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Trajectories of future sickness absence and disability pension days among individuals with a new sickness absence spell due to osteoarthritis diagnosis ≥21 days: a prospective cohort study with 13-month follow-up
  1. Kristin Farrants1,
  2. Emilie Friberg1,
  3. Sara Sjölund1,2,
  4. Kristina Alexanderson1
  1. 1Division of Insurance Medicine, Karolinska Institutet Department of Clinical Neuroscience, SE-171 77, Stockholm, Sweden
  2. 2Department of Health Sciences, The Swedish Red Cross University College, Stockholm, Sweden
  1. Correspondence to Dr Kristin Farrants; kristin.farrants{at}


Introduction Osteoarthritis is one of the most common types of musculoskeletal diagnoses also among working-age populations, and often leads to long-term sickness absence (SA) spells or even disability pension (DP).

The aim was to identify future trajectories of days of SA and/or DP among people with a new SA spell due to osteoarthritis that became ≥21 long, and to investigate sociodemographic and morbidity characteristics of individuals in identified trajectories.

Methods This is a prospective population-based cohort study using data from several Swedish registers. We studied future SA/DP among all 4894 individuals aged 16–64 years who, during the first 6 months of 2010, had an incident SA spell due to osteoarthritis (ICD-10 codes M15-19) ≥21 days. Using group-based trajectory modelling, we identified trajectories of mean SA/DP net days/month and 95% CIs for the 13 months from the 21st day of the index SA spell. Sociodemographic and morbidity characteristics were compared by χ2 tests and multinomial logistic regression.

Results We identified five trajectories of SA/DP days: ‘fast decrease’ (36% of the cohort), ‘medium fast decrease’ (29%), ‘slow decrease’ (15%), ‘fluctuating’ (12%) and ‘late decrease’ (8%). Individuals in the two trajectories who still had SA/DP days at end of follow-up (late decrease and fluctuating) were more likely to be older, born outside the EU and have indicators of more severe morbidity than those in the other trajectories.

Conclusion Five trajectories of future SA/DP days were identified; 80% of the cohort belonged to trajectories with no SA/DP by the end of follow-up. Identifying trajectories of future SA/DP provides new insights regarding the developments of SA/DP over time among people on SA due to osteoarthritis; not only days in the initial SA spell but also in new spells during follow-up need to be included for a better understanding.

  • sick leave
  • disability pension
  • osteoarthritis
  • return to work

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  • Contributors KF contributed to the analysis and interpretation of data, and wrote the first draft of the manuscript. EF and SS contributed to the interpretation of data and revised the manuscript. KA designed the study, was responsible for data management, contributed to the analysis and interpretation of data, and revised the manuscript. All authors approved the final version of the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement The data used in this study is administered by the Division of Insurance Medicine, Karolinska Institutet, and cannot be made publically. According to the General Data Protection Regulation, the Swedish law SFS 2018:218, the Swedish Data Protection Act, the Swedish Ethical Review Act and the Public Access to Information and Secrecy Act, these type of sensitive data can only be made available, after legal review, for researchers who meet the criteria for access to this type of sensitive and confidential data. Readers may contact Professor Kristina Alexanderson ( regarding the data.

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