POS1368 THE LONGITUDINAL ASSOCIATION OF HAND OA WITH PAID AND UNPAID WORK IMPAIRMENT AND RELATED COSTS: THE HOSTAS COHORT

<h3>Background</h3> Hand osteoarthritis (OA) is associated with impairment in paid and unpaid work and contributes to societal burden and costs of OA. However, the longitudinal development of hand OA-related work impairment and related societal costs are unknown. <h3>Objectives</h3> To investigate the association of hand OA with paid and unpaid work productivity loss, hinder and societal costs longitudinally. <h3>Methods</h3> We used annual data of the Dutch Hand OSTeoArthritis in Secondary care (HOSTAS) cohort, consisting of patients with primary hand OA primary hand OA defined by the treating rheumatologist. Data from baseline to four years of follow-up was used. The Health and Labour Questionnaire (HLQ) was assessed over the last two weeks on (i) hand OA-related limitations and hours of productivity loss while at work, (ii) hours of sick leave, and (iii) limitations and hours of unpaid work replacement. Patients with HLQ data on &gt;1 timepoint were included in this study. Societal costs of paid work productivity loss (=all hourly costs in order to employ a worker, such as salary and premiums) were estimated by multiplying the number of unproductive and sick leave hours due to hand OA by the estimated hourly costs of paid work in The Netherlands based on age and sex. Costs of unpaid work were estimated by multiplying the hours of unpaid work replaced by others by the Dutch gross average hourly salary of a household help (2021:€12.50). Costs were adjusted to 2021 values using conversion factors provided by the Dutch government, and to yearly values. <h3>Results</h3> 470 patients had data on more than one timepoint. Baseline data was available for 381 patients, of whom 256 patients (67%) completed four years of follow-up, and 215 (56%) completed all five follow-up moments. Of 256 patients with baseline and four years follow-up, 113 (52%) had paid work at baseline and 104 (41%) at four years (<b>Table</b> 1 for patient characteristics). Unproductive hours at any timepoint were present for 85/470 patients (18%), for whom unproductive hours fluctuated over time (<b>Figure 1</b>). Median paid work hinder score (score range: 6-24) remained stable at 7 (interquartile range (IQR): 6;8) over the study period. Unproductive hours at any timepoint were present for 85/470 patients (18%). Regarding unpaid work, 105/256 (41%) required unpaid task replacement by others due to hand OA at baseline, which remained stable over time (108/256 at four years (42%)). Unpaid work hinder was reported by 100/256 patients (39%) at baseline and 97/256 (36%) at four years. Costs related to loss of paid and unpaid productivity were incurred at baseline by 136/256 patients, with a median of €63 per patient ((IQR) 38;125) per two weeks (€1630 per patient (978;3261 per year). At four years, these costs were present for 120/256 patients, with a median of €50 (38;100) per two weeks (€1304 (978;2609) per year). <h3>Conclusion</h3> Patients with hand OA experience significant impairment in paid and unpaid work participation over the years, which translates into substantial societal costs. Impairment and costs fluctuate on individual level but seem to remain stable over four years on group level. <h3>REFERENCES:</h3> NIL. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> Sietse Terpstra: None declared, Lotte A. van de Stadt: None declared, Annelies Boonen: None declared, Frits Rosendaal: None declared, Margreet Kloppenburg Grant/research support from: Received funding for the HOSTAS cohort, all paid to the institution.