Objectives To comprehensively study the comorbidities, healthcare and public transfer (allowance) costs in patients with psoriatic arthritis (PsA) before and after diagnosis. Methods Nationwide cohort study, using data from Danish registries from January 1998 through December 2014. A total of 10â 525 patients with PsA and 20â 777 matched general population comparator (GPC) subjects were included. Societal costs, employment status and occurrence of comorbidities in patients with PsA both before and after diagnosis were compared with GPC subjects. Results At baseline, patients with PsA had significantly more comorbidities, including cardiovascular disease (OR 1. 70 95% CI 1. 55 to 1. 86), respiratory diseases (OR 1. 73 95% CI 1. 54 to 1. 96) and infectious diseases (OR 2. 03 95% CI 1. 69 to 2. 42) compared with GPC subjects. At all time points, patients with PsA had higher total healthcare and public transfer costs; they also had lower income (p<0.001) and incurred a net average increased societal cost of 10â 641 per patient-year compared with GPC subjects following diagnosis. The relative risk (RR) for being on disability pension 5â years prior to PsA diagnosis was 1. 36 (95% CI 1. 24 to 1. 49) compared with GPC subjects. The RR increased to 1. 60 (95% CI 1. 49 to 1. 72) at the time of diagnosis and was 2. 69 (95% CI 2. 40 to 3. 02) 10â years after diagnosis, where 21. 8% of the patients with PsA received disability pension. Conclusions Our findings are suggestive of health inequity for patients with PsA and call for individual preventive measures and societal action.