BackgroundHIV-1 diversity causes important differences in the virus’ biological properties and their interactions with hosts, such as cell tropism, responses to antiretroviral therapy, drug-resistance, and disease progression.ObjectivesWe evaluated the interrelationship of phylogenetic inference with epidemiological and laboratory data for HIV-1 isolates circulating in Pernambuco, Northeast Region—Brazil.Study designA total of 168 HIV-1 pol sequences were analysed, 64 were obtained from 2002–2003, and 104, from 2007–2009. Socio-demographic, clinical, and behavioural data were obtained from medical records. Laboratory testing enabled the determination of recent HIV-1 infections and co-infections with HBV, HCV, HTLV, or syphilis. Surveillance drug-resistance mutation analysis and antiretroviral susceptibility profiling were performed using HIV Drug-Resistance Database.ResultsHIV-1 non-B was associated with female, lower education, lower viral loads, and higher T cell counts mean. Frequencies of co-infection HIV-HBV, HIV-HCV, and HIV-syphilis were 27.8% (95% CI: 19.8–37.7), 1.04% (95% CI: 0.05–5.00) and 14.7% (95% CI: 8.6–23.0), respectively. Drug-resistant mutations rate was 2.98% (95% CI: 1.10–6.47). HIV-HBV subtype B co-infection was associated with men who have sex with men (MSM), higher education, higher viral loads and males. HIV-syphilis subtype non-B co-infection was associated with MSM status, lower T cell counts and males.ConclusionsData showed the importance of molecular characterisations of the HIV-1 epidemic and its relation with epidemiological and clinical characteristics of the population, as well as its association with other infectious diseases, so they can effort to improve preventive measures for health services and more information about the progress and effects of the epidemic in Northeastern–Brazil.