2.3 Assessment of Clinical Data
The patients’ baseline characteristics were assessed by physicians and recorded by clinical research assistants. Hypertension was diagnosed if patients had a blood pressure of >140/90 mmHg on ≥2 occasions or were already on antihypertensive therapy. Diabetes was diagnosed based on the classification of diabetes mellitus by an expert committee. Dyslipidemia was diagnosed in patients with a history of total cholesterol >240 mg/dL or those who received lipid-lowering medication.
Parameters related to RA disease activity were also collected, including swollen joint count based on the assessment of 28 joints (SJC28), tender joint count based on assessment of 28 joints (TJC28), the presence of rheumatoid factor (RF) and/or anti-citrullinated protein antibodies (ACPA), C-reactive protein (CRP) level, erythrocyte sedimentation rate (ESR), Health Assessment Questionnaire (HAQ) disability index score, and the patient’s assessment of pain measured using a 100-mm visual analog scale (VAS).
Disease activity of RA was evaluated with the disease activity score 28-joint count using erythrocyte sedimentation rate (DAS28-ESR), Simplified Disease Activity Index (SDAI), Clinical Disease Activity Index (CDAI), and physical disability by the HAQ index. SDAI, CDAI, and DAS28-ESR were calculated using the following formulas: SDAI = SJC28 + TJC28 + (VAS by patient) + (VAS by clinician) + CRP; CDAI = SJC28 + TJC28 + (VAS by patient) + (VAS by clinician); DAS28-ESR = 0.56 × √(TJC) + 0.28 × √(SJC) + 0.7 × ln(ESR) + 0.014 × (VAS)14.
The DAS28-ESR disease activity of RA was defined as DAS28-ESR <2.6 for remission, <3.2 for low disease activity, ≤5.1 for moderate disease activity, and >5.1 for high disease activity. SDAI disease activity was defined as SDAI <3.3 for remission, <11 for low disease activity, ≤26 for moderate disease activity, and >26 for high disease activity. CDAI disease activity was defined as CDAI <2.8 for remission, <10 for low disease activity, ≤22 for moderate disease activity, and >22 for high disease activity. With regard to treatment, the use of prednisolone, disease-modifying anti-rheumatic drugs (DMARDs), methotrexate, and biologic agents were collected.