Objective: To study the trends of transmitted drug resistance (TDR) in HIV-1 patients newly diagnosed in Sweden, 2010-2016. Design: Register-based study including all antiretroviral therapy-naive patients ≥18 years diagnosed with HIV-1 in Sweden 2010-2016. Methods: Patient data and viral pol sequences were extracted from the national InfCareHIV database. TDR was defined as the presence of surveillance drug resistance mutations (SDRMs). A CD4+ T-cell decline trajectory model estimated time of infection. Phylogenetic inference was used for cluster analysis. Chi-square tests and logistic regressions were used to investigate relations between TDR, epidemiological and viral factors. Results: One thousand, seven hundred and thirteen pol sequences were analyzed, corresponding to 71% of patients with a new HIV-1 diagnosis (heterosexuals: 53%; MSM: 34%). The overall prevalence of TDR was 7.1% (95% CI 5.8-8.3%). Nonnucleoside reverse transcriptase inhibitor (NNRTI) TDR increased significantly from 1.5% in 2010 to 6.2% in 2016, and was associated to infection and/or origin in sub-Saharan Africa (SSA). An MSM transmission cluster dating back to the 1990s with the M41L SDRM was identified. Twenty-five (1.5%) patients exhibited TDR to tenofovir (TDF; n = 8), emtricitabine/lamivudine (n = 9) or both (n = 8). Conclusion: NNRTI TDR has increased from 2010 to 2016 in HIV-1-infected migrants from SSA diagnosed in Sweden, mirroring the situation in SSA. TDR to tenofovir/emtricitabine, used in preexposure prophylaxis, confirms the clinical and epidemiological need for resistance testing in newly diagnosed patients.
