Application for disability pension and change in use of prescribed drugs. A regional Danish cohort study

Aim: To investigate if a pending application for disability pension had an influence on the applicant's purchase of medical drugs, with a particular focus on musculoskeletal disorders and the use of painkillers. Methods: We performed a registry-based follow-up study including 12,020 applicants for disability pension in a Danish county from 1995 to 2000 and linked this information to a database of drug prescriptions. Purchase of drug was calculated for the 6-month period just before the decision and for the 6-month period 2 years later. Changes in a 2-year time period were estimated by differences in purchase rates. Furthermore, the proportion of applicants with an increased purchase of drugs and the proportion of applicants who ceased buying drugs were estimated. The results were stratified by diagnosis and result of application (awarded/rejected). The analyses were furthermore restricted to musculoskeletal disorders and the use of painkillers. Results and conclusions: At baseline 81% had a purchase and after the 2-year time period 11% ceased buying prescribed drugs. Half of all applicants increased the purchase of drugs. For musculoskeletal disorders one third had an increased purchase rate of painkillers while one fourth ceased purchase of drugs with variations in different diagnostic subgroups. The major changes of drug purchase after a pending application for disability pension are probably ascribed to characteristics of the diseases underlying the disability.