Adherence to antiretroviral and pneumocystis prophylaxis in HIV disease

BACKGROUND

Medication nonadherence in the treatment of chronic diseases compromises the effectiveness of therapy. Little information is available about the extent of medication adherence or determinants of medication adherence in HIV disease, an issue of increasing importance in this new therapeutic era of combination antiretroviral therapy.

METHODS

We studied 244 HIV-infected Medicaid-insured patients attending an HIV hospital-based clinic regarding the extent of and predictors of adherence to antiretroviral therapy and Pneumocystis carinii pneumonia (PCP) prophylaxis. Patients were asked to report medications being taken, patterns of use, and knowledge and attitudes about HIV therapies. Medical record report of type, dose, and frequency of medication was compared with self-report using the kappa statistic. Urine sulfamethoxazole assay was obtained from patients prescribed sulfamethoxazole-trimethoprim.

RESULTS

Among patients prescribed antiretroviral therapy, 60% reported > or = 80% adherence in the previous 7 days; 49% reported > or = 80% adherence with PCP prophylaxis in the previous seven days. Seventy-nine percent of patients who reported taking daily sulfamethoxazole-trimethoprim had detectable urinary sulfamethoxazole. In multivariate analysis, > or = 80% adherence to antiretroviral therapy was associated with taking medication < or = twice a day (odds ratio [OR]=1.44; 95% confidence interval [CI], 1.01, 1.96), being likely to take medication when not at home, (OR=1.41; 95% CI, 1.04, 2.00) and patients' belief in their ability to adhere to therapy (OR=1.57; 95% CI, 1.13, 2.17). For PCP prophylaxis, > or = 80% adherence was associated with presence of family (OR=2.39; 95% CI, 1.01, 5.63) and patients' belief in their ability to adhere to therapy (OR=2.87; 95% CI, 1.44-1.78). Sociodemographic characteristics and belief in the efficacy of medications were not associated with adherence.

CONCLUSIONS

A relatively low level of adherence to antiretroviral therapy and PCP prophylactic regimens was found. Although our results are principally from patients receiving antiretroviral monotherapy, these findings may have important implications for patients receiving highly active antiretroviral therapy (HAART). Decreasing the complexity of antiretroviral regimens, and working with patients to modify identified barriers to adherence may improve effectiveness of medications and prolong survival.

Understanding the clinical and economic outcomes of HIV therapy: the Johns Hopkins HIV clinical practice cohort

The Johns Hopkins AIDS Service is the principal provider of medical care for HIV-infected patients in Maryland, a state in which the majority of HIV-infected patients live in an urban environment. A component of the HIV service at Johns Hopkins Medical Center is an information system that is used to track longitudinally the ambulatory and inpatient care of HIV-infected patients. Enrollment into this database coincides with first enrollment into the HIV Service. Extensive laboratory, diagnostic, clinical, and pharmaceutical information is collected at enrollment and is updated every 6 months. Outpatient and inpatient medical records, Johns Hopkins Health System automated databases, supplemental medical records from outside facilities, vital records, and patient and provider interviews are all used to obtain the detailed data that are stored on the database. The database also includes an economic component, which was added in 1994. This component links all Maryland state Medicaid claims data to that relating to patients who are insured by the Maryland Medical Assistance program, who account for approximately 60% of patients using the Johns Hopkins HIV Service. This data linkage facilitates detailed quantification of the costs of medical care for the HIV-infected patient throughout the course of the infection. We currently have data on about 3,000 HIV-infected patients representing a heterogeneous mix by race, sex, socioeconomic status, and risk factors for HIV transmission. Our data have been used to address a variety of issues regarding access to, utilization of, and clinical outcomes of HIV therapeutics. Clinical practice data such as ours will be increasingly important as the number and types of antiretroviral and other drugs for HIV infection continue to increase.

Implications for macrolide treatment in community-acquired pneumonia. Hopkins CAP Team

STUDY OBJECTIVES

To identify associated clinical parameters, concurrent respiratory tract infections, and the association between macrolide-based therapy and mortality in patients with community-acquired pneumonia ascribed to atypical.

DESIGN

Secondary analysis of prospective, cross-sectional study.

SETTING

Tertiary care hospital.

PATIENTS

Three hundred eighty-five consecutive patients who were admitted to the Johns Hopkins Hospital from November 11, 1990, through November 10, 1991, and treated for community-acquired pneumonia.

RESULTS

An atypical pathogen was identified in 29 of 385 adults (7.5%). A second pathogen was detected in 16 of 29 patients (55.2%) in whom an atypical pathogen was detected, compared with 13 of 137 patients (9.5%) in whom conventional bacterial pathogens were detected (odds ratio, 10.22; 95% confidence interval, 3.7 to 28.8; p<0.0001). During hospitalization, only four patients (13.8%) with detection of an atypical pathogen received at least 7 days of either a macrolide or tetracycline. No patient identified to have an atypical pathogen died. For patients who either provided paired sera or who died, 24 of 197 (12.2%) had atypical pathogens detected.

CONCLUSIONS

Despite vigorous study methods, atypical pathogens were uncommon in our hospitalized population. A second concurrent respiratory pathogen was identified for most patients with atypical pneumonia. Although macrolide use was rare in this patient population, mortality was zero for patients in whom an atypical pathogen was detected, affirming that macrolide-based therapy need not be routine in the therapeutic management of community-acquired pneumonia.

Cost analysis of alternative approaches to colorectal screening in familial adenomatous polyposis

BACKGROUND & AIMS

The commercial availability of gene testing for familial adenomatous polyposis (FAP) represents an important advance in screening for inherited colon cancer. We investigated the financial impact of this diagnostic tool on colorectal screening for FAP.

METHODS

Decision analysis was used to compare per-person costs with third-party payers of three colorectal screening strategies used to diagnose FAP in at-risk persons. The strategies included conventional serial flexible sigmoidoscopy and two different APC gene testing approaches.

RESULTS

For 1 at-risk relative who begins screening at age 12 years, average screening costs are $2625 when genotyping the proband first, $2674 when genotyping the at-risk relative first, and $3208 for conventional sigmoidoscopy. The cost advantage of genotyping increases as the pedigree size increases. For a pedigree of 5 at-risk relatives, sigmoidoscopy would have to cost less than $85.60 (professional plus facility fee) for conventional screening to compete with genotyping. The cost advantage of genotyping is diminished for at-risk relatives who begin FAP screening at older ages.

CONCLUSIONS

The choice of least expensive FAP screening strategy depends on the cost of flexible sigmoidoscopy, patient age when screening starts, and pedigree size. Genotyping can substantially reduce the cost of FAP screening and, when possible, should start with the proband.

Vancomycin-resistant and vancomycin-susceptible enterococcal bacteremia: comparison of clinical features and outcomes

Vancomycin-resistant Enterococcus (VRE) is a major nosocomial pathogen. We collected clinical and laboratory data on 93 hospitalized adults with VRE bacteremia and 101 adults with vancomycin-susceptible enterococcal (VSE) bacteremia. Risk factors for VRE bacteremia included central venous catheterization, hyperalimentation, and prolonged hospitalization prior to the initial blood culture. VRE-infected patients were less likely to have undergone recent surgery or have polymicrobial bacteremia, suggesting a pathogenesis distinct from traditional VSE bacteremia. Prior exposure to metronidazole was the only significant pharmacologic risk factor for VRE bacteremia. Animal studies suggest metronidazole potentiates enterococcal overgrowth in the gastrointestinal tract and translocation into the bloodstream. An increasing APACHE II score was the major risk factor for death in a multivariate analysis, with VRE status being of only borderline significance.

IRLED-based patient localization for linac radiosurgery

PURPOSE

Currently, precise stereotactic radiosurgery delivery is possible with the Gamma Knife or floor-stand linear accelerator (linac) systems. Couch-mounted linac radiosurgery systems, while less expensive and more flexible than other radiosurgery delivery systems, have not demonstrated a comparable level of precision. This article reports on the development and testing of an optically guided positioning system designed to improve the precision of patient localization in couch-mounted linac radiosurgery systems.

METHODS AND MATERIALS

The optically guided positioning system relies on detection of infrared light-emitting diodes (IRLEDs) attached to a standard target positioner. The IRLEDs are monitored by a commercially available camera system that is interfaced to a personal computer. An IRLED reference is established at the center of stereotactic space, and the computer reports the current position of the IRLEDs relative to this reference position. Using this readout from the computer, the correct stereotactic coordinate can be set directly.

RESULTS

Bench testing was performed to compare the accuracy of the optically guided system with that of a floor-stand system, that can be considered an absolute reference. This testing showed that coordinate localization using the IRLED system to track translations agreed with the absolute to within 0.1 +/- 0.1 mm. As rotations for noncoplanar couch angles were included, the inaccuracy was increased to 0.2 +/- 0.1 mm.

CONCLUSIONS

IRLED technology improves the accuracy of patient localization relative to the linac isocenter in comparison with conventional couch-mounted systems. Further, the patient's position can be monitored in real time as the couch is rotated for all treatment angles. Thus, any errors introduced by couch inaccuracies can be detected and corrected.

Cryptosporidiosis in northeastern Brazilian children: association with increased diarrhea morbidity

To evaluate the impact of Cryptosporidium infection on diarrheal disease burden and nutrition status, a nested case-control study was done among children who were followed from birth in Fortaleza, Brazil. The diarrhea history and growth records of 43 children with a symptomatic diarrhea episode of cryptosporidiosis (case-children) were compared with those of 43 age-matched controls with no history of cryptosporidiosis. After Cryptosporidium infection, case-children < or = 1 year old experienced an excessive and protracted (nearly 2 years) diarrheal disease burden. Case-children < or = 1 year old with no history of diarrhea prior to their Cryptosporidium infection also experienced a subsequent increased diarrheal disease burden with an associated decline in growth. Control subjects experienced no change in their diarrhea burden over time. This study suggests that an episode of symptomatic Cryptosporidium infection in children < or = 1 year of age is a marker for increased diarrhea morbidity.

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.

Prevention of opportunistic infections in the era of improved antiretroviral therapy

Patients with advanced human immunodeficiency virus (HIV) infection who are severely immunosuppressed develop a variety of opportunistic infections that have a significant impact on their well-being, quality of life, health-care costs, and survival. The risk for development of opportunistic infections depends on exposure to potential pathogens, the virulence of the pathogens, the degree of host immunity, and the use of antimicrobial prophylaxis. Many studies have confirmed the benefits of prophylaxis in severely immunosuppressed patients. Factors that affect the use of prophylaxis for prevention of opportunistic infections in HIV-infected patients include the prevalence and potential severity of the disease, ease of treatment if infection occurs, the cost-effectiveness of the prophylactic regimen, and the potential for increased survival, drug toxicity, drug interactions, and emergence of resistance with the regimen. The United States Public Health Service and the Infectious Diseases Society of America (USPHS/IDSA) have established disease-specific recommendations for use of prophylaxis for opportunistic infections in HIV-infected patients. These guidelines identify regimens that are strongly recommended as standards of care, regimens that should be seriously considered in selected patients, and regimens that are not routinely indicated but may be considered in selected patients. Although further study is needed, advances in antiretroviral therapy may have an important impact on the recommendations for prophylaxis and may eventually allow discontinuation of these regimens in patients who regain functional immunity.

Gynecologic causes of the acute abdomen and the acute abdomen in pregnancy

Evaluation of a female patient who presents with an acute abdomen must always consider surgical and gynecologic disorders. Laparoscopy and pelviscopy have had a major impact on the surgical approach in gynecology. Most acute abdomens can now be approached laparoscopically. Certain conditions that are discussed require the traditional laparotomy. Preservation of reproductive capability has a major impact on the wellness of a woman.

Bacteroides fragilis toxin exhibits polar activity on monolayers of human intestinal epithelial cells (T84 cells) in vitro

Strains of Bacteroides fragilis associated with diarrhea in children (termed enterotoxigenic B. fragilis, or ETBF) produce a heat-labile ca. 20-kDa protein toxin (BFT). The purpose of this study was to examine the activity of BFT on polarized monolayers of human intestinal epithelial cells (T84 cells). In Ussing chambers, BFT had two effects. First, BFT applied to either the apical or basolateral surfaces of T84 monolayers diminished monolayer resistance. However, the time course, magnitude, and concentration dependency differed when BFT was applied to the apical versus basolateral membranes. Second, only basolateral BFT stimulated a concentration-dependent and short-lived increase in short circuit current (Isc; indicative of C1- secretion). Time course experiments indicated that Isc returned to baseline as resistance continued to decrease, indicating that these two electrophysiologic responses to BFT are distinct. Light microscopic studies of BFT-treated monolayers revealed only localized cellular changes after apical BFT, whereas basolateral BFT rapidly altered the morphology of nearly every cell in the monolayer. Transmission and scanning electron microscopy after basolateral BFT confirmed a striking loss of cellular microvilli and complete dissolution of some tight junctions (zonula occludens) and zonula adherens without loss of desmosomes. The F-actin structure of BFT-treated monolayers (stained with rhodamine-phalloidin) revealed diminished and flocculated staining at the apical tight junctional ring and thickening of F-actin microfilaments in focal contacts at the basolateral monolayer surface compared to those in similarly stained control monolayers. BFT did not injure T84 monolayers, as assessed by lactic dehydrogenase release and protein synthesis assays. These studies indicate that BFT is a nonlethal toxin which acts in a polar manner on T84 monolayers to stimulate C1- secretion and to diminish monolayer resistance by altering the apical F-actin structure of these cells. BFT may contribute to diarrheal disease associated with ETBF infection by altering epithelial barrier function and stimulating C1- secretion.

Cost-utility analysis of prophylactic treatment with oral ganciclovir for cytomegalovirus retinitis

OBJECTIVE

Cytomegalovirus (CMV) retinitis is a relatively common opportunistic infection in late-stage HIV disease, causing significant morbidity and mortality. Prophylactic use of oral ganciclovir has recently been shown to decrease the incidence of CMV retinitis but is relatively expensive and may not be very well tolerated by many patients. We performed a decision analysis to assess the cost-effectiveness of prophylactic oral ganciclovir therapy.

METHODS

A decision analysis using a Markov approach compared absence of prophylaxis and prophylaxis with oral ganciclovir. Estimates of effectiveness of prophylaxis and costs of illness were obtained from published literature. Drug costs were based on national average wholesale prices. All health care costs were based on 1996 U.S. dollars. Sensitivity analyses were done over ranges of estimates of cost and effectiveness.

RESULTS

Using our baseline estimates of cost and effectiveness, use of oral ganciclovir prophylaxis in patients with CD4 counts <50 cells/mm3 would be associated with average lifetime health care costs of $104,746, compared with $90,985 for no prophylaxis. Using oral ganciclovir, the average quality-adjusted life-years (QALYs) would be 2.05, and the CMV retinitis-free life-years would be 1.64, compared with 1.87 and 1.27, respectively, for no prophylaxis. The incremental cost-utility of oral ganciclovir is $76,676 per year of life saved and $37,542 per year of additional CMV retinitis-free life. Oral ganciclovir would become more cost-effective relative to no prophylaxis if the probability of CMV retinitis while taking oral ganciclovir declined. Oral ganciclovir would be less cost-effective if the cost of treating CMV retinitis declines, if our estimates of quality of life are low, or if the overall incidence of CMV retinitis declines.

CONCLUSIONS

Oral ganciclovir is a less cost-effective approach than several other interventions used for HIV-disease prophylaxis. It would potentially become cost-effective if it is possible to target oral ganciclovir prophylaxis to patients who are most likely to benefit.

Prior antimicrobials and staphylococcal bacteremia in HIV-infected patients

OBJECTIVE

Many drugs used for prophylaxis against opportunistic infections in AIDS also have activity against common bacteria. This study was performed to delineate relationships between prior use of antimicrobials and Staphylococcus aureus bacteremia.

DESIGN

To compare prior exposure to selected antimicrobial drugs in patients who had S. aureus bacteremia and in controls who did not, a nested case-control study was conducted within a cohort of HIV-infected persons followed in an outpatient clinic.

METHODS

Using a computerized database based on HIV clinic records, 48 cases with S. aureus bacteremia were compared against 188 controls selected from patients with CD4 cell counts < 200 x 10(6)/l. Information on demographic risk factors and antimicrobial drug use was analysed using conditional logistic regression.

RESULTS

Injecting drug use was strongly associated with S. aureus bacteremia. Rifabutin use was associated with decreased risk of S. aureus bacteremia [conditional relative risk (RR) 0.308, 95% confidence interval (CI) 0.096-0.991] in univariate analysis, near statistical significance in multivariate analysis (RR 0.314, 95% CI 0.096-1.023). The bacteremias were not significantly associated with use of trimethoprim-sulfamethoxazole, quinolones, newer macrolides (azithromycin and clarithromycin), clindamycin or dapsone.

CONCLUSIONS

Rifabutin may be associated with diminished risk of S. aureus bacteremia incidental to use for other purposes in HIV infection. Further study is needed to assess effects on microbial resistance.

The impact of neurologic disease on hospitalizations related to human immunodeficiency virus infection in Maryland, 1991-1992

OBJECTIVES

To determine the impact of neurologic disease on length of stay and total hospital charges for hospitalizations related to human immunodeficiency virus (HIV) infection.

DESIGN

Review of all HIV-related hospitalizations from all acute nonfederal hospitals in Maryland in 1991 and 1992. Neurologic status and HIV disease status were determined by codes from the International Classification of Diseases, Ninth Revision Clinical Modification, in an administrative database. Total hospital charges and length of stay were also included in this database.

RESULTS

Of 12 128 HIV-related hospitalizations (6013 patients with the acquired immunodeficiency syndrome [AIDS], 308 HIV-seropositive patients with symptoms without AIDS, and 5807 HIV-seropositive patients without symptoms), neurologic disease occurred in 1013 (8.4%), predominantly in patients with AIDS. In all HIV-seropositive patients, those with primary neurologic disease had a long mean (+/- SD) length of stay (16.4 +/- 16.5 days vs 9.3 +/- 11.3 days; P < .001) and higher mean (+/- SD) total charges ($12,733 +/- $12,009 vs $8069 +/- $11,247; P < .001) than those without neurologic disease. In patients with AIDS, those with primary neurologic disease also had a longer mean (+/- SD) length of stay (17.2 +/- 17.2 days vs 11.7 +/- 12.7 days; P < .001) and higher mean (+/- SD) total charges ($13,430 +/- $12,470 vs $10,794 +/- $13,537; P < .001) than those without neurologic disease. After adjustment for age, sex, race, and stage of HIV infection in all HIV-seropositive patients, our results indicated that neurologic disease increased the length of stay by 3.3 days (95% confidence interval [CI], 2.9-3.8) and total charges by $2552 (95% CI, $2111-$2993). After adjustment for age, sex, and race in discharged patients with AIDS, the results showed that neurologic disease increased length of stay by 2.24 days (95% CI, 0.73-3.77) and total charges by $1512 (95% CI, $40-$2894).

CONCLUSION

Neurologic disease increases the length of stay and total hospital charges of HIV-infected patients.

Acyclovir in combination with zidovudine does not prolong survival in advanced HIV disease

The aim of this study was to evaluate the association between acyclovir use and survival in HIV-infected patients. To achieve this, we used survival analysis in an observational cohort of HIV-infected patients enrolled in primary care at an urban HIV clinic. We measured survival in a cohort of HIV-infected patients who had CD4 cell counts < or = 500/mm3 and who enrolled for care at a single urban HIV clinic between December 1988 and April 1995. We compared survival in users of acyclovir alone, zidovudine alone, and acyclovir and zidovudine in combination with the survival of those using neither drug. Factors associated with improved survival were identified using Cox proportional hazards analysis. Among the 1408 patients enrolled, there were no significant differences in overall survival between acyclovir users and non-users. After adjustment for CD4 cell count, the use of other antiretroviral agents, race, transmission risk and a history of herpesvirus infection, acyclovir use alone was independently associated with a relative hazard (RH) of death of 1.008 (P = 0.969); zidovudine use alone with a RH of 0.559 (P < 0.001); and combination use of acyclovir and zidovudine associated with a RH of 1.062 (P = 0.788). Therefore we conclude that the use of acyclovir is not associated with prolonged survival in this cohort of HIV-infected patients.

Costs to Medicaid of advancing immunosuppression in an urban HIV-infected patient population in Maryland

Human immunodeficiency virus (HIV) infection is increasingly an urban disease in the United States, and Medicaid is the principal payer of the health care costs of patients with HIV. We wished to determine the costs to Medicaid of patients in Maryland infected with HIV as immunosuppression progresses, and to determine how costs varied by demographic characteristics of the patient. We analyzed combined economic and clinical data in patients from the Johns Hopkins HIV Service, the provider of primary and specialty care for a majority of HIV-infected patients in the Baltimore metropolitan region. All patients were enrolled in Medicaid and received care longitudinally in Maryland from July 1992 to June 1995. Monthly Medicaid payments were calculated for all inpatient and outpatient services by sex, race, age, use of injecting drugs, CD4+ count (>500, 201-500, 51-200, < or =50 cells/mm3), several opportunistic diseases, and death. Lifetime costs were also calculated by use of a Markov simulation. During 13,174 person-months of follow-up in 606 patients, a total of $18,223,700 in Medicaid payments was made. Mean monthly payments ranged from $2,436 (SE $171) for patients with CD4+ counts < or =50 cells/mm3 to $1,015 (SE $177) for patients with CD4+ counts >500 cells/mm3. Mean monthly inpatient costs ranged from $1,355 (SE $131) for CD4+ counts < or =50 cells/mm3 and $617 (SE $164) for CD4- counts >500 cells/mm3. For those with CD4+ counts < or =50 cells/mm3, outpatient pharmacy costs averaged $515 (SE $57) monthly, second only to inpatient costs. In bivariate analysis, costs were significantly higher (p = .013) in men (mean $1696; SE $126) than in women (mean $1,208; SE $101), though the difference was not significant with multivariate adjustment. Cytomegalovirus retinitis was the most costly opportunistic disease, with mean monthly costs of $7,825 (SE $1,141) within the 6 mo after diagnosis. Within 6 mo of death, mean monthly costs are $4,600 (SE $424). Lifetime costs for treating an HIV-infected patient who presents with a CD4+ count >500 cells/mm3 are $133,500 over 8.3 years of life. We concluded that in the clinic where the analysis was done, average costs to Medicaid of treating patients increase more than two-fold as the CD4+ count declines from >500 cells/mm3 to < or =50 cells/mm3. Interventions that decrease hospitalization, opportunistic disease, and the costs of terminal care may be most likely to decrease overall costs. Demographic patient characteristics do not affect costs significantly when access to care is comparable.

Infection due to fluconazole-resistant Candida in patients with AIDS: prevalence and microbiology

A cross-sectional study was conducted to assess the prevalence and microbiology of oral infection due to fluconazole-resistant Candida in patients with AIDS. Oral swab specimens for fungal cultures were obtained from 100 consecutive outpatients with CD4 lymphocyte counts of < 200/mm3. At least one fungal organism demonstrating in vitro resistance to fluconazole (minimum inhibitory concentration, > or = 8 micrograms/mL) was isolated from 26 (41%) of 64 patients for whom cultures were positive. When fluconazole-resistant C. albicans was isolated, in vitro resistance correlated with clinical thrush. None of 10 patients from whom only non-albicans species of Candida were isolated had active thrush. The patients from whom fluconazole-resistant Candida albicans was isolated had lower CD4 cell counts (median, 9/mm3), a greater number of treated episodes of thrush (median, 4.5), and a greater median duration of prior fluconazole treatment (231 days) than did patients from whom fluconazole-susceptible C. albicans was isolated (median CD4 cell count, 58/mm3 [P = .004]; median number of treated episodes of thrush, 2.0 [P = .001]; and median duration of prior fluconazole treatment, 10 days [P = .01]; respectively). In a multivariate analysis, the number of episodes and duration of fluconazole therapy were independent predictors of resistance.

Hydroxyurea and sickle cell anemia. Clinical utility of a myelosuppressive "switching" agent. The Multicenter Study of Hydroxyurea in Sickle Cell Anemia

Painful crises in patients with sickle cell anemia are caused by vaso-occlusion and infarction. Occlusion of blood vessels depends on (at least) their diameter, the deformability of red cells, and the adhesion of blood cells to endothelium. Deoxygenated sickle cells are rigid because they contain linear polymers of hemoglobin S (Hb S); polymerization is highly concentration dependent, and dilution of Hb S by a nonsickling hemoglobin such as fetal hemoglobin (Hb F) would be expected to lead ultimately to a decrease in the frequency of painful crises. It might also be expected to decrease the severity of anemia, although the pathogenesis of anemia in sickle cell anemia (SS disease) is not clearly understood. Reversion to production of fetal rather than adult hemoglobin became practical with the discovery that HU was an orally effective and relatively safe "switching agent." Preliminary dose-ranging studies led to a double-blind randomized controlled clinical trial, the Multicenter Study of Hydroxyurea in Sickle Cell Anemia (MSH), designed to test whether patients treated with HU would have fewer crises than patients treated with placebo. The MSH was not designed to assess the mechanism(s) by which a beneficial effect might be achieved, but it was hoped that observations made during the study might illuminate that question. The 2 MSH treatment groups were similar to each other and were representative of African-American patients with relatively severe disease. The trial was closed earlier than expected, after demonstration that median crisis rate was reduced by almost 50% (2.5 versus 4.5 crises per year) in patients assigned to HU therapy. Hospitalizations, episodes of chest syndrome, and numbers of transfusions were also lower in patients treated with HU. Eight patients died during the trial, and treatment was stopped in 53. There were no instances of alarming toxicity. Patients varied widely in their maximum tolerated doses, but it was not clear that all were taking their prescribed treatments. When crisis frequency was compared with various clinical and laboratory measurements, pretreatment crisis rate and treatment with HU were clearly related to crisis rate during treatment. Pretreatment laboratory measurements were not associated with crisis rates during the study in either treatment group. It was not clear that clinical improvement was associated with an increase in Hb F. Crisis rates of the 2 treatment groups became different within 3 months. Mean corpuscular volumes (MCVs) and the proportion of Hb F containing red cells (F cells) rose, and neutrophil and reticulocyte counts fell, within 7 weeks. When patients were compared on the basis of 2-year crisis rates, those with lower crisis rates had higher F-cell counts and MCVs and lower neutrophil counts. Neutrophil, monocyte, reticulocyte, and platelet counts were directly associated, and F cells and MCV were inversely associated, with crisis rates in 3-month periods. In multivariable analyses, there was strong evidence of independent association of lower neutrophil counts with lower crisis rates. F-cell counts were associated with crisis rate only in the first 3 months of treatment; MCV showed an association over longer periods of time. Overall, the evidence that decreased neutrophil counts played a role in reducing crisis rates was strong. Increased F cells or MCV and evidence of cytoreduction by HU were also associated with decreased crisis rates, but no definitive statement can be made regarding the mechanism of action of HU because the study was not designed to address that question. Future studies should be designed to explore the mechanism of action of HU, to identify the optimal dosage regimen, and to study the effect of HU when combined with other antisickling agents.

Cost-effectiveness of directly observed versus self-administered therapy for tuberculosis

Decision analysis was used to compare three alternative strategies for a 6-mo course of treatment for tuberculosis: directly observed drug therapy (DOT), self-administered fixed-dose combination drug therapy, and self-administered conventional individual drug therapy. Estimates of effectiveness were obtained from the published literature. Estimates of costs were obtained from the literature and the Baltimore City Health Department. Both DOT and fixed-dose combination therapy were less costly and more effective than conventional therapy, although DOT was most cost-effective. In total, the average cost per patient treated was $13,925 for DOT, $13,959 for fixed-dose combination therapy, and $15,003 for conventional therapy. Per 1,000 patients treated, 31 relapses and three deaths could be expected for DOT, 96 relapses and eight deaths for fixed-dose combination therapy, and 133 relapses and 13 deaths for conventional therapy. The marginal cost-effectiveness of DOT relative to fixed-dose combination therapy was most sensitive to variability in the direct cost of DOT and less sensitive to relapse rates for DOT and fixed-dose combination therapy. The inferior cost-effectiveness of conventional therapy was not sensitive to plausible variability in cost or effectiveness. Both DOT and fixed-dose combination therapy were cost-effective relative to conventional therapy, although DOT is probably most cost-effective.

Adverse events from drug therapy for human immunodeficiency virus disease

PURPOSE

Drug therapies for patients with human immunodeficiency virus (HIV) infection are associated with adverse events that can potentially limit their effectiveness. We sought to quantify the incidence of these events in clinical practice and determine whether there were demographic and clinical differences in adverse event rates for these drugs.

PATIENT AND METHODS

We calculated specific and overall adverse event rates from use of zidovudine, didanosine, zalcitabine, cotrimoxazole, and dapsone in an observational urban cohort of 1,450 HIV-infected patients with a CD4+ count of 500 cells/mm3 or less. We compared adverse event rates by gender, race, age, injecting drug use, and CD4+ count.

RESULTS

Overall adverse event rates in order of incidence were dapsone, 16.2 per 100 person-years (PY); didanosine, 24.1 per 100 PY; zidovudine, 26.3 per 100 PY; cotrimoxazole, 26.3 per 100 PY; and zalcitabine, 37.0 per 100 PY. Rates increased significantly with decline in CD4+ count from > 200 to < 100 cells/mm3 for all drugs but dapsone. In addition, women were more likely than men to have an adverse event for didanosine (relative risk [RR] = 2.7, P = 0.03) and from cotrimoxazole (RR 1.5; P = 0.05). Whites were at greater risk than blacks for adverse events from cotrimoxazole (RR = 1.6, P = 0.03). Only 22 of 357 total events (6%) required hospitalization, and there were no deaths.

CONCLUSIONS

Adverse events from antiretroviral drugs and Pneumocystis carinii pneumonia prophylaxis that interrupt therapy are relatively common, although serious events requiring hospitalization are rare. Adverse event rates increase progressively with decline in CD4+ count. The gender and race of the patient modify the risk of adverse events for some drugs.

Duration of the survival benefit of zidovudine therapy in HIV infection

BACKGROUND

Zidovudine therapy improves survival in advanced human immunodeficiency virus (HIV) infection and delays progression from earlier stages to advanced stage of HIV disease. The duration of the benefit of zidovudine therapy, however, may be limited.

OBJECTIVE

To quantitate the duration of the survival benefit of zidovudine therapy in a heterogeneous patient population receiving care for HIV infection in an urban clinic.

METHODS

We analyzed data from 393 HIV-infected patients with CD4+ cell counts of 0.5 x 10(9)/L (500 cells/microliter.) or less who first presented for care at The Johns Hopkins HIV Clinic, Baltimore, Md, from July 1989 through December 1993. Follow-up extended to a maximum of 3 years (median, 2 years). Survival probabilities in patients who received and who did not receive zidovudine therapy were analyzed by Kaplan-Meier methods and by multivariate Cox proportional hazards regression analysis adjusting for both time-dependent and fixed prognostic covariates.

RESULTS

Adjusting for baseline differences in CD4+ cell count, clinical stage of HIV disease, and prophylaxis for Pneumocystis carinii pneumonia, Cox regression analysis showed a significant effect of zidovudine compared with no treatment on the risk of dying during the first year of therapy (relative hazard for death, 0.32; 95% confidence interval [CI], 0.18 to 0.59). However, analysis of the time-dependent effect of zidovudine therapy showed that there was a diminishing relative hazard between treatment and no treatment of 0.75 (95% CI, 0.45 to 1.26) at 1 to 2 years of therapy and a relative hazard of 1.61 beyond 2 years (95% CI, 0.70 to 3.71).

CONCLUSION

The survival advantage of zidovudine therapy is time dependent, lasting between 1 and 2 years in patients with CD4+ cell counts of 0.5 x 10(9)/L or less. Alternative antiretroviral treatment may be indicated at that time.

Effects of an incentive and education program on return rates for PPD test reading in patients with HIV infection

To determine the impact of a food voucher incentive and patient education program on compliance with tuberculin skin test (PPD, purified protein derivative) performance in HIV-infected adults, we analyzed return rates for PPD reading for patients at our urban HIV clinic. The groups studied included patients who received no intervention (controls), patients offered a food voucher incentive, and patients offered a food voucher and patient education intervention. Return rates for PPD reading were 96 (35%) of 272 for the control group, 111 (48%, p = 0.004) of 229 for the food voucher group, and 96 (61%, p < 0.0001) of 158 for the food voucher and patient education group. By univariate analysis, black patients (p = 0.01), males (p = 0.01), older patients (p = 0.04), city residents (p = 0.001), and injection drug users were more likely to return for PPD reading. By logistic regression, food voucher, food voucher plus education, city residence, and male sex were significantly associated with return for PPD reading. Two simple, inexpensive interventions were found to increase compliance with tuberculin skin test performance in HIV-infected adults. Additional interventions are required to achieve better rates of return for PPD reading.