Workability in Patients With Seropositive Rheumatoid Arthritis

Chronic diseases like RA are negatively associated with workability and RA has been shown to be an economic burden for society and patients. RA patients seem also to be more prone to frailty which is characterized by slowed walking speed, low physical activity, and low grip strength. Also poor sleep has been shown to negatively influence work ability and the majority of patients with RA experience insomnia, general fatigue and mental fatigue. RA has also been shown affect sexual functioning.

This monocentric cross sectional study will be conducted at a Viennese rheumatological outpatient clinic and day hospital on about 100 seropositive RA patients. The primary objective of this study is to compare workability in subjects with seropositive RA in the working age with high and low disease activity. Secondary interest is to clarify the influence of frailty, functional ability and muscle strength on workability and to determine the effect of disease activity on selected physiological needs (sleep quality, sexual functioning). Disease activity will be assessed during the patient's routine visit at the clinic via the clinical disease activity index (CDAI). Workability will be determined by the Work Ability Index questionnaire. The influencing determinants frailty and functional disability will be also assessed via questionnaires and/or with physical examinations (Survey of Health, Ageing and Retirement in Europe Frailty instrument, Short Physical Performance Battery, Health Assessment Questionnaire-Disability Index). For muscle strength assessment hand grip and maximum quadriceps strength will be measured . Contributing physiologic needs quality sleep and sexual functioning will be additionally determined vial self reported questionnaire (Medical Outcome Study -Sleep Scale, Index for sexual functioning).

In order to compare patients with low and high disease activity regarding metric data (like sleep quality or sexual functioning) unpaired Students t-tests (given normal distributed data and homogeneous variances), Welch corrected unpaired Student t-tests (in case of normal distributed data but heterogenous variances) or Mann-Whitney-U tests (in case of skewed data) will be used. Kolmogorov-Smirnov and Levene tests will be used to test for normal distribution and homogenous variances.To assess the impact of frailty, functional ability, muscle strength on workability (high versus low) binary logistic regression will be applied. In general the alpha level is set to 5%.