Combining Charlson comorbidity and VACS indices improves prognostic accuracy for all-cause mortality for patients with and without HIV in the Veterans Health Administration

Introduction

As people age with HIV (PWH), many comorbid diseases are more common than among age matched comparators without HIV (PWoH). While the Veterans Aging Cohort (VACS) Index 2.0 accurately predicts mortality in PWH using age and clinical biomarkers, the only included comorbidity is hepatitis C. We asked whether adding comorbid disease groupings from the Charlson Comorbidity Index (CCI) improves the accuracy of VACS Index.

Methods

To maximize our ability to model mortality among older age groups, we began with PWoH in Veterans Health Administration (VA) from 2007-2017, divided into development and validation samples. Baseline predictors included age, and components of CCI and VACS Index (excluding CD4 count and HIV RNA). Patients were followed until December 31, 2021. We used Cox models to develop the VACS-CCI score and estimated mortality using a parametric (gamma) survival model. We compared accuracy using C-statistics and calibration curves in validation overall and within subgroups (gender, age

Results

The analytic sample consisted of 6,588,688 PWoH and 30,539 PWH. Among PWoH/PWH, median age was 65/55 years; 6%/3% were women; 15%/48% were Black and 5%/7% Hispanic. VACS-CCI provided the best discrimination (C-statistic = 0.81) with excellent calibration (predicted and observed mortality largely overlapped) overall and within subgroups. When VACS-CCI was applied to PWH it demonstrated similar discrimination as VACS Index 2.0 (C-statistic = 0.77 for both) but superior calibration among those with CD4 < 200. Discrimination was improved when CD4 and HIV RNA were added VACS-CCI (C-statistic = 0.79). Liver and kidney disease, congestive heart failure, malignancy, and dementia were negatively associated with CD4 (p-trends all <0.0001).

Discussion

Among PWH and PWoH in VA care, age alone weakly discriminates risk of mortality. VACS Index 2.0, CCI, and VACS-CCI all provide better discrimination, but VACS-CCI is more consistently calibrated. The association of comorbid diseases with lower CD4 underscores the likely role of HIV in non-AIDS conditions. Future work will include adding CD4 and HIV RNA to VACS-CCI and validating it in independent data.

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Key Words

• Charlson Comorbidity Index
• HIV
• VACS Index
• mortality
• prediction

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MESH Headings Collapse

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Affiliation(s)

Kathleen A. McGinnis VA Connecticut Healthcare System, West Haven, CT, United States
Amy C. Justice VA Connecticut Healthcare System, West Haven, CT, United States Yale School of Medicine, New Haven, CT, United States
Vincent C. Marconi The Atlanta Veterans Affairs Medical Center, Emory University School of Medicine and Rollins School of Public Health, Atlanta, GA, United States VA Medical Center, Decatur, GA, United States
Maria C. Rodriguez-Barradas Infectious Diseases Section, Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, United States Department of Medicine, Baylor College of Medicine, Houston, TX, United States
Ronald G. Hauser VA Connecticut Healthcare System, West Haven, CT, United States Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT, United States
Krisann K. Oursler Department of Internal Medicine, Virginia Tech Carilion School of Medicine, Roanoke, VA, United States VA Salem Healthcare System, Salem, VA, United States
Sheldon T. Brown James J. Peters VA Medical Center, Bronx, NY, United States
Kendall J. Bryant National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, United States
Janet P. Tate VA Connecticut Healthcare System, West Haven, CT, United States Yale School of Medicine, New Haven, CT, United States
for the Veterans Aging Cohort Study

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Periods of Homelessness Linked to Higher VACS Index Among HIV-Positive People Who Use Drugs

We sought to evaluate the impact of homelessness on HIV disease progression among people who use unregulated drugs (PWUD) living with HIV and test if this association was mediated by adherence to antiretroviral therapy (ART). We applied general linear mixed-effects modeling to estimate the longitudinal relationship between homelessness and the Veterans Aging Cohort Study (VACS) Index, a validated measure of HIV disease progression that predicts all-cause mortality, among a prospective cohort of PWUD. In a longitudinal model adjusted for ART adherence, homelessness was significantly associated with increased VACS Index scores and 16% of the association was mediated by ART adherence. These findings indicate that homelessness was a significant risk factor for HIV disease progression and this association was marginally mediated by ART adherence. Future studies are needed to quantify the other mechanisms (e.g., food insecurity, mental health) by which homelessness increases mortality risk among PWUD living with HIV.

Association between Veterans Aging Cohort Study (VACS) index and neurocognitive function among people living with HIV-a cross sectional study in coastal South India

Background

HIV is an infectious disease affecting 36.7 million people worldwide. In recent times, Antiretroviral Therapy (ART) has become accessible to the majority of People Living with HIV (PLHIV) and this has transformed the course of infection to one that is chronic, characterized by fewer diseases pathognomonic of AIDS. In view of this, there is a pressing need for better markers, apart from the routine HIV indicators, to detect comorbidities such as Neurocognitive Impairment (NCI). The aim of this study was to find out the association between Veterans Aging Cohort Study (VACS) index and Neurocognitive function in HIV positive patients.

Methods

In our study, we included 97 HIV positive patients and their Neurocognitive function was assessed using a combination of Montreal Cognitive Assessment and Grooved Pegboard Test, while VACS index was calculated using the most recent laboratory values. Binomial Logistics Regression analyses, adjusting for potential confounding variables, was performed to determine the association between VACS score and Neurocognitive Impairment.

Results

We found that a higher VACS Index was associated with global and domain-wise Neurocognitive impairment (p < 0.01), specifically in the domains of attention (p < 0.01) and fine motor skills (p = 0.01). Our study also showed that among all the VACS components, older age (p = 0.02) and lower hemoglobin (p < 0.01) values were associated with global NCI. After plotting an ROC curve, a VACS cut-off score of 11.00 was identified as it had good sensitivity (87.0%) and specificity (71.4%) in identifying Global NCI.

Conclusion

Our findings extend prior research on the use of VACS Index to predict global and domain-wise NCI in HIV-positive patients. However, further research with more comprehensive neurocognitive testing is required in our setting before VACS Index can be used as a tool to screen for neurocognitive dysfunction among PLHIV.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12981-021-00368-6.

Post-traumatic Stress Disorder, Cocaine Use, and HIV Persistence

BACKGROUND

Post-traumatic stress disorder (PTSD) and stimulant use disorders are highly prevalent, commonly co-occur, and predict faster clinical HIV progression. However, scant research has examined if PTSD and cocaine use are associated with the HIV reservoir that persists in immune cells, lymphoid tissue, and organs of people living with HIV that are receiving effective treatment.

METHOD

This cross-sectional study enrolled 48 HIV-positive persons with sustained undetectable viral load (< 20 copies/mL) in the past year to examine the associations of PTSD and recent cocaine use with two measures of HIV persistence in immune cells: (1) proviral HIV DNA and (2) cell-associated (CA)-HIV RNA.

RESULTS

Greater PTSD symptoms were significantly associated with lower proviral HIV DNA (r = - 0.30, p = 0.041) but not with CA-HIV RNA. Greater severity of PTSD symptom clusters for intrusions (Standardized Beta = - 0.30, p = 0.038) and hyperarousal (Standardized Beta = - 0.30, p = 0.047) were independently associated with lower proviral HIV DNA. Although participants with recent cocaine use had a significantly shorter duration of sustained undetectable HIV viral load (19.9 versus 26.9 months; p = 0.047), cocaine use was not significantly associated with proviral HIV DNA or CA-HIV RNA.

CONCLUSION

Further research is needed to examine the potentially bi-directional pathways linking PTSD symptom severity and HIV persistence.

Direct and Indirect Effects of Heavy Alcohol Use on Clinical Outcomes in a Longitudinal Study of HIV Patients on ART

In a cohort of patients receiving care for HIV, we examined longitudinally the impact of past 30-day frequency of heavy drinking (consuming 5+ drinks on one occasion) on HIV-related (detectable viral load and CD4+ T cell count) and non-HIV-related (hemoglobin and biomarkers of kidney function and liver fibrosis) clinical outcomes and the extent to which these effects were due to reduced antiretroviral therapy (ART) adherence. Data came from the Study to Understand the Natural History of HIV/AIDS in the Era of Effective Therapy. Between March 2004 and June 2006, 533 individuals receiving ART were recruited and followed every 6 months for six years. Using longitudinal mediation analysis, we estimated natural direct effects (NDE) of heavy drinking frequency (never, 1-3 times, or 4+ times in the past 30 days) on clinical outcomes and natural indirect effects (NIE) mediated via ART adherence. A one-level increase in heavy drinking frequency had a significant negative NDE on CD4+ T-cell counts (-10.61 cells/mm³; 95 % CI [-17.10, -4.12]) and a significant NIE through reduced ART adherence of -0.72 cells/mm³ (95 % CI [-1.28, -0.15]), as well as a significant NIE on risk of detectable viral load (risk ratio = 1.03; 95 % CI [1.00, 1.05]). Heavy drinking had a significant detrimental NIE on a combined index of 5-year mortality risk and detrimental NDE and total effect on a biomarker of liver fibrosis. Heavy drinking has deleterious effects on multiple clinical outcomes in people living with HIV, some of which are mediated through reduced ART adherence.

Baseline, Time-Updated, and Cumulative HIV Care Metrics for Predicting Acute Myocardial Infarction and All-Cause Mortality

BACKGROUND

 After adjustment for cardiovascular risk factors and despite higher mortality, those with human immunodeficiency virus (HIV+) have a greater risk of acute myocardial infarction (AMI) than uninfected individuals.

METHODS

 We included HIV+ individuals who started combination antiretroviral therapy (cART) in the Veterans Aging Cohort Study (VACS) from 1996 to 2012. We fit multivariable proportional hazards models for baseline, time-updated and cumulative measures of HIV-1 RNA, CD4 counts, and the VACS Index. We used the trapezoidal rule to build the following cumulative measures: viremia copy-years, CD4-years, and VACS Index score-years, captured 180 days after cART initiation until AMI, death, last clinic visit, or 30 September 2012. The primary outcomes were incident AMI (Medicaid, Medicare, and Veterans Affairs International Classification of Diseases-9 codes) and death.

RESULTS

 A total of 8168 HIV+ individuals (53 861 person-years) were analyzed with 196 incident AMIs and 1710 deaths. Controlling for known cardiovascular risk factors, 6 of the 9 metrics predicted AMI and all metrics predicted mortality. Time-updated VACS Index had the lowest Akaike information criterion among all models for both outcomes. A time-updated VACS Index score of 55+ was associated with a hazard ratio (HR) of 3.31 (95% confidence interval [CI], 2.11-5.20) for AMI and a HR of 31.77 (95% CI, 26.17-38.57) for mortality.

CONCLUSIONS

 Time-updated VACS Index provided better AMI and mortality prediction than CD4 count and HIV-1 RNA, suggesting that current health determines risk more accurately than prior history and that risk assessment can be improved by biomarkers of organ injury.

Risk of mortality and physiologic injury evident with lower alcohol exposure among HIV infected compared with uninfected men

BACKGROUND

HIV infected (HIV+) individuals may be more susceptible to alcohol-related harm than uninfected individuals.

METHODS

We analyzed data on HIV+ and uninfected individuals in the Veterans Aging Cohort Study (VACS) with an Alcohol Use Disorders Identification Test-Consumption AUDIT-C score from 2008 to 2012. We used Cox proportional hazards models to examine the association between alcohol exposure and mortality through July, 2014; and linear regression models to assess the association between alcohol exposure and physiologic injury based on VACS Index Scores. Models were adjusted for age, race/ethnicity, smoking, and hepatitis C infection.

RESULTS

The sample included 18,145 HIV+ and 42,228 uninfected individuals. Among HIV+ individuals, 76% had undetectable HIV-1 RNA (<500 copies/ml). The threshold for an association of alcohol use with mortality and physiologic injury differed by HIV status. Among HIV+ individuals, AUDIT-C score ≥4 (hazard ratio [HR] 1.25, 95% CI 1.09-1.44) and ≥30 drinks per month (HR, 1.30, 95% CI 1.14-1.50) were associated with increased risk of mortality. Among uninfected individuals, AUDIT-C score ≥5 (HR, 1.19, 95% CI 1.07-1.32) and ≥70 drinks per month (HR 1.13, 95% CI 1.00-1.28) were associated with increased risk. Similarly, AUDIT-C threshold scores of 5-7 were associated with physiologic injury among HIV+ individuals (beta 0.47, 95% CI 0.22, 0.73) and a score of 8 or more was associated with injury in uninfected (beta 0.29, 95% CI 0.16, 0.42) individuals.

CONCLUSIONS

Despite antiretroviral therapy, HIV+ individuals experienced increased mortality and physiologic injury at lower levels of alcohol use compared with uninfected individuals. Alcohol consumption limits should be lower among HIV+ individuals.