Background/Purpose: The prevalence of osteoporotic vertebral fractures (VF) in psoriatic arthritis (PsA) is not known. We aim to determine the prevalence and factors associated with non-traumatic radiographic VF in patients with PsA. 

Methods: The most recent digital plain radiographs of the thoracic and lumbar spine as well as demographic, clinical, laboratory and imaging information on a large cohort of patients diagnosed with PsA, satisfying CASPAR classification criteria, were retrieved from a database. Fractures were diagnosed by quantitative morphometric assessment (QMA) on lateral spinal radiographs of lumbar and thoracic spine (T6-L4) that was previously demonstrated to have high inter- and intra-assessor reliability. Covariates including demographic features, measures of disease activity, body mass index and pharmacologic treatment, particularly OP-causing treatments like corticosteroids and methotrexate were investigated as factors associated with VF in PsA using descriptive statistics and logistic regression.

Results:

Data on 450 patients [191 (42%) females, mean age at the time of x-ray 54.4 ±13.6 years, mean PsA duration 18±11.9 years] were retrieved from the database. Only 24 (5.3%) patients (1 fracture-13, 2 fractures-9, >2 fractures-2) were diagnosed with VF. Univariate logistic regression analyses revealed that age (OR 1.08, 95% CI [1.04, 1.12], p value <0.0001), duration of psoriasis (OR 1.03, 95% CI [1.004, 1.062], p=0.027), PsA duration (OR 1.05, 95% CI [1.02, 1.09], p=0.002) and therapy with bisphosphonates (OR 4.92, 95% CI [1.29, 18.76], p=0.02) were associated with increased odds of the presence of VF, whereas race, sex, menopausal status, smoking, BMI, damaged joint count, presence of DISH, axial disease, enthesitis, dactylitis, time-averaged ESR, therapy with topical or systemic corticosteroids, NSAIDs, and methotrexate, HAQ and SF36 physical and mental component summary scores were not. Therapy with biologic agents showed a trend towards less odds of the presence of VF (OR 0.42, 95% CI [0.17, 1.02] p=0.056). Multivariate logistic regression analysis with backward elimination with age, sex, psoriasis and PsA duration, and therapy with bisphosphonates and biologics in the model revealed that only age (OR 1.08, 95% CI [1.04,1.12], P<0.0001) was independently associated with VF in PsA.

Conclusion: Prevalence of VF is low in PsA. PsA related variables are not associated with the presence of VF in patients with PsA.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/prevalence-and-factors-associated-with-non-traumatic-vertebral-fractures-in-psoriatic-arthritis/