Incremental Costs for Psoriasis and Psoriatic Arthritis in a Population-based Cohort in Southern Sweden: Is It All Psoriasis-attributable Morbidity?

Objective: To estimate incremental costs for patients with psoriasis/psoriatic arthritis (PsO/PsA) compared to population-based referents free from PsO/PsA and estimate costs attributable specifically to PsO/PsA.

Methods: Patients were identified by International Classification of Diseases, 10th ed., codes for PsO/PsA using information from 1998 to 2007 in the Skåne Healthcare Register, covering healthcare use for the population of the Skåne region of Sweden. For each patient, 3 population-based referents were selected. Data were retrieved from Swedish registers on healthcare, drugs, and productivity loss. The human capital method was used to value productivity losses. Mean annual costs for 2008 to 2011 were assessed from a societal perspective.

Results: We identified 15,283 patients fulfilling the inclusion criteria for PsO [n = 12,562, 50% women, mean age (SD) 52 (21) yrs] or PsA [n = 2721, 56% women, mean age 54 (16) yrs] and included 45,849 referents. Mean annual cost per patient with PsO/PsA was 55% higher compared to referents: €10,500 vs €6700. The cost was 97% higher for PsA compared to PsO. Costs due to productivity losses represented the largest share of total costs, ranging from 52% for PsO to 60% for PsA. Biological drug costs represented 10% of the costs for PsA and 1.6% for PsO. The proportion of cost identified as attributable to PsO/PsA problems was greatest among the patients with PsA (drug costs 71% and healthcare costs 31%).

Conclusion: Annual mean incremental societal cost per patient was highest for PsA, mainly because of productivity losses and biological treatment. A minor fraction of the costs were identified as attributable to PsO/PsA specifically, indicating an increased morbidity in these patients that needs to be further investigated.