Missed Opportunities for HIV Diagnosis and Their Clinical Repercussions in the Portuguese Population-A Cohort Study.

Late human immunodeficiency virus (HIV) diagnosis has been associated with missed opportunities for earlier diagnosis. We conducted a retrospective, longitudinal, single-centre cohort study evaluating these missed opportunities and their clinical repercussions in adults with a new HIV diagnosis or who were drug-naïve, who attended our Infectious Diseases Department between 2018 and 2023. We assessed missed opportunities in the two years prior to diagnosis or after the last negative HIV test. We compared clinical and laboratorial data from individuals with and without missed opportunities. The primary outcome considered was AIDS-defining conditions at diagnosis. Among the 436 included individuals, 27.1% experienced at least one missed opportunity. Those with missed opportunities were more likely to be female ( = 0.007), older at their first consultation ( < 0.001), born in Africa ( < 0.001) and in countries with a high HIV prevalence ( < 0.001), and have heterosexual transmission ( < 0.001). The adjusted analysis showed that missed opportunities were significantly associated with AIDS-defining conditions at diagnosis (OR 3.23, CI 95% [1.62-6.46], < 0.001). These findings highlight the impact of missed opportunities on HIV severity, underscoring the need for more targeted interventions to reduce them.