A genome-wide association study of survival in patients with sepsis.

BACKGROUND: Sepsis is a severe systemic inflammatory response to infections that is accompanied by organ dysfunction and has a high mortality rate in adult intensive care units. Most genetic studies have identified gene variants associated with development and outcomes of sepsis focusing on biological candidates. We conducted the first genome-wide association study (GWAS) of 28-day survival in adult patients with sepsis. METHODS: This study was conducted in two stages. The first stage was performed on 687 European sepsis patients from the GEN-SEP network and 7.5 million imputed variants. Association testing was conducted with Cox regression models, adjusting by sex, age, and the main principal components of genetic variation. A second stage focusing on the prioritized genetic variants was performed on 2,063 ICU sepsis patients (1362 European Americans and 701 African-Americans) from the MESSI study. A meta-analysis of results from the two stages was conducted and significance was established at p < 5.0 × 10-8. Whole-blood transcriptomic, functional annotations, and sensitivity analyses were evaluated on the identified genes and variants. FINDINGS: We identified three independent low-frequency variants associated with reduced 28-day sepsis survival, including a missense variant in SAMD9 (hazard ratio [95% confidence interval] = 1.64 [1.37-6.78], p = 4.92 × 10-8). SAMD9 encodes a possible mediator of the inflammatory response to tissue injury. INTERPRETATION: We performed the first GWAS of 28-day sepsis survival and identified novel variants associated with reduced survival. Larger sample size studies are needed to better assess the genetic effects in sepsis survival and to validate the findings.

Whole-Blood Mitochondrial DNA Copies Are Associated With the Prognosis of Acute Respiratory Distress Syndrome After Sepsis.

Acute respiratory distress syndrome (ARDS) is an inflammatory process of the lungs that develops primarily in response to pulmonary or systemic sepsis, resulting in a disproportionate death toll in intensive care units (ICUs). Given its role as a critical activator of the inflammatory and innate immune responses, previous studies have reported that an increase of circulating cell-free mitochondrial DNA (mtDNA) is a biomarker for fatal outcome in the ICU. Here we analyzed the association of whole-blood mtDNA (wb-mtDNA) copies with 28-day survival from sepsis and sepsis-associated ARDS. We analyzed mtDNA data from 687 peripheral whole-blood samples within 24 h of sepsis diagnosis from unrelated Spanish patients with sepsis (264 with ARDS) included in the GEN-SEP study. The wb-mtDNA copies were obtained from the array intensities of selected probes, with 100% identity with mtDNA and with the largest number of mismatches with the nuclear sequences, and normalized across the individual-probe intensities. We used Cox regression models for testing the association with 28-day survival. We observed that wb-mtDNA copies were significantly associated with 28-day survival in ARDS patients (hazard ratio = 3.65, 95% confidence interval = 1.39-9.59, p = 0.009) but not in non-ARDS patients. Our findings support that wb-mtDNA copies at sepsis diagnosis could be considered an early prognostic biomarker in sepsis-associated ARDS patients. Future studies will be needed to evaluate the mechanistic links of this observation with the pathogenesis of ARDS.

Sepsis-associated acute respiratory distress syndrome in individuals of European ancestry: a genome-wide association study.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is a lung inflammatory process caused mainly by sepsis. Most previous studies that identified genetic risks for ARDS focused on candidates with biological relevance. We aimed to identify novel genetic variants associated with ARDS susceptibility and to provide complementary functional evidence of their effect in gene regulation. METHODS: We did a case-control genome-wide association study (GWAS) of 1935 European individuals, using patients with sepsis-associated ARDS as cases and patients with sepsis without ARDS as controls. The discovery stage included 672 patients admitted into a network of Spanish intensive care units between January, 2002, and January, 2017. The replication stage comprised 1345 individuals from two independent datasets from the MESSI cohort study (Sep 22, 2008-Nov 30, 2017; USA) and the VISEP (April 1, 2003-June 30, 2005) and MAXSEP (Oct 1, 2007-March 31, 2010) trials of the SepNet study (Germany). Results from discovery and replication stages were meta-analysed to identify association signals. We then used RNA sequencing data from lung biopsies, in-silico analyses, and luciferase reporter assays to assess the functionallity of associated variants. FINDINGS: We identified a novel genome-wide significant association with sepsis-associated ARDS susceptibility (rs9508032, odds ratio [OR] 0·61, 95% CI 0·41-0·91, p=5·18 × 10-8) located within the Fms-related tyrosine kinase 1 (FLT1) gene, which encodes vascular endothelial growth factor receptor 1 (VEGFR-1). The region containing the sentinel variant and its best proxies acted as a silencer for the FLT1 promoter, and alleles with protective effects in ARDS further reduced promoter activity (p=0·0047). A literature mining of all previously described ARDS genes validated the association of vascular endothelial growth factor A (VEGFA; OR 0·55, 95% CI 0·41-0·73; p=4·69 × 10-5). INTERPRETATION: A common variant within the FLT1 gene is associated with sepsis-associated ARDS. Our findings support a role for the vascular endothelial growth factor signalling pathway in ARDS pathogenesis and identify VEGFR-1 as a potential therapeutic target. FUNDING: Instituto de Salud Carlos III, European Regional Development Funds, Instituto Tecnológico y de Energías Renovables.

A vascular endothelial growth factor receptor gene variant is associated with susceptibility to acute respiratory distress syndrome.

BACKGROUND: The acute respiratory distress syndrome (ARDS) is one of the main causes of mortality in adults admitted to intensive care units. Previous studies have demonstrated the existence of genetic variants involved in the susceptibility and outcomes of this syndrome. We aimed to identify novel genes implicated in sepsis-induced ARDS susceptibility. METHODS: We first performed a prioritization of candidate genes by integrating our own genomic data from a transcriptomic study in an animal model of ARDS and from the only published genome-wide association study of ARDS study in humans. Then, we selected single nucleotide polymorphisms (SNPs) from prioritized genes to conduct a case-control discovery association study in patients with sepsis-induced ARDS (n = 225) and population-based controls (n = 899). Finally, we validated our findings in an independent sample of 661 sepsis-induced ARDS cases and 234 at-risk controls. RESULTS: Three candidate genes were prioritized: dynein cytoplasmic-2 heavy chain-1, fms-related tyrosine kinase 1 (FLT1), and integrin alpha-1. Of those, a SNP from FLT1 gene (rs9513106) was associated with ARDS in the discovery study, with an odds ratio (OR) for the C allele of 0.76, 95% confidence interval (CI) 0.58-0.98 (p = 0.037). This result was replicated in an independent study (OR = 0.78, 95% CI = 0.62-0.98, p = 0.039), showing consistent direction of effects in a meta-analysis (OR = 0.77, 95% CI = 0.65-0.92, p = 0.003). CONCLUSIONS: We identified FLT1 as a novel ARDS susceptibility gene and demonstrated that integration of genomic data can be a valid procedure to identify novel susceptibility genes. These results contribute to previous firm associations and functional evidences implicating FLT1 gene in other complex traits that are mechanistically linked, through the key role of endothelium, to the pathophysiology of ARDS.

Antiretroviral purchasing and prescription practices in Mexico: constraints, challenges and opportunities.

OBJECTIVE: This study examines the antiretroviral (ARV) market characteristics for drugs procured and prescribed to Mexico's Social Protection System in Health beneficiaries between 2008 and 2013, and compares them with international data. MATERIALS AND METHODS: Procurement information from the National Center for the Prevention and the Control of HIV/AIDS was analyzed to estimate volumes and prices of key ARV. Annual costs were compared with data from the World Health Organization's Global Price Reporting Mechanism for similar countries. Finally, regimens reported in the ARV Drug Management, Logistics and Surveillance System database were reviewed to identify prescription trends and model ARV expenditures until 2018. RESULTS: Results show that the first-line ARV market is concentrated among a small number of patented treatments, in which prescription is clinically adequate, but which prices are higher than those paid by similar countries. The current set of legal and structural options available to policy makers to bring prices down is extremely limited. CONCLUSIONS: Different negotiation policies were not successful to decrease ARV high prices in the public health market. The closed list approach had a good impact on prescription quality but was ineffective in reducing prices. The Coordinating Commission for Negotiating the Price of Medicines and other Health Supplies also failed to obtain adequate prices. To maximize purchase efficiency, policy makers should focus on finding long-term legal and political safeguards to counter the high prices imposed by pharmaceutical companies.

Assessment of PaO2/FiO2 for stratification of patients with moderate and severe acute respiratory distress syndrome.

OBJECTIVES: A recent update of the definition of acute respiratory distress syndrome (ARDS) proposed an empirical classification based on ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) at ARDS onset. Since the proposal did not mandate PaO2/FiO2 calculation under standardised ventilator settings (SVS), we hypothesised that a stratification based on baseline PaO2/FiOv would not provide accurate assessment of lung injury severity. DESIGN: A prospective, multicentre, observational study. SETTING: A network of teaching hospitals. PARTICIPANTS: 478 patients with eligible criteria for moderate (100300). PRIMARY AND SECONDARY OUTCOMES: Group severity and hospital mortality. RESULTS: At ARDS onset, 173 patients had a PaO2/FiO2≤100 but only 38.7% met criteria for severe ARDS at 24 h under SVS. When assessed under SVS, 61.3% of patients with severe ARDS were reclassified as moderate, mild and non-ARDS, while lung severity and hospital mortality changed markedly with every PaO2/FiO2 category (p<0.000001). Our model of risk stratification outperformed the stratification using baseline PaO2/FiO2 and non-standardised PaO2/FiO2 at 24 h, when analysed by the predictive receiver operating characteristic (ROC) curve: area under the ROC curve for stratification at baseline was 0.583 (95% CI 0.525 to 0.636), 0.605 (95% CI 0.552 to 0.658) at 24 h without SVS and 0.693 (95% CI 0.645 to 0.742) at 24 h under SVS (p<0.000001). CONCLUSIONS: Our findings support the need for patient assessment under SVS at 24 h after ARDS onset to assess disease severity, and have implications for the diagnosis and management of ARDS patients. TRIAL REGISTRATION NUMBERS: NCT00435110 and NCT00736892.

Antiretroviral purchasing and prescription practices in Mexico: constraints, challenges and opportunities / Compras y prescripciones de medicamentos antirretrovirales en México: restricciones, retos y oportunidades

Objective. This study examines the antiretroviral (ARV) market characteristics for drugs procured and prescribed to Mexico's Social Protection System in Health beneficiaries between 2008 and 2013, and compares them with international data. Materials and methods. Procurement information from the National Center for the Prevention and the Control of HIV/AIDS was analyzed to estimate volumes and prices of key ARV. Annual costs were compared with data from the World Health Organization's Global Price Reporting Mechanism for similar countries. Finally, regimens reported in the ARV Drug Management, Logistics and Surveillance System database were reviewed to identify prescription trends and model ARV expenditures until 2018. Results. Results show that the first-line ARV market is concentrated among a small number of patented treatments, in which prescription is clinically adequate, but which prices are higher than those paid by similar countries. The current set of legal and structural options available to policy makers to bring prices down is extremely limited. Conclusions. Different negotiation policies were not successful to decrease ARV high prices in the public health market. The closed list approach had a good impact on prescription quality but was ineffective in reducing prices. The Coordinating Commission for Negotiating the Price of Medicines and other Health Supplies also failed to obtain adequate prices. To maximize purchase efficiency, policy makers should focus on finding long-term legal and political safeguards to counter the high prices imposed by pharmaceutical companies.

Objetivo. Este estudio analiza el mercado de los medicamentos antiretrovirales (ARV) adquiridos y prescritos a los beneficiarios del Seguro Popular entre 2008 y 2013, en México, comparándolo con información internacional. Material y métodos. Se analiza información sobre la compra de medicamentos por parte del Centro para la Prevención y el Control del VIH y el Sida (Censida) para estimar precios y volúmenes de compra de los principales ARV. Los costos anuales de tratamiento estimados fueron comparados con información del Global Price Reporting Mechanism (GPRM) de la Organización Mundial de la Salud, para países similares. Finalmente se revisaron los esquemas reportados en el Sistema de Administración, Logística y Vigilancia de ARV para identificar tendencias y proyectar el gasto en ARV hasta 2018. Resultados. El mercado mexicano de ARV está concentrado en pocos esquemas de primera línea y, aunque la prescripción es clínicamente adecuada, los precios son más altos que en otros países similares. El conjunto actual de opciones legales y estructurales disponibles para los formuladores de políticas para reducir los precios es muy limitado. Conclusiones. Las políticas de negociación han sido poco exitosas para disminuir los precios de los ARV en México. La Coordinating Commission for Negotiating the Price of Medicines and other Health Supplies y la integración de las guías de tratamiento han tenido impacto significativo en la calidad de la prescripción, pero moderado en la reducción de precios. Por ello es necesario buscar garantías jurídicas y políticas a largo plazo para hacer frente a los altos precios de los ARV.

Interleukin-1 receptor-associated kinase 3 gene associates with susceptibility to acute lung injury.

Sepsis is the most common cause of acute lung injury (ALI), leading to organ dysfunction and death in critically ill patients. Previous studies associated variants of interleukin-1 receptor-associated kinase genes (IRAKs) with differential immune responses to pathogens and with outcomes during sepsis, and revealed that increased expression levels of the IRAK3 gene were correlated with poor outcomes during sepsis. Here we explored whether common variants of the IRAK3 gene were associated with susceptibility to, and outcomes of, severe sepsis. After our discovery of polymorphism, we genotyped a subset of seven single-nucleotide polymorphisms (SNPs) in 336 population-based control subjects and 214 patients with severe sepsis, collected as part of a prospective study of adults from a Spanish network of intensive care units. Whereas IRAK3 SNPs were not associated with susceptibility to severe sepsis, rs10506481 showed a significant association with the development of ALI among patients with sepsis (P = 0.007). The association remained significant after adjusting for multiple comparisons, population stratification, and clinical variables (odds ratio, 2.50; 95% confidence interval, 1.15-5.47; P = 0.021). By imputation, we revealed three additional SNPs independently associated with ALI (P < 0.01). One of these (rs1732887) predicted the disruption of a putative human-mouse conserved transcription factor binding site, and demonstrated functional effects in vitro (P = 0.017). Despite the need for replication in independent studies, our data suggest that common SNPs in the IRAK3 gene may be determinants of sepsis-induced ALI.

Common variants of TLR1 associate with organ dysfunction and sustained pro-inflammatory responses during sepsis.

BACKGROUND: Toll-like receptors (TLRs) are critical components for host pathogen recognition and variants in genes participating in this response influence susceptibility to infections. Recently, TLR1 gene polymorphisms have been found correlated with whole blood hyper-inflammatory responses to pathogen-associated molecules and associated with sepsis-associated multiorgan dysfunction and acute lung injury (ALI). We examined the association of common variants of TLR1 gene with sepsis-derived complications in an independent study and with serum levels for four inflammatory biomarkers among septic patients. METHODOLOGY/PRINCIPAL FINDINGS: Seven tagging single nucleotide polymorphisms of the TLR1 gene were genotyped in samples from a prospective multicenter case-only study of patients with severe sepsis admitted into a network of intensive care units followed for disease severity. Interleukin (IL)-1ß, IL-6, IL-10, and C-reactive protein (CRP) serum levels were measured at study entry, at 48 h and at 7(th) day. Alleles -7202G and 248Ser, and the 248Ser-602Ile haplotype were associated with circulatory dysfunction among severe septic patients (0.001 ≤ p ≤ 0.022), and with reduced IL-10 (0.012 ≤ p ≤ 0.047) and elevated CRP (0.011 ≤ p ≤ 0.036) serum levels during the first week of sepsis development. Additionally, the -7202GG genotype was found to be associated with hospital mortality (p = 0.017) and ALI (p = 0.050) in a combined analysis with European Americans, suggesting common risk effects among studies. CONCLUSIONS/SIGNIFICANCE: These results partially replicate and extend previous findings, supporting that variants of TLR1 gene are determinants of severe complications during sepsis.

Serum lipopolysaccharide binding protein levels predict severity of lung injury and mortality in patients with severe sepsis.

BACKGROUND: There is a need for biomarkers insuring identification of septic patients at high-risk for death. We performed a prospective, multicenter, observational study to investigate the time-course of lipopolysaccharide binding protein (LBP) serum levels in patients with severe sepsis and examined whether serial serum levels of LBP could be used as a marker of outcome. METHODOLOGY/PRINCIPAL FINDINGS: LBP serum levels at study entry, at 48 hours and at day-7 were measured in 180 patients with severe sepsis. Data regarding the nature of infections, disease severity, development of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), and intensive care unit (ICU) outcome were recorded. LBP serum levels were similar in survivors and non-survivors at study entry (117.4+/-75.7 microg/mL vs. 129.8+/-71.3 microg/mL, P = 0.249) but there were significant differences at 48 hours (77.2+/-57.0 vs. 121.2+/-73.4 microg/mL, P<0.0001) and at day-7 (64.7+/-45.8 vs. 89.7+/-61.1 microg/ml, p = 0.017). At 48 hours, LBP levels were significantly higher in ARDS patients than in ALI patients (112.5+/-71.8 microg/ml vs. 76.6+/-55.9 microg/ml, P = 0.0001). An increase of LBP levels at 48 hours was associated with higher mortality (odds ratio 3.97; 95%CI: 1.84-8.56; P<0.001). CONCLUSIONS/SIGNIFICANCE: Serial LBP serum measurements may offer a clinically useful biomarker for identification of patients with severe sepsis having the worst outcomes and the highest probability of developing sepsis-induced ARDS.

A common haplotype of the LBP gene predisposes to severe sepsis.

OBJECTIVE: To investigate whether common variants across the LBP gene contribute to the development of severe sepsis. Sepsis is the leading cause of multiple system organ dysfunction and death in critically ill patients. The lipopolysaccharide-binding protein is an acute-phase protein that plays a dominant role in the genesis of sepsis by initiating signal transduction pathways leading to the activation of the inflammatory host response. DESIGN: Prospectively enrolled case-control study of adults with severe sepsis. SETTING: A network of intensive care units. PATIENTS: We enrolled 175 patients meeting international definition criteria for severe sepsis and 357 population-based controls for comparison. INTERVENTIONS: Genotyping of the LBP gene was performed and disease association was tested. Serum lipopolysaccharide-binding protein levels were measured in patients and related to genetic variants. MEASUREMENTS AND MAIN RESULTS: A haplotype window analysis revealed that a common 4-SNP risk haplotype from the 5'-flanking region of the LBP gene, comprising positions -1978 to -763 from the transcription start site, was strongly associated with susceptibility to severe sepsis. Risk haplotype homozygous carriers had an increased risk for severe sepsis (odds ratio = 2.21; 95% confidence interval = 1.39-3.51; unadjusted p < .001; adjusted p < .025). Mean serum lipopolysaccharide-binding protein levels from inclusion to 7th day were significantly higher in homozygous carriers patients (130.1 [102.9-164.5] and 98.9 [79.7-122.8] microg/mL, respectively) than in noncarriers (101.6 [87.9-117.5] and 58.7 [51.4-67.2] microg/mL, respectively) (p = .046). CONCLUSIONS: This study strongly supports the involvement of LBP gene variants in severe sepsis susceptibility and reinforces the merit of further exploration of the role of lipopolysaccharide-binding protein in sepsis.

Angiotensin-converting enzyme insertion/deletion polymorphism is not associated with susceptibility and outcome in sepsis and acute respiratory distress syndrome.

OBJECTIVE: The insertion/deletion (I/D) of a 289 base pair Alu repeat sequence polymorphism in the angiotensin-converting enzyme gene (ACE) has been shown to predict susceptibility and outcome in the acute respiratory distress syndrome (ARDS). We hypothesized that the I/D polymorphism also confers susceptibility to sepsis and is a predisposing factor for morbidity and mortality of patients with severe sepsis. DESIGN AND SETTING: Case-control study including 212 consecutive patients fulfilling criteria for severe sepsis admitted to a Spanish network of postsurgical and critical care units, and 364 population-based controls. Susceptibility to severe sepsis was evaluated as primary outcome; mortality in severe sepsis, susceptibility to sepsis-induced ARDS, and mortality in sepsis-induced ARDS were examined as secondary outcomes. An additive model of inheritance in which patients were classified into three genotype groups (II, ID, and DD) was used for association testing. MEASUREMENTS AND RESULTS: Genotype and allele frequencies of I/D were distributed similarly in all septic, ARDS, and non-ARDS patients and in population-based controls. ACE I/D polymorphism was not associated with severe sepsis susceptibility or mortality. The ACE I/D polymorphism was associated neither with sepsis-induced ARDS susceptibility (p=0.895) or mortality (p=0.950). These results remained nonsignificant when adjusted for other covariates using multiple logistic regression analysis or Kaplan-Meier estimates of 28-day survival. CONCLUSIONS: Our data do not support an association of the ACE gene I/D polymorphism with susceptibility or mortality in severe sepsis or with sepsis-induced ARDS in Spanish patients.

A CXCL2 polymorphism is associated with better outcomes in patients with severe sepsis.

OBJECTIVE: Several studies have implicated the CXCL2 chemokine as a mediator in the development of sepsis. We hypothesized that a tandem repeat polymorphism (AC)n in the CXCL2 gene, previously associated with susceptibility to severe sepsis, contributes to morbidity and mortality in severe sepsis. DESIGN: Prospective, observational, genetic study of septic patients. SETTING: A network of Spanish postsurgical and critical care units. PATIENTS: A total of 183 critically ill patients fulfilling the International Sepsis Criteria for severe sepsis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients were classified into three groups according to the presence of compound 24 +/- 1 (AC) repeat genotypes: homozygote 24 +/- 1 carriers (HC group), heterozygote 24 +/- 1 carriers (HTC), and non 24 +/- 1 carriers (NC group). Mortality, development of acute respiratory distress syndrome, and number of failing organs were determined for each group. Overall mortality was 46.4%. HC patients had a lower mortality (39.9%) than HTC (52.2%) and NC (72.7%) patients (trend test p = .018). This difference remained significant when using a multiple logistic regression analysis (p = .035). The presence of population stratification was ruled out, since 20 independent genomic control markers demonstrated homogeneity among groups. An exploratory analysis of the effect of acute respiratory distress syndrome on mortality showed a relative risk of 2.60 in the HC group (p = .0004), while in the nonhomozygote carriers (NHC) group the relative risk was 3.34 (p = .0001). CONCLUSIONS: Our data suggest that a tandem repeat polymorphism (AC)n at position -665 in the CXCL2 gene may be an independent predictor of mortality for severe sepsis. Additional studies are needed to confirm these results.