Bacterial Pneumonia in the HIV-Infected Patient

CD4+ cell counts and HIV-RNA levels do not predict outcomes of community-acquired pneumonia in hospitalized HIV-infected patients

BACKGROUND

Outcomes of community-acquired pneumonia (CAP) in relation to CD4+ cell counts have not been established. We examined the correlation of CD4+ cell count and HIV-RNA level with the clinical outcomes of CAP in hospitalized HIV-infected patients.

METHODS

This was a retrospective study of 127 adult hospitalized patients with HIV infection enrolled with the CAP Organization (CAPO), examining the time to clinical stability (TCS), length of hospital stay (LOS), and all-cause mortality.

RESULTS

Mortality data were available for 117 HIV-infected patients with CAP. Death within 28 days was reported in 28 patients. The risk of mortality at 28 days was not significant when adjusted for CD4+ cell count (p=0.123), HIV-RNA <400-1000 copies/ml (p=0.093), HIV-RNA ≥ 1000-10,000 copies/ml (p=0.543), and HIV-RNA ≥ 10,000-100,000 copies/ml (p=0.383). The propensity-adjusted Cox proportional hazards regression models did not show any statistically significant differences in LOS or TCS for CD4+ cell counts (p=0.590 and p=0.420, respectively) or HIV-RNA levels (p=0.470 and p=0.080, respectively). Multivariable Cox proportional hazards models did not reveal any statistically significant relationships between CD4+ cell counts or HIV-RNA levels with LOS or TCS.

CONCLUSIONS

Our study shows that clinical outcomes of HIV-infected patients with CAP are not predicted by CD4+ cell counts or HIV-RNA levels after adjusting for confounders. The management of CAP in patients with HIV infection should not be based on CD4+ cell counts or HIV-RNA levels of the HIV infection.

[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.

A rapid staging system for predicting mortality from HIV-associated community-acquired pneumonia

STUDY OBJECTIVE

Community-acquired pneumonia (CAP) accounts for an increasing proportion of the pulmonary infections in individuals with HIV infection. During the mid-1990s, hospital mortality rates for HIV-associated CAP ranged from 0 to 28%. While hospital differences in case mix may account for mortality rate variation, few methods to evaluate illness severity for HIV-associated CAP have been reported previously. The study objective was to develop a staging system for categorizing mortality risk of patients with HIV-associated CAP using information available prior to hospital admission.

DESIGN/SETTING/PATIENTS

Retrospective medical records review of 1,415 patients hospitalized with HIV-associated CAP from 1995 to 1997 at 86 hospitals in seven metropolitan areas.

MEASUREMENTS

In-patient mortality rate.

RESULTS

Hierarchically optimal classification tree analysis was used to develop a preadmission staging system for predicting inpatient mortality. The overall inpatient mortality rate was 9.1%. The significant predictors of mortality included the presence of neurologic symptoms, respiratory rate > or = 25 breaths/min, and creatinine > 1.2 mg/dL. The model identified a five-category staging system, with the mortality rate increasing by stage: 2.3% for stage 1, 5.8% for stage 2, 12.9% for stage 3, 22.0% for stage 4, and 40.5% for stage 5. The classification accuracy of the model was 85.2%.

CONCLUSIONS

Our staging system categorizes inpatient mortality risk for patients with HIV-associated CAP using three routinely available variables. The staging system may be useful for guiding clinical decisions about the intensity of patient care and for case-mix adjustment in future studies addressing variation in hospital mortality rates.

Prospective study of etiologic agents of community-acquired pneumonia in patients with HIV infection

OBJECTIVES

To study prospectively HIV-positive patients admitted to the hospital because of pneumonia by extensive laboratory tests to determine specific microbiologic diagnoses and to establish the best clinical diagnosis after review of all available data by expert clinicians.

METHODS

Patients admitted to one of two hospitals had extensive questionnaires completed and defined diagnostic tests performed on blood, sputum, urine and bronchoalveolar lavage specimens, when available.

RESULTS

A total of 230 patients had a diagnosis of pneumonia verified. A definite or probable etiologic diagnosis was made in 155 (67%) of these patients. Pneumocystis carinii caused 35% of all cases of pneumonia. Twenty-seven percent of cases of pneumonia with a single etiology had a definite or probable bacterial etiology. 'Atypical agents' were distinctly uncommon. Few clinical or laboratory parameters could differentiate specific etiologies.

CONCLUSIONS

P. carinii continues to be a common cause of pneumonia in these patients. The rarity of 'atypical agents' could simplify the empiric approach to therapy. Despite the use of extensive testing we did not find a definite etiology in a large number of cases.

Humoral immune response to influenza vaccination in patients from high risk groups

Influenza is one of the most common respiratory diseases. Infections caused by this virus may be very serious and can lead to severe complications. So far, the most effective method of protection against influenza is annual vaccination. The Advisory Committee on Immunisation Practices recommends vaccination against influenza for some groups of people. Unfortunately, in spite of these clear indications, a large number of patients are not vaccinated. This article reviews the current scientific literature on immunological response to influenza vaccination in patients who are at especially high risk for serious post-influenza complications and for whom immunisation against this virus is strongly recommended. Results of studies carried out in Poland and other countries in elderly people, in patients with pulmonary diseases, renal diseases, diabetes mellitus, cancer and haemophilia, and in those with HIV infection are presented. In this review, we focus on the immune response to haemagglutinin. There are some discrepancies between the results of studies carried out by different authors in high risk groups of patients. Some investigations indicated poorer humoral response to influenza vaccine in these groups, while others showed responses comparable to those in healthy individuals. These differences may be explained by differences in types and stages of the chronic diseases, in the treatment and composition of influenza vaccines, and also patients' ages, vaccination history and prevaccination antibody titres. Influenza vaccines are well tolerated in high risk patients, and all adverse reactions are generally mild and similar to those observed in healthy people. Although, in some cases, immunological responses to influenza vaccination measured in the whole study group were poor, there were some individual patients who, after vaccination, developed antihaemaglutinin antibody titres which are considered to give protection against the infection or contribute to a milder course of the disease.

Effect of trimethoprim-sulfamethoxazole as Pneumocystis carinii pneumonia prophylaxis on bacterial illness, Pneumocystis carinii pneumonia, and death in persons with AIDS

To measure the effect of trimethoprim-sulfamethoxazole (TMP-SMX) in preventing bacterial illness, Pneumocystis carinii pneumonia (PCP), and death in people with AIDS, we conducted a retrospective medical record review of 1078 persons who were observed for 3 years on average who attended nine outpatient facilities in Seattle, Washington between January 1990 and April 1996. We calculated relative risk estimates to measure the protective effect of TMP-SMX on the development of major bacterial illnesses, PCP, and death. Use of TMP-SMX decreased the risk of PCP (relative risk [RR] = 0.23; 95% confidence interval [CI], 0.14-0.36) and deaths not attributable to PCP (RR = 0.59; 95% CI, 0.47-0.73). Prevention of major bacterial illnesses of known etiology was of borderline significance (RR = 0.77; 95% CI, 0.57-1.05) and became statistically significant with the addition of patients with infections of unknown etiology (RR = 0.77; 95% CI 0.61-0.97). Use of TMP-SMX PCP prophylaxis significantly reduced the risks of death and of PCP and was associated with a trend toward reduced risk of major bacterial infections.

Empiric treatments impair the diagnostic yield of BAL in HIV-positive patients

OBJECTIVE

To investigate the influence of empiric treatments prior to fiberoptic bronchoscopy (FOB) on the diagnostic yield of BAL in HIV-positive patients with respiratory symptoms.

METHOD

We studied 123 consecutive FOBs with BAL in HIV-positive patients; 101 of these patients (82%) had received previous antimicrobial treatment from 1 to 60 days. Diagnostic yield of BAL for Pneumocystis carinii, Mycobacterium tuberculosis, and bacterial pneumonia was compared between patients with and without previous empiric treatments.

RESULTS

A diagnosis was obtained in 85 patients (69%), of whom 17 (20%) had multiple infections. Diagnostic yield was higher in patients without previous treatment, 91% (20/22) compared with 64% (65/101), p < 0.03. Diagnostic yield was also higher for bacterial pneumonia: seven isolations from 22 patients not receiving previous empiric treatment (32%), compared with 11 of those who had (11%; p < 0.02). The duration of empiric treatment against P carinii in patients in whom it was isolated was significantly shorter than in those in whom P carinii was not detected (3.5 +/- 1.8 days compared with 5.2 +/- 2.4 days; p = 0.003). FOB permitted a change in treatment in 62% of patients with a final diagnosis.

CONCLUSION

This study demonstrates that empiric treatments prior to FOB significantly impair the diagnostic yield of BAL in detecting common pathogens in HIV-infected patients with respiratory symptoms.

Bacterial infections

Non-opportunistic bacterial infections are an important cause of morbidity and mortality for HIV-infected adults and children. Factors associated with increased risk of these include altered B- and T-cell function; altered phagocytic cell function; skin and mucous membrane defects; and use of indwelling vascular catheters, antibiotics, or cytotoxic agents. The pathogens encountered most frequently are S. aureus, S. pneumoniae, H. influenzae, Salmonella sp., and Pseudomonas aeruginosa. Less commonly encountered organisms include Rhodococcus equi, Listeria monocytogenes, Shigella sp., and Nocardia asteroides, Strategies for prevention as well as diagnosis and treatment of these are discussed.

Bacterial pneumonia associated with HIV-1 infection

Bacterial pneumonia remains an important cause of treatable morbidity among HIV-1-infected persons. These pneumonias occur at all CD4 counts but are especially common as the HIV-1 infection progresses. Bronchopneumonia should be considered particularly in the setting of segmental or lobar consolidation associated with productive cough and fever. S. pneumoniae remains the most common pathogen causing bronchopneumonia. Because of the high rate of bacteremia, diagnosis may be facilitated by blood cultures. Treatment is similar to management of HIV-1-seronegative persons, although drug resistance against some bacteria may be an emerging problem. Several opportunities exist for prevention, and these should be pursued vigorously.

Bacterial pneumonia in persons infected with the human immunodeficiency virus. Pulmonary Complications of HIV Infection Study Group

BACKGROUND

Patients with human immunodeficiency virus (HIV) infection are at increased risk for bacterial pneumonia in addition to opportunistic infection. However, the risk factors for bacterial pneumonia and its incidence in this population are not well defined.

METHODS

In a multicenter, prospective, observational study, we monitored 1130 HIV-positive and 167 HIV-negative participating adults for up to 64 months for pulmonary disease. The HIV-positive group comprised 814 homosexual or bisexual men, 261 injection-drug users, and 55 female partners of HIV-infected men.

RESULTS

There were 237 episodes of bacterial pneumonia among the HIV-positive participants (rate, 5.5 per 100 person-years), as compared with 6 episodes among the HIV-negative participants (rate, 0.9 per 100 person-years; P < 0.001). The rate of bacterial pneumonia increased with decreasing CD4 lymphocyte counts (2.3, 6.8, and 10.8 episodes per 100 person-years in the strata with more than 500, 200 to 500, and fewer than 200 cells per cubic millimeter, respectively; P < or = 0.022 for each comparison). Injection-drug users had a higher rate of bacterial pneumonia than did homosexual or bisexual men or female partners. In the stratum with the fewest CD4 lymphocytes, cigarette smoking was associated with an increased rate of pneumonia. Mortality was almost four times higher among participants with an episode of pneumonia than among the others. Prophylaxis with trimethoprim-sulfamethoxazole was associated with a 67 percent reduction in confirmed episodes of bacterial pneumonia (P = 0.007).

CONCLUSIONS

Bacterial pneumonia is more frequent in HIV-positive persons than in seronegative controls, and the risk is highest among those with CD4 lymphocyte counts below 200 per cubic millimeter and among injection-drug users.