Do workers with chronic nonspecific musculoskeletal pain, with and without sick leave, have lower functional capacity compared with healthy workers?

Objectives: (1) To analyze whether functional capacity (FC) of sick listed workers with chronic nonspecific musculoskeletal pain (CMP) referred for rehabilitation (SL-Rehab group) and workers with CMP who stay at work (SAW group) differ from the FC of healthy workers (HW group). (2) To analyze if FC of workers with CMP is insufficient to meet work demands, and to assess factors associated with insufficient FC.

Design: A 3-group cross-sectional comparison.

Setting: Rehabilitation center.

Participants: Workers (N=942) were included (SL-Rehab group: n=122, SAW group: n=119, and HW group: n=701).

Interventions: All subjects performed a short Functional Capacity Evaluation (FCE) and completed questionnaires assessing demographics, personal, and work characteristics.

Main outcome measure: FCE performances. Participants' FC was insufficient to meet their work demands when their FC was lower than the 5th percentile of the HW group's FC.

Results: Both the SL-Rehab and SAW groups had significantly lower FC compared with the HW group; 15% to 71% demonstrated insufficient FC. Insufficient FC was associated with group status (SL Rehab group: odds ratio [OR]=6.5; SAW group: OR=7.2), having physically high demanding work (OR=35.1), being a woman (OR=35.7), higher age (OR=1.2), and lower effort level during FCE (OR=1.9). Among subjects with CMP, kinesiophobia, physical health, and perceived disability were associated with having an insufficient FC for work.

Conclusions: Workers in the SL-Rehab group have lower FC than their working counterparts. Many workers in both groups with CMP demonstrated insufficient FC. Not the pain itself, but personal and work-related factors are related to insufficient FC.