September 14, 2012
HIV-infected people who are hospitalized with acute myocardial infarction (AMI) are significantly more likely to die than their HIV-uninfected counterparts, U.S. researchers have found. The findings add to the growing body of evidence suggesting that close monitoring of cardiovascular health is particularly important for people living with HIV.
We're at an uncomfortable time in our evolving understanding of cardiovascular complications among HIV-infected people: It's well-established at this point that people with HIV have an elevated risk for these complications occurring, but it is far from clear precisely what mechanisms are contributing to this elevated risk, and in what proportion. Meanwhile, relatively few studies have explored the true clinical impact of this higher cardiovascular risk -- in particular, its impact on a patient's risk of death. This study may be one of the first to explore that question in a hospital setting.
Daniel Pearce, D.O., of Loma Linda University in California, and colleagues tapped into the Nationwide Inpatient Sample, a massive, public database cataloging all-payer inpatient care throughout the U.S. Pearce et al identified 1,428,146 adult individuals -- 5,984 of whom were HIV infected -- who had received in-hospital care for AMI. They used a Cox proportional hazard model to estimate the differences in mortality risk between HIV-infected and HIV-uninfected patients.
Those differences were clear: In unadjusted results, HIV-infected patients were 43% more likely to die than HIV-uninfected patients (P = .015). After adjusting for age, ethnicity, sex and comorbidities, the likelihood actually increased to 53% greater risk (P < .001).
In the fully adjusted analysis, among HIV-infected people included in the study, the relative risk of AMI death was similar across all racial groups, but was 11% higher for men than women, and understandably increased considerably along with a patient's score on the Charlson's Comorbidity Index, a tool that gauges mortality risk for patients by assessing the presence of comorbid conditions such as diabetes, liver disease and cancer.
A bivariate analysis revealed that, in terms of raw percentages, 4.3% of the hospitalized HIV-infected patients died from their AMI, compared to 2.4% of hospitalized HIV-uninfected patients. The HIV-infected patients tended to be of much lower age than the HIV-uninfected patients, to the tune of approximately 54 years versus 64 years. The HIV-infected patients also tended to remain in the hospital longer (6.19 days versus 5.29 days) and had a higher number of comorbidities (1.14 versus .94), yet were significantly less likely to undergo some of the most common hospital procedures to address AMI, such as cardiac catherterization, coronoary arteriography and angiography of the left heart structures.
Importantly, and perhaps related to some of the above findings, the HIV-infected patients in this study were drastically more likely to have Medicare or Medicaid as their primary form of insurance (62.3%, compared to 24.9% of the HIV-uninfected patients), suggesting a different socioeconomic strata for many of the HIV-infected patients -- as well as all of the implicit ramifications that reality carries regarding a person's engagement with and receipt of regular, reliable health care. That said, the researchers said that adjusting for form of insurance did not significantly alter the mortality disparities between HIV-infected and HIV-uninfected patients.
Despite its unique methodology, this study was not remotely the first to find a higher cardiovascular mortality risk among HIV-infected patients, and it leaves us with as many questions as we had before regarding the precise causes of, and potential solutions for, the disparity in mortality risk by HIV status. But there are still messages we can take home from these results.
As we eagerly await more data from other research on this issue, study results such as these speak to the importance of continued vigilance in preventive care and testing for emerging cardiovascular risk, particularly at younger ages than we might typically begin to screen for signs of potential cardiovascular complications. These results also drive home the importance of redoubling our efforts as a community, and as a country, to ensure that HIV-infected patients are more engaged in their health care to begin with. After all, one of the most effective ways to avoid AMI-related death is to help patients take steps to ensure that no AMI occurs in the first place.