Background Musculoskeletal disorders, including inflammatory arthritis (IA), are among the most common reasons for work disability and sick leave. Early IA patients with risk factors for persistent and/or erosive disease, such as high swollen joint count (SJC), acute-phase reactants, RF- or ACPA-positivity, are treated aggressively to prevent joint damage and disability.
Objectives To study the rate of sick leave according to clinical diagnosis in an unselected very early IA cohort, and to investigate whether the predictors for sick leave are the same as the known predictors for persistent and/or erosive disease.
Methods Data from the Norwegian Very Early Arthritis Clinic (NOR-VEAC), a longitudinal observational study of adults with IA of ≤16 weeks' duration, were used. Exclusion criteria were arthritis due to crystal deposits, trauma, osteoarthritis and septic arthritis. For the present study we included patients eligible for work participation, i.e. <65 years with no retirement or disability pension, who had information about work in the baseline and six-month case report forms. Independent samples t-test, Mann-Whitney-U test or chi-square test were used as appropriate to compare patients on sick leave after 6 months with patients not reporting sick leave. Clinically relevant baseline variables with univariate p-value <0.2, as well as age and sex, were included in the multivariable logistic regression analyses with manual backwards selection to find predictors for sick leave after six months.
Results Of 880 patients eligible for analysis (<65 years, no retirement or disability pension), 664 (75.5%) had complete work participation data. Duration of joint swelling before inclusion [median (25–75 perc.)] was 35 (14–69) days, mean (SD) age 42.1 (12.1) years, 56.0% were females, 27.3% current smokers, and 22.4% anti-CCP and/or RF positive. The most common final clinical diagnoses were undifferentiated arthritis (35.2%), rheumatoid arthritis (22.1%) and reactive arthritis (19.7%).
The overall rate of sick leave at presentation was 37.7% and after 6 months 23.2%. More than one-third of the patients reported sick leave at first visit, regardless of diagnosis (Figure 1). At six months >20% sick leave was still reported in all groups except sarcoid arthritis and reactive arthritis. Smoking, low education (≤ high school), longer duration of joint swelling, ACPA and RF positivity, joint pain, fatigue, patient's global assessment, SF-36 (physical and mental component summary scores), HAQ-DI and tender joint count at baseline were univariably associated with sick leave after six months, whereas SJC, ESR and CRP were not. Independent predictors were current smoking (OR 2.1 (95% CI 1.4–3.2)), low education (OR 1.7 (95% CI 1.1–2.5)), longer duration of joint swelling and low SF-36 (physical and mental component summary scores).
Conclusions Sick leave in IA is common, even six months after diagnosis. Predictors for sick leave after six months were associated with lifestyle and level of education rather than factors commonly considered to be predictive for unfavourable arthritis outcomes. In early IA care, health care providers should focus not only on disease activity, but also on work ability and early facilitation efforts at work.
Disclosure of Interest E. S. Norli: None declared, G. Hetland Brinkmann: None declared, T. K. Kvien Consultant for: Tore K Kvien has received fees for speaking and/or consulting from AbbVie, Biogen, BMS, Boehringer Ingelheim, Celltrion, Eli Lilly, Epirus, Janssen, Merck-Serono, MSD, Mundipharma, Novartis, Oktal, Orion Pharma, Hospira/Pfizer, Roche, Sandoz and UCB, S. Lillegraven: None declared, O. Bjørneboe: None declared, A. Julsrud Haugen: None declared, H. Nygaard: None declared, C. Thunem: None declared, E. Lie: None declared, M. Mjaavatten: None declared