Sex-based differences in sonographic and clinical findings among patients with psoriatic arthritis.

OBJECTIVE: To investigate sex-based sonographic differences in psoriatic arthritis (PsA) patients.

METHODS: The study population included consecutive prospectively recruited PsA patients (CASPAR criteria) who underwent clinical and physical examinations, followed by a detailed ultrasound (US) evaluation (gray scale and Doppler) that included 52 joints, 40 tendons and 14 points of entheses (MASES index plus lateral epicondyles) performed by an experienced sonographer blinded to the clinical data. The US score was based upon the summation of a semi-quantitative score for synovitis, tenosynovitis and enthesitis. The US enthesitis score was categorized into inflammatory (hypoechogenicity, thickening, bursitis and Doppler) and structural (enthesophytes/calcifications and erosions).

RESULTS: The study population of 158 patients included 70 males and 88 females. The males had higher rates of employment ( P =0.01), psoriasis severity area index (PASI) scores ( P =0.04) and mean swollen joint counts ( P =0.04). The total US score and its subcategories, the synovitis and tenosynovitis scores, were similar for both sexes, whereas the total enthesitis score and its subcategory, the inflammatory enthesitis score, were significantly higher for the males compared to the females ( P =0.01 and P =0.005, respectively). Hypoechogenicity, thickening and enthesophytes were more prevalent in males compared to females ( P <0.05). Multivariate ordinal logistic regression models showed that male sex was associated with a higher score of US inflammatory enthesitis compared to female sex (odds ratio 1.96, P =0.02).

CONCLUSION: Sonographic enthesitis was more prevalent in males compared to females with PsA. These differences were not reflected by enthesitis disease activity scores derived from clinical assessment.