Distinct acute and chronic brain health phenotypes among people living with HIV in a Ugandan clinical cohort: a comorbidity network analysis

Background. Individual brain health conditions among people living with HIV in sub-Saharan Africa are increasingly well documented, but the co-occurrence of comorbidity and multimorbidity across distinct neurological and psychiatric conditions remains poorly characterized in this setting. We examined the co-occurrence structure of brain health conditions in a specialist HIV clinical cohort in Uganda. Methods. We analyzed 1,137 ICD-10-coded records from 581 patients in a specialist HIV neuropsychiatric cohort in Kampala (2017 to April 2026). All ICD-10 codes were classified, based on expert clinical consultation, into eight brain health domains and a two-level phenotype (acute versus chronic). Pairwise co-occurrence among domains with at least ten patients was tested using phi coefficients with bootstrap confidence intervals and Benjamini-Hochberg correction; latent class analysis was a pre-specified sensitivity analysis. Results. Of 573 classifiable patients, 476 (83.1%) carried a single brain health domain and only 12 (2.1%) carried diagnoses from both the acute and chronic phenotypes. Depression, bipolar and psychosis spectra co-aggregated (phi 0.11 to 0.25), while opportunistic CNS infection was mutually exclusive with every chronic domain (phi as low as -0.734). Cognitive impairment showed no significant association with major depressive disorder (12 patients with both domains; phi − 0.064, q = 0.203). Latent class analysis independently recovered a multimorbid chronic phenotype (24.6% of patients). Conclusions. Brain health conditions in this cohort partition into two clearly separated phenotypes: an acute opportunistic-infection phenotype and a chronic phenotype in which depressive, bipolar and psychotic presentations co-aggregate. Cognitive impairment and major depressive disorder, a comorbidity widely assumed to be common in HIV, showed no significant association in this cohort. Precise, clinically grounded classification of ICD-10 diagnoses is important for valid comorbidity research in HIV neuropsychiatry.