Community viral load in patients harboring HIV drug-resistant strains and new cases of TDR in Northern Greece-a retrospective cohort study

Abstract

Purpose of the study

Recent studies suggest an association between community viral load and new diagnoses of HIV infection. Aim of our study was to explore a potential association between the pattern of new cases of transmitted drug resistance (TDR) in Northern Greece and the community viral load in the subset of patients who harbored HIV drug-resistant strains during 2000–2007.

Methods

Data on viral load measurements and genotypic HIV drug resistance were extracted from the respective databases of the Infectious Diseases Division of the AHEPA University Hospital and the National Reference Laboratory for AIDS of Northern Greece which provide healthcare services free of charge for the majority of HIV-positive individuals in Northern Greece. Patients who had undergone at least once genotypic resistance testing were included in the study. The 2009 SDRM list was used to categorize patients in subsets with regard to genotypic resistance results. Community viral load (CVL) was calculated as follows: The per-year weighed mean viral load was calculated for each individual patient and the median value of this set was defined as the community viral load. Poisson log-linear regression models with robust estimators were employed to examine the association between new cases of TDR and CVL of patients with genotypic drug resistance, patient number and year.

Results

512 patients out of 701 ever recorded had undergone genotypic HIV drug resistance testing at least once (73%). Overall, 202 out of 512 patients (39.4%) were identified with at least one resistance mutation (106/512 NNRTI, 175/512 NRTI, 104/512 PI). Poisson log-linear multivariate models correlated new cases of TDR with either log CVL (p = 0.068, RR: 7.59, 95% CI: 0.863–66.71) and year (p = 0.013, RR: 2.19, 95% CI: 1.18–4.08) or log CVL (p = 0.030, RR: 5.08, 95% CI: 1.17–22.06) and number of patients with drug resistance (p = 0.0001, RR: 1.03, 95% CI: 1.01–1.06).

Conclusions

Our results indicate that the community viral load of patients with HIV drug resistance may affect the number of new patients with TDR, underline the need for successful viral suppression in patients with resistant HIV strains from a public health standpoint and, should they be supported by further studies, suggest that community viral load could be used as a biomarker for TDR surveillance.

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