Information about the prediagnosis period in psoriatic arthritis (PsA) is limited. The present study was undertaken to compare health care utilization related to musculoskeletal issues during a 5-year period prior to the diagnosis of PsA versus that of subjects with no prior inflammatory arthritis within a primary care setting.
We conducted a population-based, matched cohort study using electronic medical records and administrative data in Ontario, Canada. Age- and sex-matched cohorts of PsA patients and comparators from the same family physicians were assembled. Comparators were not allowed to have prior spondyloarthritis, ankylosing spondylitis, or rheumatoid arthritis billing code diagnoses. The study outcomes included health care utilization and costs related to nonspecific musculoskeletal issues during a 5-year period prior to the index date.
We studied 462 PsA patients and 2,310 matched comparators. The odds ratio (OR) related to visiting a primary care physician for nonspecific musculoskeletal issues in patients with PsA was 2.14 (95% confidence interval 1.73-2.64) in the year immediately preceding the index date and was similarly elevated up to 5 years prior. The OR related to using other musculoskeletal-related health care services, including musculoskeletal specialists visits, joint injections, joint imaging, and emergency department visits, was higher in PsA as early as 5 years preceding the index date. Total and musculoskeletal-related health care costs prior to the index date were higher for patients with PsA versus comparators.
A prodromal PsA phase characterized by nonspecific musculoskeletal symptoms may exist. Further study is needed to determine if this represents a window for earlier diagnosis of PsA.