Serum Albumin as a Prognostic Marker for Serious Non-AIDS Endpoints in the Strategic Timing of Antiretroviral Treatment (START) Study

Serum albumin and white matter hyperintensities

People living with HIV and those diagnosed with alcohol use disorders (AUD) relative to healthy individuals commonly have low levels of serum albumin, substantiated as an independent predictor of cardiovascular events. White matter hyperintensities (WMH)-a neuroimaging feature of cerebral small vessel disease-are also related to cardiovascular disease. Despite consensus regarding associations between high levels of urine albumin and WMH prevalence, and low serum albumin levels and impaired cognitive functioning, relations between serum albumin and WMH burdens have rarely been evaluated. Here, a sample including 160 individuals with AUD, 142 living with HIV, and 102 healthy controls was used to test the hypothesis that serum albumin would be inversely related to WMH volumes and directly related to cognitive performance in the two diagnostic groups. Although serum albumin and periventricular WMH volumes showed an inverse relationship in both AUD and HIV groups, this relationship persisted only in the HIV group after consideration of traditional cardiovascular (i.e., age, sex, body mass index (BMI), nicotine use, hypertension, diabetes), study-relevant (i.e., race, socioeconomic status, hepatitis C virus status), and disease-specific (i.e., CD4 nadir, HIV viral load, HIV duration) factors. Further, serum albumin contributed more significantly than periventricular WMH volume to variance in performance on a verbal learning and memory composite score in the HIV group only. Relations in both HIV and AUD groups between albumin and hematological red blood cell markers (e.g., hemoglobin, hematocrit) suggest that in this sample, serum albumin reflects hematological abnormalities. Albumin, a simple serum biomarker available in most clinical settings, may therefore help identify periventricular WMH burden and performance levels in specific cognitive domains in people living with HIV. Whether serum albumin contributes mechanistically to periventricular WMH in HIV will require additional investigation.

Serum albumin and white matter hyperintensities

Urine albumin, high in kidney disease, predicts cardiovascular incidents and CNS white matter hyperintensity (WMH) burdens. Serum albumin - a more general biomarker which can be low in several disorders - including kidney and liver disease, malnutrition, and inflammation - also predicts cardiovascular events and is associated with cognitive impairment in several clinical populations; relations between serum albumin and WMH prevalence, however, have rarely been evaluated. In a sample of 160 individuals with alcohol use disorder (AUD), 142 infected with HIV, and 102 healthy controls, the hypothesis was tested that lower serum albumin levels would predict larger WMH volumes and worse cognitive performance irrespective of diagnosis. After considering traditional cardiovascular risk factors (e.g., age, sex, body mass index (BMI), nicotine use, hypertension, diabetes) and study-relevant variables (i.e., primary diagnoses, race, socioeconomic status, hepatitis C virus status), serum albumin survived false discovery rate (FDR)-correction in contributing variance to larger periventricular but not deep WMH volumes. This relationship was salient in the AUD and HIV groups, but not the control group. In secondary analyses, serum albumin and periventricular WMH along with age, sex, diagnoses, BMI, and hypertension were considered for hierarchical contribution to variance in performance in 4 cognitive domains. Albumin survived FDR-correction for significantly contributing to visual and verbal learning and memory performance after accounting for diagnosis. Relations between albumin and markers of liver integrity [e.g., aspartate transaminase (AST)] and blood status (e.g., hemoglobin, red blood cell count, red cell distribution width) suggest that in this sample, albumin reflects both liver dysfunction and hematological abnormalities. The current results suggest that albumin, a simple serum biomarker available in most clinical settings, can predict variance in periventricular WMH volumes and performance in visual and verbal learning and memory cognitive domains. Whether serum albumin contributes mechanistically to periventricular WMH prevalence will require additional investigation.

Modeling the interplay between albumin-globulin metabolism and HIV infection

Human immunodeficiency virus (HIV) infection is a major public health concern with 1.2 million people living with HIV in the United States. The role of nutrition in general, and albumin/globulin in particular in HIV progression has long been recognized. However, no mathematical models exist to describe the interplay between HIV and albumin/globulin. In this paper, we present a family of models of HIV and the two protein components albumin and globulin. We use albumin, globulin, viral load and target cell data from simian immunodeficiency virus (SIV)-infected monkeys to perform model selection on the family of models. We discover that the simplest model accurately and uniquely describes the data. The selection of the simplest model leads to the observation that albumin and globulin do not impact the infection rate of target cells by the virus and the clearance of the infected target cells by the immune system. Moreover, the recruitment of target cells and immune cells are modeled independently of globulin in the selected model. Mathematical analysis of the selected model reveals that the model has an infection-free equilibrium and a unique infected equilibrium when the immunological reproduction number is above one. The infection-free equilibrium is locally stable when the immunological reproduction number is below one, and unstable when the immunological reproduction number is greater than one. The infection equilibrium is locally stable whenever it exists. To determine the parameters of the best fitted model we perform structural and practical identifiability analysis. The structural identifiability analysis reveals that the model is identifiable when the immune cell infection rate is fixed at a value obtained from the literature. Practical identifiability reveals that only seven of the sixteen parameters are practically identifiable with the given data. Practical identifiability of parameters performed with synthetic data sampled a lot more frequently reveals that only two parameters are practically unidentifiable. We conclude that experiments that will improve the quality of the data can help improve the parameter estimates and lead to better understanding of the interplay of HIV and albumin-globulin metabolism.

Level of Hypoalbuminemia as a Prognostic Factor in Patients admitted to a Tertiary Care Intensive Coronary Care Unit

Introduction

Hypoalbuminemia is common in acute and chronic diseases. It has been proposed as a potential biomarker of frailty, which itself is associated with worse outcomes. However, data regarding the level of hypoalbuminemia and its prognosis in contemporary intensive coronary care unit (ICCU) patients is scarce.

Materials and Methods

All patients who had albumin level on admission to an ICCU at a tertiary care center between January 1, 2020, and December 31, 2020, were included in the study. Patients were divided into 3 groups according to their albumin level on admission: low (< 3 g/dL), intermediate (3 g/dL≤ and ≤ 4 g/dL) and high albumin level (> 4 g/dL). Survival and in-hospital interventions and complications were compared.

Results

Overall 1,036 consecutive patients were included, mean age was 67±16 years and 70% were males. Of them 88 (8.5%) had low, 739 (71.5%) intermediate and 209 (20%) had high albumin levels. In a multivariate cox proportional hazards analysis, low albumin level was independently associated with higher 1-year mortality rate as compared with high albumin level (HR=9.5; 95% CI: 3.2-25.5, p<0.001). Intermediate albumin level had also a trend toward higher 1-year mortality rate as compared with high albumin level (HR=2.1; 95% CI: 0.9-5.6, p=0.09).

Conclusion

Hypoalbuminemia in ICCU patients is a poor prognostic factor associated with in-hospital complications and an independent risk factor for 1-year mortality rate, while intermediate albumin level shows a trend towards higher 1-year mortality rate as well.

Epidemiology, comorbidities at diagnosis and outcomes associated with HIV late diagnosis from 2010 to 2019 in a Belgian reference centre: A retrospective study

OBJECTIVES

Our objective was to investigate the demographic factors, comorbidities, and outcomes of patients with a late diagnosis (LD) of HIV in a Belgian HIV reference centre.

METHODS

All patients with HIV who presented for care between 2010 and 2019 were included. They were excluded if time between diagnosis and presentation or first CD4 count exceeded 6 months or if they had previously received antiretroviral therapy (ART). LD was defined as a CD4 cell count ≤350/mm³ or an AIDS-defining event at diagnosis. Data were retrospectively collected and included data on demographic variables, cardiovascular risk factors, comorbidities at diagnosis, first prescribed ART, and outcomes. Logistic regression was used to determine factors associated with LD.

RESULTS

Of 1078 patients, 427 (39.6%) were LD. In multivariable analysis, the following factors were associated with LD: non-homosexual transmission route, being born in Sub-Saharan Africa (SSA), and age ≥35 years. Prevalence at diagnosis of malignancies, diabetes, and cardiovascular diseases did not differ between non-LD and LD, whereas renal impairment was more frequent in LD. In univariable analysis, high-density lipoprotein (HDL) cholesterol <40 mg/dL and estimated glomerular filtration rate <60 ml/min were associated with LD; in multivariable analysis, only HDL cholesterol <40 mg/dL was associated. Patients with LD experienced more adverse events leading to a switch in ART, virological failure, and death during follow-up.

CONCLUSION

LD remains common in our centre, especially in non-homosexual patients and those born in SSA. Although not associated with an important burden of comorbidities at diagnosis, it still results in poorer outcomes, emphasizing the need to expand coverage and access to HIV testing.

Epigenome-wide association study of biomarkers of liver function identifies albumin-associated DNA methylation sites among male veterans with HIV

Background: Liver disease (LD) is an important cause of morbidity and mortality for people with HIV (PWH). The molecular factors linked with LD in PWH are varied and incompletely characterized. We performed an epigenome-wide association study (EWAS) to identify associations between DNA methylation (DNAm) and biomarkers of liver function-aspartate transaminase, alanine transaminase, albumin, total bilirubin, platelet count, FIB-4 score, and APRI score-in male United States veterans with HIV. Methods: Blood samples and clinical data were obtained from 960 HIV-infected male PWH from the Veterans Aging Cohort Study. DNAm was assessed using the Illumina 450K or the EPIC 850K array in two mutually exclusive subsets. We performed a meta-analysis for each DNAm site measured by either platform. We also examined the associations between four measures of DNAm age acceleration (AA) and liver biomarkers. Results: Nine DNAm sites were positively associated with serum albumin in the meta-analysis of the EPIC and 450K EWAS after correcting for multiple testing. Four DNAm sites (cg16936953, cg18942579, cg01409343, and cg12054453), annotated within the TMEM49 and four of the remaining five sites (cg18181703, cg03546163, cg20995564, and cg23966214) annotated to SOCS3, FKBP5, ZEB2, and SAMD14 genes, respectively. The DNAm site, cg12992827, was not annotated to any known coding sequence. No significant associations were detected for the other six liver biomarkers. Higher PhenoAA was significantly associated with lower level of serum albumin (β = -0.007, p-value = 8.6 × 10^-4, CI: -0.011116, -0.002884). Conclusion: We identified epigenetic associations of both individual DNAm sites and DNAm AA with liver function through serum albumin in men with HIV. Further replication analyses in independent cohorts are warranted to confirm the epigenetic mechanisms underlying liver function and LD in PWH.

Multiple substance use, inflammation and cardiac stretch in women living with HIV

BACKGROUND

Cardiovascular disease (CVD) and heart failure (HF) are disproportionately high in people living with HIV and differ by sex. Few CVD-related studies focus on drug use, yet it is common in low-income women living with HIV (WLWH) and increases cardiac dysfunction.

SETTING

We recruited unsheltered and unstably housed WLWH from San Francisco community venues to participate in a six-month cohort study investigating linkages between drug use, inflammation, and cardiac dysfunction.

METHODS

Adjusting for CVD risk factors, co-infections, medications, and menopause, we examined the effects of toxicology-confirmed drug use and inflammation (C-reactive protein, sCD14, sCD163 and sTNFR2) on levels of NT-proBNP, a biomarker of cardiac stretch and HF.

RESULTS

Among 74 WLWH, the median age was 53 years and 45 % were Black. At baseline, 72 % of participants had hypertension. Substances used included tobacco (65 %), cannabis (53 %), cocaine (49 %), methamphetamine (31 %), alcohol (28 %), and opioids (20 %). Factors significantly associated with NT-proBNP included cannabis use (Adjusted Relative Effect [ARE]: -39.6 %) and sTNFR2 (ARE: 65.5 %). Adjusting for heart failure and restricting analyses to virally suppressed persons did not diminish effects appreciably. Cannabis use was not significantly associated with sTNFR2 and did not change the association between sTNFR2 and NT-proBNP.

CONCLUSIONS

Among polysubstance-using WLWH, NT-proBNP levels signaling cardiac stretch were positively associated with sTNFR2, but 40 % lower in people who used cannabis. Whether results suggest that cardiovascular pathways associated with cannabis use mitigate cardiac stress and dysfunction independent of inflammation in WLWH who use multiple substances merits further investigation.

Albumin replacement therapy in immunocompromised patients with sepsis - Secondary analysis of the ALBIOS trial

BACKGROUND

The best fluid replacement strategy and the role of albumin in immunocompromised patients with sepsis is unclear.

METHODS

We performed a secondary analysis of immunocompromised patients enrolled in the ALBIOS trial which randomized patients with severe sepsis or septic shock to receive either 20% albumin (target 30 g per liter or more) and crystalloid or crystalloid alone during ICU stay.

RESULTS

Of 1818 patients originally enrolled, 304 (16.4%) were immunocompromised. One-hundred-thirty-nine (45.7%) patients were randomized in the albumin while 165 (54.2%) in the crystalloid group. At 90 days, 69 (49.6%) in the albumin group and 89 (53.9%) in the crystalloids group died (hazard ratio - HR - 0.94; 95% CI 0.69-1.29). No differences were observed with regards to 28-day mortality, SOFA score (and sub-scores), length of stay in the ICU and in the hospital, proportion of patients who had developed acute kidney injury or received renal replacement therapy, duration of mechanical ventilation. Albumin was not independently associated with a higher or lower 90-day mortality (HR 0.979, 95% CI 0.709-1.352) as compared to crystalloid.

CONCLUSION

Albumin replacement during the ICU stay, as compared with crystalloids alone, did not affect clinical outcomes in a cohort of immunocompromised patients with sepsis.

Plasma Albumin and Incident Cardiovascular Disease: Results From the CGPS and an Updated Meta-Analysis

OBJECTIVE

We studied the association of plasma albumin with cardiovascular disease (CVD) and explored potential mechanisms behind the association in the CGPS (Copenhagen General Population Study). We also performed a meta-analysis to summarize the association between plasma albumin and CVD in individuals without preexisting CVD. Approach and Results: We included 100 520 individuals without prior CVD with 8247 incident CVD events developed during a median follow-up of 8.5 years. Rates of CVD outcomes were calculated using Cox regression and Fine and Gray competing-risks regression. The association of plasma albumin and CVD was approximately linear and confounder adjustment had little influence on the effect estimates, except for some attenuation after CRP (C-reactive protein) adjustment. In analyses according to subtypes of CVD events, the hazard ratios for each 10 g/L lower plasma albumin were 1.17 (95% CI, 1.08-1.28) for ischemic heart disease, 1.25 (95% CI, 1.09-1.43) for myocardial infarction, 1.37 (95% CI, 1.21-1.54) for any stroke, and 1.46 (95% CI, 1.28-1.68) for ischemic stroke. In the meta-analysis, we combined estimates from prospective and nested case-control studies investigating the association of plasma albumin with CVD. The meta-analysis included 14 studies with 150 652 individuals (12 studies reported events totaling 11 872). The risk ratio for a CVD event per 10 g/L lower plasma albumin was 1.96 (95% CI, 1.43-2.68) in previous studies and 1.85 (95% CI, 1.39-2.47) including our study with 57% weight in the meta-analysis. Exploratory analyses of the mechanism of the association indicated that it was probably not due to fatty acid binding but may be due to the regulation of plasma albumin by inflammation.

CONCLUSIONS

There is a robust, independent association of low plasma albumin with CVD, partly explained by plasma albumin as a negative acute-phase reactant.

CLINICAL TRIAL REGISTRATION

URL: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=95796. Unique identifier: CRD42018095796.

The Plasma [Kynurenine]/[Tryptophan] Ratio and Indoleamine 2,3-Dioxygenase: Time for Appraisal

The plasma kynurenine to tryptophan ([Kyn]/[Trp]) ratio is frequently used to express or reflect the activity of the extrahepatic Trp-degrading enzyme indoleamine 2,3-dioxygenase (IDO). This ratio is increasingly used instead of measurement of IDO activity, which is often low or undetectable in immune and other cells under basal conditions, but is greatly enhanced after immune activation. The use of this ratio is valid in in vitro studies, eg, in cell cultures or isolated organs, but its ‘blanket’ use in in vivo situations is not, because of modulating factors, such as supply of nutrients; the presence of multiple cell types; complex structural and functional tissue arrangements; the extracellular matrix; and hormonal, cytokine, and paracrine interactions. Determinants other than IDO may therefore be involved in vivo. These are hepatic tryptophan 2,3-dioxygenase (TDO) activity and the flux of plasma-free Trp down the Kyn pathway. In addition, conditions leading to accumulation of Kyn, eg, inhibition of activities of Kyn monooxygenase and kynureninase, could lead to elevation of the aforementioned ratio. In this review, the origin of use of this ratio will be discussed, variations in extent of its elevation will be described, evidence against its indiscriminate use will be presented, and examining determinants other than IDO activity and their correlates will be proposed for future studies.

Albumin, white blood cell count, and body mass index improve discrimination of mortality in HIV-positive individuals

OBJECTIVE

Despite viral suppression and immune response on antiretroviral therapy, people with HIV infection experience excess mortality compared with uninfected individuals. The Veterans Aging Cohort Study (VACS) Index incorporates clinical biomarkers of general health with age, CD4 cell count, and HIV-1 RNA to discriminate mortality risk in a variety of HIV-positive populations. We asked whether additional biomarkers further enhance discrimination.

DESIGN AND METHODS

Using patients from VACS for development and from the Antiretroviral Therapy Cohort Collaboration (ART-CC) for validation, we obtained laboratory values from a randomly selected visit from 2000 to 2014, at least 1 year after antiretroviral therapy initiation. Patients were followed for 5-year, all-cause mortality through September 2016. We fitted Cox models with established predictors and added new predictors based on model fit and Harrell's c-statistic. We converted all variables to continuous functional forms and selected the best model (VACS Index 2.0) for validation in ART-CC patients. We compared discrimination using c-statistics and Kaplan-Meier plots.

RESULTS

Among 28 390 VACS patients and 12 109 ART-CC patients, 7293 and 722 died, respectively. Nadir CD4, CD8, and CD4 : CD8 ratio did not improve discrimination. Addition of albumin, white blood count, and BMI, improved c-statistics in VACS from 0.776 to 0.805 and in ART-CC from 0.800 to 0.831. Results were robust in all nine ART-CC cohorts, all lengths of follow-up and all subgroups.

CONCLUSION

VACS Index 2.0, adding albumin, white blood count, and BMI to version 1.0 and using continuous variables, provides improved discrimination and is highly transportable to external settings.

Serum Albumin Is Associated With Higher Inflammation and Carotid Atherosclerosis in Treated Human Immunodeficiency Virus Infection

Background

This study was conducted to explore the associations between serum albumin and markers of inflammation and cardiovascular disease in treated human immunodeficiency virus (HIV)-infected adults.

Methods

We conducted a nested study within in the SATURN-HIV trial in which 147 HIV⁺ adults on stable antiretroviral therapy were (1) virally suppressed, (2) had a low-density lipoprotein (LDL)-cholesterol level <130 mg/dL, and (3) were randomized to 10 mg daily rosuvastatin or placebo. Measures of serum albumin, carotid intima media thickness ([cIMT] surrogate marker of atherosclerosis), inflammation, T cells, monocyte activation, and gut integrity were assessed at baseline, 48 and 96 weeks later. Spearman correlations and linear mixed-effect models were used to assess associations with serum albumin.

Results

Mean age was 45 years, 80% of participants were male, and 69% were African American. Mean serum albumin was similar between the groups at all time points (4.01-4.09 g/dL in statin arm vs 4.02-4.11 g/dL in placebo arm; P = .08-0.35). Lower baseline serum albumin significantly predicted larger changes in cIMT, interleukin 6, D-dimer, tumor necrosis factor α receptor 1, fibrinogen, and high-sensitivity C-reactive protein (P ≤ .03) over 96 weeks independently of statin therapy. After adjusting for age, gender, smoking, body mass index, creatinine clearance, and LDL cholesterol, every 1 g/dL decrease in serum albumin at baseline remained associated with a 0.05-mm increase in cIMT over 96 weeks (P = .05).

Conclusions

Lower serum albumin in controlled HIV is associated with higher markers of chronic inflammation and hypercoagulation, which could explain the prior observation that serum albumin predicts nonacquired immune deficiency syndrome events in HIV. Serum albumin may predict progression of carotid atherosclerosis independent of traditional risk factors.

Associations between serum albumin and serious non-AIDS events among people living with HIV

OBJECTIVE

Lower serum albumin (sAlb) has been associated with an increased risk of mortality and AIDS among people living with HIV and may be associated with the development of serious non-AIDS events (SNAEs). We evaluated the long-term association between sAlb and the risk of SNAEs.

DESIGN

Prospective multinational cohort study.

METHODS

D:A:D participants without SNAEs were followed from first routine sAlb value to the first of a new SNAE [cardiovascular disease (CVD), end-stage liver disease (ESLD), end-stage renal disease (ESRD), non-AIDS malignancy (NADM), death from non-AIDS cause], AIDS-death, 6 months after last visit or 1 February 2016. Poisson regression was used to determine associations between sAlb and a new SNAE, CVD, or NADM event, with adjustment for potential confounders. Models additionally tested whether the associations were modified by age, follow-up time, smoking status, CD4 and viral load.

RESULTS

Of 16 350 participants (71.8% male, median age 44 years), 1463 developed an SNAE (371 CVD, 200 ESLD, 40 ESRD, 553 NADM, 299 deaths from other non-AIDS causes) over 80 264 person-years. Increased sAlb was associated with a decreased risk of an SNAE [adjusted rate ratio per 5 g/l: SNAE 0.79 (95% confidence interval: 0.76, 0.83); CVD 0.87 (0.80, 0.94); NADM 0.88 (0.82, 0.95)]. The association did not appear to wane with additional years of follow-up (P-interaction = 0.79) but was stronger for current smokers than for never smokers (P-interaction <0.01).

CONCLUSION

sAlb is a durable risk factor for SNAE. Future studies are needed to determine the mechanism underlying this association and to evaluate the value of sAlb in predictive tools.

Pathogenic factors associated with development of disseminated intravascular coagulopathy (DIC) in a tertiary academic hospital in South Africa

Introduction

Disseminated intravascular coagulopathy (DIC) is a thrombotic microangiopathy arising from consumption of both coagulation factors and platelets. DIC is triggered by a number of clinical conditions including severe infection, trauma and obstetric complications. Early diagnosis and treatment of the underlying condition is paramount. A high clinical index of suspicion is needed to ensure that patients at risk of developing DIC are appropriately investigated.

Methods

In order to establish the clinical conditions most frequently associated with DIC, we reviewed all DIC screens received at a tertiary hospital in Johannesburg, South Africa over a 1 year period.

Results

The commonest clinical condition associated with DIC in our population was infection with 84% of patients infected with an identified pathogen. The most frequently diagnosed pathogen was HIV followed by Mycobacterium tuberculosis and other bacterial infections. In the majority of cases, bacteria were isolated from blood cultures. In 47 patients, HIV was the only pathogen which could be isolated. A relative risk ratio of 2.73 and an odds ratio of 29.97 was attributed to HIV for development of a DIC. A malignancy was present in 51 of the patients of which approximately 60% had co-existing infection. No cause could be attributed in 30 patients.

Conclusion

Infection was identified in the majority of the patients diagnosed with DIC in this study. HIV showed the highest relative risk ratio of all pathogens although previous studies have not suggested that HIV was strongly associated with DIC. In almost half of the HIV infected patients, there was no other pathogen isolated despite extensive investigation. This suggests that HIV has a strong association with the development of DIC, warranting further research into the relationship between HIV and disseminated microvascular thrombosis.