Advances in the management of human immunodeficiency virus (HIV) infection has improved survival of those affected by the disease. In the highly active antiretroviral therapy (HAART) era, mortality in HIV patients has been largely associated to cardiovascular disease, including heart failure (HF)1 and coronary syndromes.2 Generally, in patients with advanced HF, heart transplantation (HT) remains the gold standard therapy; however, this option is restricted to those with HIV among other conditions.3 Mechanical circulatory support (MCS) devices have become an important strategy for the treatment of cardiogenic shock or end-stage HF.4,5 In spite of its widespread implementation, MCS has been underutilized in HIV patients owing in part to lack of data supporting its usage.6 The aim of this population-based, cohort comparison study is to describe MCS therapies in HIV-infected patients across US hospitals and to compare outcomes with the general population without HIV.
The study cohort was derived from the 2010–2014 Nationwide Inpatient Sample (NIS) database. We used International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes to identify people with asymptomatic HIV status (ICD-9-CM code V08), HIV disease (prior or current AIDS or symptomatic HIV infection) (ICD-9-CM code 042), and noninfected adult hospitalized patients who underwent short-term support with an intra-aortic balloon pump (IABP) (ICD-9-CM code 37.61), percutaneous external heart assist device (pVAD) (ICD-9-CM code 37.68), extracorporeal membrane oxygenation (ECMO) (ICD-9-CM code 39.65), and long-term support with a ventricular assist device (VAD) (ICD-9-CM code 37.66). NIS variables were used to identify demographic characteristics and comorbid conditions were identified using ICD-9 codes in the diagnosis fields. The severity of comorbid conditions was defined using the Elixhauser comorbidity index.7 Univariate logistic regression and linear regression were used to compare baseline characteristics according to HIV-status. Multivariate logistic regression models were generated to compare specific outcomes and in-hospital mortality in HIV and AIDS patients compared with noninfected patients. Multivariate analysis models were adjusted by statistically significant differences in baseline characteristics between groups (Table 1). The level of significance was set at 5% (0.05) for all analyses.
Of the estimated 280,976 MCS devices implanted between 2010 and 2014, the most common device used in the HIV/AIDS population was IABP (HIV = 483/AIDS = 422) and the least common was VAD (HIV = 16/AIDS = 20). The use of pVAD and ECMO varied slightly according to HIV status (pVAD: HIV = 25/AIDS = 40; ECMO: HIV = 15/AIDS = 55). A detailed description of the baseline demographics and hospital characteristics can be found in (Table 1, Supplemental Digital Content, http://links.lww.com/ASAIO/A355).
The HIV (non-AIDS) cohort had higher incidence of implant-related complications after pVAD and hemorrhagic stroke after VAD (Table 1). In the AIDS cohort, patients supported with IABP had more infectious complications (28.2% vs. 10.7% OR = 2.34; P = 0.001), and those supported with VADs had considerably longer lengths of stay (122.38 vs. 35.02 mean days; P < 0.001) and greater risk of limb amputation (25% vs. 0.7% OR = 48.68; P = 0.002). Other complications analyzed appeared to be similar or the statistical model failed due to small sample size. The overall in-hospital mortality was not higher in the HIV/AIDS group compared with noninfected people regardless of the device utilized (Table 1).
Our analysis shows that there is a substantially low number of HIV patients being exposed to MCS despite its outburst during the last decade.8 Although it is impossible from our analysis to speculate the magnitude of HIV patients in which MCS therapy was withheld or not offered, our findings seem to concur with a recent survey conducted by Uriel et al.6 suggesting that HIV patients have been excluded from receiving equal access of care and HIV-positive status has been considered as a contraindication to advanced HF therapy. With the advent of HAART, HIV has transformed from a fatal disorder to a chronic disease. As a result, the proportion of HIV patients who die from cardiovascular causes is increasing and the risk of HF in HIV patients has been estimated to be nearly two-fold higher when compared with uninfected people.1 We can thus speculate that the true national extent of HIV patients in need of MCS is likely greater than the estimated 0.37% actually receiving this therapy according to our national cohort.
HIV-infected patients receiving MCS may carry a greater risk of some in-hospital complications; nonetheless, in-hospital mortality rate remains the same. This is true for patients codified as aymptomatic and symptomatic HIV (or AIDS) patients. In this regard, it is possible that selection bias may confound this finding. Our AIDS cohort had significantly less burden of AIDS-defining illnesses compared with what has been described in national estimates.9 Patients with HIV/AIDS considered for MCS within this analysis most probably represent younger, less comorbid people, likely with optimally controlled baseline disease activity. In this arguably highly selected sample of HIV patients, in whom MCS might really had been used as rescue therapy, there is no increased mortality. This can serve to support broadening the use of MCS in adequately selected cases of patients with HIV.
It is important to mention that HIV/AIDS patients have been excluded from the large landmark, industry-sponsored left-VAD trials and, to date, our analysis may be the only one that explores early, in-hospital outcomes in HIV/AIDS patients receiving MCS. Although no safety conclusions should be drawn from our analysis, we hope it enlightens further research to diminish the gap in healthcare for this population in whom HT remains limited and long-term MCS support appears to be reserved.
Being an administrative database, NIS poses some intrinsic limitations. There might be selection bias arising from coding inaccuracies, HIV viral load is unknown and long-term outcomes cannot be assessed. Although acknowledging these limitations, we believe our study has important strengths and includes previously undescribed data that contribute to the gap of knowledge impacting the treatment of HIV-infected patients.
In conclusion, there are substantially lower number of HIV-infected patients exposed to MCS and, while there appears to be greater risk of some in-hospital complications, in-hospital mortality is similar when compared with uninfected recipients.
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