Epidemiological factors associated with recent HIV infection among newly-diagnosed cases in Singapore, 2013-2017

Background

Early diagnosis is crucial in securing optimal outcomes in the HIV care cascade. Recent HIV infection (RHI) serves as an indicator of early detection in the course of HIV infection. Surveillance of RHI is important in uncovering at-risk groups in which HIV transmission is ongoing. The study objectives are to estimate the proportion of RHI among persons newly-diagnosed in 2013–2017, and to elucidate epidemiological factors associated with RHI in Singapore.

Methods

As part of the National HIV Molecular Surveillance Programme, residual plasma samples of treatment-naïve HIV-1 positive individuals were tested using the biotinylated peptide-capture enzyme immunoassay with a cutoff of normalized optical density ≤ 0.8 for evidence of RHI. A recent infection testing algorithm was applied for the classification of RHI. We identified risk factors associated with RHI using logistic regression analyses.

Results

A total of 701 newly-diagnosed HIV-infected persons were included in the study. The median age at HIV diagnosis was 38 years (interquartile range, 28–51). The majority were men (94.2%), and sexual route was the predominant mode of HIV transmission (98.3%). Overall, 133/701 (19.0, 95% confidence interval [CI] 16.2–22.0%) were classified as RHI. The proportions of RHI in 2015 (31.1%) and 2017 (31.0%) were significantly higher than in 2014 (11.2%). A significantly higher proportion of men having sex with men (23.4, 95% CI 19.6–27.6%) had RHI compared with heterosexual men (11.1, 95% CI 7.6–15.9%). Independent factors associated with RHI were: age 15–24 years (adjusted odds ratio [aOR] 4.18, 95% CI 1.69–10.31) compared with ≥55 years; HIV diagnosis in 2015 (aOR 2.36, 95% CI 1.25–4.46) and 2017 (aOR 2.52, 95% CI 1.32–4.80) compared with 2013–2014; detection via voluntary testing (aOR 1.91, 95% CI 1.07–3.43) compared with medical care; and self-reported history of HIV test(s) prior to diagnosis (aOR 1.72, 95% CI 1.06–2.81).

Conclusion

Although there appears to be an increasing trend towards early diagnosis, persons with RHI remain a minority in Singapore. The strong associations observed between modifiable behaviors (voluntary testing and HIV testing history) and RHI highlight the importance of increasing the accessibility to HIV testing for at-risk groups.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10478-5.

Analytical methods used in estimating the prevalence of HIV/AIDS from demographic and cross-sectional surveys with missing data: a systematic review

BACKGROUND

Sero- prevalence studies often have a problem of missing data. Few studies report the proportion of missing data and even fewer describe the methods used to adjust the results for missing data. The objective of this review was to determine the analytical methods used for analysis in HIV surveys with missing data.

METHODS

We searched for population, demographic and cross-sectional surveys of HIV published from January 2000 to April 2018 in Pub Med/Medline, Web of Science core collection, Latin American and Caribbean Sciences Literature, Africa-Wide Information and Scopus, and by reviewing references of included articles. All potential abstracts were imported into Covidence and abstracts screened by two independent reviewers using pre-specified criteria. Disagreements were resolved through discussion. A piloted data extraction tool was used to extract data and assess the risk of bias of the eligible studies. Data were analysed through a quantitative approach; variables were presented and summarised using figures and tables.

RESULTS

A total of 3426 citations where identified, 194 duplicates removed, 3232 screened and 69 full articles were obtained. Twenty-four studies were included. The response rate for an HIV test of the included studies ranged from 32 to 96% with the major reason for the missing data being refusal to consent for an HIV test. Complete case analysis was the primary method of analysis used, multiple imputations 11(46%) was the most advanced method used, followed by the Heckman's selection model 9(38%). Single Imputation and Instrumental variables method were used in only two studies each, with 13(54%) other different methods used in several studies. Forty-two percent of the studies applied more than two methods in the analysis, with a maximum of 4 methods per study. Only 6(25%) studies conducted a sensitivity analysis, while 11(46%) studies had a significant change of estimates after adjusting for missing data.

CONCLUSION

Missing data in survey studies is still a problem in disease estimation. Our review outlined a number of methods that can be used to adjust for missing data on HIV studies; however, more information and awareness are needed to allow informed choices on which method to be applied for the estimates to be more reliable and representative.

Real life results of direct acting antiviral therapy for HCV infection in HIV-HCV-coinfected patients: Epi-Ter2 study

The aim of this study was to evaluate the baseline demographics and real-life efficacy of direct acting antivirals (DAAs) in HIV-HCV-positive patients as compared to patients with HCV monoinfection. The analysis included 5690 subjects who were treated with DAAs: 5533 were HCV-positive and 157 were HIV-HCV-positive. Patients with HCV-monoinfection were older (p < .0001) and in HIV-HCV group there were more men (p < .0001). Prevalence of genotype 1a (p = .002), as well as of genotypes 3 and 4 (p < .0001) was higher in HIV-HCV-coinfected patients. Genotype 1b was more frequent (p < .0001) in the HCV-mono-infection group. Patients with HCV-monoinfection had a higher proportion of fibrosis F4 (p = .0004) and lower proportion of fibrosis F2 (p < .0001). HIV-HCV-coinfected individuals were more often treatment-naïve (p < .0001). Rates of sustained viral response after 12 weeks did not differ significantly between both groups (95.9% versus 97.3% in coinfection and monoinfection group, respectively; p > .05). They were, however, influenced by HCV genotype (p < .0001), stage of hepatic fibrosis (p < .0001), male sex (p < .0001), BMI (p = .0001) and treatment regimen modifications (p < .0001). Although factors associated with worse response to therapy (male sex, genotype 3) occurred more often in the HIV coinfection group, real-life results of DAAs did not differ significantly between both populations.

Long-term trends in HIV care entry: over 15 years of clinical experience from Poland

INTRODUCTION

Delay in HIV diagnosis and consequently late care entry with low CD4 counts remain a major challenge for the control of the HIV/AIDS epidemic. The aim of this study was to analyse the evolution of characteristics of the HIV epidemic in Poland.

METHODS

Cross-sectional data were collected for 3972 HIV-infected patients followed up in 14 of 17 Polish HIV treatment centres in the years 2000-2015. Clinical data were analysed and factors associated with late presentation (baseline CD4 count < 350 cells/μL or history of AIDS-defining illness) and advanced HIV disease (baseline CD4 count < 200 cells/μL or history of AIDS) were identified.

RESULTS

The majority (57.6%) of patients entered care late, while 35.6% presented with advanced HIV disease. The odds of being linked to care late or with advanced HIV disease increased consistently across age categories, increasing from 2.55 [95% confidence interval (CI) 1.46-4.47] for late presentation and 3.13 (95% CI 1.49-6.58) for advanced disease for the 21-30-year-old category to 5.2 (95% CI 1.94-14.04) and 8.15 (95% CI 2.88-23.01), respectively, for individuals > 60 years of age. Increased risks of late entry and advanced HIV disease were also observed for injecting drug users [adjusted odds ratio (aOR) 1.74 (95% CI 1.16-2.60) and 1.55 (95% CI 1.05-2.30), respectively], with lower aOR associated with the men who have sex with men transmission route [aOR 0.3 (95% CI 0.31-0.59) and 0.39 (95% CI 0.29-0.53), respectively]. The frequencies of cases in which patients were linked to care late and with advanced HIV disease decreased over time from 67.6% (2000) to 53.5% (2015) (P < 0.0001) and from 43.5% (2000) to 28.4% (2015) (P = 0.001), respectively.

CONCLUSIONS

Despite improvements over time, most patients diagnosed with HIV infection entered care late, with a third presenting with advanced HIV disease. Late care entry remains common among people who inject drugs and heterosexual groups.

Transmission patterns of HIV-1 non-R5 strains in Poland

HIV-1 env sequencing enables predictions of viral coreceptor tropism and phylogenetic investigations of transmission events. The aim of the study was to estimate the contribution of non-R5 strains to the viral spread in Poland. Partial proviral env sequences were retrieved from baseline blood samples of patients with newly diagnosed HIV-1 infection between 2008-2014, including 46 patients with recent HIV-1 infection (RHI), and 246 individuals with long-term infection (LTHI). These sequences were subjected to the genotypic coreceptor tropism predictions and phylogenetic analyses to identify transmission clusters. Overall, 27 clusters with 57 sequences (19.5%) were detected, including 15 sequences (26.3%) from patients with RHI. The proportion of non-R5 strains among all study participants was 23.3% (68/292), and was comparable between patients with RHI and LTHI (11/46, 23.9% vs 57/246, 23.2%; p = 1.000). All 11 patients with non-R5 strains and RHI were men having sex with men (MSM). Among these patients, 4 had viral sequences grouped within phylogenetic cluster with another sequence of non-R5 strain obtained from patient with LTHI, indicating potential acquisition of non-R5 HIV-1 for at least 4/46 (8.7%) patients with RHI. We were unable to confirm the contribution of patients with RHI to the forward transmission of non-R5 strains, but a relatively high proportion of non-R5 strains among them deserves attention due to the limited susceptibility to CCR5 antagonists.

Correlates of Serosorting and Knowledge of Sexual Partner's HIV Status Among Men Who have Sex with Men in Ukraine

Ukraine has among the highest rates of newly diagnosed HIV infections in the WHO European region. Men who have sex with men (MSM) is the least studied group in the context of the HIV epidemics in Ukraine. The present paper aims to estimate the prevalence and correlates of knowledge of sexual partner's HIV status and potentially discordant anal intercourse (failure to serosort) among MSM. Data of the cross-sectional study among 8100 MSM in Ukraine in 2013 were used for this analysis. Less than half of the participants (42.5%) reported that they knew the HIV serostatus of their most recent male sexual partner, and about 13% of participants reported failure to serosort during their most recent anal sexual intercourse with a male partner. Targeted interventions can be implemented to increase knowledge about sexual partner's HIV status, both among HIV-negative and HIV-positive MSM, to reduce the risk of HIV acquisition and transmission.

Meeting the WHO 90% target: antiretroviral treatment efficacy in Poland is associated with baseline clinical patient characteristics

Introduction: Modern combined antiretroviral therapies (cART) allow to effectively suppress HIV-1 viral load, with the 90% virologic success rate, meeting the WHO target in most clinical settings. The aim of this study was to analyse antiretroviral treatment efficacy in Poland and to identify variables associated with virologic suppression.

Methods: Cross-sectional data on 5152 (56.92% of the countrywide treated at the time-point of analysis) patients on cART for more than six months with at least one HIV-RNA measurement in 2016 were collected from 14 Polish centres. Patients’ characteristics and treatment type-based outcomes were analysed for the virologic suppression thresholds of <50 and <200 HIV-RNA copies/ml. CART was categorized into two nucleos(t)ide (2NRTI) plus non-nucleoside reverse transcriptase (NNRTI) inhibitors, 2NRTI plus protease (PI) inhibitor, 2NRTI plus integrase (InI) inhibitor, nucleos(t)ide sparing PI/r+InI and three drug class regimens. For statistics Chi-square and U-Mann Whitney tests and adjusted multivariate logistic regression models were used.

Results: Virologic suppression rates of <50 copies/mL were observed in 4672 (90.68%) and <200 copies/mL in 4934 (95.77%) individuals. In univariate analyses, for the suppression threshold <50 copies/mL higher efficacy was noted for 2NRTI+NNRTI-based combinations (94.73%) compared to 2NRTI+PI (89.93%), 2NRTI+InI (90.61%), nucleos(t)ide sparing PI/r+InI (82.02%) and three drug class regimens (74.49%) (p < 0.0001), with less pronounced but significant differences for the threshold of 200 copies/mL [2NRTI+NNRTI-97.61%, 2NRTI+PI-95.27%, 2NRTI+InI-96.61%, PI/r+InI- 95.51% and 86.22% for three drug class cART) (p < 0.0001). However, in multivariate model, virologic efficacy for viral load <50 copies/mL was similar across treatment groups with significant influence by history of AIDS [OR:1.48 (95%CI:1.01–2.17) if AIDS diagnosed, p = 0.046], viral load < 5 log copies/mL at care entry [OR:1.47 (95%CI:1.08–2.01), p = 0.016], baseline lymphocyte CD4 count ≥200 cells/µL [OR:1.72 (95%CI:1.04–2.78), p = 0.034] and negative HCV serology [OR:1.97 (95%CI:1.29–2.94), p = 0.002]. For viral load threshold <200 copies/mL higher likelihood of virologic success was only associated with baseline lymphocyte CD4 count ≥200 cells/µL [OR:2.08 (95%CI:1.01–4.35), p = 0.049] and negative HCV status [OR:2.84 (95%CI:1.52–5.26), p = 0.001].

Conclusions: Proportion of virologically suppressed patients is in line with WHO treatment target confirming successful application of antiretroviral treatment strategy in Poland. Virological suppression rates depend on baseline patient characteristics, which should guide individualized antiretroviral tre0atment decisions.

Modelling the cost-effectiveness of HIV care shows a clear benefit when transmission risk is considered in the calculations - A message for Central and Eastern Europe

BACKGROUND

HIV epidemic remains a major global health issue. Data from cost-effectiveness analyses base on CD4+ count and morbidity in patients with symptomatic and asymptomatic HIV infection. The approach adopted in these analyses includes many other factors, previously not investigated. Additionally, we evaluate the impact of sexual HIV transmission due to delayed cART on the cost-effectiveness of care.

METHODS

A lifetime Markov model (1-month cycle) was developed to estimate the cost per quality adjusted life years (QALY) for a 1- and 3-year delay in starting cART (as compared to starting immediately at linkage to care) lifetime costs, clinical outcomes and cost-effectiveness. Patients were categorized into having asymptomatic HIV, AIDS, Hodgkin's Lymphoma, and non-AIDS defining condition. Mortality rates and utility values were obtained from published literature. The number of new infected persons was estimated on the basis of sexual orientation, the number of sexual partners per year, the number of sex acts per month, frequency of condom use and use of cART. For the input Test and Keep in Care (TAK) project cohort data were used. Costs of care, cART and potential life-years lost were based on estimated total costs and the difference in expected QALY gained between an HIV-positive and an average person in Polish population. Costs were based on real expenditures of the Ministry of Health, National Health Fund, available studies and experts' opinion. Costs and effects were discounted at rates of 5% and 3.5%, respectively.

RESULTS

Input data were available for 141 patients form TAK cohort. The estimated number of new HIV infections in low, medium and high risk transmission groups were 0.28, 0.61, 2.07 with 1 and 0.82, 1.80, 6.11 with a 3-year delay, respectively. This reflected QALY loss due to cART delay of 0.52, 1.13, 3.84 and 2.02, 4.43, 15.03 for a 1- and 3-year delay, respectively. If additional costs of treatment and potential life-years lost due to new HIV infections were not taken into account, initiating cART immediately at linkage to care was not cost-saving irrespective of cART delay. Otherwise, when additional costs and QALY lost due to new HIV infections were included, immediate cART initiation was cost-saving regardless of the chosen scenarios.

CONCLUSIONS

If new HIV infections are not taken into account, then starting cART immediately does not dominate comparing to delaying cART. When taking into account HIV transmission in cost-effectiveness analysis, immediate initiation of HIV treatment is a profitable decision from the public payer's perspective.

Expanding HIV-1 subtype B transmission networks among men who have sex with men in Poland

INTRODUCTION

Reconstruction of HIV transmission links allows to trace the spread and dynamics of infection and guide epidemiological interventions. The aim of this study was to characterize transmission networks among subtype B infected patients from Poland.

MATERIAL AND METHODS

Maximum likelihood phylogenenetic trees were inferred from 966 HIV-1 subtype B protease/reverse transcriptase sequences from patients followed up in nine Polish HIV centers. Monophyletic clusters were identified using 3% within-cluster distance and 0.9 bootstrap values. Interregional links for the clusters were investigated and time from infection to onward transmission estimated using Bayesian dated MCMC phylogeny.

RESULTS

Three hundred twenty one (33.2%) sequences formed 109 clusters, including ten clusters of ≥5 sequences (n = 81, 8.4%). Transmission networks were more common among MSM (234 sequences, 68.6%) compared to other infection routes (injection drug use: 28 (8.2%) and heterosexual transmissions: 59 (17.3%) cases, respectively [OR:3.5 (95%CI:2.6-4.6),p<0.001]. Frequency of clustering increased from 26.92% in 2009 to 50.6% in 2014 [OR:1.18 (95%CI:1.06-1.31),p = 0.0026; slope +2.8%/year] with median time to onward transmission within clusters of 1.38 (IQR:0.59-2.52) years. In multivariate models clustering was associated with both MSM transmission route [OR:2.24 (95%CI:1.38-3.65),p<0.001] and asymptomatic stage of HIV infection [OR:1.93 (95%CI:1.4-2.64),p<0.0001]. Additionally, interregional networks were linked to MSM transmissions [OR:4.7 (95%CI:2.55-8.96),p<0.001].

CONCLUSIONS

Reconstruction of the HIV-1 subtype B transmission patterns reveals increasing degree of clustering and existence of interregional networks among Polish MSM. Dated phylogeny confirms the association between onward transmission and recent infections. High transmission dynamics among Polish MSM emphasizes the necessity for active testing and early treatment in this group.

HIV prevalence among men who have sex with men in Istanbul

OBJECTIVES

The re-emergence of the HIV epidemic among men who have sex with men (MSM) represents a serious health issue. This study aimed to assess the HIV prevalence among MSM in a very low prevalence population of a large city.

METHODS

A public campaign to raise awareness of HIV infection and to provide access to anonymous testing was conducted in places frequented by MSM and through a mobile phone application. No identity information was requested from individuals contacting the call centre, and anonymous and free HIV testing was offered proactively. Those who agreed to have a test were provided a code number, which was used in blood sampling procedures.

RESULTS

Of 1200 subjects who contacted the call centre, 197 consented to undergo HIV testing and visited the laboratory to give a blood sample. Twenty-five subjects were found to have a reactive ELISA result on two different occasions plus a positive Western blot test result. Thus, the HIV prevalence in this group of MSM was 12.7%.

CONCLUSIONS

MSM remain a high risk group for HIV infection in a low prevalence setting, and thus represent a key target population for diagnostic and therapeutic interventions.

Bayesian evidence synthesis to estimate HIV prevalence in men who have sex with men in Poland at the end of 2009

HIV spread in men who have sex with men (MSM) is an increasing problem in Poland. Despite the existence of a surveillance system, there is no direct evidence to allow estimation of HIV prevalence and the proportion undiagnosed in MSM. We extracted data on HIV and the MSM population in Poland, including case-based surveillance data, diagnostic testing prevalence data and behavioural data relating to self-reported prior diagnosis, stratified by age (⩽35, >35 years) and region (Mazowieckie including the capital city of Warsaw; other regions). They were integrated into one model based on a Bayesian evidence synthesis approach. The posterior distributions for HIV prevalence and the undiagnosed fraction were estimated by Markov Chain Monte Carlo methods. To improve the model fit we repeated the analysis, introducing bias parameters to account for potential lack of representativeness in data. By placing additional constraints on bias parameters we obtained precisely identified estimates. This family of models indicates a high undiagnosed fraction [68·3%, 95% credibility interval (CrI) 53·9-76·1] and overall low prevalence (2·3%, 95% CrI 1·4-4·1) of HIV in MSM. Additional data are necessary in order to produce more robust epidemiological estimates. More effort is urgently needed to ensure timely diagnosis of HIV in Poland.

Distribution and time trends of HIV-1 variants in Poland: Characteristics of non-B clades and recombinant viruses

The spread of HIV-1 subtypes varies considerably both worldwide and within Europe, with non-B variants commonly found across various exposure groups. This study aimed to analyse the distribution and temporal trends in HIV-1 subtype variability across Poland. For analysis of the subtype distribution, 1219 partial pol sequences obtained from patients followed up in 9 of 17 Polish HIV treatment centres were used. Subtyping was inferred using the maximum likelihood method; recombination was assessed using the bootscanning and jumping profile hidden Markov model methods. Subtype B dominated in the studied group (n=1059, 86.9%); in 160 (13.1%) sequences, non-B variants were present [A1 (n=63, 5.2%), D (n=43, 3.5%), C (n=22, 1.8%), and F1 (n=2, 0.2%)]. In 25 (2.1%) cases circulating recombinant forms (CRFs) were found. Five A1 variants (0.4%) were unique AB recombinant forms (URF) not previously identified in Poland. Non-B clades were notably more common among females (n=73, 45.6%, p<0.001) and heterosexual individuals (n=103, 66.5%, p<0.001) and less frequent among men who have sex with men (MSM) (n=27, 17.42%, p<0.001). HIV-1 viral load at diagnosis was higher among non-B cases [median: 5.0 (IQR: 4.4-5.6)] vs. [median: 4.8 (IQR: 4.3-5.4) log copies/ml for subtype B (p<0.001)] with a lower CD4(+) lymphocyte count at baseline [median: 248 (IQR: 75-503) for non-B vs. median: 320 (IQR: 125-497) cells/μl for subtype B; p<0.001]. The frequency of the non-B subtypes proved stable from 2008 (11.5%) to 2014 (8.0%) [OR: 0.95 (95% CI: 0.84-1.07), p=0.4], with no temporal differences for exposure groups, gender, age and AIDS. Despite the predominance of subtype B, the variability of HIV in Poland is notable; both CRFs and URFs are present in the analysed population. Non-B variants are associated with heterosexual transmission, more advanced HIV disease and have stable temporal frequencies.

Incident risk factors as predictors of HIV seroconversion in the Lisbon cohort of men who have sex with men: first results, 2011-2014

HIV incidence in men who have sex with men (MSM) is increasing in western countries, including Portugal. We aimed to estimate HIV incidence and to assess how individual short-term changes in exposures over time predict seroconversion. We evaluated participants of an open cohort of HIV-negative MSM enrolled after testing at a community-based voluntary HIV counselling and testing centre in Lisbon. At each evaluation a structured questionnaire was completed and HIV status was ascertained using rapid followed by confirmatory testing. Between April 2011 and February 2014, 804 MSM were followed for a total of 893 person-years. Predictors of HIV seroconversion were identified using Poisson generalised linear regression. The overall seroincidence was 2.80/100 person-years (95% confidence interval: 1.89-4.14). Men who seroconverted had a higher mean number of tests per year. Seroconversions were significantly associated with partner disclosure of HIV status during follow-up, newly-adopted unprotected anal intercourse (UAI) with a steady partner and being newly-diagnosed with syphilis during follow-up. Likewise, sexual intercourse with HIV-positive men, having an HIV-positive steady partner at least once during follow-up and persistent UAI with occasional partners were predictors of seroconversion. High HIV incidence in this cohort is likely driven by short-term contextual and behavioural changes during follow-up.

An overview of the HIV epidemic among men who have sex with men in the United Kingdom, 1999-2013

We describe epidemiological trends in HIV among men who have sex with men (MSM) in the United Kingdom (UK) to inform prevention strategies. National HIV surveillance data were analysed for trends. Multivariable analyses identified predictors of late diagnosis (<350 copies/µL) and mortality. Between 1999 and 2013, 37,560 MSM (≥15 years) were diagnosed with HIV in the UK. New diagnoses rose annually from 1,440 in 1999 to 3,250 in 2013. The majority of MSM were of white ethnicity (85%) and UK-born (68%). Median CD4 count increased steadily from 350 cells/µL to 463 cells/µL. HIV testing in England increased from 10,900 tests in 1999 to 102,600 in 2013. One-year death rates after diagnosis declined among late presenters (4.7% to 1.9%). Despite declining late diagnosis (50% to 31%), the number of men diagnosed late annually has remained high since 2004. Older age (≥50 years), and living outside London were predictors of late presentation; older age and late presentation were predictors of one-year mortality. Increases in new diagnoses reflect increased testing and ongoing transmission. Over 900 men present late each year and mortality in this group remains high and preventable. Appropriate prevention and testing strategies require strengthening to reduce HIV transmission and late diagnosis.

Ten years after Dublin: principal trends in HIV surveillance in the EU/EEA, 2004 to 2013

In 2004, the 31 countries of the European Union and European Economic Area (EU/EEA) adopted the Dublin Declaration on Partnership to Fight HIV/AIDS in Europe and Central Asia. In 2013, 29,157 persons were diagnosed with HIV in 30 EU/EEA countries (adjusted rate: 6.2/100,000); new diagnoses have increased by 33% since 2004 among men who have sex with men and late diagnosis remains common. Evidence-based prevention measures and efforts towards earlier testing need to be expanded.

Transmitted HIV drug resistance in antiretroviral-treatment-naive patients from Poland differs by transmission category and subtype

OBJECTIVES

The surveillance of HIV-transmitted drug resistance mutations (t-DRMs), including temporal trends across subtypes and exposure groups, remains a priority in the current management of the epidemic worldwide.

METHODS

A cross-sectional analysis of 833 treatment-naive patients from 9 of 17 Polish HIV treatment centres. Partial pol sequences were used to analyse drug resistance with a general time reversible (GTR)-based maximum likelihood algorithm used for cluster/pair identification. Mutation frequencies and temporal trends were investigated.

RESULTS

t-DRMs were observed in 9% of cases (5.8% for NRTI, 1.2% NNRTI and 2.0% PI mutations) and were more common among heterosexually infected (HET) individuals (13.4%) compared with MSM (8.3%, P = 0.03) or injection drug users (IDUs; 2.9%, P = 0.001) and in MSM compared with IDUs (P = 0.046). t-DRMs were more frequent in cases infected with the non-B variant (21.6%) compared with subtype B (6.6%, P < 0.001). With subtype B a higher mutation frequency was found in MSM compared with non-MSM cases (8.3% versus 1.8% for IDU + HET, P = 0.038), while non-B variants were associated with heterosexual exposure (30.4% for HET versus 4.8% for MSM, P = 0.019; versus 0 for IDU, P = 0.016). Trends in t-DRM frequencies were stable over time except for a decrease in NNRTI t-DRMs among MSM (P = 0.0662) and an NRTI t-DRM decrease in HET individuals (P = 0.077). With subtype B a higher frequency of sequence pairs/clusters in MSM (50.4%) was found compared with HET (P < 0.001) and IDUs (P = 0.015).

CONCLUSIONS

Despite stable trends over time, patterns of t-DRMs differed notably between transmission categories and subtypes: subtype B was associated with MSM transmission and clustering while in non-B clades t-DRMs were more common and were associated with heterosexual infections.