Patterns of opportunistic infections in patients with HIV infection

Trimethoprim-Sulfamethoxazole (Bactrim) Dose Optimization in Pneumocystis jirovecii Pneumonia (PCP) Management: A Systematic Review

(1) Background: Pneumocystis jirovecii pneumonia (PCP) has a substantial impact on the morbidity and mortality of patients, especially those with autoimmune disorders, thus requiring optimal dosing strategies of Trimethoprim–Sulfamethoxazole (TMP-SMX). Therefore, to ensure the safety of TMP-SMX, there is a high demand to review current evidence in PCP patients with a focus on dose optimization strategies; (2) Methods: Various databases were searched from January 2000 to December 2021 for articles in English, focusing on the dose optimization of TMP-SMX. The data were collected in a specific form with predefined inclusion and exclusion criteria. The quality of each article was evaluated using a Newcastle–Ottawa Scale (NOS) for retrospective studies, Joanna Briggs Institute (JBI) critical checklist for case reports, and Cochrane bias tool for randomized clinical trials (RCTs); (3) Results: Thirteen studies met the inclusion criteria for final analysis. Of the 13 selected studies, nine were retrospective cohort studies, two case reports, and two randomized controlled trials (RCT). Most of the studies compared the high-dose with low-dose TMP-SMX therapy for PCP. We have found that a low dose of TMP-SMX provides satisfactory outcomes while reducing the mortality rate and PCP-associated adverse events. This strategy reduces the economic burden of illness and enhances patients’ compliance to daily regimen plan; (4) Conclusions: The large-scale RCTs and cohort studies are required to improve dosing strategies to prevent initial occurrence of PCP or to prevent recurrence of PCP in immune compromised patients.

Disparities in the Magnitude of Human Immunodeficiency Virus-related Opportunistic Infections Between High and Low/Middle-income Countries: Is Highly Active Antiretroviral Therapy Changing the Trend?

Opportunistic infections (OIs) cause significant morbidity/mortality in human immunodeficiency virus (HIV)-infected individuals globally. Disparities between high-income countries (HICs) and low/middle-income countries (LMICs) in the magnitude of HIV-related OIs in pre-highly active antiretroviral therapy (HAART) populations was reviewed, and HAART-induced decline in OIs was further compared between the two settings. Studies published in English from onset of HIV epidemic up to December 2013 were searched in PubMed, Google, Google Scholar, and African Journal online. An article was included if (a) the study was conducted in HIC or LMIC, (b) the age of the participants was ≥12 years, (c) the HAART status of the participants was stated, and (d) various types of OIs were investigated. In predominantly pre-HAART populations, the incidence and prevalence of overall HIV-related OIs in HIC ranged from 5.5 to 50.0 per 100 person-years (PY) and 27.4-56.7%, respectively. In LMIC, the respective overall incidence and prevalence of OIs were 12.2-93.9 per 100 PY and 32.0-77.7%. Pneumocystis jirovecii pneumonia, candidiasis, Cytomegalovirus disease, Mycobacterium avium complex disease, and Kaposi's sarcoma were the most frequent OIs in HICs while tuberculosis, candidiasis, chronic diarrhea, and cryptococcosis were predominant in LMICs. The introduction of HAART led to substantial reduction in the incidence of OIs with more impressive percentage decline in HICs (43-97%) compared to 30-79% in LMICs. Disparities in the magnitude of HIV-related OIs between HICs and LMICs are evident both in the pre-HAART and post-HAART era. Efforts to optimize HAART-induced decline in HIV-related OIs should become a global health priority irrespective of prevailing socioeconomic circumstances.

Clinical profile of human immunodeficiency virus patients with opportunistic infections: A descriptive case series study

BACKGROUND

Human immunodeficiency virus (HIV) virus, causative agent in acquired immunodeficiency syndrome, is fast becoming a major threat in the Indian subcontinent, with an estimated 3.7 million persons being infected with HIV. HIV infection is complicated by various opportunistic infections (OIs) such as tuberculosis (TB), candidiasis, herpes zoster, Pneumocystis jirvoceii, cytomegalovirus (CMV) etc., This study carried out to know the clinical profile of HIV patients with OIs.

METHODS

A case series study was carried out at a tertiary care hospital in Bellary, Karnataka, India. A hospital based case series study was conducted among 164 HIV patients with OIs admitted to various wards as well as attending outpatient department at Vijayanagara Institute of Medical Sciences Hospital, Bellary during Jan 2013 to Nov 2013. Both primary and secondary data was collected to gather information on clinical profile. The statistical tests used were descriptive statistics and independent t test.

RESULTS

Among 164 patients, 29.3% were females and 68.3% males. High proportions of patients were observed in 28-37 years of age group and heterosexual route was the most common mode of transmission. TB (50%) is the most frequent OI followed by candidiasis (49%), pneumocystis (16%) and others. The mean CD4 cell count in TB was 237.02/mL and in candidiasis 189.07/mL. Low values were observed in promyelocytic leukemia (18.10/mL), CMV (18.5/mL) and in toxoplasmosis (73.1/mL).

CONCLUSIONS

Respiratory system was the most common system involved by OIs and most of patients with OIs had CD4 T cell count below 200/mL, whereas there were no patients in the study with counts above 500/mL.

Recent trends in the spectrum of opportunistic infections in human immunodeficiency virus infected individuals on antiretroviral therapy in South India

Background:

Opportunistic infections (OI) are the major cause of morbidity and mortality among human immunodeficiency virus (HIV) infected individuals. The pattern of OIs differs widely, hence it is necessary to correlate spectrum of OIs and CD4 counts among HIV infected individuals in specific localities.

Materials and Methods:

The present study describes the clinical and laboratory profiles of different OIs among 55 HIV seropositive patients. CD4 count was estimated and antiretroviral therapy (ART) was started in 27 patients as per National Acquired Immunodeficiency Syndrome Control Organization guidelines. These 27 patients were classified into stage 1, stage 2 and stage 3 based on CD4 counts of >500 cells/μl, 200-499 cells/μl and <200 cells/μl respectively. The OIs presented by respective groups were documented.

Results:

Pulmonary tuberculosis was found to be the most common OI constituting 43.6% of all cases followed by candidiasis (30.9%), cryptosporidial diarrhea (21.8%), herpes zoster (16.3%), cryptococcal meningitis (3.63%), Pneumocystis jirovecii pneumonia (1.81%), and other miscellaneous infections (23.6%). Only 1 patient was found in stage I while 13 patients each were grouped in stage II or stage III. The mean CD4 count in our study population who were on ART was 230 ± 150 cells/µl.

Conclusion:

The pattern of OIs among our study group did not differ significantly from patients not receiving ART. The effect of ART on CD4 count differs from patient to patient based on the degree of depletion of CD4 count before the initiation of ART, drug adherence, concomitant OIs and their treatment.

A bivariate pseudolikelihood for incomplete longitudinal binary data with nonignorable nonmonotone missingness

For analyzing longitudinal binary data with nonignorable and nonmonotone missing responses, a full likelihood method is complicated algebraically, and often requires intensive computation, especially when there are many follow-up times. As an alternative, a pseudolikelihood approach has been proposed in the literature under minimal parametric assumptions. This formulation only requires specification of the marginal distributions of the responses and missing data mechanism, and uses an independence working assumption. However, this estimator can be inefficient for estimating both time-varying and time-stationary effects under moderate to strong within-subject associations among repeated responses. In this article, we propose an alternative estimator, based on a bivariate pseudolikelihood, and demonstrate in simulations that the proposed method can be much more efficient than the previous pseudolikelihood obtained under the assumption of independence. We illustrate the method using longitudinal data on CD4 counts from two clinical trials of HIV-infected patients.

A weighted combination of pseudo-likelihood estimators for longitudinal binary data subject to non-ignorable non-monotone missingness

For longitudinal binary data with non-monotone non-ignorably missing outcomes over time, a full likelihood approach is complicated algebraically, and with many follow-up times, maximum likelihood estimation can be computationally prohibitive. As alternatives, two pseudo-likelihood approaches have been proposed that use minimal parametric assumptions. One formulation requires specification of the marginal distributions of the outcome and missing data mechanism at each time point, but uses an 'independence working assumption,' i.e. an assumption that observations are independent over time. Another method avoids having to estimate the missing data mechanism by formulating a 'protective estimator.' In simulations, these two estimators can be very inefficient, both for estimating time trends in the first case and for estimating both time-varying and time-stationary effects in the second. In this paper, we propose the use of the optimal weighted combination of these two estimators, and in simulations we show that the optimal weighted combination can be much more efficient than either estimator alone. Finally, the proposed method is used to analyze data from two longitudinal clinical trials of HIV-infected patients.

Incidence of noninfectious conditions in perinatally HIV-infected children and adolescents in the HAART era

OBJECTIVE

To estimate highly active antiretroviral therapy (HAART)-era incident rates for the first episode of noninfectious conditions in human immunodeficiency virus (HIV)-infected youth in order to identify HAART-era changes in the natural history of perinatal HIV infection.

DESIGN

Multicenter prospective cohort study.

SETTING

More than 80 sites in the United States including Puerto Rico.

PATIENTS

Perinatally HIV-infected youth.

MAIN OUTCOME MEASURES

Incidence rates (IRs) per 100 person-years were calculated for targeted noninfectious conditions occurring in perinatally HIV-infected children. A chi(2) test for linear trend was used to evaluate changes in the rates from 2001 to 2006.

RESULTS

Two thousand five hundred seventy-five perinatally HIV-infected children (51%, female; 59%, black, non-Hispanic) were enrolled in Pediatric AIDS Clinical Trials Group (PACTG) 219C between 2000 and 2006 and were followed up for a median of 59 months. The 10 most common noninfectious conditions were pregnancy conditions (IR = 6.16; 95% confidence interval (CI), 3.9-9.3), birth defects (IR = 0.19; 95% CI, 0.1-0.3), gynecological dysplasias (IR = 5.92; 95% CI, 3.9-8.6), condyloma (IR = 0.15; 95% CI, 0.1-0.2), encephalopathy (IR = 0.38; 95% CI, 0.3-0.5), pancreatitis (IR = 0.30; 95% CI, 0.2-0.4), cardiac disorders (IR = 0.28; 95% CI, 0.2-0.4), renal disorders (IR = 0.26; 95% CI, 0.2-0.4), peripheral neuropathy (IR = 0.23; 95% CI, 0.2-0.4), and idiopathic thrombocytic purpura (IR = 0.15; 95% CI, 0.1-0.3). Among these conditions, 5 showed significant trends, with IRs increasing over time in pregnancy-related conditions (P < .001) and gynecological dysplasias (P = .02) while IRs decreased over time for encephalopathy (P < .001), pancreatitis (P = .002), and cardiac disorders (P = .007).

CONCLUSIONS

Between 2001 and 2006, the incidence for 3 conditions decreased and increased for 2 others, demonstrating the change in medical issues and conditions in perinatally infected youth. Continued surveillance with appropriate tools will be needed to assess the long-term effects of HAART and HIV as well as development of new noninfectious conditions of HIV.

Impact of highly active antiretroviral therapy (HAART) on the incidence of opportunistic infections, hospitalizations and mortality among children and adolescents living with HIV/AIDS in Belo Horizonte, Minas Gerais State, Brazil

The impact of highly active antiretroviral therapy (HAART) can be evaluated using indicators, such as rates of opportunistic infections, hospitalizations by cause of infection, and associated death. This study aimed to estimate the impact of HAART on the incidence of these indicators, in children and adolescents with HIV/AIDS. It was a hybrid cohort study; 371 patients were followed from 1989 to 2003. In December 2003, 76% of the patients were still being followed, while 12.1% had died, 9.5% had dropped out, and 2.4% had been transferred. The overall rate of opportunistic infections was 18.32 infections/100 persons-year and 2.63 in the pre- and post-HAART periods, respectively. In the multivariate analysis, the risk of developing an opportunistic infection was 5.4 times greater and 3.3 times greater for hospitalization risk before HAART. Respiratory causes represented 65% of the hospitalizations and they were reduced by 44.6% with therapeutic intervention. The average hospital stay of 15 days was reduced to 9. There was a post-HAART decline in deaths of 38%. This study demonstrates the effectiveness of HAART in significantly reducing opportunistic infections, hospitalizations, and deaths in this Brazilian cohort.

Pseudo-likelihood estimation for a marginal multivariate survival model

In this paper, we propose a multivariate Plackett-Dale model for survival outcomes. A pseudo-likelihood method for the estimation of the parameters is proposed and these ideas are applied to two case studies. The modelling approach is similar in spirit but different from Parner's approach. The first study is in AIDS, where the overall survival time and different opportunistic infections in HIV-infected patients are studied. The second study is on adoption data where the association of the survival times within families is modelled, illustrating the use of the proposed methodology for the context of population genetics.

Declining incidence of AIDS and increasing prevalence of AIDS presenters among AIDS patients in Italy

Presented here are the results of a cohort study conducted on 3,483 consecutive HIV/AIDS patients between January 1993 and December 2000 to determine trends in AIDS incidence and presentation. The incidence of AIDS was calculated in the general population and examined further according to gender, age (< or = or >49 years), and heterosexual behaviour as a risk factor for HIV. Multivariate analysis was used to identify variables associated with AIDS presenters (defined as patients diagnosed with AIDS within 1 month of the first HIV-positive test). The numbers of patients with AIDS classified as (i) AIDS presenters, (ii) known HIV-positive patients on antiretroviral treatment, and (iii) known HIV-positive patients not receiving antiretroviral treatment were calculated. The overall incidence of AIDS decreased over time, mainly due to the lower number of patients on antiretroviral treatment developing AIDS. Factors associated with a higher risk of being an AIDS presenter were male gender and year of HIV diagnosis. Among patients with AIDS, the proportion of AIDS presenters increased from 13.8% prior to 1997 (when protease inhibitors were introduced in Italy) to 32.5% after 1997. Variables predictive of being an AIDS presenter were male gender, age at diagnosis, and AIDS diagnosis in the years 1997-2000. Heterosexuals had a higher risk of being AIDS presenters and a lower risk of being HIV-positive and not receiving antiretroviral treatment than intravenous drug users. In Italy, AIDS occurs mainly in subjects unaware of their HIV status (especially males, the elderly, and those infected heterosexually) or in patients refusing antiretroviral therapy (mainly intravenous drug users who do not refer to specialised centres).

Risk factors for pneumonia in urban-dwelling HIV-infected women: a case-control study in Nairobi, Kenya

In sub-Saharan Africa, respiratory tract infections (RTI) are the leading cause of serious morbidity and mortality in HIV-infected persons. This study sought to investigate demographic, socioeconomic, and environmental risk factors for pneumonia in a cohort of HIV-infected women. The authors performed a nested case-control study in a cohort of HIV-1-infected adults followed in Nairobi, Kenya. Thirty-nine women who developed pneumonia during the follow-up period were selected as cases, and 66 women who did not develop pneumonia were randomly chosen to serve as control subjects. A questionnaire was administered in subjects' homes that assessed demographics, home environment, and socioeconomic status. Women were followed in the cohort for a median of 36.8 months (range, 27.3-39.3). Adjusting for length of follow-up period, factors associated with lower socioeconomic status (lower monthly spending [OR = 3.2; 95% CI, 1.2-8.4 per 10,000 Kenyan shilling decrease], having no savings [OR = 4.1; 95% CI, 1.4-11.9], less sturdy home construction material such as mud or cement walls [OR = 2.6; 95% CI, 1.1-5.9] or dirt floors [OR = 2.8; 95% CI, 1.0-7.6], and lack of a window in the home [OR = 5.5; 95% CI, 0.9-32.2]) and being widowed (OR = 4.3; 95% CI, 1.2-15.1) or single (OR = 3.3; 95% CI, 1.0-11.2) were associated with an increased risk of pneumonia. In multivariate analysis, widowed (AOR = 5.9; 95% CI, 1.3-26.3), single (AOR = 7.7; 95% CI, 1.6-36.4), and divorced (AOR = 4.5; 95% CI, 1.0-20.1) women, those without savings (AOR = 3.7; 95% CI, 1.2-11.7), and those living in more crowded and contagious conditions (AOR = 1.5; 95% CI, 1.1-2.1) remained at increased risk of pneumonia. If confirmed by prospective investigation, these findings could help identify persons and subpopulations of HIV-infected women with the greatest risk of pneumonia.

Modelling the relationship between continuous covariates and clinical events using isotonic regression

In a medical study we are often interested in graphically displaying the relationship between continuous variables and clinical events indicating disease progression. Often, it is reasonable to make the minimal assumption that the risk of progression is an arbitrary monotone function of the continuous variable. Sometimes the continuous variable is a disease marker which is recorded longitudinally, and so the goal is to provide a graphical display of the relationship between the hazard for progression and the most recent measurement of the longitudinal marker. For example, we know that for a patient with HIV infection, declining CD4 count is associated with an increased risk of opportunistic infection. The goal of this paper is to extend isotonic regression techniques to failure time data with a continuous covariate, to obtain a non-parametric estimate for the hazard of disease progression as a monotonic function of the continuous variable. We propose two methods for modelling the relationship of the hazard and covariate: the first assumes that the hazard is constant over time, and the second allows the hazard to be an arbitrary function of time. These methods will be applied to graphically display the risk for an AIDS patient of an opportunistic infection as a function of CD4 count.

Robust inference for event probabilities with non-Markov event data

Multistate event data, in which a single subject is at risk for multiple events, is common in biomedical applications. This article considers nonparametric estimation of the vector of probabilities of state membership at time t. Estimators, derived under the Markov assumption, have been shown (Datta and Satten, 2001, Statistics and Probability Letters 55, 403-411) to be consistent for data that is non-Markov. Inference, however, must take into account possibly non-Markov transitions when constructing confidence bands for event curves. We develop robust confidence bands for these curves, evaluate them via simulation, and illustrate the method on two datasets.

Prediction of survival and opportunistic infections in HIV-infected patients: a comparison of imputation methods of incomplete CD4 counts

In evaluating the risk of mortality or development of opportunistic infections in HIV-infected patients, the number of CD4 lymphocyte cells per cubic millimetre of blood is widely recognized as one of the best available predictors of such future events. However, its usefulness is limited by the incompleteness and variability of such CD4 measurements during follow-up. Because of these limitations, analysis of such data requires the missing measurements to be 'filled in' or the patients without them to be excluded. We consider multiple imputation of CD4 values based partly on information from other health status measures such as haemoglobin, as well as on the event status of interest. These alternative health status measures are also considered as possible independent predictors of survival endpoints. Our work is motivated by a cohort of 1530 patients enrolled in two AIDS clinical trials. We compare our approach to other strategies such as basing evaluation of risk on baseline CD4, the last measured CD4 before an event, or a time-dependent covariate based on carrying the last CD4 value forward; we conclude with a strong recommendation for multiple imputation.

Disseminated Mycobacterium avium complex disease among patients infected with human immunodeficiency virus, 1985-2000

Disseminated Mycobacterium avium complex disease remains a substantial cause of morbidity and mortality among patients with acquired immunodeficiency syndrome. From 1985 through 2000, we studied 1458 consecutive patients at Grady Memorial Hospital, Atlanta, with disseminated M. avium complex disease. There was a peak of 198 patients in the 1995, which decreased to 66 patients in 2000. In 1997, significantly more patients than in 1991 or 1994 were female (P<.001) or black (P<.001) and significantly fewer had acquired human immunodeficiency virus through homosexual contact (P<.001). In 1997, 50 (51%) of 99 of patients acquired M. avium complex disease despite receiving antimicrobial prophylaxis, but 32 (89%) of 36 patients did not adhere to the prophylaxis regimen. The median duration of survival of patients in 1991 was 110 days, whereas in 1994 it was 185 days, and in 1997 it was 339 days (P<.001). Prolonged survival was associated with receiving therapy that included clarithromycin and receiving combination antiretroviral therapy that included a protease inhibitor.

Pulmonary infections in immunocompromised hosts: the importance of correlating the conventional radiologic appearance with the clinical setting

The lung is one of the most frequently involved organs in a variety of complications in the immunocompromised host. Among the pulmonary complications that occur in this kind of patient, infection is the most common and is associated with high morbidity and mortality. Although chest radiography and computed tomography (CT) are essential diagnostic tools, radiologists often have difficulty in establishing the correct diagnosis on the basis of radiologic findings alone. The reasons are that the immunocompromised host is potentially susceptible to infection from many different microorganisms and that radiologic findings are seldom specific for the detection of a particular pathogen. Experience has shown that a particular clinical setting predisposes patients to infection by particular pathogens. The setting comprises (a) the specific epidemiologic or environmental exposure, (b) the type of underlying immune defect, (c) the duration and severity of immune compromise, and (d) the progression rate and pattern of the radiologic abnormality. Correlating the radiologic appearance with the clinical setting can expedite diagnosis and appropriate therapy. In this review, the authors describe the clinical settings that are helpful in choosing the radiologic approach to treatment of the immunocompromised host who presents with suspected pulmonary infection.

GEE with Gaussian estimation of the correlations when data are incomplete

This paper considers a modification of generalized estimating equations (GEE) for handling missing binary response data. The proposed method uses Gaussian estimation of the correlation parameters, i.e., the estimating function that yields an estimate of the correlation parameters is obtained from the multivariate normal likelihood. The proposed method yields consistent estimates of the regression parameters when data are missing completely at random (MCAR). However, when data are missing at random (MAR), consistency may not hold. In a simulation study with repeated binary outcomes that are missing at random, the magnitude of the potential bias that can arise is examined. The results of the simulation study indicate that, when the working correlation matrix is correctly specified, the bias is almost negligible for the modified GEE. In the simulation study, the proposed modification of GEE is also compared to the standard GEE, multiple imputation, and weighted estimating equations approaches. Finally, the proposed method is illustrated using data from a longitudinal clinical trial comparing two therapeutic treatments, zidovudine (AZT) and didanosine (ddI), in patients with HIV.

Joint effects of HIV-1 RNA levels and CD4 lymphocyte cells on the risk of specific opportunistic infections

OBJECTIVES

To evaluate the predictive value of baseline plasma HIV-1 RNA levels and CD4 lymphocyte counts and early changes in these markers after initiating antiretroviral therapy on the risk of development of specific opportunistic infections (OIs).

DESIGN

Patient data from four antiretroviral therapy studies were combined for a retrospective analysis. The analysis included 842 participants from the virology substudies of these trials who had baseline measurements for both HIV-1 RNA levels and CD4 cell counts.

METHODS

Cox proportional hazards models were used to assess the joint effects of baseline CD4 cell count and HIV-1 RNA level and early treatment-associated changes in these values on the risk of development of Pneumocystis carinii pneumonia (PCP), cytomegalovirus (CMV), or Mycobacterium avium complex (MAC). The effects of potential confounders such as prior prophylaxis and previous OIs were also addressed.

RESULTS

Baseline CD4 cell counts and HIV-1 RNA measurements showed significant associations with the risk of PCP, CMV, and MAC. Patients with higher levels of HIV-1 RNA were estimated to have three to six times the risk of these OIs than those with lower levels. Reductions in viral load were linked to significantly reduced risks of PCP, CMV, and MAC. Early decreases in RNA were generally more predictive of risk than were early increases in CD4 cell counts.

CONCLUSIONS

Baseline viral load and reductions in viral load during therapy appeared to influence the risk of these OIs independently of the CD4 cell count. Future guidelines for the initiation of prophylaxis for these OIs may be improved by incorporating information on viral load.

Mycobacterium tuberculosis infection and disease are not associated with protection against subsequent disseminated M. avium complex disease

OBJECTIVE

To determine the relationship between Mycobacterium tuberculosis infection and disease and subsequent disseminated M. avium complex (MAC) disease in HIV-infected persons.

DESIGN

A prospective observational cohort study.

SETTING

The AIDS Linked to the Intravenous Experience (ALIVE) cohort of injecting drug users and the Johns Hopkins Hospital Adult HIV Clinic (JHHAHC).

PARTICIPANTS

HIV-infected persons aged > 18 years with CD4 lymphocytes < 100 x 10(6)/l were followed between July 1989 and 31 October 1996. There were 182 persons in the ALIVE cohort and 1129 persons in JHHAHC who met these criteria.

MAIN OUTCOME MEASURE

The relative risk of disseminated MAC was determined according to a history of prior opportunistic infection, MAC prophylaxis, antiretroviral therapy, M. tuberculosis infection or disease, race, sex, and injecting drug use.

RESULTS

Amongst the 30 patients with active tuberculosis, eight developed disseminated MAC, compared with 208 cases of disseminated MAC amongst 1148 patients without prior M. tuberculosis infection or disease [relative risk (RR), 1.5; 95% confidence interval (CI), 0.8-2.7; P=0.2]. Amongst the 10 patients with extrapulmonary tuberculosis, five developed disseminated MAC (RR, 2.8; 95% CI, 1.5-5.2; P=0.02). Injecting drug use was associated with a decreased risk of disseminated MAC (RR, 0.7; 95% CI, 0.6-0.9; P=0.007). In a logistic regression analysis, disseminated MAC was significantly associated with extrapulmonary tuberculosis and other opportunistic disease, whereas antibiotic prophylaxis and injecting drug use were protective.

CONCLUSIONS

A history of M. tuberculosis infection or disease was not associated with protection against subsequent disseminated MAC disease in HIV-infected persons. However, persons with extrapulmonary tuberculosis were at increased risk for disseminated MAC, particularly at low CD4 cell levels.

Preventing Mycobacterium avium complex in patients who are using protease inhibitors: a cost-effectiveness analysis

BACKGROUND

Practice guidelines recommending Mycobacterium avium complex (MAC) prophylaxis for patients with HIV disease were based on clinical trials in which individuals did not receive protease inhibitors.

OBJECTIVE

To estimate the cost-effectiveness of strategies for MAC prophylaxis in patients whose treatment regimen includes protease inhibitors.

DESIGN

Decision analysis with Markov modelling of the natural history of advanced HIV disease. Five strategies were evaluated: no prophylaxis, azithromycin, rifabutin, clarithromycin and a combination of azithromycin plus rifabutin.

MAIN OUTCOME MEASURES

Survival, quality of life, quality-adjusted survival, health care costs and marginal cost-effectiveness ratios.

RESULTS

Compared with no prophylaxis, rifabutin increased life expectancy from 78 to 80 months, increased quality-adjusted life expectancy from 50 to 52 quality-adjusted months and increased health care costs from $233000 to $239800. Ignoring time discounting and quality of life, the cost-effectiveness of rifabutin relative to no prophylaxis was $44300 per life year. Adjusting for time discounting and quality of life, the cost-effectiveness of rifabutin relative to no prophylaxis was $41500 per quality-adjusted life year (QALY). In comparison with rifabutin, azithromycin was associated with increased survival, increased costs and an incremental cost-effectiveness ratio of $54300 per QALY. In sensitivity analyses, prophylaxis remained economically attractive unless the lifetime chance of being diagnosed with MAC was less than 20%, the rate of CD4 count decline was less than 10 x 10(6) cells/l per year, or the CD4 count was greater than 50 x 10(6) cells/l.

CONCLUSION

MAC prophylaxis increases quality-adjusted survival at a reasonable cost, even in patients using protease inhibitors. When not contraindicated, starting azithromycin or rifabutin when the patient's CD4 count is between 50 and 75 x 10(6) cells/l is the most cost-effective strategy. The main determinants of cost-effectiveness are CD4 count, viral load, place of residence and patient preference.

Analysis of life-long strategies to prevent Pneumocystis carinii pneumonia in patients with variable HIV progression rates

OBJECTIVE

To compare strategies for life-long prophylaxis of Pneumocystis carinii pneumonia (PCP) in a group of AIDS patients with a wide range of disease progression rates.

DESIGN

Markov decision models.

METHODS

Prophylaxis strategies using high and low doses of trimethoprim-sulfamethoxazole (TS), dapsone, and/or aerosolized pentamidine in sequence, were compared. Efficacy and toxicity rates for prophylaxis regimens were taken from a meta-analysis of pertinent randomized controlled trials. Outcomes measured included lifetime episodes of PCP and drug toxicity per 100 patients treated, average life expectancy, and cost.

RESULTS

For patients with an expected survival of 3 years after commencement of prophylaxis, the use of standard or low dose TS as the first choice agent was comparable, and both were superior to the other strategies for preventing PCP (between nine and 26 fewer episodes of PCP per 100 patients treated) though they were more toxic (11-44 more episodes of toxicity per 100 patients treated). Life expectancy was similar for all of the treatment strategies. With slower rates of disease progression (expected survival > 3.8 years), as seen with current antiretroviral regimens, the use of low dose TS as the first choice agent dominated the use of standard dose TS; when the expected survival time was 7 years, initial use of low dose TS led to 2.8 fewer episodes of PCP per 100 patients treated, 32 fewer episodes of toxicity per 100 patients treated, and US$1381 per patient lower cost, compared with prophylaxis with standard dose TS.

CONCLUSION

For patients with AIDS and expected survival > 3.8 years, low dose TS is better than standard dose TS as the first choice agent for preventing PCP. As patients with AIDS live longer, the routine use of low dose TS will be more than adequate for patients at risk for PCP.

Predictive factors of occurrence of cytomegalovirus disease and impact on survival in the Aquitaine Cohort in France, 1985 to 1994. Groupe d'Epidémiologie Clinique du SIDA en Aquitaine

Our objectives were to determine the factors associated with the occurrence of a first episode of cytomegalovirus (CMV) disease in an HIV-infected population and to estimate the overall impact of CMV disease on survival. The study population consisted of the 3525 patients included in the Aquitaine Cohort between 1985 and December 31, 1993. Eligible patients (n = 1868) must have had at least one CD4+ lymphocyte count of <200 cells/mm3 during follow-up, which represents the baseline period. CMV disease manifestations were investigated using standardized definitions. A Cox proportional hazards regression analysis was used to determine the factors independently associated with the probability of developing a first episode of CMV infection and the probability of death. During follow-up, 111 patients presented with a first episode of CMV disease. Four factors were independently associated with the onset of CMV disease: older age at baseline (risk ratio [RR] = 1.03 by a 1-year increase; 95% confidence interval [CI] = 1.02-1.05), homosexuality (RR = 1.90; CI = 1.18-3.02), the progression to a CD4+ lymphocyte count <50/mm3 (RR = 10.58; CI = 5.58-20.05), and the occurrence of toxoplasmosis (RR = 3.00; CI = 1.97-4.57) or a neurologic disease (RR = 2.59; CI = 1.38-4.86) during follow-up. After other predictors were controlled for, CMV disease was associated with a high risk of death in the cohort (RR = 1.58; CI = 1.24-1.94). The development of prophylactic strategies for CMV disease for selected groups of HIV-infected patients must be a priority to improve their quality of life.

Impact of opportunistic disease on survival in patients with HIV infection

OBJECTIVE

To assess the impact of opportunistic diseases on survival in patients with HIV disease.

METHODS

A cohort of 2081 patients followed for a mean of 30 months was studied. Time-dependent Cox proportional hazards analyses were performed using incident opportunistic diseases and CD4 cell counts as independent variables.

RESULTS

During follow-up, 730 (35%) patients died. The occurrence of Pneumocystis carinii pneumonia (PCP), cytomegalovirus (CMV) disease, Mycobacterium avium complex (MAC) disease, Candida esophagitis, Kaposi's sarcoma, lymphoma, progressive multifocal leukoencephalopathy (PML), dementia, wasting, toxoplasmosis, and cryptosporidiosis were all significantly associated with death, independently of CD4 cell count (all P<0.001 for opportunistic diseases controlling for CD4 cell count). The magnitude of increased risk was greatest for lymphoma [relative hazard (RH), 7.2], PML (RH, 3.9), MAC (RH, 3.0) and CMV (RH, 2.2). Cryptococcosis (RH, 0.94) and herpes zoster (RH, 0.85) were not associated with death. In a multivariate Cox proportional hazards analysis, MAC [RH, 2.56; 95% confidence interval (CI), 2.1-3.1], CMV (RH, 1.63; 95% CI, 1.3-2.1), toxoplasmosis (RH, 1.85; 95% CI, 1.3-2.6), PCP (RH, 1.29; 95% CI, 1.1-1.5), and CD4 cell count were significantly associated with death. Patients who had opportunistic diseases had significantly greatly monthly declines in CD4 counts (-11 x 10(6)/l per month) than those who did not (-6 x 10(6)/l per month; P <0.001).

CONCLUSION

Most opportunistic diseases increase the risk of death independently of CD4 cell count. These data support the hypothesis that opportunistic diseases enhance HIV pathogenesis and further underscore the importance of prophylaxis.

Survival after AIDS diagnosis in a cohort of hemophilia patients. Multicenter Hemophilia Cohort Study

We studied factors affecting survival after the diagnosis of AIDS in a cohort of 1253 patients with hemophilia. The nature of the AIDS-defining condition was found to be as important as age at seroconversion and CD4+ lymphocyte level in predicting survival. A multivariate analysis yielded estimates of median survival for groups defined by age at seroconversion (0 through 15, 16 through 69), CD4+ lymphocyte count (<100 cells/microl versus > or = 100 cells/microl), and 10 AIDS-defining disease groups. Estimates of median survival after a single AIDS-defining condition ranged from 3 to 51 months, depending on the diseases. Median survival after a second AIDS-defining condition was about 1.5- to 2.0-fold shorter than after an initial, isolated AIDS-defining condition. HIV-related neurologic disease (i.e., AIDS dementia complex or multifocal leukoencephalopathy) was a notable exception. It correlated with the shortest estimates of median survival (3 to 9 months), and this poor prognosis was no worse for patients who had a second AIDS-defining condition. The results of this analysis were consistent in most respects with other published analyses of factors affecting survival. These findings may be useful in the clinical care of persons with AIDS and in estimating the number of persons alive who have had a particular AIDS-defining disease.

Geographic and seasonal variation in Mycobacterium avium bacteremia among North American patients with AIDS

Analysis of geographic risk was performed for Mycobacterium avium complex (MAC) bacteremia among North American patients with AIDS. Monthly mycobacterial blood cultures were taken from patients who were placebo recipients in a prospective evaluation of MAC prophylaxis. Of 571 patients, 102 (17.9%) acquired MAC bacteremia during an average follow-up of 256 days. The area with the highest risk for MAC was the South Central region (27.9%; P < 0.02), whereas the area with the lowest risk was Canada (11.3%; P = 0.12). When the southern states were combined and compared with the northern states and Canada, the incidence of MAC bacteremia was higher in the southern states (21.6% versus 14.0%, P < 0.03). Proportional hazards analysis was performed for the difference between the North and South and controlled for baseline CD4 cell count. In this analysis, time to MAC was significantly longer in the North (hazard ratio = 0.587, 95% confidence interval 0.390 to 0.883, P = 0.01). Although overall variation in seasonality was not marked, there was a significant decrease in cases in the North during the summer months (P < 0.01). We conclude that geographic location is a risk factor for MAC bacteremia in patients with advanced AIDS, with decreased risk in northern North America.