Work Ability and Employment in Rheumatoid Arthritis: A Cross-Sectional Study on the Role of Muscle Strength and Lower Extremity Function

Abstract

Objective The aim of the present study was to assess the association between muscle strength, lower extremity function, employment status, and work ability in RA patients. Methods One hundred seropositive RA outpatients of working age were included in this cross-sectional study. Employment status was assessed by interview and work ability by the Work Ability Index-Single Item Scale (WAS). Muscle strength was determined using dynamometer measurement of isometric hand grip and knee extensor strength. Lower extremity function was measured using the short physical performance battery (SPPB). Regression models estimate the association between unemployment, work ability and muscle strength, and lower extremity function, controlling for sociodemographic and disease-related factors. Results Forty-one percent of the RA patients were not gainfully employed, and their median work ability had a good WAS value (7.00 [4.00-7.00]). Patients with better knee extensor strength (OR=1.07, 95% CI [1.02-1.12) and better physical performance (OR=1.71, 95% CI [1.18-2.49]) had a significantly better chance of gainful employment. The odds for hand grip strength remained significant when adjusted for sociodemographic (OR=1.5, 95% CI [1.00-1.09]), but not for disease-specific variables. Better hand grip strength (β=0.25, p=0.039) and better knee extensor strength (β=0.45, p=0.001) as well as better lower extremity function (SPPB) (β=0.51, p<0.001) remained significantly associated with work ability following adjustment for sociodemographic and disease-specific variables. Conclusions The association of employment status and work ability with parameters of physical fitness suggests that improvement in muscle strength and lower extremity function may positively influence work ability and employment in individuals with RA.

Normative reference values and physical factors associated with work ability: a cross-sectional observational study

“…This study has highlighted a significant association between physical performance and work ability by investigating a comprehensive physical profile that encapsulates strength, flexibility and several gross motor, fine motor and balance tests. Our modest correlations between work ability and strength and flexibility have also been reported in previous studies (r=0.16 to 0.368, p<0.05) 16–20 33. However, previous studies have assessed the flexibility of only a single joint20 and limited strength measures such as grip16 19 33 or knee strength 17 18 33.…”

“…Our modest correlations between work ability and strength and flexibility have also been reported in previous studies (r=0.16 to 0.368, p<0.05) 16–20 33. However, previous studies have assessed the flexibility of only a single joint20 and limited strength measures such as grip16 19 33 or knee strength 17 18 33. Few studies have investigated the relationships between multiple functional measures and work ability.…”

“…However, the reasons for sick leave are not assessed and may relate to factors other than work ability, such as carer responsibilities. Work ability was significantly higher in employed individuals, which matches the findings of studies that attribute employment to better physical and mental health, job stability and confidence in the ability to work at maximum capacity 1 33. Some studies report that blue/intermediate collar workers have lower work ability due to greater exposure to biomechanical stresses 19 30 34–36.…”

“…Those that investigated functional measures such as balance also reported greater associations with work ability (OR 3.6 to 6.5, 95% CI 1 to 12.7) than with strength or flexibility and hypothesised that functional measures give a more global representation of health than measures of a single muscle or joint in isolation 18 21. Comparison with other studies investigating physical performance and work ability is difficult; this is due to the collection of information on physical capabilities by self-report33 and the use of tests not yet validated such as the Five Step Test21 33 or functional balance assessments on a wooden plank 16–18 21…”

Illuminating an Invisible Epidemic: A Systemic Review of the Clinical and Economic Benefits of Early Diagnosis and Treatment in Inflammatory Disease and Related Syndromes

“…The peak onset of adult RA typically occurs within the sixth decade of life [19,74]. Ultimately, joint destruction can lead to loss of physical function, an inability to carry out daily activities, and can result in difficulty maintaining employment [75].…”