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

ABSTRACT

BACKGROUND: Evaluate 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. METHODS: A 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. FINDINGS: 76 patients were included with a mean age of 57 ±â€¯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. INTERPRETATION: In 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.