A modified Sharp score demonstrates disease progression in established psoriatic arthritis

Area of Science:

• Rheumatology
• Radiology
• Orthopedics

Background:

• Psoriatic arthritis (PsA) is a chronic inflammatory disease affecting joints.
• Assessing radiologic progression in PsA is crucial for disease management.
• Existing scoring methods may not fully capture the extent of joint damage.

Purpose of the Study:

• To evaluate the modified Sharp score (MSS) for measuring radiologic progression in PsA.
• To correlate MSS with clinical joint disease, physical function (HAQ), and other radiographic features.
• To determine if MSS can detect progressive damage in established PsA.

Main Methods:

• Hand radiographs from 139 PsA patients (median 5.75-year interval) were scored using MSS.
• Clinical joint scores and Health Assessment Questionnaire (HAQ) data were collected for 74 patients.
• Radiographic features like erosion, joint space narrowing, bony proliferation, and periostitis were analyzed.

Main Results:

• Radiologic damage increased from 58% at baseline to 74% at followup.
• Median MSS significantly increased over time (P < 0.001), with a progression rate of +1.08 units/year.
• MSS strongly correlated with clinical joint scores (r=0.72-0.81) and showed moderate correlation with HAQ at followup (r=0.48). Soft-tissue swelling was linked to increased MSS change.

Conclusions:

• The MSS demonstrates strong construct validity for assessing peripheral joint involvement in PsA.
• MSS is a reliable tool for tracking radiologic progression in PsA.
• Radiologic damage in PsA progresses even in established disease, as shown by MSS.