A Randomized, Open, Parallel, Controlled, Multi-center, Interventional, Cross-sectional Study to Evaluate the Detection Rate of Psoriatic Arthritis in Korean Moderate-to-severe Psoriasis Patients, With or Without Active Screening for Arthritis in Psoriasis (ASAP Study)

After the completion of EARP questionnaire evaluation and the investigator's judgement as per routine practice in each group, all the participants were evaluated using Classification criteria for psoriatic arthritis (CASPAR). According to the CASPAR, participants having inflammatory articular disease with 3 or more points from the CASPAR were diagnosed as PsA, and the detection rate of PsA in each group was evaluated and compared.

The detection rate of Psoriatic Arthritis (PsA) amongst moderate to severe Psoriasis (PsO) patients between the EARP group and the Routine practice groups was defined as the percentage of patients with true positive results divided by all patients in each EARP and Routine practice group.

The true positive results were defined as patients with a classification criteria for psoriatic arthritis (CASPAR) score >= 3 among EARP >= 3 for the EARP group and among those suspected of PsA by investigator's judgement for the Routine Practice group.

Sensitivity was summarized with the number and percentage of patients who have true positive (TP) among those who have true positive (TP) and false negative (FN).

Specificity was summarized with the number and percentage of patients who have true negative (TN) among those who have true negative (TN) and false positive (FP).

Positive predictive value (PPV) was summarized with the number and percentage of patients who have true positive (TP) among those who have true positive (TP) and false positive (FP).

Negative predictive value (NPV) was summarized with the number and percentage of patients who have true negative (TN) among those who have true negative (TN) and false negative (FN).

Age characteristics between patients with PsA and without PsA were analyzed and compared.

Gender characteristics between patients with PsA and without PsA were analyzed and compared.

Body Mass Index (BMI) characteristics between patients with PsA and without PsA were analyzed and compared.

Drinking and smoking history characteristics between patients with PsA and without PsA were analyzed and compared.

Duration of Psoriasis (PsO) characteristics between patients with PsA and without PsA were analyzed and compared.

Family history of psoriasis (PsO) and psoriatic arthritis (PsA) characteristics between patients with PsA and without PsA were analyzed and compared.

PASI combines the assessment of the severity of lesions and the area affected into a single score in the range 0 (no disease) to 72 (maximal disease). The body is divided into four sections (head (H) (10% of a person's skin); arms (A) (20%); trunk (T) (30%); legs (L) (40%)). Each of these areas is scored by itself, and then the four scores are combined into the final PASI. For each section, the percent of area of skin involved, is estimated and then transformed into a grade from 0 (0% of involved area) to 6 (90-100% of involved area). Within each area, the severity is estimated by three clinical signs: erythema (redness), induration (thickness) and desquamation (scaling). Severity parameters are measured on a scale of 0 (none) to 4 (maximum). The sum of all three severity parameters is then calculated for each section of skin, multiplied by the area score for that area and multiplied by weight of respective section (0.1 for head, 0.2 for arms, 0.3 for body and 0.4 for legs).

The presence or absence of hard-to-treat area involvement (scalp, palmoplantar, nails) and presence or absence of musculoskeletal symptoms between patients with PsA and without PsA were analyzed and compared.

The Nail Psoriasis Severity Index (NAPSI) score is used to measure psoriasis of the nails. Each nail is divided into 4 equal and symmetrical quadrants to properly assess nail matrix and nail bed changes. Each nail is given a score for nail bed PsO and nail matrix PsO ranging from 0 (none) to 4 (present in 4/4 nail) depending on the presence of any of the features of nail PsO in that quadrant. A total score per nail is 0-8, and the range of the total scores from all nails is 0-160 (toenails are included).

66 swollen and 68 tender joints are assessed (the hips are not assessed for swelling). The joint count is scored as a sum of the tender joints and a sum of the swollen joints. SJC66: swollen joint count in 66 joints; TJC68: tender joint count in 66 joints.

The presence or absence of co-morbidities (heart diseases, stroke, diabetes, hyperlipidemia, hypertension and fatty liver)) between patients with PsA and without PsA were analyzed and compared.

The presence or absence of PsO related treatment other than medications (UV light therapy, Psoralen with ultraviolet A (PUVA), Phototherapy and Laser therapy and Naturopathy) between patients with PsA and without PsA was analyzed and compared.