David A. Leaf

The Impact of Cigarette Smoking on Mortality, Quality of Life, and Comorbid Illness Among HIV‐Positive Veterans

AbstractBACKGROUND: The impact of smoking on outcomes among those with HIV infection has not been determined in the era of highly active antiretroviral therapy (HAART). STUDY OBJECTIVE: Determine the impact of smoking on morbidity and mortality in HIV-positive patients post-HAART. DESIGN: Prospective observational study. PARTICIPANTS: Eight hundred and sixty-seven HIV-positive veterans enrolled in the Veterans Aging Cohort 3 Site Study. MEASUREMENTS: Clinical data were collected through patient questionnaire, International Classification of Diseases—9th edition codes, and standardized chart extraction, and laboratory and mortality data through the national VA database. Quality of life was assessed with the physical component summary (PCS) of the Short-Form 12. RESULTS: Current smokers had increased respiratory symptoms, chronic obstructive pulmonary disease (COPD), and bacterial pneumonia. In analyses adjusted for age, race/ethnicity, CD4 cell count, HIV RNA level, hemoglobin, illegal drug and alcohol use, quality of life was substantially decreased (β=−3.3, 95% confidence interval [CI] −5.3 to −1.4) and mortality was significantly increased (hazard ratio 1.99, 95% CI 1.03 to 3.86) in current smokers compared with never smokers. CONCLUSIONS: HIV-positive patients who currently smoke have increased mortality and decreased quality of life, as well as increased respiratory symptoms, COPD, and bacterial pneumonia. These findings suggest that smoking cessation should be emphasized for HIV-infected patients.

Hepatitis C Virus Infection and the Risk of Coronary Disease

BACKGROUND The association between hepatitis C virus (HCV) infection and coronary artery disease (CAD) is controversial. We conducted this study to determine and quantify this association. METHODS We used an established, national, observational cohort of all HCV-infected veterans receiving care at all Veterans Affairs facilities, the Electronically Retrieved Cohort of HCV Infected Veterans, to identify HCV-infected subjects and HCV-uninfected control subjects. We used the Cox proportional-hazards model to determine the risk of CAD among HCV-infected subjects and control subjects. RESULTS We identified 82,083 HCV-infected and 89,582 HCV-uninfected subjects. HCV-infected subjects were less likely to have hypertension, hyperlipidemia, and diabetes but were more likely to abuse alcohol and drugs and to have renal failure and anemia. HCV-infected subjects had lower mean (+/- standard deviation) total plasma cholesterol (175 +/- 40.8 mg/dL vs. 198 +/- 41.0 mg/dL), low-density lipoprotein cholesterol (102 +/- 36.8 mg/dL vs. 119 +/- 38.2 mg/dL), and triglyceride (144 +/- 119 mg/dL vs. 179 +/- 151 mg/dL) levels, compared with HCV-uninfected subjects (P < .001 for all comparisons). In multivariable analysis, HCV infection was associated with a higher risk of CAD (hazard ratio, 1.25; 95% confidence interval, 1.20-1.30). Traditional risk factors (age, hypertension, chronic obstructive pulmonary disease, diabetes, and hyperlipidemia) were associated with a higher risk of CAD in both groups, whereas minority race and female sex were associated with a lower risk of CAD. CONCLUSIONS HCV-infected persons are younger and have lower lipid levels and a lower prevalence of hypertension. Despite a favorable risk profile, HCV infection is associated with a higher risk of CAD after adjustment for traditional risk factors.

HIV infection and the risk of diabetes mellitus.

Background:The influence of HIV infection on the risk of diabetes is unclear. We determined the association and predictors of prevalent diabetes mellitus in HIV infected and uninfected veterans. Methods:We determined baseline prevalence and risk factors for diabetes between HIV infected and uninfected veterans in the Veterans Aging Cohort Study. Logistic regression was used to determine the odds of diabetes in HIV infected and uninfected persons. Results:We studied 3227 HIV-infected and 3240 HIV-uninfected individuals. HIV-infected individuals were younger, more likely to be black males, have HCV coinfection and a lower BMI. HIV-infected individuals had a lower prevalence of diabetes at baseline (14.9 vs. 21.4%, P < 0.0001). After adjustment for known risk factors, HIV-infected individuals had a lower risk of diabetes (odds ratio = 0.84, 95% confidence interval = 0.72–0.97). Increasing age, male sex, minority race, and BMI were associated with an increased risk. The odds ratio for diabetes associated with increasing age, minority race and BMI were greater among HIV-infected veterans. HCV coinfection and nucleoside and nonnucleoside reverse transcriptase inhibitor therapy were associated with a higher risk of diabetes in HIV-infected veterans. Conclusion:Although HIV infection itself is not associated with increased risk of diabetes, increasing age; HCV coinfection and BMI have a more profound effect upon the risk of diabetes among HIV-infected persons. Further, long-term ARV treatment also increases risk. Future studies will need to determine whether incidence of diabetes mellitus differs by HIV status.

Veterans aging cohort study (VACS) : Overview and description

Background:The Veterans Aging Cohort Study (VACS) is a study of human immunodeficiency virus (HIV) infected and uninfected patients seen in infectious disease and general medical clinics. VACS includes the earlier 3 and 5 site studies (VACS 3 and VACS 5) as well as the ongoing 8 site study. Objectives:We sought to provide background and context for analyses based upon VACS data, including study design and rationale as well as its basic protocol and the baseline characteristics of the enrolled sample. Research Design:We undertook a prospectively consented multisite observational study of veterans in care with and without HIV infection. Measures:Data were derived from patient and provider self report, telephone interviews, blood and DNA samples, focus groups, and full access to the national VA “paperless” electronic medical record system. Results:More than 7200 veterans have been enrolled in at least one of the studies. The 8 site study (VACS) has enrolled 2979 HIV-infected and 3019 HIV-uninfected age–race–site matched comparators and has achieved stratified enrollment targets for race/ethnicity and age and 99% of its total target enrollment as of October 30, 2005. Participants in VACS are similar to other veterans receiving care within the VA. VACS participants are older and more predominantly black than those reported by the Centers for Disease Control. Conclusions:VACS has assembled a rich, in-depth, and representative sample of veterans in care with and without HIV infection to conduct longitudinal analyses of questions concerning the association between alcohol use and related comorbid and AIDS-defining conditions.

HIV status, burden of comorbid disease, and biomarkers of inflammation, altered coagulation, and monocyte activation

BACKGROUND Biomarkers of inflammation, altered coagulation, and monocyte activation are associated with mortality and cardiovascular disease (CVD) in the general population and among human immunodeficiency virus (HIV)-infected people. We compared biomarkers for inflammation, altered coagulation, and monocyte activation between HIV-infected and uninfected people in the Veterans Aging Cohort Study (VACS). METHODS Biomarkers of inflammation (interleukin-6 [IL-6]), altered coagulation (d-dimer), and monocyte activation (soluble CD14 [sCD14]) were measured in blood samples from 1525 HIV-infected and 843 uninfected VACS participants. Logistic regression was used to determine the association between HIV infection and prevalence of elevated (>75th percentile) biomarkers, adjusting for confounding comorbidities. RESULTS HIV-infected veterans had less prevalent CVD, hypertension, diabetes, obesity, hazardous drinking, and renal disease, but more dyslipidemia, hepatitis C, and current smoking than uninfected veterans. Compared to uninfected veterans, HIV-infected veterans with HIV-1 RNA ≥500 copies/mL or CD4 count <200 cells/µL had a significantly higher prevalence of elevated IL-6 (odds ratio [OR], 1.54; 95% confidence interval [CI],1.14-2.09; OR, 2.25; 95% CI, 1.60-3.16, respectively) and d-dimer (OR, 1.97; 95% CI, 1.44-2.71, OR, 1.68; 95% CI, 1.22-2.32, respectively) after adjusting for comorbidities. HIV-infected veterans with a CD4 cell count <200 cells/µL had significantly higher prevalence of elevated sCD14 compared to uninfected veterans (OR, 2.60; 95% CI, 1.64-4.14). These associations still persisted after restricting the analysis to veterans without known confounding comorbid conditions. CONCLUSIONS These data suggest that ongoing HIV replication and immune depletion significantly contribute to increased prevalence of elevated biomarkers of inflammation, altered coagulation, and monocyte activation. This contribution is independent of and in addition to the substantial contribution from comorbid conditions.

Impact of cigarette smoking on mortality in HIV-positive and HIV-negative veterans.

It is unknown whether smoking confers similar mortality risk in HIV-positive as in HIV-negative patients. We compared overall mortality stratified by HIV and smoking of 1,034 HIV-positive block-matched to 739 HIV-negative veterans, enrolled 2001-2002 in the Veterans Aging Cohort 5 Site Study. Adjusted incidence rate ratios (IRR) for mortality were calculated using Poisson regression. Mortality was significantly increased in HIV-positive veterans according to both smoking status and pack-years in unadjusted and adjusted analyses (adjusted IRR 2.31, 95% confidence interval [CI] 1.53-3.49 for HIV-positive current smokers and IRR 1.32, 95% CI 0.67-2.61 for HIV-negative current smokers). Comorbid diseases were also significantly increased according to smoking status and pack-years. Current smoking is associated with poor outcomes; even lower levels of exposure appear to be detrimental in HIV-infected veterans. These findings support the need for improvements in smoking cessation and for studies of mechanisms and diseases underlying increased mortality in smokers with HIV.

The Risk of Incident Coronary Heart Disease Among Veterans With and Without HIV and Hepatitis C

Background—Whether hepatitis C virus (HCV) confers additional coronary heart disease (CHD) risk among human immunodeficiency virus (HIV) infected individuals is unclear. Without appropriate adjustment for antiretroviral therapy, CD4 count, and HIV-1 RNA and substantially different mortality rates among those with and without HIV and HCV infection, the association between HIV, HCV, and CHD may be obscured. Methods and Results—We analyzed data on 8579 participants (28% HIV+, 9% HIV+HCV+) from the Veterans Aging Cohort Study Virtual Cohort who participated in the 1999 Large Health Study of Veteran Enrollees. We analyzed data collected on HIV and HCV status, risk factors for and the incidence of CHD, and mortality from January 2000 to July 2007. We compared models to assess CHD risk when death was treated as a censoring event and as a competing risk. During the median 7.3 years of follow-up, there were 194 CHD events and 1186 deaths. Compared with HIV−HCV− Veterans, HIV+HCV+ Veterans had a significantly higher risk of CHD regardless of whether death was adjusted for as a censoring event (adjusted hazard ratio, 2.03; 95% confidence interval, 1.28 to 3.21) or a competing risk (adjusted HR, 2.45; 95% confidence interval, 1.83 to 3.27 respectively). Compared with HIV+HCV− Veterans, HIV+HCV+ Veterans also had a significantly higher adjusted risk of CHD regardless of whether death was treated as a censored event (adjusted hazard ratio, 1.93; 95% confidence interval, 1.02 to 3.62) or a competing risk (adjusted hazard ratio, 1.46; 95% confidence interval, 1.03 to 2.07). Conclusions—HIV+HCV+ Veterans have an increased risk of CHD compared with HIV+HCV− and HIV−HCV− Veterans.

HIV infection, cardiovascular disease risk factor profile, and risk for acute myocardial infarction

Background:Traditional cardiovascular disease risk factors (CVDRFs) increase the risk of acute myocardial infarction (AMI) among HIV-infected (HIV+) participants. We assessed the association between HIV and incident AMI within CVDRF strata. Methods:Cohort—81,322 participants (33% HIV+) without prevalent CVD from the Veterans Aging Cohort Study Virtual Cohort (prospective study of HIV+ and matched HIV− veterans) participated in this study. Veterans were followed from first clinical encounter on/after April 1, 2003, until AMI/death/last follow-up date (December 31, 2009). Predictors—HIV, CVDRFs (total cholesterol, cholesterol-lowering agents, blood pressure, blood pressure medication, smoking, diabetes) used to create 6 mutually exclusive profiles: all CVDRFs optimal, 1+ nonoptimal CVDRFs, 1+ elevated CVDRFs, and 1, 2, 3+ major CVDRFs. Outcome—Incident AMI [defined using enzyme, electrocardiogram (EKG) clinical data, 410 inpatient ICD-9 (Medicare), and/or death certificates]. Statistics—Cox models adjusted for demographics, comorbidity, and substance use. Results:Of note, 858 AMIs (42% HIV+) occurred over 5.9 years (median). Prevalence of optimal cardiac health was <2%. Optimal CVDRF profile was associated with the lowest adjusted AMI rates. Compared with HIV− veterans, AMI rates among HIV+ veterans with similar CVDRF profiles were higher. Compared with HIV− veterans without major CVDRFs, HIV+ veterans without major CVDRFs had a 2-fold increased risk of AMI (HR: 2.0; 95% confidence interval: 1.0 to 3.9; P = 0.044). Conclusions:The prevalence of optimal cardiac health is low in this cohort. Among those without major CVDRFs, HIV+ veterans have twice the AMI risk. Compared with HIV− veterans with high CVDRF burden, AMI rates were still higher in HIV+ veterans. Preventing/reducing CVDRF burden may reduce excess AMI risk among HIV+ people.

The effect of physical exercise on reverse cholesterol transport.

High-density lipoproteins (HDL) are recognized for their role in coronary artery disease (CAD) risk reduction. Plasma HDL plays a pivotal role in the reverse cholesterol transport (RCT) process. Physical exercise is well recognized as a modality that affects HDL metabolism. The purpose of this discussion is to describe the effects of physical exercise on RCT.

Isometric Exercise Increases the Size of Forearm Veins in Patients with Chronic Renal Failure

ObjectivesDelay in maturation or failure of maturation of Cimino-Brescia fistulae contributes to the significant vascular access-related morbidity of chronic hemodialysis patients. Increased size and capacitance of native veins before the formation of vascular access has been considered an important variable in the success rate of native fistulae. We evaluated whether a formal exercise program might alter the size of native veins. MethodsThe effect of exercise on venous size was evaluated in 5 patients with severe chronic renal failure [glomerular filtration rate, 30.6 ± 5.3 mL/min (mean ± SD)]. Five male patients with a mean age of 57 ± 9 years underwent a 6-week forearm exercise training program, involving nondominant arms, that included isometric hand-grip contractions to 25 to 35% of MVC lasting 40 to 120 seconds and repetitive squeezing of squash and racquet balls. Both the volume and intensity of exercise training was increased weekly based on strength measured by hand-grip dynamometer and on the patients’ indicated level of comfort. Cephalic vessel size in both the nondominant (trained) and dominant (control) arms, with and without a tourniquet, were obtained using Doppler ultrasound before and after the 6-week exercise training program. ResultsThe size of the cephalic vein of the exercised arm increased significantly (P < 0.05) compared with the control arm when measured in both the absence (048 ± 0.016 versus 0.024 ± 0.023 cm2) and the presence of a tourniquet (0.056 ± 0.022 versus 028 ± 0.027 cm2). ConclusionsThese findings indicate that a simple, incremental resistance, exercise-training program can cause a significant increase in the size of the cephalic vein commonly used in the creation of an arteriovenous fistula. The increase in size and resultant probable increase in blood flow might accelerate the maturation of native arteriovenous fistulae, thereby lessening the morbidity associated with vascular access.