Costs of shoulder disorders in Denmark: a nationwide cost-of-illness study investigating 617,334 patients and matched controls.

Shoulder disorders are very common musculoskeletal conditions. Few studies have focused on the costs associated with shoulder disorders, and the economic burden has never been established in a nationwide cost-of-illness study. We aimed to evaluate the healthcare costs and costs of productivity loss (sick leave) and to evaluate if costs were higher for specific subgroups. Using national Danish registers, we identified individuals with shoulder disorders (subacromial pain, stiffness, fracture, or dislocation) diagnosed between 2005 and 2017 and controls matched on age and gender without shoulder disorders. Health care usage, sick leave, and related costs were estimated. During the 13-year inclusion period, 617,334 unique individuals were identified and the incidence rate was 1215 per 100,000 person-years in 2017. The expected additional societal costs were €1.21 billion annually. The mean additional total costs for the 6-year period were €11,334 (11,014-11,654) for individuals aged ≥65 years and €25,771 (25,531-26,012) for individuals aged <65 years. For individuals in the working age, the costs of sick leave accounted for approximately 70% of the total costs. Individuals aged ≥65 years had healthcare costs that were twice as high as individuals aged <65 years. Additionally, the 20% of cases accruing the highest costs accounted for 66% of the total costs. In conclusion, incidence rates of shoulder disorders were high and costs of sick leave accounted for a large proportion of total costs associated with illness in working age people. Furthermore, a minority of patients accounted for a substantial share of the total costs.