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Background: The extensive and continuous reuse of sensitive health data could enhance the role of population health research on public decisions. This paper describes the design principles and the different building blocks that have supported the implementation and deployment of Population Health Information Research Infrastructure (PHIRI), the strengths and challenges of the approach and some future developments., Methods: The design and implementation of PHIRI have been developed upon: (i) the data visiting principle-data does not move but code moves; (ii) the orchestration of the research question throughout a workflow that ensured legal, organizational, semantic and technological interoperability and (iii) a 'master-worker' federated computational architecture that supported the development of four uses cases., Results: Nine participants nodes and 28 Euro-Peristat members completed the deployment of the infrastructure according to the expected outputs. As a consequence, each use case produced and published their own common data model, the analytical pipeline and the corresponding research outputs. All the digital objects were developed and published according to Open Science and FAIR principles., Conclusion: PHIRI has successfully supported the development of four use cases in a federated manner, overcoming limitations for the reuse of sensitive health data and providing a methodology to achieve interoperability in multiple research nodes., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Public Health Association.)

Background: We studied the association of obesity-related single-nucleotide polymorphisms (OR-SNPs) with weight gain after antiretroviral therapy (ART) in people with human immunodeficiency virus (HIV; PWH)., Methods: Participants were ART-naive PWH from the Spanish HIV Research Cohort who started ART from 2014 onward and had blood/DNA deposited in the cohort Biobank. The primary outcome was change in weight at 96 weeks after starting ART. We genotyped 14 OR-SNPs from a meta-analysis of genome-wide association studies of body mass index (BMI) loci. Changes over time in weight and BMI were studied using adjusted linear mixed models., Results: A total of 1021 PWH were included. The mean weight gain over 96 weeks was 2.90 (95% confidence interval, 2.54-3.26) kg. Factors associated with higher weight gain were female sex, birth in sub-Saharan Africa, prior AIDS, CD4+ <200 cells/µL, HIV-RNA >100 000 copies/mL, negative hepatitis C virus serology, and use of tenofovir alafenamide. A significant association was found between ZC3H4 rs3810291 GG genotype and BCDIN3D/FAIM2 rs7138803 GG genotype polymorphisms and weight and BMI increase. The estimated adjusted mean (standard error [SE]) of weight gain was 4.26 (0.56) kg in ZC3H4 rs3810291 GG carriers and 2.66 (0.19) kg in AA/AG carriers (P = .007). Likewise the estimated weight gain at 96 weeks was 3.35 (0.29) kg in BCDIN3D/FAIM2 rs7138803 GG carriers and 2.51 (0.24) kg in AG/AA carriers (P = .020)., Conclusions: Genetic factors may play a role in weight gain after ART initiation. Further work is needed to replicate our findings and understand how the identified SNPs lead to higher weight gain in this context., Competing Interests: Potential conflicts of interest. J. B. reports honoraria for advice or public speaking from Gilead Sciences, Inc, GSK, Janssen Pharmaceuticals, MSD, and ViiV Healthcare; grants from Gilead Sciences, Inc, MSD, and ViiV Healthcare; and support for attending meetings and/or travel from MSD, ViiV Healthcare, and Janssen Pharmaceuticals. I. J. reports honoraria for advice or public speaking from GILEAD, and ViiV Healthcare; honoraria for performing statistical analyses from Fundación Investigación Biomédica Hospital Gregorio Marañón and grants from MSD. J. G.-G. reports honoraria for advice or public speaking from Gilead Sciences, Inc, Janssen Pharmaceuticals, MSD, and ViiV Healthcare; grants or contracts from MSD, ViiV Healthcare, and Gilead Sciences, Inc; support for attending meetings and/or travel from Gilead Sciences, Inc (paid to author); and participation on a DSMB or advisory board for ViiV Healthcare and Janssen-Cilag, S.A. D. D. reports honoraria for public speaking from Gilead Sciences, Inc, Janssen Pharmaceuticals, and ViiV Healthcare (some of this payment was made to author's institution); support for attending meetings and/or travel from Gilead Sciences, Inc; and plays a role in the Spanish AIDS Society and Spanish HIV/AIDS Research Network of Excellence. J. O. reports honoraria for advice or public speaking from Gilead Sciences, Inc, Janssen Pharmaceuticals, MSD, ViiV Healthcare, Pfizer, and GSK; grants from Gilead Sciences, Inc, MSD, and ViiV Healthcare, including consulting fees from Janssen, ViiV, MSD, Gilead Sciences, Inc, and Pfizer; and support for attending meetings and/or travel from Gilead Sciences, Inc, and ViiV. P. D. reports honoraria for advice or public speaking or grants and participation on a DSMB or advisory board from AbbVie, Boehringer-Ingelheim, Bristol-Myers Squibb, Gilead Sciences, Inc, GSK, MSD, Janssen Pharmaceuticals, Pfizer, Theratechnologies, and ViiV Healthcare. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: The role of extracellular vesicles (EVs) in human immunodeficiency virus (HIV) pathogenesis is unknown. We examine the cellular origin of plasma microvesicles (MVs), a type of ectocytosis-derived EV, the presence of mitochondria in MVs, and their relationship to circulating cell-free mitochondrial deoxyribonucleic acid (ccf-mtDNA) in HIV-infected patients and controls., Methods: Five participant groups were defined: 30 antiretroviral therapy (ART)-naive; 30 ART-treated with nondetectable viremia; 30 elite controllers; 30 viremic controllers; and 30 HIV-uninfected controls. Microvesicles were quantified and characterized from plasma samples by flow cytometry. MitoTrackerDeepRed identified MVs containing mitochondria and ccf-mtDNA was quantified by real-time polymerase chain reaction., Results: Microvesicle numbers were expanded at least 10-fold in all HIV-infected groups compared with controls. More than 79% were platelet-derived MVs. Proportions of MVs containing mitochondria (22.3% vs 41.6%) and MV mitochondrial density (706 vs 1346) were significantly lower among HIV-infected subjects than controls, lowest levels for those on ART. Microvesicle numbers correlated with ccf-mtDNA levels that were higher among HIV-infected patients., Conclusions: A massive release of platelet-derived MVs occurs during HIV infection. Some MVs contain mitochondria, but their proportion and mitochondrial densities were lower in HIV infection than in controls. Platelet-derived MVs may be biomarkers of platelet activation, possibly reflecting pathogenesis even in absence of HIV replication., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America.)

Background: Patients with a significant decrease in hepatic venous pressure gradient (HVPG) have a considerable reduction of liver complications and higher survival after HCV eradication., Objectives: To evaluate the association between the baseline blood microbiome and the changes in HVPG after successful direct-acting antiviral (DAA) therapy in patients with HCV-related cirrhosis., Methods: We performed a prospective study in 32 cirrhotic patients (21 HIV positive) with clinically significant portal hypertension (HVPG ≥10 mmHg). Patients were assessed at baseline and 48 weeks after HCV treatment completion. The clinical endpoint was a decrease in HVPG of ≥20% or HVPG <12 mmHg at the end of follow-up. Bacterial 16S ribosomal DNA was sequenced using MiSeq Illumina technology, inflammatory plasma biomarkers were investigated using ProcartaPlex immunoassays and the metabolome was investigated using GC-MS., Results: During the follow-up, 47% of patients reached the clinical endpoint. At baseline, those patients had a higher relative abundance of Corynebacteriales and Diplorickettsiales order, Diplorickettsiaceae family, Corynebacterium and Aquicella genus and Undibacterium parvum species organisms and a lower relative abundance of Oceanospirillales and Rhodospirillales order, Halomonadaceae family and Massilia genus organisms compared with those who did not achieve the clinical endpoint according to the LEfSe algorithm. Corynebacteriales and Massilia were consistently found within the 10 bacterial taxa with the highest differential abundance between groups. Additionally, the relative abundance of the Corynebacteriales order was inversely correlated with IFN-γ, IL-17A and TNF-α levels and the Massilia genus with glycerol and lauric acid., Conclusions: Baseline-specific bacterial taxa are related to an HVPG decrease in patients with HCV-related cirrhosis after successful DAA therapy., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Little is known about the effects of eradication of hepatitis C virus (HCV) on bone mineral density (BMD) and biomarkers of bone remodeling in human immunodeficiency virus (HIV)/HCV-coinfected patients., Methods: We prospectively assessed standardized BMD (sBMD) at the lumbar spine and femoral neck, World Health Organization BMD categories at both sites, and plasma concentrations of soluble receptor activator of NF-κβ ligand (sRANKL), and osteoprotegerin (OPG) at baseline (the date of initiation of anti-HCV therapy) and at 96 weeks., Results: A total of 238 patients were included. The median age was 49.5 years, 76.5% were males, 48.3% had cirrhosis, 98.3% were on antiretroviral therapy, median CD4+ cell count was 527 cells/μL, and 86.6% had HIV-1 RNA <50 copies/mL. The prevalence of osteoporosis at baseline at the lumbar spine (LS) and femoral neck (FN) was 17.6% and 7.2%, respectively. Anti-HCV therapy comprised pegylated interferon (peg-IFN) and ribavirin (RBV) plus 1 direct-acting antiviral in 53.4%, peg-IFN/RBV in 34.5%, and sofosbuvir/RBV in 12.2%. A total of 145 (60.9%) patients achieved sustained virologic response (SVR). No significant effect of SVR was observed on sBMD for the interaction between time and SVR either in the LS (P = .801) or the FN (P = .911). Likewise, no significant effect of SVR was observed in plasma levels of sRANKL (P = .205), OPG (P = .249), or sRANKL/OPG ratio (P = .123) for the interaction between time and SVR. No significant correlation was found between fibrosis by transient elastography, and LS and FN sBMD, at baseline and week 96., Conclusions: SVR was not associated with significant changes in BMD nor biomarkers of bone remodeling in HIV/HCV-coinfected persons., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

This prospective study of 34 patients with HCV cirrhosis (17 HIV positive) with baseline clinically significant portal hypertension (CSPH; HVPG ≥10 mmHg) and SVR after DAA therapy showed that disappearance of CSPH (primary endpoint) is a rare event (6/18 patients; 18%), indicating a persistent risk of clinical progression or death., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Objectives: INSIGHT (ClinicalTrials.gov NCT01513941) evaluated the efficacy, safety and pharmacokinetics of telaprevir-based therapy and specific antiretroviral agents in hepatitis C virus genotype 1 (HCV-1)/HIV-1-coinfected patients., Patients and Methods: Open-label, Phase IIIb, multicentre study of telaprevir with pegylated-IFN (Peg-IFN) α2a and ribavirin in treatment-naive or -experienced HCV-1/HIV-1-coinfected patients on stable HIV HAART comprising efavirenz, atazanavir/ritonavir, darunavir/ritonavir, raltegravir, etravirine or rilpivirine with two nucleos(t)ide analogues. Patients received 750 mg telaprevir (1125 mg, if on efavirenz) every 8 h plus 180 μg/week Peg-IFNα2a and 800 mg/day ribavirin for 12 weeks, followed by Peg-IFNα2a and ribavirin alone for 12 weeks (HCV treatment naive and relapsers without cirrhosis, with extended rapid virological response) or 36 weeks (all others)., Results: Overall, 162 patients (median age of 46 years, 78% male, 92% Caucasian and mean CD4 count of 687 cells/mm(3)) were treated; 13% had cirrhosis. One-hundred-and-thirty-two patients (81%) completed telaprevir; 14 (9%) discontinued due to an adverse event (AE). Sustained virological response (SVR) 12 rates (<25 IU/mL HCV RNA 12 weeks after the last planned treatment dose) in treatment-naive patients, relapsers and non-responders were 64% (41 of 64), 62% (18 of 29) and 49% (34 of 69), respectively. SVR12 rates ranged from 51% (33 of 65) (patients receiving efavirenz) to 77% (13 of 17) (patients receiving raltegravir). Most frequently reported AEs during telaprevir treatment were pruritus (43%) and rash (34%) special search categories. Anaemia special search category occurred in 15% of patients; 6% of patients reported a serious AE., Conclusions: In treatment-naive/-experienced HCV-1/HIV-1 patients there were significantly higher SVR rates with telaprevir-based therapy compared with pre-specified historical controls, and safety comparable to that in HCV-monoinfected patients., (© The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Background: We compared the prognostic value of liver biopsy (LB) and FIB-4 index in patients with human immunodeficiency virus (HIV)/hepatitis C virus (HCV) coinfection., Methods: We studied patients from the Grupo de Estudio del SIDA 3603 study cohort, in whom fibrosis was evaluated at baseline using both LB (Metavir score) and FIB-4 index. We assessed overall death (OD) and liver-related events (LREs), defined as decompensation or hepatocellular carcinoma, whichever occurred first. We used receiver operating characteristic (ROC) curves to determine the ability of LB and FIB-4 to predict outcomes. We also assessed the association between advanced fibrosis-LB (F3 or greater) or FIB-4 (≥3.25)-and outcomes using multivariate Cox regression analysis., Results: The study sample comprised 903 patients (328 with sustained virologic response [SVR]). Baseline fibrosis by LB was as follows: F0, n = 71; F1, n = 242; F2, n = 236; F3, n = 236; F4, n = 118. Fibrosis by FIB-4 was as follows: ≤1, n = 148; >1 to <3.25, n = 597; ≥3.25, n = 158. After a median follow-up of 62 months, there were 46 deaths and 71 LREs. The area under the ROC curves for OD/LREs was 0.648 and 0.742 for LB and FIB-4, respectively (P = .006). Similar results were found for patients without SVR and for OD and LREs separately. The adjusted hazard ratios of OD or LRE were 1.740 (95% confidence interval [CI], 1.119-2.7.06; P = .014) for advanced fibrosis assessed by LB and 3.896 (95% CI, 2.463-6.160; P < .001) assessed by FIB-4., Conclusions: FIB-4 outperformed LB as a predictor of OD and LRE. These findings are of relevance for clinical practice and research and call into question the role of LB as a gold standard for assessing prognosis in HIV/HCV coinfection., (© The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Background: The evolution of neurocognitive performance in aviremic human immunodeficiency virus (HIV)-positive patients treated with <3 antiretrovirals is unknown., Methods: We prospectively included aviremic (≥1 year) HIV-positive patients, without concomitant major neurocognitive confounders, currently receiving boosted lopinavir or darunavir as monotherapy (n = 67) or triple antiretroviral therapy (ART) (n = 67) for ≥1 year. We evaluated neurocognitive function (7 domains) at baseline and after 1 year. We performed analysis of covariance to evaluate if 1 additional year of exposure to monotherapy compared with triple ART had an effect on Global Deficit Score (GDS) changes after adjustment for potential confounders. We also compared the evolution of neurocognitive performance and impairment rates., Results: Intention-to-treat analysis showed that monotherapy did not influence 1-year GDS change after adjustment for significant confounders (age, ethnicity, duration of therapy, hepatitis C virus status, and HOMA-IR index); the adjusted effect was -0.04 (95% confidence interval, -.14 to .05; P = .38). Neurocognitive stability was observed with monotherapy and triple therapy (GDS crude mean change, -0.09 [95% confidence interval, -.16 to -.01] vs -0.08 [-.14 to -.02]), after 1 year of follow-up, similar proportions of patients changed neurocognitive status from impaired to unimpaired (monotherapy, 4 of 18 [22.2%]; triple therapy, 4 of 19 [21.1%]; P = .91) and vice versa (monotherapy, 5 of 44 [10.2%] and triple therapy, 3 of 45 [6.3%]; P = .48). Similar results were observed in an on-treatment analysis and with use of clinical ratings instead of GDS changes., Conclusions: The number of antiretrovirals included in the ART regimen does not seem to influence the evolution of neurocognitive function in HIV-infected patients with suppressed plasma viremia., (© The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Background: Sustained virological response (SVR) after therapy with interferon plus ribavirin reduces liver-related complications and mortality in patients coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV). We assessed the effect of SVR on HIV progression and mortality not related to liver disease., Methods: An observational cohort study including consecutive HIV/HCV-coinfected patients treated with interferon plus ribavirin between 2000 and 2008 in 19 centers in Spain., Results: Of 1599 patients, 626 (39%) had an SVR. After a median follow-up of approximately 5 years, we confirmed that failure to achieve an SVR was associated with an increased risk of liver-related events and liver-related death. We also observed higher rates of the following events in nonresponders than in responders: AIDS-defining conditions (rate per 100 person years, 0.84 [95% confidence interval (CI), .59-1.10] vs 0.29 [.10-.48]; P= .003), non-liver-related deaths (0.65 [.42-.87] vs 0.16 [.02-.30]; P = .002), and non-liver-related, non-AIDS-related deaths (0.55 [.34-.75] vs 0.16 [.02-.30]; P = .002). Cox regression analysis showed that the adjusted hazard ratios of new AIDS-defining conditions, non-liver-related deaths, and non-liver-related, non-AIDS-related deaths for nonresponders compared with responders were 1.90 (95% CI, .89-4.10; P = .095), 3.19 (1.21-8.40; P = .019), and 2.85 (1.07-7.60; P = .036), respectively., Conclusions: Our findings suggest that eradication of HCV after therapy with interferon plus ribavirin in HIV/HCV-coinfected patients is associated not only with a reduction in liver-related events but also with a reduction in HIV progression and mortality not related to liver disease.

Objectives: The effects of antiretroviral drugs on the response to pegylated interferon plus ribavirin remain uncertain. We evaluated whether antiretroviral drugs affected the response to pegylated interferon plus ribavirin in patients co-infected with HIV and hepatitis C virus (HCV)., Methods: We conducted a retrospective analysis of two cohorts of HIV/HCV-co-infected patients treated with pegylated interferon plus ribavirin between 2001 and 2007 in Spain. The outcome measure was sustained virological response (SVR). Logistic regression models were used to test possible associations between non-response and pre-treatment characteristics, including accompanying antiretroviral drugs., Results: The study sample comprised 1701 patients: 63% were infected with HCV genotype (G) 1 or 4 and 88% were taking highly active antiretroviral therapy (HAART). Factors independently associated with increased odds of SVR were G2 or 3, HVC RNA <500,000 IU/mL and CDC clinical category A or B. When we adjusted for these prognostic factors and dose of ribavirin/kg, the adjusted odds ratio (AOR) of SVR for patients without HAART was 1.31 [95% confidence interval (CI) 0.91-1.88; P = 0.144]. Taking the backbone of tenofovir and lamivudine/emtricitabine as a reference, we found that, with the exception of regimens including zidovudine, the effect of other nucleoside reverse transcriptase inhibitor backbones had little effect on SVR. The AOR of SVR for zidovudine and lamivudine was 0.65 (95% CI 0.46-0.93, P = 0.017). We carried out several sensitivity analyses, the results of which were consistent with the findings of the primary analysis., Conclusions: Our results suggest that, with the exception of regimens including zidovudine, accompanying antiretroviral drugs have little effect on the virological response to pegylated interferon plus ribavirin in HIV/HCV-co-infected patients.

Objectives: The aim of this study was to identify mutations within the fingers, palm and thumb subdomains of the HIV-1 reverse transcriptase (RT) associated with therapy failure to various combinations of two nucleoside analogues., Methods: RT nucleotide sequences of 1893 HIV-1 isolates from 1680 persons with different treatment histories (including naive and treated patients) were analysed. chi(2) contingency tests were performed to detect mutations within positions 1-333 of HIV-1 RT, associated with therapy failure, and correlated mutations were identified using statistical methods., Results: Thymidine analogue resistance mutations were strongly associated with therapy failure to all nucleoside analogue combinations analysed. Previously identified accessory mutations at positions 35, 39, 43, 90, 98, 101, 122, 178, 196, 203, 208, 221, 223 and 228 were associated with therapy failure with at least one of the drug combinations studied. Interestingly, several mutations affecting RT thumb subdomain polymorphisms were strongly associated (P < 10(-3)) with therapy failure to abacavir/stavudine, stavudine/didanosine and abacavir/stavudine/didanosine. Mutations A272P, K277R and V293I were more prevalent in patients failing treatment with abacavir/stavudine than in naive individuals, while mutation frequencies of T286A, V292I and to a lesser extent E291D and E297K decreased in the treated population. These effects were also detected for A272P, T286A and V292I, when analysing didanosine/stavudine therapy failure, although statistical significance was higher for T286A., Conclusions: RT thumb subdomain polymorphisms are strongly associated with therapy failure to nucleoside analogues. Based on their structural location, we suggest a role for those residues in controlling the balance between RNase H degradation and nucleotide excision during DNA polymerization.

Tuberculosis characteristics and incidence were assessed among patients with concurrent human immunodeficiency virus infection and chronic hepatitis C virus infection who were receiving interferon-based therapy at 3 hospitals in Spain. Four of 570 patients (0.7 cases per 100 person-years; 95% confidence interval, 0.19-1.78 cases per 100 person-years) received a diagnosis of tuberculosis; all of them presented with a decrease in CD4+ cell count before diagnosis, and 3 of them received a delayed diagnosis. After tuberculosis treatment, all patients were cured.

Objectives: Data are scarce on the long-term efficacy of lopinavir/ritonavir monotherapy for the maintenance of HIV suppression. Four years of results of patients randomized to monotherapy in the Only Kaletra (OK) pilot clinical trial are presented., Patients and Methods: Twenty-one HIV-infected patients with suppressed HIV replication (<50 copies/mL) for at least 6 months and without previous failure while receiving a protease inhibitor-based regimen started lopinavir/ritonavir monotherapy. Follow-up was performed within the OK pilot clinical trial during the first 2 years and according to routine clinical practice during the 3rd and 4th years., Results: Fourteen patients (67%) remain on monotherapy and with RNA <50 copies/mL (intention-to-treat analysis, with missing patients scored as failures). Five patients (24%) had virological rebound and all of them were successfully re-suppressed by adding two nucleosides. No major protease inhibitor mutations were found., Conclusions: Our data support the long-term efficacy and safety of lopinavir/ritonavir monotherapy for the maintenance of HIV suppression, a finding that must be confirmed in larger studies.

Objectives: The aim of this study was to evaluate the frequency, characteristics and risk factors of lipid changes associated with lopinavir/ritonavir treatment in antiretroviral-naive patients., Methods: A prospective cohort of 107 antiretroviral-naive HIV-infected patients was followed for 12 months after starting lopinavir/ritonavir-based highly active antiretroviral therapy., Results: At 12 months, percentages of patients with hypercholesterolaemia and hypertriglyceridaemia were 17.4% and 40%, respectively. Mean increases in total cholesterol and triglycerides were 40.7 and 73.3 mg/dL. There was a significant increase in both low-density and high-density (HDL) cholesterol, and no increase in the total cholesterol/HDL ratio (from 4.16 at baseline to 4.49 after 12 months). Baseline cholesterol > 200 mg/dL and triglycerides > 150 mg/dL were independent risk factors for dyslipidaemia, while hepatitis C coinfection appeared to be protective., Conclusions: Patients with elevated lipid values at baseline have the greatest risk of developing hypercholesterolaemia and hypertriglyceridaemia after starting lopinavir/ritonavir. Antiretroviral-naive patients coinfected with hepatitis C have a low risk of developing hyperlipidaemia after starting lopinavir/ritonavir.

Lactic acidosis is a rare but often fatal complication reported in some human immunodeficiency virus (HIV)-infected patients treated with nucleoside-analogue reverse-transcriptase inhibitors. We report a series of 12 patients with HIV infection treated with nucleoside analogues who developed unexplained metabolic acidosis. We have also reviewed 60 additional published cases. The aim of the present study is to describe the clinical picture, prognostic factors, and final outcome for nucleoside-associated lactic acidosis. The mortality rate is high: 33% for our patients, and 57% for the patients described in the literature. In the multivariate analysis, a lactate serum level of >10 mM (odds ratio [OR], 13.23; 95% confidence interval [CI], 2.96-59.25) was the only factor associated with higher mortality. The administration of specific therapy with cofactors against acidosis was associated with a lower mortality (OR, 0.17; 95% CI, 0.04-0.73). We conclude that specific therapy with cofactors may improve the outcome for patients with this syndrome.