Do Patients and Physicians Agree in Their Assessment of the Severity of Psoriasis? Insights from to Facitinib Phase 3 Clinical Trials

Background: Previous research has highlighted discrepancies between patient and physician ratings of disease severity. Whether this is also the case in psoriasis requires investigation. We investigate using study data on tofacitinib, an oral Janus kinase inhibitor that is being investigated for psoriasis. Objective: To examine the level of concordance between two measures – Patient Global Assessment (PtGA) and Physician Global Assessment (PGA) – at baseline and at primary endpoints. Methods: Pooled data were analyzed from four Phase 3 clinical trials (3,641 patients) of oral tofacitinib for the treatment of patients with moderate-to-severe chronic plaque psoriasis. Descriptive statistics and weighted kappa statistics were calculated. A repeated measures model was applied with PtGA as outcome and PGA as predictor. Results: At baseline, physicians tended to rate the disease as “moderate” on the PGA while patients rated it as “severe” on the PtGA (weighted kappa=0.05). At post-baseline, there was moderate-to-substantial level of agreement (weight kappa=0.61). At baseline correlations were consistently low across the four trials (0.09, p<0.01 in all cases), whereas by the primary time point the correlations were substantially higher for each trial (range: 0.65–0.71, p<0.001 in all cases), as a result of trial inclusion and exclusion criteria. In general, a clear trend surfaced with lower (less severe) PGA scores systematically corresponding to higher (more severe) PtGA scores. For example, for a PGA score of 0 (“clear”) the corresponding PtGA score was 0.987, numerically very close to 1 (“almost clear”). Conclusion: In psoriasis the physician ratings of disease severity tend to consistently rate severity lower than the corresponding patient ratings of severity.