C106-05 Imaging Characteristics and Spirometry Phenotypes of Pulmonary Tuberculosis Among People With HIV Initiating Tuberculosis Treatment in Uganda

Abstract Rationale Tuberculosis (TB) is a major driver of mortality and morbidity among people with HIV (PWH), responsible for nearly one-third of all AIDS-related deaths globally. Understanding the relationship between structural and functional lung indices is important for predicting long-term pulmonary outcomes and guiding interventions during and after TB treatment. Methods We analyzed baseline data of PWH enrolled in the Tuberculosis, Alcohol, and Lung Comorbidities (TALC) study in Uganda. CT characteristics were categorized into obstructive (bronchiolar disease, emphysema, bronchiectasis, and tree-in-bud opacities), restrictive (consolidation, fibrosis, cavitation, irregular septal thickening, calcified nodules and ground glass opacities), mixed (presence of both), and normal. Spirometry phenotypes were similarly defined as obstructive (FEV1/FVC <0.7), restrictive (FVCz_category < -1.645 and FEV1/FVC≥ 0.70), mixed (FEV1/FVC<0.70 and FVCz_category < -1.645) and normal categories.We compared demographics, HIV/TB history, alcohol use disorders identification test (AUDIT), physiologic (6-minute walk distance [6MWD]), functional (FEV1, FVC), symptoms (St. George’s Respiratory Questionnaire [SGRQ]), and structural indices across the three categories of concordant, discordant, and mixed. We assessed agreement between CT and spirometry-defined categories using Cohen’s Kappa. Results Among 140 participants (mean age 37 years, 49% female), 36% (n = 51) were concordant, 30% (n = 42) discordant, and 34% (n = 47) mixed when comparing CT and spirometry patterns. CT-defined obstructive and restrictive patterns were 9% and 19% respectively, while spirometry-defined obstructive and restrictive phenotypes were both 17%. Participants with discordant CT and spirometry patterns (cross-modality mixed category) had the lowest FEV1 %predicted (66 vs 92 vs 82), lowest FVC %predicted (87 vs 96 vs 89), and the lowest FEV1/FVC (0.63 vs 0.80 vs 0.79). They also had higher prevalence of altered lung anatomy (89% vs 28% vs 67%), highest SGRQ total scores (46 vs 31 vs 42; p = 0.013) and highest AUDIT scores (12 vs 8 vs 8; p = 0.021). 6MWD did not differ significantly across categories. Agreement between spirometry and CT scan categories was poor (Kappa=0.18; 95% CI 0.08–0.28; p < 0.001). Conclusions CT scan showed extensive structural lung abnormalities even when spirometry was normal, while spirometry identified functional impairment not evident on imaging. This highlights the complementary role of the two modalities in providing insights into lung damage among PWH initiating TB treatment. Characterizing these baseline patterns is essential for understanding the evolution of post-TB lung disease (PTLD) over time. This abstract is funded by: National Institute on Alcohol Abuse and Alcoholism