SAT0577 ABSENTEEISM OF PATIENTS WITH RA AND AS IN SLOVENIA: TREND ANALYSIS BASED ON NATIONAL LEVEL DATA BETWEEN 2001 AND 2016

Abstract

Background: Indirect costs due to absenteeism of rheumatoid arthritis (RA) and ankylosing spondylitis (AS) in Slovenia have not been thoroughly researched despite availability of national administrative data on sick leave and evidence from other countries on their sizable burden [1, 2]. Objectives: To compare absenteeism trends in Slovenia in the 2001-2016 period between three age cohorts of RA and AS patients given that age is an important determinant of sick leave [3]. Methods: Retrospective population data on sick leave from the Slovenian National Institute of Public Health was collected. Total annual number of days on sick leave was used as an indicator of absenteeism. Patients were classified into three age cohorts (20-39 years, 40-54 years and 55-69 years). Changes in absenteeism during the 16-year period were estimated using a linear trend function. Results: In the 2001-2016 period, patients with RA spent 448.828 days on sick leave. For AS patients the number of sick days was 92.990. Patients aged 40-54 accounted for 66.6% of all sick days of RA patients, while the shares for patients aged 20-39 and 55-69 were 16.6% and 16.8%, respectively. Estimated linear trend reveals a statistically significant reduction of sick days in RA patients from all age cohorts throughout the observed period. RA patients aged 20-39 experienced a decrease of 483.7 days spent on sick leave annually on average (p=0.000; R2=0.849). Patients aged 40-54 experienced a higher average annual decrease of 952.3 days (p=0.000, R2=0.74). RA patients aged 55-69 experienced an average annual increase of 250.3 days spent on sick leave in the 2001-2016 period (p=0.001; R2=0.567). Sick days of AS patients aged 40-54 represented 64.4% of all sick days of AS patients. For AS patients aged 20-39 this share was 25.0%, and 10.6% for those aged 55-69. Estimated linear trend shows that, on average, patients with AS aged 20-39 and 40-54 experienced an 11.4 and 5.9 decrease of sick days, respectively, whereas the patients with AS aged 55-69 experienced an average annual increase of 19.4 days spent on sick leave in the observed period. However, none of the linear trends were statistically significant for AS patients. Conclusion: Results indicate that RA patients aged 20-39 and 40-54 experienced a significant average annual decrease in days spent on sick leave during the 2001-2016 period. This suggests a general decline in economic burden due to absenteeism in patients with RA, which could be attributed to innovative treatments, improved disease management practices and other organizational and process changes in treating RA. Yet, the results do not show any statistically significant changes in days spent on sick leave for AS patients, regardless of age. This implies that factors other than age should be investigated to explain changes in absenteeism for AS patients. Future studies should focus on other potential associations and causal mechanisms of changes in days spent on sick leave in AS and RA patients.