OBJECTIVES: To evaluate the all-cause healthcare costs among patients with PsA, who received anti-TNF treatment. METHODS: A retrospective study using the PharMetrics database, compiled from managed care plans throughout the United States from January 2000 through June 2005, was conducted. Patients continuously enrolled for 6 months pre- and 12 months post-diagnosis, and having 2 distinct claims of PsA, were included in the study. A 6-month period prior to the index diagnosis date was used to establish anti-TNF and/or MTX treatment, naïve patients, and to identify new PsA patients. Per patient per month treatment (PPPM) costs was calculated for patients during their treatment period. The cost of adverse events could not be identified separately in this analysis. A multivariate model was used to adjust for covariates including age, gender, number of medical visits, Charlson Co-morbidity Index, and pre-period healthcare costs. RESULTS: 357 patients with PsA were included in the analysis. Nearly half of the patients were females. The mean age and Charlson Co-morbidity Index score were higher among patients who received INF compared to those on ETA. All-cause PPPM costs were higher among patients who received ETA ($6,320) compared to patients who received INF ($2,313). The magnitude of the difference was greater among patients who received INF alone ($3,368) compared to ETA alone ($8,257, p<0.05). Differences in total healthcare costs persisted after adjustment for covariates (p=0.0366). Similar results were obtained when excluding outlier patients with high cost (outliers were defined as those patients with values more than 2 standard deviations above the mean). CONCLUSION: This study indicates that INF therapy is associated with lower all cause healthcare costs compared to ETA therapy, in the treatment of patients with PsA. The choice of a biologic treatment on healthcare costs should be considered when evaluating treatment strategies.