O27 Frailty and co-morbidity in people with osteoarthritis and rheumatoid arthritis
Authors: Cook Michael J , Lunt Mark , Verstappen Suzanne M M , O'Neill Terence W 
Published: April 2021

Abstract
Background/Aims
People with osteoarthritis (OA) and rheumatoid arthritis (RA) are at increased risk of frailty, though the role of co-morbidities in contributing to frailty risk in these arthritides is uncertain. The aim of this study was i) to determine the association between common co-morbidities and frailty in OA and RA; and ii) to determine whether co-morbidities interact synergistically with OA and RA to increase the likelihood of frailty.
Methods
A cross-sectional analysis of the UK Biobank data was carried out. In this national cohort of participants aged 40-69 years, self-reported physician-diagnosed diseases including OA, RA, and common co-morbidities (including hypertension, coronary heart disease, diabetes, stroke/TIA, chronic obstructive pulmonary disease (COPD), and depression) were recorded. Frailty was assessed using a modification of the frailty phenotype (FP), comprising five components: self-reported weight loss, exhaustion, low physical activity (international activity questionnaire), slow walking speed, and low hand-grip strength. Pre-frailty and frailty, was identified based on the presence of 1-2 and ≥3 of these components, respectively. Among participants with OA and RA at baseline, the likelihood of being pre-frail or frail (vs not frail) at baseline among people with (vs without) each of the co-morbidities was assessed using multinomial logistic regression. To determine whether co-morbidities interact synergistically with OA and RA to increase the likelihood of frailty, deviation from additivity of risk was estimated by calculating the attributable proportion (AP) of risk due to biological interaction. An AP &gt; 0 indicates positive (synergistic) biological interaction. Analyses were adjusted for age, sex, smoking status, BMI, and deprivation.
Results
In total, 457,561 people were included in the analysis; 35,884 (7.8%) had OA and 4,894 (1.1%) had RA. Overall, the mean (SD) age was 56.5 (8.1) years and 54% were female. The overall prevalence of frailty was 3.4%. The prevalence of frailty was higher among those with OA (10.0%) and RA (18.6%). Each of the co-morbidities considered was associated with increased relative risk of pre-frailty and frailty particularly COPD in OA, relative risk ratio (95%CI): pre-frailty, 2.09 (1.80, 2.42) and frailty, 4.45 (3.71, 5.33) and stroke/TIA in RA: pre-frailty, 1.97 (1.18, 3.29) and frailty, 3.64 (2.11, 6.29). Most of the co-morbidities considered interacted synergistically with OA and RA to increase the risk of pre-frailty and frailty, particularly diabetes in OA, AP (95% CI): pre-frailty, 0.13 (0.04, 0.23) and frailty, 0.49 (0.42, 0.55) and stroke/TIA in RA: pre-frailty, 0.34 (0.003, 0.68) and frailty 0.60 (0.38, 0.82).
Conclusion
Co-morbidity is associated with an increased occurrence of pre-frailty and frailty among people with OA and RA and interacts synergistically with OA and RA to increase the likelihood of pre-frailty and frailty.
Disclosure
M.J. Cook: None. M. Lunt: None. S.M.M. Verstappen: None. T.W. O'Neill: None.