Ultrasound and Shear Wave Elastography Assessment of Entheses in Psoriatic Arthritis

Comparison of the total Madrid Sonography Enthesitis Index (MASEI) score between patients with psoriatic arthritis and healthy controls. The total MASEI score is calculated by combining the predefined grayscale ultrasonography and Power Doppler findings assessed at six bilateral enthesis sites: the plantar fascia, Achilles tendon, proximal and distal patellar tendon, quadriceps tendon, and triceps tendon insertions. The total score ranges from 0 to 136 points, with higher scores indicating greater entheseal involvement.

Comparison of shear wave elastography measurements between patients with psoriatic arthritis and healthy controls. Young's modulus will be measured in kilopascals (kPa) at the bilateral plantar fascia, Achilles tendon, proximal and distal patellar tendon, quadriceps tendon, and triceps tendon insertions. Three separate SWE images will be acquired at each enthesis site, with two 1-mm circular regions of interest placed on each image, resulting in a total of six measurements per enthesis. The arithmetic mean of the six measurements will be used as the SWE value for that enthesis. Results will be evaluated separately for each enthesis site.

Comparison of shear wave velocity measurements between patients with psoriatic arthritis and healthy controls. Shear wave velocity will be measured in meters per second (m/s) at the bilateral plantar fascia, Achilles tendon, proximal and distal patellar tendon, quadriceps tendon, and triceps tendon insertions. Three separate SWE images will be acquired at each enthesis site, with two 1-mm circular regions of interest placed on each image, resulting in a total of six measurements per enthesis. The arithmetic mean of the six measurements will be used as the shear wave velocity value for that enthesis. Results will be evaluated separately for each enthesis site.

Physical function in patients with psoriatic arthritis will be assessed using the Health Assessment Questionnaire Disability Index (HAQ-DI), which consists of 20 items covering eight domains of daily functioning. Each domain is scored from 0 to 3, and the overall HAQ-DI score ranges from 0 to 3 points. Higher scores indicate greater functional disability.

Hand-related functional disability in patients with psoriatic arthritis will be assessed using the Duruöz Hand Index (DHI), which consists of 18 items evaluating activities of daily living. Each item is scored from 0 to 5, resulting in a total score ranging from 0 to 90 points. Higher scores indicate greater hand-related functional disability.

Physical health-related quality of life in patients with psoriatic arthritis will be assessed using the Physical Component Summary of the 12-Item Short Form Health Survey (PCS-12). The score ranges from 0 to 100 points, with higher scores indicating better physical health-related quality of life.

Mental health-related quality of life in patients with psoriatic arthritis will be assessed using the Mental Component Summary of the 12-Item Short Form Health Survey (MCS-12). The score ranges from 0 to 100 points, with higher scores indicating better mental health-related quality of life.

Fibromyalgia-related symptoms in patients with psoriatic arthritis will be assessed using the Fibromyalgia Rapid Screening Tool (FiRST). The questionnaire consists of six yes-or-no items. Each affirmative response is scored as 1 point, resulting in a total score ranging from 0 to 6 points. Higher scores indicate a greater likelihood of fibromyalgia, and a score of 5 or 6 is considered a positive screening result.

Systemic inflammation in patients with psoriatic arthritis will be assessed by measuring the serum C-reactive protein (CRP) level. CRP will be reported in milligrams per liter (mg/L), with higher values indicating greater systemic inflammation.

Systemic inflammation in patients with psoriatic arthritis will be assessed using the erythrocyte sedimentation rate (ESR). ESR will be reported in millimeters per hour (mm/hour), with higher values indicating greater systemic inflammation.

Peripheral joint disease activity in patients with psoriatic arthritis will be assessed using the Disease Activity Index for Psoriatic Arthritis (DAPSA). The score is calculated as the sum of the 68-joint tender joint count, 66-joint swollen joint count, patient global assessment measured on a 0-to-10 scale, patient pain assessment measured on a 0-to-10 scale, and C-reactive protein level expressed in mg/dL. The minimum possible score is 0, and there is no fixed maximum because C-reactive protein is included as a continuous variable. Higher scores indicate greater disease activity. Scores of 4 or lower indicate remission; scores above 4 and up to 14 indicate low disease activity; scores above 14 and up to 28 indicate moderate disease activity; and scores above 28 indicate high disease activity.

Axial and related disease activity in patients with psoriatic arthritis will be assessed using the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). The index consists of six questions evaluating fatigue, spinal pain, peripheral joint pain or swelling, enthesitis, morning stiffness severity, and morning stiffness duration. Each question is scored from 0 to 10. The mean of the two morning stiffness item scores is calculated. This mean and the scores of the remaining four items are summed and divided by five, resulting in an overall score ranging from 0 to 10 points. Higher scores indicate greater disease activity.

Axial disease activity in patients with psoriatic arthritis will be assessed using the Ankylosing Spondylitis Disease Activity Score using C-reactive protein (ASDAS-CRP). The score combines back pain, duration of morning stiffness, patient global assessment, and peripheral joint pain or swelling, each assessed on a 0-to-10 scale, with the C-reactive protein level expressed in mg/L. The minimum possible score is 0, and there is no fixed maximum because C-reactive protein is included as a continuous variable. Higher scores indicate greater disease activity. Scores below 1.3 indicate inactive disease, scores from 1.3 to below 2.1 indicate low disease activity, scores from 2.1 to 3.5 indicate high disease activity, and scores above 3.5 indicate very high disease activity.

Minimal disease activity in patients with psoriatic arthritis will be assessed using the established MDA criteria. A patient will be classified as achieving MDA when at least five of the following seven criteria are met: tender joint count of 1 or lower; swollen joint count of 1 or lower; Psoriasis Area and Severity Index score of 1 or lower or affected body surface area of 3% or lower; patient pain visual analogue scale score of 15 mm or lower; patient global disease activity visual analogue scale score of 20 mm or lower; Health Assessment Questionnaire Disability Index score of 0.5 or lower; and tender entheseal point count of 1 or lower. MDA status will be recorded as a binary categorical outcome: achieved or not achieved.

Psoriasis severity in patients with psoriatic arthritis will be assessed using the Psoriasis Area and Severity Index (PASI). The index combines the extent of affected body surface area with the severity of erythema, induration, and scaling across four body regions: the head, upper extremities, trunk, and lower extremities. The total score ranges from 0 to 72 points, with higher scores indicating more severe psoriasis.

Clinical enthesitis in patients with psoriatic arthritis will be assessed using the Leeds Enthesitis Index (LEI). Tenderness will be evaluated at six entheseal sites: the bilateral lateral epicondyles, bilateral medial femoral condyles, and bilateral Achilles tendon insertions. Each tender site is scored as 1 point and each non-tender site as 0 points, resulting in a total score ranging from 0 to 6 points. Higher scores indicate a greater burden of clinical enthesitis.

Pain severity in patients with psoriatic arthritis will be assessed using a 10-cm visual analogue scale (VAS). The score ranges from 0 to 10, where 0 indicates no pain and 10 indicates the worst imaginable pain. Higher scores indicate greater pain severity.

Overall disease activity from the patient's perspective will be assessed using a 10-cm visual analogue scale. The score ranges from 0 to 10, where 0 indicates no disease activity and 10 indicates the highest possible disease activity. Higher scores indicate greater patient-perceived disease activity.

Overall disease activity from the physician's perspective will be assessed using a 10-cm visual analogue scale. The score ranges from 0 to 10, where 0 indicates no disease activity and 10 indicates the highest possible disease activity. Higher scores indicate greater physician-assessed disease activity.