2.1 Study participants
This was a secondary analysis of data collected from two large multicenter cohort studies conducted among antiretroviral naïve HIV-infected or first-line treatment failure adult patients by the China AIDS Clinical Trial network. These multicenter cohorts were established to evaluate the efficacy, toxicity, and co-morbidities of the first-line or second-line ART regimens available during each study.
The first study [China AIDS Clinical Trial 1810 (CACT1810); clinical trials.gov ID: NCT00872417] recruited adult HIV patients20 in 8 cities across China: Beijing, Shanghai, Zhengzhou, Fuzhou, Guangzhou, Shenzhen, Xi' an and Yunnan between 2008 and 2010. This CACT1810 trial was grouped into three arms: treatment-naïve, treatment-experienced, and drug resistance. Treatment-naïve and treatment-experienced patients received government-sponsored first-line drugs in 2008, including Stavudine(d4T) or Zidovudine(AZT) plus lamivudine(3TC) and nevirapine(NVP) or efavirenz (EFV). The ART regimen of drug resistance patients converted into the second-line ART regimens 3TC + TDF + LPV/RTV. The initial 96-week follow-up period of efficacy and safety evaluation was completed, and the participants are still being followed up. The present study included treatment-naïve patients and first-line resistance patients in the CACT1810 trial.
The second trial (CACT1215 clinical trials) enrolled HIV patients between 2012 and 2015 in 9 cities across China (Beijing, Shanghai, Guangzhou, Chengdu, Changsha, Nanning, Liuzhou, Zhengzhou, Shenyang)21,22. The sub-cohort of CACT1215 clinical trials (gov ID: NCT01844297) recruited ART-naïve HIV patients who received the first-line ART regimens at that time [tenofovir disoproxil fumarate (TDF) plus 3TC and EFV]. Another sub-cohort of CACT1215 (NCT01844310) evaluated the safety and efficacy of the RAL-based regimen in treatment-experienced patients with resistant HIV infection. This clinical trial's primary and secondary outcomes were obtained for a 96-week follow-up period, and the participants are still being followed up.
The study centers were divided into five regions based on geographic location, including North (Beijing, Shenyang), East (Shanghai, Fuzhou), South (Guangzhou, Shenzhen, Nanning, Liuzhou), Central(Zhengzhou, Changsha), and West (Xi' an, Yunnan, Chengdu).
All participants in the present study had viremia at baseline (at least 400cps/ml). Patients with OIs within three months but still unstable within 14 days prior to recruitment were excluded in prior clinical trials. All patients in the two-parent clinical trials with complete baseline data were enrolled in the present study. After enrollment, participants were treated with ART and followed up at weeks 4, 12, 24, and once every 12 weeks after that for clinical and laboratory evaluations by trained physicians. Data were recorded and uploaded into the collaboration network database.
The Institutional Review Board of Peking Union Medical College Hospital (PUMCH) approved the parent clinical trial prior to initiation of the study, and each participant provided written informed consent at the time of enrollment, and all procedures were performed in compliance with the ethical standards of The Declaration of Helsinki.
2.2 Serum collection and Laboratory methods
Blood samples were collected from all confirmed HIV-infected patients at baseline, 4, 12, 24, and once every 12 weeks. At every encounter, laboratory measurements were detected, and clinical status was examined at study centers according to the protocol. HIV-1 RNA was measured by COBAS Ampliprep/TaqMan48 real-time RT-PCR (Roche Diagnostics). CD4 and CD8 T cell count was determined by flow cytometry ((FACS Canto, BD Biosciences, NJ, USA). CMV IgM was tested at baseline, 96, 144, and 192 weeks by chemiluminescence assays (Abbott automatic immunoassay analyzer, Abbott Park, IL, USA).
A recent CMV infection was considered in longitudinal cohorts when a positive IgM was tested among patients with negative IgM at baseline. For these cases of recent CMV infection, a retrospective review and interviews of clinical symptoms that may have occurred in the past three months were conducted.
2.3 Statistical analysis
SPSS 26 software was used for statistical analysis. Descriptive data were expressed as means ± standard deviations and frequencies. Continuous variables were compared by Student’s t-test or Mann-Whitney U test and categorical variables by the Chi-squared test. Variables were chosen based on the literature and the clinical experiences. Multicollinearity was assessed by a variance inflation factor (VIF). Then logistic regression was performed to evaluate the risk of CMV-IgM positive at baseline. A generalized estimating equation (GEE) was applied to estimate whether CMV coinfection affects CD4, CD8 T cell counts level, CD4/CD8 ratio at different visits. Incidence rates of seropositivity per 1000 person-years (PYs) during the observation period were calculated. Follow-up time was defined from baseline until the first seropositivity occurring, death, loss to follow-up, or end of the study period (192 weeks). All statistical tests were treated as two-sided, and results with p < 0.05 were considered statistically significant.