Due to the limited availability of eligible patients who met the study's criteria, as well as there has not been a case of tuberculosis, the study was terminated early.

This was a retrospective observational study that relied on data extracted from patient's chart review at the participating centers. Data was entered into an electronic Case Report Form (eCRF) designed to capture all relevant information to achieve the study objectives.

After the ethical approval for each participating site, the respective Investigator and/or designated qualified study staff were responsible for including all eligible patients in a consecutive manner and entering their information into the eCRF. Patients were primarily identified with ankylosing spondylitis (AS), psoriatic arthritis (PsA), and psoriasis (PsO) diagnosis according to the International Classification of Diseases (ICD)-10 code (M45, M07, and L40, respectively). Alternatively, the written diagnosis from applicable departments, such as payment, computing, or data office were also used for patient screening. Potentially eligible patients had their charts reviewed for all selection criteria. Inclusion was performed up to the number of patients determined for each site prior to study initiation or up to completion of sample size. Patient's identification (name, address, and other identifiable data) was not collected and remained confidential.

Inclusion criteria:

1. Documented diagnosis with AS, PsA, or PsO, regardless of its severity, by a physician as per patient chart up to secukinumab introduction.
2. Patient treated with secukinumab monotherapy for at least 24 months since 01 January 2016 in Brazil, in accordance with local labelling approval.
3. Biologic-naïve or secondary-naïve patient, who was not using biologic drug for at least 3 months prior to secukinumab introduction.
4. Medical history available from the entire study period i.e., at least 6 months before and 24 months after secukinumab introduction.

Exclusion criteria:

1. No access or availability of patient medical chart.
2. Patient who did not use approved dosing regimens for secukinumab therapy, as per local label.
3. Patient with confirmed clinical history of active tuberculosis or mendelian susceptibility to mycobacterium diseases prior to secukinumab use.
4. Patient treated with systemic corticosteroid doses with immunosuppressant features (prednisone dose higher than 10 milligrams [mg] or its equivalent) for at least 2 consecutive weeks or other concomitant immunosuppressant drug during the study period.

This was a retrospective, noninterventional cohort study.