['New treatments are available for psoriasis that complement or replace the use of topical corticosteroids.', 'The purpose of this article is to assess the relative overall cost difference between regimens based on topical steroids and those using the nonsteroidal anti- psoriasis medication, topical calcipotriene.', 'Retrospective data on the cost of therapy of psoriasis were attained through analysis of claims from a national pharmaceutical-and-medical-visit claims-database. Episodes of psoriasis treatment were defined and analyzed for patients whose therapy was initiated with either topical calcipotriene or topical corticosteroids of different potency classes.', 'The average medication cost per episode was greater for topical calcipotriene ($111/episode) compared to ultra-high potency ($70/episode), high potency ($57/episode), mid potency ($47/episode), and low-potency, ($75/episode) topical corticosteroids (p <.05). The average total cost of therapy for the topical calcipotriene regimen ($218) fell within the range for the cost of therapy for topical steroid base regimens ($197 to $457); there were no significant differences in the total cost of therapy between topical calcipotriene monotherapy and other treatment groups.'] Is per-gram cost of medication by itself a poor indicator for comparing costs of different psoriasis treatments : a retrospective cohort study of the cost of psoriasis treatment with topical corticosteroids versus topical calcipotriene?