The VACS Index Predicts Mortality in a Young, Healthy HIV Population Starting Highly Active Antiretroviral Therapy

Abstract

Background The Veterans Aging Cohort Study (VACS) Index is a weighted combination of age and eight clinical variables. It has been well correlated with all-cause mortality among HIV-infected patients. The U.S. Military HIV Natural History Study (NHS) cohort provides a different validation population profile, being younger and healthier. A significant portion of the US HIV population is similarly composed, so evaluation of the VACS Index in this population is of great interest. Methods NHS subjects have medical history and laboratory data collected at six month visits. We performed an external validation of the VACS Index in the NHS evaluating correlation, discrimination, and calibration for all-cause mortality following HAART initiation (HI). We then tested whether combining longitudinal VACS Index values at different time points improves prediction of mortality. Results The VACS Index at one year after HI was well correlated with all-cause mortality (Harrell’s c-statistic 0.78), provided good discrimination (log-rank p <0.05), and was marginally well calibrated using Brier score. Accounting for VACS Index at HI and 6 months after HI significantly improved a standard model including only the VACS Index at 1 year after HI (Net Reclassification Improvement=25.2%, 10.9-48.9% 95% CI). Conclusions The VACS Index was well correlated and provided good discrimination with respect to all-cause mortality among HAART initiating subjects in the NHS. Moderate overprediction of mortality in this young, healthy population suggests minor recalibration could improve fit among similar patients. Considering VACS Index at HI and 6 months improved outcome prediction and allowed earlier risk assessment.

Guideline-Concordant Management of Opioid Therapy Among Human Immunodeficiency Virus (HIV)-Infected and Uninfected Veterans

“…We also relied on ICD-9-CM data for defining co-morbidities, as a number of validation studies support the use of diagnostic codes for this purpose. 3, 22, 23, 29 For ICD-9-CM codes related to chronic pain, we found that HIV-infected patients were less likely to receive a chronic pain diagnosis; we postulate that these findings may reflect differences in coding practices between Infectious Disease vs. General Medicine providers, in particular differences in their approach to pain management, with Infectious Disease providers more likely to code for infectious or medical comorbidities. 13 Finally, our use of two OT guidelines, both of which were published and subsequently updated during the period of observation, would appear to present a challenge to assessing guideline-concordant care.…”

Risk Prediction Tool for Medical Appointment Attendance Among HIV-Infected Persons with Unsuppressed Viremia

“…Although risk stratification tools have been developed to predict HIV disease progression and prognosis, [24][25][26] a similar tool to aid in the identification of patients likely to miss appointments is not available. Beginning in July 2013, clinicians at the Vanderbilt Comprehensive Care Clinic (VCCC, Nashville, TN) implemented an evidence-based tool for assessing the risk of virologic failure at 1 year 27 among patients with uncontrolled viremia-defined as HIV-1 viral load (VL) > 200 copies/milliliter (mL).…”

The Association Between Receipt of Guideline-Concordant Long-Term Opioid Therapy and All-Cause Mortality

“…As a measure of overall severity of illness, we used the VACS Index, which incorporates age, HIV-1 RNA viral load, CD4 count, hemoglobin, FIB-4, estimated glomerular filtration rate, and hepatitis C virus. The VACS Index is a validated prognostic measure, 28,29,[37][38][39][40] which is predictive of morbidity and mortality in both HIVinfected and uninfected patients (in calculating the index, the assumption is made that uninfected patients have a CD4 count > 500 cells/μL and viral load < 20 copies/ml). 29,41 Higher scores are indicative of higher all-cause mortality risk.…”