Duration of Human Immunodeficiency Virus Infection at Diagnosis among New Human Immunodeficiency Virus Cases in Dehong, Yunnan, China, 2008-2015

Background: On diagnosis of human immunodeficiency virus (HIV) infection, a person may have been infected already for many years. This study aimed to estimate the duration of HIV infection at the time of diagnosis. Methods: Newly diagnosed HIV cases in Dehong, China, from 2008 to 2015 were studied. Duration of infection at the time of diagnosis was calculated using the first CD4 cell count result after diagnosis and a CD4 depletion model of disease progression. Multiple linear regression analysis was used to investigate the associated risk factors. Results: A total of 5867 new HIV cases were enrolled. Overall, mean duration of infection was 6.3 years (95% confidence interval [CI]: 6.2, 6.5). After adjusting for confounding, significantly shorter durations of infection were observed among participants who were female (beta: -0.37, 95% CL: -0.64, -0.09), Dai ethnicity (beta: -0.28, 95% CI: -0.57, 0.01), and infected through injecting drug use (beta: -1.82, 95% CI: -2.25, -1.39). Compared to the hospital setting, durations were shorter for those diagnosed in any other settings, and compared to 2008, durations were shorter for those diagnosed all years after 2010. Conclusion: Although the reduction in duration of infection at the time of diagnosis observed in Dehong was significant, it may not have had a meaningful impact.