Work outcomes and cost of illness in patients with ankylosing spondylitis: Contrubuting factors

AS primarily affects the axial skeleton and axial, articular, and extra-articular manifestations can result in impairment of functionality and reduction in the patient's health-related quality of life. AS begins at an early age and causes significant problems with work retention and work productivity, so it has a high lifetime economic burden. The impact of illness on work productivity, work instability and work disability in working AS patients has been limitedly studied. In some studies, factors affecting work outcomes examined. To date, there is no consensus on which of these factors has an impact on work outcomes. In this study, it is aimed to examine the effect of clinical and work-related factors on decreased work productivity, work disability and the cost of the disease to the country's economy in AS patients. The study included 100 patients diagnosed with AS according to the modified New York criteria, who applied to the Physical Medicine and Rehabilitation- Rheumatology outpatient clinic of Akdeniz University Medical Faculty Hospital. The clinical, sociodemographic and work characteristics of the patients were recorded. Disease activity was evaluated with the BASDAI and ASDAS-CRP scale. Functional capacity was evaluated with the BASFI scale. Spinal and hip mobility were evaluated with the BASMI scale, and quality of life was evaluated with the ASQoL index. WPAI-SpA and AS-WIS were used to evaluate work outcomes. In cost evaluation, direct and indirect costs were calculated. The SAS 9.4 program was used for the statistical analysis of the data obtained in the study. A value of 0.05 was accepted as the level of significance in the entire study. In our study, average absenteeism was 7.4%, presentesism was 33.8%, overall work productivity loss was 38.6%, and daily activity impairment was 31.8%. Absenteeism, presenteeism, overall work productivity loss and daily activity impairment were found to be significantly higher in the BASDAI≥4 group than in the BASDAI<4 group. It was determined that 43.7% of 87 working AS patients had moderate-to-high work instability, and there was an average of 10.3 working days of sick leave in the last year. In patients with high job instability, the rate of absenteeism, presenteeism, overall work productivity loss, and daily activity impairment were found to be significantly higher in the last year due to AS. ASWIS score was associated with presenteeism, overall work productivity loss, daily activity impairment, BASMI, BASFI, BASDAI, ASDAS-CRP, VAS patient global score, back pain, morning stiffness, and peripheral pain severity. Absenteeism was weakly associated with BASMI score and CRP level and moderately with overall work productivity loss. BASMI, BASFI, BASDAI, ASDAS-CRP, VAS patient global score, back pain, morning stiffness, and peripheral pain severity were associated with presenteeism, overall work productivity loss and daily activity impairment. Factors such as back pain, lateral lumbar spine mobility, BASMI, BASFI, ASQoL score, CRP level, smoking, educational status, family history of AS, not changing job due to AS, job type, number of sick leave days in the last year, presenteeism, prolonged sitting or standing at work have been shown to be predictive for work instability, work productivity, and impairment in daily activities. We calculated the mean annual cost for AS patients as € 5,495.67/person/year. Medication costs constituted the most important part of all costs. Apart from health care costs, costs associated with unemployment, absenteeism and presenteeism also account for a significant proportion of all costs, revealing the negative impact of AS on the country's economy. This is why maximizing business retention seems crucial in AS. AS can be treated prior to work disability to alleviate the socioeconomic burden of the disease. If work instability and impairment in work productivity are detected early, the risk of work disability can be reduced or eliminated with appropriate clinical and workplace interventions. Therefore, it seems necessary for clinicians to assess the risk of work instability in AS patients.