Background Even now, in clinical practice, most of RA patients have long-standing disease and structural damage in their joints. Reconstructive joint surgery should be needed for further improvements of physical function for long-standing RA patients. It is very important to understand how much range of motion (ROM) should be needed to gain better physical function in each case.
Objectives The purpose of this study is to explore the characteristics of functional impairment in RA patients who were needed joint surgery based on ROM of joints using multicenter prospective cohort.
Methods We conducted this prospective study from 2012 to2015 (Study registration: UMIN000012649) We collected data on age, sex, disease duration, drug therapies, disease activity, and physical functional including HAQ-DI. Joint range of motion including shoulder, elbow, wrist, hip knee ankle was also measured. ROM in each joint by disability in HAQ-DI categories was compared by ANOVA with adjustment of age and sex. Association between ROM of each joint and no disability of daily activity in each 8 HAQ-DI categories was determined using ROC curve and logistic regression analysis.
Results 460 patients who have data of ROM of any joints in registry were analyzed. Mean values for age, disease duration, DAS28-CRP and sex were 64.6 years, 16.9 years, 3.17, and 86.3% female, respectively. Median values for CRP was 0.2 mg/dl. We could find significant association between ROM and disability in HAQ-DI category based on area under the ROC curve. ROM of each joints had different impact on disability of each category (ie, ROC curve for category Arising, Fig. 1). The cut-off values of ROM of each joints for daily activity in each HAQ-DI category was shown in Table 1 using ROC curves (Table 1). Multivariate analysis adjusting disease activity, age, and sex, showed which joint had significant impact on disability of each category (Table 2).
Conclusions ROMs of the joints were significantly associated with functional impairment. The information should be important for assessment of disability in patients with long-standing RA. The cut-off of ROM as shown in this study could be target of surgical procedure. It will be validated by further analysis of longitudinal data of this study.
Acknowledgement This study was supported by grant from the Japanese Ministry of Health, Labour and Welfare.
Disclosure of Interest None declared