Dutch epidemiological study, 8904 subjects (≥18 years old) completed a questionnaire on socio-demographic and lifestyle factors, self-reported physician-diagnosed diseases & work status. Persons at working age (18-65 years) who were either employed, formally WD, economically unemployed or receiving LA were included in the analyses (n=5396). Two multinomial regression models were computed with work status (i.e. employed, WD, unemployed or LA) as outcome and adjusted for age, gender, education, body mass index and smoking status. In model 1 the number of morbidities was the independent variable of interest and in model 2 either the single diseases (distinguishing MSKD from all other single diseases) or combinations of 2 or ≥3 diseases, including and excluding MSKD. Paid employment was used as reference outcome and estimates were compared to the healthy.

Results: MSKD occurred in 925 cases (17%) of the sample. Multimorbidity was present in 755 cases (14%). Of all cases with 2 morbidities 265/490 (54%) reported a MSKD. In cases with ≥3 morbidities 198/265 (75%) reported a MSKD .The odds to be WD increased steeply with every additional morbidity and the same trend but less pronounced was seen for unemployment and dependence on a LA (Table 1). Small (but no significant) increments were seen when exploring the role of MSKD in multimorbidity (e.g. the odds to be WD were 9.2 times higher than to be employed for persons suffering from 2 morbidities including MSKD and these odds were somewhat lower (8.8) when none of the 2 morbidities was MSKD). The odds to be unemployed or to receive a LA were slightly (but not significantly) higher for persons suffering from 2 co-occurring morbidities when 1 of these was a MSKD compared to 2 co-occurring morbidities without MSKD. (Table 1)

Conclusion:  An increasing number of morbidities is associated with increased odds of WD, and to a lesser extent also with unemployment and dependence on a LA. There is a small additional adverse influence of the co-occurrence of MSKD in those suffering from 2 morbidities on all work outcomes. Multimorbidity requires more attention in considering patients’ work outcome.