Background/Purpose:   In studies of rheumatoid arthritis (RA), disease activity and patient reported outcomes are often used as endpoints. However, these measures may not reflect the full impact of RA on function in all patients. The objective of this study were to: 1) investigate grip strength in early RA; 2) assess grip strength in patients with limited self-reported disability.

Methods:   An inception cohort of patients with early RA (symptom duration ≤12 months), recruited in 1995-2005, was investigated. Grip force (Newton, N) was measured using the electronic instrument Grippit (AB Detektor, Gothenburg, Sweden). Average and peak grip force values of the dominant hand were evaluated and compared to the expected, based on age- and sex-specific reference values from the literature (Nilsen T et al. Scand J Occup Ther 2012; 19: 288-96). The paired t-test was used for these comparisons and for analysis of changes in grip force between visits. At each visit, expected values were subtracted from observed grip force values, and delta values were used for age-corrected analysis of changes over time. Limited self-reported disability was defined as a Health Assessment Questionnaire Disability Index (HAQ-DI) score of ≤ 0.5.

Results:   A total of 225 patients with early RA (71 % women, mean age 60 years, 61 % RF positive, 57 % anti-CCP2 positive) were investigated. At baseline, the median HAQ-DI score was 0.75 (interquartile range 0.38-1.25). The mean baseline average grip force was 105 N [standard deviation (SD) 78], which was significantly lower than the corresponding expected values [266 N (SD 91) (p<0.001)]. Patients were managed according to usual care, with no pre-specified protocol for pharmacotherapy or rehabilitation. At 5 years, 44 % of the patients reported limited disability (HAQ-DI ≤ 0.5). The average grip force improved significantly from inclusion to the 12 month visit [age-corrected mean change: 34 N; 95 % confidence interval (CI) 26-43], and there was also some improvement between the 1-year and 5-year follow-up evaluations (age-corrected mean change 23 N; 95 % CI 14-32). At 5 years, the average grip force was still lower than expected overall (mean 139 N vs 244 N; p<0.001), and also among those with HAQ-DI ≤ 0.5 (mean 184 N vs 273 N; p<0.001). Similar patterns were observed for all comparisons of peak grip force values.

Conclusion:   Grip strength improved in early RA, in particular during the first year, probably due to effects of pharmacologic anti-inflammatory treatment and rehabilitation. A substantial proportion of the patients had limited self-reported disability at 5 years after diagnosis. Among these, there was however still a significant reduction in grip strength. This suggests that further efforts to improve hand function are important in early RA.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/despite-early-improvement-and-limited-self-reported-disability-patients-with-rheumatoid-arthritis-still-have-impaired-grip-strength-5-years-after-diagnosis/