Factors associated with hand and upper arm functional disability in people with rheumatoid arthritis: A systematic review

Objective: This original systematic review aimed to summarize evidence within observational studies on the factors associated with hand functional disability in adults with rheumatoid arthritis (RA). Methods: A rigorous extensive systematic literature search was conducted in 6 medical databases for peer‐reviewed English language observational studies that explore the factors associated with hand function for people with RA. Factors were critically classified under the domains of the International Classification of Functioning, Disability and Health (ICF) framework and health‐related factors. The methodologic quality was determined using the appraisal tool for cross‐sectional studies. Factors related to hand function that were investigated in ≥2 studies were explored using a best‐evidence synthesis. Results: Twenty articles from 1,271 citations met the inclusion criteria. All presented cross‐sectional data (5 high‐quality and 15 low‐quality articles), resulting in limited evidence in the best‐evidence synthesis. For the factors classified under the ICF domains, the best‐evidence synthesis indicated that a diverse range of positive and negative factors were associated with hand function. However, key factors were hand strength, disease activity, and pain intensity. It is evident that few sociodemographic factors have been explored for the association with hand function. Conclusion: Although the level of evidence was limited, modifiable factors such as grip strength, disease activity, and pain were identified as the most influential factors on hand function in people with RA. The findings of the present review indicate that important sociodemographic factors that impact hand function in individuals with RA have not yet been considered or reported in clinical research.