Relationship between structural damage with loss of strength and functional disability in psoriatic arthritis patients

Abstract

BackgroundEvaluate the relationship between structural damage assessed by radiography or ultrasonography in the hands of patients with psoriatic arthritis (PsA) with loss of strength together with functional disability. MethodsA cross-sectional study was conducted in patients with PsA involving the hands. Erosions and loss of radiographic joint space were measured in the dominant hand using a modified Sharp van der Heijde method and an ultrasound assessment. Hand strength was assessed with a dynamometer and disability was assessed using the Health Assessment Questionnaire (HAQ). The statistical analysis was performed using multiple linear regression models. Findings76 patients were included with a mean age of 57 ± 9.9 years, with 56.6% women. A statistically significant relationship was found between presence of erosions and reduction in lateral (p = 0.027) and tip (p = 0.030) pinch strength in the hand. This was also the case for loss of joint space and reduction in lateral (p = 0.012) and tip (p = 0.006) pinch strength. There was an association between total ultrasound (US) alterations and reduction in lateral pinch strength (p = 0.03). An association was also observed between erosions, loss of joint space and total US alterations and disability measured by the HAQ (p < 0.001; <0.001; 0.012, respectively). HAQ scores were associated with a decrease in mean lateral (p < 0.001) and tip (p < 0.001) pinch strength. InterpretationIn patients with PsA involving the hands, structural alterations of the dominant hand assessed by conventional x-ray and ultrasound are associated with loss of strength measured objectively with dynamometry and greater disability also studied subjectively using the HAQ.