ATS 2012, SAN FRANCISCO - The expanded use of antiretrovirals, potent drugs used to treat retroviral infections such as human immunodeficiency virus (HIV), has been linked to significant decreases in hospital mortality rates among severely ill HIV-positive(HIV+) patients nationwide, primarily due to a decrease in opportunistic infections, according to a new study by researchers at Stanford University. Despite these encouraging data, the study also revealed that in this population, chronic diseases and bloodstream infections are on the rise.
The study results will be presented at the ATS 2012 International Conference in San Francisco.
"The national expansion of antiretroviral programs has appeared to yield benefits well beyond the outpatient setting," said study lead author Monica Bhargava, MD, MS, adjunct clinical instructor in Stanford University's Division of Pulmonary and Critical Care Medicine. "In the 1980s, HIV+ patients were often declined ICU admission because their prognosis was deemed far too grave. Our work shows that this has changed substantially since the advent of the antiretroviral era. The broader use of such medications is having a wide-ranging impact."
Although previous studies have shown that the initiation in the mid-1990s of antiretroviral therapy (ART) for the treatment of HIV has led to sharp reductions in mortality across the United States, Dr. Bhargavasaid that until now, the effect on critically ill HIV+ patients had not been assessed with a nationally-representative sample.
"We wanted to examine the impact of the ART era on in-hospital mortality among critically ill HIV+ patients, particularly those requiring mechanical ventilation, using a nationwide sample," she said. "We also wanted to evaluate hospital length of stay (LOS), hospital charges and the prevalence of selected diseases among these patients."
For their study, the researchers used data spanning the 16-year period from 1993 to 2008, culled from the Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample (NIS), a database of hospital inpatient stays used by researchers and policymakers to identify, track and analyze national trends in health care. For each year, statistical analyses were performed to isolate the effect of HIV+ status on mortality, controlling for socioeconomic, demographic and hospital characteristics.
"We found that, although nationally, the number of HIV+ requiring mechanical ventilation rose from 7,632 in 1993 to 10,775 in 2008, mortality in that population declined from over 63 percent in 1993 to 41.4 percent in 2008, with the sharpest decline occurring in 1996-1997, the beginning of the ART era," Dr. Bhargava said.
This decrease is most likely due to the concomitant decline in the occurrence of opportunistic infections, which are less likely in those on antiretroviral drugs, Dr. Bhargava said.In this study, Dr. Bhargavalooked at one such infection commonly associated with patients on mechanical ventilation, Pneumocystis carinii pneumonia (PCP), and found that among HIV+ patients who received mechanical ventilation, the rates of PCP infection nearly halved, from 29.2 percent in 1993 to 15.2 percent in 2008.
"It appears that the wider use of antiretroviral therapy has both decreased the percentage of patients with PCP and reduced mortalityin those patients who develop it," Dr. Bhargava said. "That is quite encouraging."
The researchers also found that median length of hospital stay declined in the HIV+ population during the study period, and this population also experienced a slower rate of growth in hospital charges relative to the general population. Black race remained the strongest independent predictor of in-hospital death.
"Our study confirms that major gains in in-hospital survival have occurred among HIV+ patients with respiratory failure, though there is still much more progress that needs to be made," Dr. Bhargava said. "In addition, there has been a notable increase in the diagnoses of sepsis, chronic obstructive airway disease, liver disease and coronary artery disease.
"Our work shows that our national efforts should focus more on managing chronic diseases and sepsis in this population," she added. "Future studies should help clarify the reasons behind the surge in sepsis and why ICU survival remains poorer among HIV+ ethnic minorities."
"HIV In The ICU: National Outcomes Of Patients In The ART Era" (Session D102, Wednesday, May 23, 2:00-4:30 p.m., Room 131, Moscone Center; Abstract 31769)
* Please note that numbers in this release may differ slightly from those in the abstract. Many of these investigations are ongoing; the release represents the most up-to-date data available at press time.
HIV In The ICU: National Outcomes Of Patients In The ART Era
Type: Scientific Abstract
Category: 02.06 - Health Outcomes (Including Assessment, Cost Effectiveness) (BS)
Authors: M. Bhargava1, J. Bhattacharya2; 1Stanford University - Stanford/US, 2Stanford University - Stanford, CA/US
Introduction: The initiation of multiclass antiretroviral therapy (ART) for the treatment of human immunodeficiency virus (HIV) in the mid-1990s has led to sharp reductions in mortality across the United States. The impact of the ART era on critically ill HIV+ patients has not been assessed with a nationally-representative sample. Objective: To examine the impact of the ART era on in-hospital mortality among critically ill HIV+ patients, particularly those requiring mechanical ventilation (MV). Secondary objectives include the evaluation of length of stay (LOS), hospital charges, and the prevalence of selected diseases. Methods: Data from the Nationwide Inpatient Sample were analyzed, spanning sixteen years (1993-2008). For each year, multivariate logistic regression was performed to isolate the effect of HIV+ status on mortality, controlling for socioeconomic, demographic, and hospital characteristics. A propensity score model was used to confirm results. Results: Nationally, the number of HIV+ requiring MV rose from 7,632 (CI: 6,117 to 9,146) in 1993 to 10,775 (CI: 8,904 to 12, 647) in 2008. Crude mortality in the HIV+ MV population declined from over 63% in 1993 to 41.4% in 2008. The sharpest decline occurred in 1996-97, the beginning of the ART era. In the multivariate logistic regression , HIV+ status increased the odds of death by 4.6 (p value < .0001) in 1993 and declined to 2.2 ( p value < .0001) by 1993. In regressions limited to the HIV+ population, Black race remained the strongest independent predictor of in-hospital death (in 2008, OR = 1.48, p value < .0001). Median length of stay in the HIV+ population declined, and this population experienced a slower rate of growth in hospital charges (relative to the HIV- population). Rates of Pneumocystis pneumonia (PCP) decreased from 29.2% of the HIV+ MV population in 1993 to 15.2% in 2008. Rates of coronary artery disease, chronic obstructive airways disease, and liver failure have all increased over time. Sepsis has also emerged as a major diagnosis in the HIV+ population. Conclusions: Substantial gains in in-hospital survival have occurred in the post-ART era among HIV+ patients with respiratory failure. Much of this can be explained by declining rates of highly lethal OIs, such as PCP. Chronic diseases and bloodstream infections are on the rise in this population. Clinical efforts and policies directed at the prevention of sepsis, atherosclerosis, and airways disease in the HIV+ population are warranted. The national expansion of antiretroviral programs has appeared to yield benefits well beyond the outpatient setting.
Funded by: NIH T32 grant, given to the Division of Pulmonary Medicine at Stanford Hospital