Time-related Decrease in Diffusion Capacity in HIV-infected Patients with Impaired Immune Function

Pulmonary Function in People Living With Human Immunodeficiency Virus: A Meta-Analysis

BACKGROUND

HIV can infect bronchial epithelial cells rendering individuals susceptible to lung damage. Our objective was to determine the effects of human immunodeficiency virus (HIV) infection on pulmonary function tests.

METHODS

We performed a meta-analysis after conducting a literature search in PubMed, Embase, Cochrane Library and Virtual Health Library databases from inception to December 31st, 2022. We employed the inverse variance method with a random effects model to calculate the effect estimate as the mean difference (MD) and 95% confidence interval (CI). We calculated the heterogeneity with the I2 statistic and performed a meta-regression analysis by age, sex, smoking, CD4 T-cells count and antiretroviral therapy. We also conducted a sensitivity analysis according to the studies' publication date, and excluding the study with the greatest weight in the effect. The PROSPERO registry number was CRD42023401105.

RESULTS

The meta-analysis included 20 studies, with 7621 living with HIV and 7410 control participants. The pooled MD (95%CI) for the predicted percentage of FEV1, FVC and DLCO were -3.12 (-5.17, -1.06); p=0.003, -1.51 (-3.04, 0.02); p=0.05, and -5.26 (-6.64, -3.87); p<0.001, respectively. The pooled MD for FEV1/FVC was -0.01 (-0.02, -0.01); p=0.002. In all cases, there was a considerable heterogeneity. The meta-regression analysis showed that among studies heterogeneity was not explained by patient age, smoking, CD4 T-cells count or antiretroviral therapy.

CONCLUSION

Pulmonary function tests are impaired in people living with HIV, independently of age, smoking, CD4 T-cells count, and geographical region.

Cigarette smoking in the HIV-infected population

As mortality due to AIDS-related causes has decreased with the use of antiretroviral therapy, there has been a rise in deaths related to non-AIDS-defining illnesses. Given the exceedingly high prevalence of cigarette smoking among individuals living with HIV infection, tobacco has been implicated as a major contributor to this paradigm shift. Evidence suggests that smoking-related illnesses, such as cardiovascular disease, respiratory illnesses, and certain malignancies, contribute substantially to morbidity and mortality among HIV-infected persons. In this review, we summarize the adverse health consequences of smoking relevant to HIV-infected individuals and discuss smoking cessation in this unique population, including a discussion of barriers to quitting and a review of studies that have examined smoking cessation interventions.

Interactions between HIV infection and chronic obstructive pulmonary disease: Clinical and epidemiological aspects

Introduction

An association between HIV infection and chronic obstructive pulmonary disease (COPD) has been observed in several studies.

Objective and methods

we conducted a review of the literature linking HIV infection to COPD, focusing on clinical and epidemiological data published before and during widespread highly active antiretroviral therapy (HAART).

Results

Interactions between HIV infection and COPD appear to be influenced by multiple factors. In particular, the bronchopulmonary tract can be damaged by HIV infection, the immunodeficiency it induces, and the resulting increase in the risk of pulmonary infections. In addition, the prevalence of smoking and intravenous drug use is higher in HIV-infected populations, also increasing the risk of COPD. Before the advent of HAART, respiratory tract infections probably played a major role. Since the late 1990s and the widespread use of HAART, the frequency of opportunistic infections has fallen but new complications have emerged as life expectancy has increased.

Conclusion

given the high prevalence of smoking among HIV-infected patients, COPD may contribute significantly to morbidity and mortality in this setting.

Pulmonary function abnormalities in HIV-infected patients during the current antiretroviral therapy era

RATIONALE

Before the introduction of combination antiretroviral (ARV) therapy, patients infected with HIV had an increased prevalence of respiratory symptoms and lung function abnormalities. The prevalence and exact phenotype of pulmonary abnormalities in the current era are unknown. In addition, these abnormalities may be underdiagnosed.

OBJECTIVES

Our objective was to determine the current burden of respiratory symptoms, pulmonary function abnormalities, and associated risk factors in individuals infected with HIV.

METHODS

Cross-sectional analysis of 167 participants infected with HIV who underwent pulmonary function testing.

MEASUREMENTS AND MAIN RESULTS

Respiratory symptoms were present in 47.3% of participants and associated with intravenous drug use (odds ratio [OR] 3.64; 95% confidence interval [CI], 1.32-10.046; P = 0.01). Only 15% had previous pulmonary testing. Pulmonary function abnormalities were common with 64.1% of participants having diffusion impairment and 21% having irreversible airway obstruction. Diffusion impairment was independently associated with ever smoking (OR 2.46; 95% CI, 1.16-5.21; P = 0.02) and Pneumocystis pneumonia prophylaxis (OR 2.94; 95% CI, 1.10-7.86; P = 0.01), whereas irreversible airway obstruction was independently associated with pack-years smoked (OR 1.03 per pack-year; 95% CI, 1.01-1.05; P < 0.01), intravenous drug use (OR 2.87; 95% CI, 1.15-7.09; P = 0.02), and the use of ARV therapy (OR 6.22; 95% CI, 1.19-32.43; P = 0.03).

CONCLUSIONS

Respiratory symptoms and pulmonary function abnormalities remain common in individuals infected with HIV. Smoking and intravenous drug use are still important risk factors for pulmonary abnormalities, but ARV may be a novel risk factor for irreversible airway obstruction. Obstructive lung disease is likely underdiagnosed in this population.

The pathophysiology of pulmonary diffusion impairment in human immunodeficiency virus infection

Numerous reports have demonstrated that prior to the development of acquired immunodeficiency syndrome (AIDS)-related pulmonary complications, human immunodeficiency virus-positive (HIV+) individuals commonly develop unexplained reductions in pulmonary diffusing capacity (DLCO). The potential relevance of this observation is underscored by recent data demonstrating that reductions in DLCO independently predict the subsequent development of opportunistic pneumonia. To delineate the alterations in gas exchange associated with HIV, we investigated a group of HIV+ subjects with unexplained reductions in DLCO, using high-resolution computed tomography (HRCT) of the chest and a separation of diffusing capacity into its membrane (Dm) and capillary blood volume (Vc) components. We compared this abnormal group with HIV+ subjects with more normal gas exchange and also with a group of HIV- volunteers matched for age and smoking history. Compared with other groups, the HIV+ group with diffusion impairment demonstrated prominent reductions in Vc, despite a well-preserved total lung capacity (TLC). HRCT demonstrated virtually no evidence of interstitial fibrosis in any HIV+ subject, but evidence of early emphysema that significantly correlated with DLCO. Our results suggest that the previously reported impairment in pulmonary gas exchange in the HIV+ population involves loss of Vc and likely represents the development of early emphysema.

Effects of smoking and clinical status on lung function in human immunodeficiency virus (HIV)-seropositive subjects

Lung function was measured at 3-month intervals for up to 1 yr in a group of Caucasian HIV-seropositive subjects. The objective was to document any deterioration in lung function and seek correlations between such deterioration and smoking history and Centers for Disease Control (CDC) status. Ninety-nine subjects were studied at enrollment; 43 were followed-up (mean duration 9 +/- 3 months). Ninety-five of the 99 enrolled subjects remained free of HIV-related respiratory disease and were included in the analysis. At enrollment, carbon monoxide diffusing capacity (TLCO) was significantly lower than predicted in non-smokers, smokers and ex-smokers (88, 77 and 88%, respectively, P < 0.001). The TLCO measurements in the smoking group were significantly lower than those of the life-long non-smoking subjects (P < 0.01). Residual volume (RV) was significantly higher than predicted in smokers (111%, P = 0.02). During follow-up, all three groups demonstrated significant declines in TLCO (7%, P = 0.01; 9%, P = 0.005; 13%, P < 0.001, respectively), and increases in RV (9%, P = 0.03; 13.5%, P = 0.02, 22%, P = 0.02, respectively). At enrollment, significantly lower than predicted values of TLCO were observed in groups stratified by CDC criteria: in asymptomatic HIV-seropositive subjects (CDC 11) 89%, P = 0.01; persistent generalized lymphadenopathy (PGL) 84%; AIDS-related complex (ARC) 81%; and in non-pulmonary AIDS (IV C1) 69%, P = 0.0001, respectively. Residual volume was significantly higher than predicted in CDC II (114%, P = 0.05). During follow-up, TLCO fell in groups PGL and ARC by 7 and 9%, respectively, while RV increased in groups CDC II, PGL and ARC by 17, 15 and 8%, respectively. Only the TLCO decline in PGL showed any linkage to clinical deterioration. This study demonstrates deficits at enrollment, and a continuing decline of TLCO and increase in RV in HIV-seropositive subjects without overt lung disease.

AIDS and the lung

Respiratory symptoms are common in HIV-infected persons. The challenge facing clinicians is to determine whether these respiratory symptoms are due to an opportunistic infection or to a chronic process, such as asthma, chronic bronchitis, bronchiectasis, or emphysema. This article reviewed the clinical presentation, diagnosis, and treatment of two important opportunistic infections, PCP and bacterial pneumonia. It also reviewed the current data on obstructive lung diseases as they relate to HIV.

Bronchial reactivity to methacholine in HIV-infected individuals without AIDS

To evaluate bronchial reactivity to methacholine in human immunodeficiency virus (HIV) infection, we submitted 25 HIV-seropositive subjects without full-blown AIDS and 25 HIV-seronegative subjects, all inmates in a drug rehabilitation center for previous intravenous drug abuse, to interview and to bronchial challenge with methacholine. Four (16 percent) HIV-seropositve and three (12 percent) HIV-seronegative subjects noted bronchospastic symptoms. Baseline FEV1 and MEF50 percent were within the normal range in every patient. Bronchial hyperreactivity to methacholine (PD20FEV1 < 1,400 micrograms) was found in two (8 percent) HIV-seropositive and in four (16 percent) HIV-seronegative subjects, with no significant difference in the frequency between the two groups. We conclude that HIV infection without AIDS in intravenous drug users does not appear to be associated with an increased frequency of bronchospastic disorders and to bronchial hyperreactivity to methacholine.