Validation of patient-reported outcome measures for dactylitis, psoriatic skin and nail disease, and uveitis in patients with psoriatic arthritis in routine care.
In routine care, Danish patients with psoriatic arthritis are monitored in the DANBIO registry. In March 2022, patient-reported outcome measures (PROMs) on selected non-musculoskeletal manifestations (NMM) were implemented.
Aim
To validate PROMs for current dactylitis, skin and nail psoriasis, and recent uveitis in patients with psoriatic arthritis.
Methods
Adaptive cross-sectional study. Patients in the rheumatologic clinic answered PROMs with 'yes'/'no'/'do not know' and assessed the extent of skin psoriasis and number of dactylitis-affected digits in DANBIO. PROM entries were compared with the physician's assessments (physical examination, review of patient file), with the physician being the gold standard. With 134 patients included, 20% had incorrectly reported dactylitis; therefore, a dactylitis photo was added to the PROM. Sensitivity, specificity, positive and negative predictive values, accuracy and Cohen's kappa were calculated. Level of agreement for dactylitis count was explored by Bland-Altman plot. From patient 200, the physician was blinded to PROs.
Results
We included 300 patients (51% female, median age=55 years), with a median disease duration of 8 years, where 43% received biologic treatment. According to the physician's assessment, 41 (14%) patients had current dactylitis, 164 (55%) psoriasis, 163 (54%) nail psoriasis and 3 (1%) recent uveitis. For the dactylitis PROM, the sensitivity/specificity/Cohen's kappa was 0.89/0.81/0.57, psoriasis 1.0/0.94/0.95, nail psoriasis 0.76/0.94/0.66 and uveitis 1.00/0.99/0.59. Agreement on psoriasis extent was 90%. Patient-reported dactylitis count was on average 1.0 unit higher than physician-reported but decreased to 0.7 after adding the dactylitis photo. Results were similar irrespective of blinding.
Conclusion
Patients reliably self-report dactylitis, psoriasis, and uveitis and the PROMs are valuable for monitoring NMMs in routine care.
