The DAPSA was developed to characterize psoriatic arthritis (PsA) disease activity. It considers the number of painful and swollen joints, the patient's assessment of their disease and the C-reactive protein (CRP) measurement for acute inflammation. Where CRP measurements are not available, the clinical DAPSA (cDAPSA) maybe be used, which omits CRP. An overall score is calculated, where higher scores correspond to higher disease activity. Cut-off values for DAPSA low and high disease activity are: ≤14 and >28 points, respectively, and for remission is ≤4 points. The cut-off values for cDAPSA are: ≤4 points for remission, >4 to ≤13 points for low disease activity, > 13 to ≤27 points for moderate disease activity, and >27 points for high disease activity.

The Leeds enthesitis index (LEI) measures the activity of enthesitis in PsA. The index measures the severity and activity of enthesitis, inflammation at the attachment of the ligaments and tendons to bone. The clinical assessor must elicit tenderness at 6 enthesitis sites: both lateral epicondyles of the humerus, both medial condyles of the femur, and the Achilles tendon insertions. Each site affected is summed to give a score out of 6, where 6 indicates all sites affected.

NRS for back and neck pain will be administered. This is a simple numbered 0-10 scale on which the patient indicates the intensity of their pain (0 represents no pain and 10 indicates the worst possible pain).

Hazard ratios for association between baseline clinical factors and persistence/effectiveness from Cox proportional hazards models will be reported.

Participant's age will be reported.

Participant's sex (male, female) will be reported

Participant's weight will be reported

Participant's height will be reported.

Participant's BMI will be reported.

Participant's smoking, use of Cannabis and Alcohol habit will be reported.

Family history of psoriasis and/or psoriatic arthritis and/or spondyloarthritis wil be reported.

Date of diagnosis of psoriatic arthritis will be reported.

Date of previous treatments of psoriatic arthritis will be reported.

Duration of previous treatments of psoriatic arthritis will be reported.

Participants medical history and current medical situation will be reported.

Participants receiving co-occurring treatments linked to psoriatic arthritis at baseline and during follow-up will be reported.

Failure to achieve or maintain response to at least 2 biologic/targeted synthetic DMARDs with at least 2 different mechanisms of action (Y/N) (For treatment refractory criteria).

The management of signs and/or symptoms that is perceived as problematic by the rheumatologist and/or the participants will be reported.

Evidence of persistent disease as defined by at least 2 of the following: a) failure to achieve or maintain low disease activity, b) the presence of active extra-musculoskeletal manifestations of PsA, c) objective evidence of inflammatory activity, namely clinical signs, elevated acute phase reactants and/or imaging findings suggestive of inflammation.

Number of participants with co-morbidities will be reported.

Number of participants with abnormal psychosocial factors will be reported.

Age group of HCP will be reported.

Sex of HCP will be reported.

Experience of HCP will be reported.

Type of practice of HCP will be reported.

AEs with onset or worsening on or after date of first dose of study treatment. Severity scale ranges from Grade 1 (Mild) to Grade 5 (Death). Grade 1 equal (=) Mild, Grade 2= Moderate, Grade 3= Severe, Grade 4= Life-threatening, and Grade 5= Death related to AE. SAE is any untoward medical occurrence that results in any of the following outcomes: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly/birth defect; suspected transmission of any infectious agent via a medicinal product or medically important.

Tolerance Related guselkumab treatment will be reported.

Dose at initiation of guselkumab will be reported.

Treatment interval at initiation of guselkumab will be reported.

Type of injection will be reported.

Participants reporting change of injection frequency (Q4 to Q8 or Q8 to Q4) and its reason will be reported.

Participants with co-occurring treatments linked to PSA will be reported.

Participants with reason for choosing guselkumab from the therapeutic arsenal will be reported.

Participants switching to new treatment in case of discontinuation of guselkumab treatment will be reported.

The PsAID-12 questionnaire was designed to assess the impact of disease, with questions on pain, physical function, fatigue, coping and depression. It is a validated, self-administered questionnaire developed for use in clinical practice that assesses the impact of PsA on patients' lives. It consists of 12 questions, each answered using a numerical rating scale. Questions related to pain, skin problems, work and/or leisure activities, discomfort, embarrassment and/or shame, social participation, and anger, fear, and uncertainty, and depression are scored from 0 (none) to 10 (extreme), functional capacity and sleep disturbance are scored from 0 (no difficulty) to 10 (extreme difficulty) and coping is scored from 0 (very well) to 10 (very poorly).

The BASDAI (Bath Ankylosing Spondylitis Disease Activity Index) was developed to measure disease activity in patients with ankylosing spondylitis. It consists of 6 questions pertaining to the 5 major symptoms of ankylosing spondylitis: fatigue, spinal pain, joint pain/swelling, areas of localized tenderness (also called enthesitis, or inflammation of tendons and ligaments), morning stiffness duration and morning stiffness severity. Each symptom is assessed on a scale of 0-10 where 0 indicates no pain or discomfort and 10 indicates maximum pain or discomfort. To give each symptom equal weighting, the mean (average) of the 2 scores relating to morning stiffness is taken. The resulting 0 to 50 score is divided by 5 to give a final 0 - 10 BASDAI score. Scores of 4 or greater suggest suboptimal control of disease.

The satisfaction of treatment for the participant will be assessed using a 5-point Likert scale, ("Very dissatisfied Dissatisfied Neither satisfied nor dissatisfied Satisfied Very satisfied"). The scale includes two patient reported questions: "1) How satisfied or dissatisfied are you with the overall convenience of this medication" and "2) How satisfied or dissatisfied are you with the ability of this medication ability to treat your condition?" Scores range from Very dissatisfied to Very satisfied and will be used to evaluate satisfaction with guselkumab treatment.

Satisfaction of treatment care management and patient relationship for the rheumatologist will be assessed using a 5-point Likert scale specified as : "Very dissatisfied, Dissatisfied, Neither satisfied nor dissatisfied, Satisfied and Very satisfied." The physician-reported questions are: "1) How satisfied or dissatisfied are you with this drug overall for this patient?" and "2) How satisfied or dissatisfied are you with the ease of managing your patient with guselkumab?"