Factors associated with pulmonary impairment in HIV-infected South African adults

Background HIV-infected individuals have increased risk of developing obstructive lung disease (OLD). Studies from developed countries report high viral load, low CD4 counts, and anti-retroviral therapy (ART) to be associated with OLD; but these findings may not be generalizable to populations in resource-limited settings. Methods We conducted a prospective cohort study of lung function in 730 HIV-infected black South African adults. Pre-bronchodilator spirometry was performed at enrollment and repeated annually for three years. Logistic regression models were used to identify factors associated with OLD, defined as FEV1/FVC < 0.70, at enrollment. Excess annual declines in FEV1 and FVC were modelled as the product-term of follow-up time and exposures using random effects regression. Results Median (IQR) age at enrollment was 36 (32-41) years, 85% were female and 30% ever-smoked with a median (IQR) exposure of 3 (1-6) pack-years. Median (IQR) CD4 count and viral load at enrollment were 372 (261-518) cells/mm(3) and 2655 (91-13,548) copies/mL respectively. Overall, 25% were receiving ART at enrollment, 16% of whom reported at least 6 months of ART receipt. OLD was found in 35 (5%) at enrollment. Increasing age (aOR = 2.08 per 10-years [95% CI 1.22-3.57], p = 0.007), current smoking (aOR = 3.55 [95% CI 1.20-10.53], p = 0.02), and CRP (aOR = 1.01 per unit-increase [95% CI 1.00-1.03], p = 0.04) were significantly associated with OLD at enrollment; while increasing CD4 count (aOR = 1.02 per-100 cells/mm(3) [95% CI 0.85-1.22], p = 0.82), viral load (aOR = 0.67 per log-increase [95% CI 0.43-1.10], p = 0.12) and receipt of ART (aOR = 0.57 [95% CI 0.18-1.75], p = 0.32) were not. The median (IQR) follow-up time was 18 (12-24) months. Participants with a history of tuberculosis (TB) had a 35 mL (95% CI 2-68, p = 0.03) and 57 mL (95% CI 19-96, p = 0.003) per year excess loss of FEV1 and FVC respectively. Conclusion Prevalent OLD was associated with older age, current smoking and higher CRP levels, but not CD4 counts and ART, in HIV-infected South African adults. Better understanding of the long-term effects of TB, smoking and inflammation on lung function in HIV-infected populations is urgently needed.