Southern Sichuan HIV Cohort Study Protocol

Inclusion Criteria: * People living with HIV (PLWH) or AIDS patients who are registered and diagnosed at the participating research centers in Luzhou, Zigong, Neijiang, or Yibin, China * Key assessment information (clinical, laboratory, or follow-up data) obtainable during the study period * Traceable medical treatment or follow-up records within the retrospective time window (1 January 2019 to 31 December 2025) * Able to understand and complete the questionnaire and provide written informed consent (for the prospective component) * Residing or visiting within the four southern Sichuan cities, or continuously managed at the local research centers Exclusion Criteria: * Missing key information that cannot be verified or supplemented from original records * Unable to complete the questionnaire and no alternative data collection method available * Obviously inconsistent or untrustworthy data that cannot be confirmed after verification * Not suitable for inclusion under ethical and compliance requirements (e.g., unable to provide consent without a legally authorized representative when required)