Seropositive Rheumatoid Arthritis Clinical Trial
This study compares workability in subjects with seropositive rheumatoid arthritis (RA) in the working age with high and low disease activity. Further 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). Methods include a physical examination, questionnaires and physical tests.
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%.
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