Impact of bacterial pneumonia and Pneumocystis carinii pneumonia on human immunodeficiency virus disease progression. Pulmonary Complications of HIV Study Group

Clinical review: Respiratory failure in HIV-infected patients--a changing picture

Respiratory failure in HIV-infected patients is a relatively common presentation to ICU. The debate on ICU treatment of HIV-infected patients goes on despite an overall decline in mortality amongst these patients since the AIDS epidemic. Many intensive care physicians feel that ICU treatment of critically ill HIV patients is likely to be futile. This is mainly due to the unfavourable outcome of HIV patients with Pneumocystis jirovecii pneumonia who need mechanical ventilation. However, the changing spectrum of respiratory illness in HIV-infected patients and improved outcome from critical illness remain under-recognised. Also, the awareness of certain factors that can affect their outcome remains low. As there are important ethical and practical implications for intensive care clinicians while making decisions to provide ICU support to HIV-infected patients, a review of literature was undertaken. It is notable that the respiratory illnesses that are not directly related to underlying HIV disease are now commonly encountered in the highly active antiretroviral therapy (HAART) era. The overall incidence of P. jirovecii as a cause of respiratory failure has declined since the AIDS epidemic and sepsis including bacterial pneumonia has emerged as a frequent cause of hospital and ICU admission amongst HIV patients. The improved overall outcome of HIV patients needing ICU admission is related to advancement in general ICU care, including adoption of improved ventilation strategies. An awareness of respiratory illnesses in HIV-infected patients along with an appropriate diagnostic and treatment strategy may obviate the need for invasive ventilation and improve outcome further. HIV-infected patients presenting with respiratory failure will benefit from early admission to critical care for treatment and support. There is evidence to suggest that continuing or starting HAART in critically ill HIV patients is beneficial and hence should be considered after multidisciplinary discussion. As a very high percentage (up to 40%) of HIV patients are not known to be HIV infected at the time of ICU admission, the clinicians should keep a low threshold for requesting HIV testing for patients with recurrent pneumonia.

HIV-1 and bacterial pneumonia in the era of antiretroviral therapy

Community-acquired pneumonia affects approximately 4 million people in the United States, with 40,000 deaths per year. The incidence is increased about 35-fold in HIV-infected individuals, and this rate has decreased since the antiretroviral era has begun. Bacterial pneumonia has decreased from 5 to 20 cases per 100 person-years to less than 1 to 5 cases per 100 person-years in the era of antiretroviral therapy. HIV-1 infection impairs the function of neutrophils in the lung and infects CD4⁺ cells and alveolar macrophages. Opportunistic infections dramatically increase local HIV replication in the lung cells, especially alveolar macrophages and CD4⁺ cells. This enhanced replication increases viral mutations and provides opportunities for viral escape from latent reservoirs. Mortality is increased with more comorbidities in this highly susceptible population. Immunization with vaccines is recommended, especially pneumococcal vaccines, although the vaccine itself may stimulate viral replication. Recent studies show that the lower respiratory tract is a microbial reservoir in HIV-infected individuals rather than being a sterile environment, as originally thought. This may provide new opportunities for preventing opportunistic infections in HIV-infected subjects. Bacterial pneumonia presents an ongoing challenge in these high-risk individuals, particularly in studying the functions of the innate and acquired immune response.

Concurrent HIV/AIDS diagnosis increases the risk of short-term HIV-related death among persons newly diagnosed with AIDS, 2002-2005

Despite the overall effectiveness and availability of highly active antiretroviral therapy (HAART), 1500 HIV-related deaths still occur annually in New York City. In considering ways to further reduce deaths, we assessed the contribution of concurrent HIV/AIDS diagnosis to HIV-related mortality in New York City among persons newly diagnosed with AIDS. We used Cox regression to conduct a retrospective cohort analysis of HIV-related mortality among 15,211 residents age 13+ reported with AIDS to the population-based HIV/AIDS registry between January 2002 and June 2005. Concurrent HIV/AIDS diagnosis was defined as a diagnosis of AIDS occurring within 1 month of initial diagnosis of HIV. HIV-related mortality was 20.2% among persons diagnosed concurrently and 12.2% among those diagnosed nonconcurrently (p < 0.0001). Concurrent HIV/AIDS was associated with more than twice the risk of HIV-related death within the 4 months after diagnosis (hazard ratio [HR] 2.27, 95% confidence interval [CI] 1.94-2.65) but no increased risk thereafter (HR 1.12, 95% CI 0.77-1.61). Other significant predictors of death included injection drug use and birth in the Caribbean or Latin America. After 4 years 11.9% of all HIV-related deaths were attributable to a concurrent HIV/AIDS diagnosis. Public health initiatives that facilitate early diagnosis of HIV may reduce HIV-related mortality by giving people the opportunity to initiate care and begin treatment with HAART before immunosuppression places them at risk for opportunistic illness and death.

Rapid diagnosis of pneumococcal pneumonia among HIV-infected adults with urine antigen detection

OBJECTIVES

Streptococcus pneumoniae is the leading cause of bacterial pneumonia and associated bacteremia during HIV infection. Rapid diagnostic assays may limit inappropriate therapy.

METHODS

Clinical signs and symptoms and sera and urine were collected prospectively from 70 adults with pneumococcal pneumonia, including 47 with HIV co-infection. Pneumococcal C-polysaccharide antigen was detected in urine using the Binax immunochromatographic test (ICT). A systematic review of 24 published studies was conducted.

RESULTS

Clinical symptoms, signs, and laboratory parameters except leukocytosis, were similar in HIV-infected and HIV-seronegative pneumonia. The performance of the urine antigen ICT was independent of HIV-status (sensitivity 81%, specificity 98%, positive (PPV) and negative predictive values (NPV) 98%, and 82%, respectively). The sensitivity of sputum Gram's stain was 58% (34/59) with sputum unable to be provided by 16%. The CRP response was identical in HIV-infected (mean+/-SD) 133+/-88 vs. seronegative 135+/-104 mg/L (p=0.9). In the systematic review, the ICT performance revealed 74% sensitivity (95% CI 72-77%) and 94% specificity (95% CI 93-95%). Urine antigen testing increases etiologic diagnosis by 23% (range: 10-59%) when testing adults with community acquired pneumonia of unknown etiology.

CONCLUSIONS

Urinary antigen detection provides a credible rapid diagnostic test for pneumococcal pneumonia regardless of HIV-status. CRP response to acute infection is similar in HIV co-infection and increases diagnostic certainty.

AIDS-defining opportunistic illnesses in the HAART era in New York City

Despite widespread availability of HAART, opportunistic illnesses (OIs) still occur and result in an increased risk of mortality among persons with AIDS. We estimated the incidence of OIs among all new adult AIDS cases in New York City in 2000 overall and in demographic and clinical subgroups and identified factors associated with occurrence of an AIDS-defining OI versus AIDS diagnosis based on low CD4+ values only. In 2000, 5,451 new AIDS cases were reported to the New York City Department of Health and Mental Hygiene. Of these 27.4% (95% CI: 22.8-32.6) had at least one OI, most frequent being Pneumocystis jiroveci pneumonia (12.2%) and M. tuberculosis (5.3%); 47.1% (41.7-52.5) had a late HIV diagnosis (i.e.< or =6 months before AIDS diagnosis). Persons with a late HIV diagnosis not in recent care had a 3.5-fold increased odds (1.29-9.63) of an OI, compared to non-late testers in care. Other predictors of an OI were injection drug use and older age. We conclude that OIs remain prevalent in the HAART era and late testers not in care are especially likely to develop an OI. Our results support comprehensive HIV programs promoting early HIV testing and linkage to care to prevent OI-related morbidity and mortality.

Bacterial pneumonia, HIV therapy, and disease progression among HIV-infected women in the HIV epidemiologic research (HER) study

BACKGROUND

To determine the rate and predictors of community-acquired bacterial pneumonia and its effect on human immunodeficiency virus (HIV) disease progression in HIV-infected women, we performed a multiple-site, prospective study of HIV-infected women in 4 cities in the United States.

METHODS

During the period of 1993-2000, we observed 885 HIV-infected and 425 HIV-uninfected women with a history of injection drug use or high-risk sexual behavior. Participants underwent semiannual interviews, and CD4+ lymphocyte count and viral load were assessed in HIV-infected subjects. Data regarding episodes of bacterial pneumonia were ascertained from medical record reviews.

RESULTS

The rate of bacterial pneumonia among 885 HIV-infected women was 8.5 cases per 100 person-years, compared with 0.7 cases per 100 person-years in 425 HIV-uninfected women (P < .001). In analyses limited to follow-up after 1 January 1996, highly active antiretroviral therapy (HAART) and trimethoprim-sulfamethoxazole (TMP-SMX) use were associated with a decreased risk of bacterial pneumonia. Among women who had used TMP-SMX for 12 months, each month of HAART decreased bacterial pneumonia risk by 8% (adjusted hazard ratio [HR(adj)], 0.92; 95% confidence interval [CI], 0.89-0.95). Increments of 50 CD4+ cells/mm3 decreased the risk (HR(adj), 0.88; 95% CI, 0.84-0.93), and smoking doubled the risk (HR(adj), 2.12; 95% CI, 1.26-3.55). Bacterial pneumonia increased mortality risk (HR(adj), 5.02; 95% CI, 2.12-11.87), with adjustment for CD4+ lymphocyte count and duration of HAART and TMP-SMX use.

CONCLUSIONS

High rates of bacterial pneumonia persist among HIV-infected women. Although HAART and TMP-SMX treatment decreased the risk, bacterial pneumonia was associated with an accelerated progression to death. Interventions that improve HAART utilization and promote smoking cessation among HIV-infected women are warranted.

Current issues in critical care of the human immunodeficiency virus-infected patient

OBJECTIVE

To provide current information on the epidemiology of human immunodeficiency virus (HIV)-infected patients admitted to the intensive care unit during the era of combination antiretroviral therapy and to review issues related to the administration of antiretroviral therapy that are relevant to the intensivist.

DESIGN

Review of literature related to intensive care of HIV-infected patients.

RESULTS

Overall mortality of HIV-infected patients in the intensive care unit has decreased in the era of combination antiretroviral therapy, and patients are more commonly admitted with non-HIV-related illnesses. Use of antiretroviral therapy in the intensive care unit is difficult but may be associated with improved outcomes.

CONCLUSIONS

HIV-infected patients are less likely to be admitted to the intensive care unit with opportunistic infections but more likely to be admitted with problems unrelated to HIV infection or with conditions related to antiretroviral therapy. With current management strategies, more patients survive intensive care unit admission. Intensivists need to be familiar with antiretroviral therapy to recognize life-threatening toxicities unique to these drugs; to avoid drug interactions, which are extremely common and potentially life-threatening; and to avoid enhancing HIV drug resistance, an occurrence that could have devastating consequences for the patient following intensive care unit discharge.

[Infectious pulmonary complications in HIV-infected patients in the high by active antiretroviral therapy era in Spain]

Pulmonary complications in HIV-infected patients are at present a first-rate problem. They are the main cause of hospital admission of these patients in our country. Most HIV-patients have a pulmonary complication during the evolution of the infection. The main etiologic diagnosis is bacterial pneumonia, especially pneumococcal pneumonia; the second most frequent cause is Pneumocystis jiroveci (previously named P. carinii) pneumonia and the third cause is mycobacteriosis, particularly Mycobacterium tuberculosis. From early studies, important changes in the epidemiology of HIV-related pulmonary complications have occurred. General prescription of P. jiroveci primary prophylaxis is probably one of the main causes, and, more recently, the use of highly active antiretroviral therapy may also be an underlying explanation. In this review, epidemiology, diagnosis and outcome of HIV-related pulmonary complications in our country are update.

Effect of co-trimoxazole prophylaxis on morbidity, mortality, CD4-cell count, and viral load in HIV infection in rural Uganda

BACKGROUND

Prophylaxis with co-trimoxazole (trimethoprim-sulphamethoxazole) is recommended for people with HIV infection or AIDS but is rarely used in Africa. We assessed the effect of such prophylaxis on morbidity, mortality, CD4-cell count, and viral load among people with HIV infection living in rural Uganda, an area with high rates of bacterial resistance to co-trimoxazole.

METHODS

Between April, 2001, and March, 2003, we enrolled, and followed up with weekly home visits, 509 individuals with HIV-1 infection and their 1522 HIV-negative household members. After 5 months of follow-up, HIV-positive participants were offered daily co-trimoxazole prophylaxis (800 mg trimethoprim, 160 mg sulphamethoxazole) and followed up for a further 1.5 years. We assessed rates of malaria, diarrhoea, hospital admission, and death.

FINDINGS

Co-trimoxazole was well tolerated with rare (<2% per person-year) adverse reactions. Even though rates of resistance in diarrhoeal pathogens were high (76%), co-trimoxazole prophylaxis was associated with a 46% reduction in mortality (hazard ratio 0.54 [95% CI 0.35-0.84], p=0.006) and lower rates of malaria (multivariate incidence rate ratio 0.28 [0.19-0.40], p<0.0001), diarrhoea (0.65 [0.53-0.81], p<0.0001), and hospital admission (0.69 [0.48-0.98], p=0.04). The annual rate of decline in CD4-cell count was less during prophylaxis than before (77 vs 203 cells per microL, p<0.0001), and the annual rate of increase in viral load was lower (0.08 vs 0.90 log(10) copies per mL, p=0.01).

INTERPRETATION

Daily co-trimoxazole prophylaxis was associated with reduced morbidity and mortality and had beneficial effects on CD4-cell count and viral load. Co-trimoxazole prophylaxis is a readily available, effective intervention for people with HIV infection in Africa.

Immunization of immunocompromised persons

Advances in medicine, science, and technology have led to increasing numbers of people in the general population with altered host defenses. The risk for clinical infection in an immunocompromised host, such as a person who has received a solid organ transplant, is determined largely by the interaction between two factors: the epidemiologic exposures the person encounters and the person's net state of immunosuppresson. Vaccination represents a crucial approach for preventing infection in the general public and immunocompromised persons. This article reviews the benefits of and risks for immunization in immunocompromised persons and provides recommendations for the use of specific vaccines.

Safety and immunogenicity of 23-valent pneumococcal polysaccharide vaccine in HIV-1 infected former drug users

The immunogenicity of 23-valent pneumococcal polysaccharide vaccine was assessed in 57 HIV-1 infected former intravenous drug users and in 20 HIV-1 negative controls. The effect of vaccination on HIV-1 infection was studied in a subgroup of 38 patients, 60% of whom under highly active antiretroviral therapy (HAART). Antibody to capsular polysaccharides from Streptococcus pneumoniae serotypes 3, 4, 6B, 19F, 23 F, and changes in CD4+ count, HIV-1 RNA, proviral DNA and HIV-1 phenotype were measured in pre- and post-vaccination samples. Vaccinations were well-tolerated. The rate of responders was higher (P<0.05) in HIV-1 negative than in HIV-1 infected individuals. No difference in antibody response was found within HIV-1 infected patients stratified according to CD4+ counts. Post-vaccination antibody geometric mean concentrations (GMCs) to the five antigens were higher (P<0.05) than baseline in HIV-1 negative subjects, but not in HIV-1 positive individuals. Those with CD4+ >500 cells/mm(3) showed a significant increase of antibody against type 3 only. Immunisation caused no significant changes in CD4+ counts and in either plasma HIV-1 RNA nor proviral DNA levels. Pneumococcal vaccination does not induce virological or immunological deterioration in HIV infected patients, but the antibody response to a single dose of vaccine is poor.

The relationship of preventable opportunistic infections, HIV-1 RNA, and CD4 Cell counts to chronic mortality

BACKGROUND

Both HIV-1 RNA and absolute CD4 cell counts have been identified as important predictors of HIV-1 disease progression and mortality. The independent impact of opportunistic infections on the risk of chronic mortality, defined as death beyond 30 days of an opportunistic infection, has not been studied when controlling for HIV-1 RNA. Our objective was to determine the relationship between a history of any of five preventable opportunistic infections (Pneumocystis carinii pneumonia, Mycobacterium avium complex, toxoplasmosis, cytomegalovirus, and candida esophagitis) and chronic mortality.

METHODS

Using the Multicenter AIDS Cohort Study (MACS) public use data set of 2193 HIV-infected men in four U.S. cities, we employed a Cox regression model to estimate the impact of a history of preventable opportunistic infection on chronic mortality while controlling for maximum HIV-1 RNA, CD4 cell count, use of antiretroviral drugs, and age.

FINDINGS

The chronic mortality rate among individuals with a history of preventable opportunistic infection was 66.7 per 100 person-years compared with 2.3 per 100 person-years for those without a history of preventable opportunistic infection (RR = 28.4, 95% CI: 24.7-32.8). In the adjusted analysis, the relative hazard of death for those with a history of preventable opportunistic infections was 7.0 (5.8-8.3), whereas antiretroviral therapy was associated with a decreased risk of death (0.37 [0.30-0.44]). We found no association between maximum HIV-1 RNA and chronic mortality. There was statistically significant effect modification between preventable opportunistic infections and CD4 cell count (p <.0001).

INTERPRETATION

Preventable opportunistic infections cause not only short-term mortality in HIV-1 disease but appear to have a major impact on chronic mortality.

Incidence and determinants of bacterial infections in HIV-positive patients receiving anti-Pneumocystis carinii/Toxoplasma gondii primary prophylaxis within a randomized clinical trial

We assessed the incidence and determinants of bacteremia, pneumonia, and sinusitis/otitis in HIV-positive people receiving cotrimoxazole (CTX) or dapsone-pyrimethamine (DP) for primary prophylaxis of Pneumocystis carinii pneumonia (PCP) and toxoplasmic encephalitis (TE) within a randomized clinical trial. In total, 244 patients were randomized: 122 were assigned to CTX and 122 to DP. In the cohort, 22 bacteremia, 63 pneumonia, and 39 sinusitis/otitis cases were observed. Incidence rates of bacteremia, pneumonia, and sinusitis/otitis as well as the 2-year probability of remaining free from any bacterial infection were not significantly different between the two groups. At multivariate analysis, the risks of developing bacteremia and pneumonia were found to be independently increased by the use of a central venous catheter (hazard ratio [HR], 4.48; p <.05 and HR, 4.13; p <.01, respectively) and by hospitalization (HR, 28.82; p <.05 and HR, 10.15; p <.05, respectively). In conclusion, CTX at the dosage employed for primary PCP/TE prophylaxis does not seem to protect against bacterial infections more than second-line DP.

Human immunodeficiency virus and respiratory infection

Pulmonary disease remains a major problem for the 33 million individuals who are thought to be infected with human immunodeficiency virus (HIV) worldwide. Respiratory infections are responsible for a large number of the 2 million deaths that occur each year in association with HIV disease. In countries where the majority of the population can access highly active antiretroviral therapy, morbidity and mortality rates have been cut by up to 80%. This has allowed the withdrawal of specific opportunistic infection prophylaxis when immune restoration is deemed to be adequate. Recommendations have been published concerning Pneumocystis carinii prophylaxis. This year has also seen further reports of drug-resistant isolates of Pneumocystis carinii. The clinical relevance of this is still debated. Tuberculosis remains a global problem. The complexity of the interactions between specific anti-HIV and anti-tuberculous treatment have been highlighted. In the developing world, the importance of immunization and prophylaxis (against bacteria and mycobacteria) have recently been further defined in a number of studies.