Objectives
We aimed to determine the incidence rate, pathogen composition, and risk factors, particularly airflow limitation, associated with bacterial respiratory infection and pneumonia in a prospective cohort of well-treated people with HIV (PWH) between 2015-2021.

Methods
We included 1007 PWH from the Copenhagen Comorbidity in HIV infection (COCOMO) study. Spirometry was performed at inclusion. Microbiology samples were collected prospectively. Cumulative incidence was determined by the Aalen-Johansen estimator. Cox proportional hazard models were used to calculate risk factors, adjusted for traditional and HIV-specific variables.

Results
The incidence rates of first bacterial respiratory infection and pneumonia were 12.4 (95% CI 9.7-15.5) and 5.5 (95% CI: 3.8-7.7) per 1000 person-years, respectively. The cumulative incidence of pneumonia was four times higher in PWH with airflow limitation (11.8% vs 3.2%, P <0.001). Risk factors for bacterial respiratory infection were airflow limitation (hazard ratio [HR] 2.9, [95% CI: 1.7-5.1], P <0.001), smoking (HR 2.3, [95% CI: 1.4-3.8], P <0.001), and previous AIDS-defining event (HR 2.0, [95% CI: 1.2-3.3], P = 0.009). For pneumonia, airflow limitation (HR 2.7, [95% CI: 1.2-6.3], P = 0.016), smoking (HR 2.5, [95% CI: 1.2-5.4], P = 0.016), and older age (HR 1.5, [95% CI: 1.1-2.1], P = 0.015) were identified as risk factors.

Conclusions
Increased emphasis on airflow limitation prevention, including smoking cessation, may reduce the burden of bacterial respiratory infection and pneumonia in PWH.