Background In Slovenia, evidence on the indirect costs of rheumatoid arthritis (RA) and ankylosing spondylitis (AS) is scarce.

Objectives To analyse changes in sick leave for RA and AS patients in Slovenia in the 2000–2014 period.

Methods National Institute of Public Health collects absenteeism data. Sick leave data for the entire population of Slovenia was used to conduct a comparative analysis of sick leave indicators (number of cases, share of lost working days, index of temporary disability measuring the number of lost days relative to the number of employees, frequency of spells reflecting the number of absenteeism cases relative to the number of employees and severity indicating the average length of absence from work) for RA and AS patients in Slovenia in the 2000–2014 period. Data were analysed using t-tests for equality of means and Chi-Squared tests of distribution uniformity. Chain indexes were used to determine average annual changes of the studied indicators.

Results Over the period 2000–2014, the number of days lost per employed worker for RA declined by over 13% and by nearly 82% for AS. For all musculoskeletal disorders (MSDs) this indicator declined by nearly 20% while for all diseases combined by nearly 16%. For RA, the average annual decline in temporary disability and severity equalled 1%. The index of temporary disability for all MSDs also declined by slightly over 1% annually on average, severity on the other increased on average by 0.32% annually. For all diseases combined temporary disability declined annually by 1.6% and severity by 1.3% on average. The changes were considerably better for AS given that temporary disability and severity declined for 11.5% and 4.7% annually on average, respectively. The frequency index for RA increased after economic crisis in 2009 while the average annual decline for AS reached 7%. The average annual declines for all MDSs and all diseases combined were much lower reaching 1.5% and 0.3%, respectively.

For both RA and AS the mean values of all studied sick leave indicators with the exception of severity statistically significantly differ between genders (p<0.001). For RA sick leave indicators are higher for women while for AS absenteeism indicators are less favourable for men. This result is in line with the gender structure of RA and AS diagnosed patients (1:3 male to female ratio for RA and 3:1 male to female ratio for AS). There are also statistically significant differences (p=0.000) in the number of absenteeism cases between three age brackets (20–34, 35–49 and 50–64 years) for both RA and AS. For RA differences between age groups in severity are not statistically significant. For AS the younger population has statistically significantly lower severity indicators while for the upper two age brackets differences are not statistically significant.

Conclusions Results indicate that indirect costs of RA and AS are declining. A more comprehensive estimation of indirect costs requires, however, also the assessment of presenteesim costs. The decline in the burden of absenteeism was larger for AS in comparison to RA. Patients diagnosed with AS are on average notably younger than RA patients. This implies that innovative treatment and disease management practices can prevent larger productivity losses created by absenteeism.

Disclosure of Interest None declared