A controlled study of inhaled pentamidine for primary prevention of Pneumocystis carinii pneumonia

Changes in insurance status and access to care for persons with AIDS in the Boston Health Study

The purpose of this study was to measure unmet needs and changes in insurance status for persons with acquired immunodeficiency syndrome (AIDS). Thirty-six percent of the study's Boston-area respondents (n = 305) had a change in insurance coverage between AIDS diagnosis and interview. Medicaid coverage increased from 14% to 41%. Pneumocystis carinii pneumonia prophylaxis was nearly universal. Only 5% did not receive zidovudine, and intravenous drug users were at higher risk. Approximately 14% to 15% of patients reported problems in obtaining medical and dental services; Blacks, homeless persons, and those who were not high school graduates were at higher risk. Use of selected treatments for which there were clear clinical guidelines was adequate, yet disadvantaged groups were more likely than other persons with AIDS to face obstacles to other services.

The Swiss HIV Cohort Study: rationale, organization and selected baseline characteristics

OBJECTIVES

This paper describes the rationale and design features of the Swiss HIV Cohort Study (SHCS) and the baseline characteristics of participants enrolled up to March 31st 1993. The objectives include epidemiological, clinical and laboratory research.

DESIGN

The SHCS is a prospective cohort study of HIV infected adolescents and adults seen at the outpatient clinics of the Swiss University Hospitals in Basle, Berne, Geneva, Lausanne and Zurich and the Cantonal Hospital St. Gall. The multicentre collaboration was initiated in September 1988 by the Swiss Federal Office of Public Health. Data collected prior to this date by several participating centers using a similar protocol were included, the earliest records dating back to 1982. Follow-up visits are scheduled every 6 months.

ENROLLMENT

As of March 31st 1993, 6253 participants (M: 4580, F: 1675) were included with a total of 16015 person-years of follow-up (mean 2.6 years). HIV transmission categories were 46% intravenous drug users (IDU), 32% men who had sex with men (MSM), 18% heterosexual contacts (HET) and 4% other. The proportion of MSM among male participants decreased from 62% in 1985 to 40% in 1987, to remain stable thereafter. The proportion of IDU among males was around 40% throughout, whereas in females, there was a pronounced decline from 90% IDU in 1985 to 50% in 1992. Conversely, there was a striking increase in registrations of women presumably infected by HET, from 8% in 1985 to 50% in 1992. Among men, the proportion classified as HET increased from 2% to 15%. It is estimated, that a large proportion of all Swiss AIDS patients (70%) and HIV infected individuals (32%-47%) are enrolled in the Swiss HIV Cohort Study. Losses to follow-up, however, are common.

CONCLUSIONS

The SHCS serves multiple purposes as a research project, as infrastructure for multidisciplinary research and as a tool to improve patient care. Several international and national trials, post-marketing surveillances and expanded access protocols were or still are based upon its infrastructure. The large number of female participants and of participants AIDS-free at entry, make the database especially valuable.

Pancreatic lesions in HIV-infected patients

The pancreas is frequently involved during HIV infection, especially by disseminated infections or neoplasms. These lesions are generally asymptomatic and are discovered at autopsy. However, hypoglycaemia secondary to massive pancreatic infiltration by a tumour or tuberculous necrosis may occur. The most important cause of pancreatic dysfunction in HIV-infected patients is a drug toxic effect (intravenous pentamidine, didanosine, zalcitabine). Hypoglycaemia, which may or may not be followed by diabetes, can develop during intravenous pentamidine therapy. In cases with increased serum amylase and/or lipase levels, potentially toxic drugs must be promptly discontinued to avoid major pancreatic involvement.

The use of aerosolized pentamidine for prophylaxis of Pneumocystis carinii pneumonia in children with leukemia

We report our experience giving aerosolized pentamidine as prophylaxis for Pneumocystis carinii pneumonia (PCP) to 9 children (mean age, 7.33 years; range 3-17 years) with leukemia who were unable to tolerate trimethoprim-sulfamethoxazole (TMP-SMX) due to allergy or myelosuppression. The dose of pentamidine was modified for each child to correct for weight and approximate alveolar ventilation. We were able to administer the drug to younger children by using a cushioned face mask in place of the standard mouthpiece. One child experienced moderate coughing with administration of pentamidine. He and four others with a past medical history suggestive of reactive airways disease were pretreated with inhaled albuterol. No other adverse effects were noted. Treatment lasted an average of 8.11 +/- 4.1 months per child; no case of PCP occurred. We conclude that aerosolized pentamidine can be administered to even very young children and may be of benefit to all immunosuppressed children unable to use TMP-SMX prophylaxis. The adjusted dose used here appears to be safe, but further studies regarding drug delivery and efficacy are needed.

Safety and cost effectiveness of early hospital discharge of lower risk children with cancer admitted for fever and neutropenia

BACKGROUND

Standard treatment for fever during periods of chemotherapy-induced neutropenia includes hospitalization and administration of intravenous antibiotics until the patient is afebrile and no longer neutropenic. This study prospectively evaluates the safety and cost-effectiveness of early discharge of selected low risk children before recovery from neutropenia.

METHODS

We studied 74 children with cancer during 131 consecutive admissions for fever during a period of neutropenia. All patients initially were hospitalized and received broad-spectrum antibiotics. Intravenous antibiotic therapy was discontinued, and the patients promptly were discharged even if they had an absolute neutrophil count (ANC) of less than 500 cells/mm3 as long as they were afebrile, appeared clinically well, had negative cultures, exhibited control of local infection, and showed hematologic evidence of bone marrow recovery.

RESULTS

Intravenous antibiotics were discontinued in 82 cases (63%) before recovery of the ANC to more than 500 cells/mm3, and 78 patients were discharged immediately. None of 70 patients discharged while neutropenic but exhibiting a rising ANC at the time of discharge developed recurrent fever and required readmission. Thirty of these children had an improving localized infection when intravenous antibiotics were discontinued and completed a course of oral antibiotics at home. The estimated mean savings in hospital charges due to early discharge was $5058 per patient.

CONCLUSIONS

Low risk children with cancer who are hospitalized and treated for fever and neutropenia but appear clinically well may have intravenous antibiotics discontinued and be discharged safely irrespective of the ANC, as long as their granulocyte count is rising. This approach shortens hospital stays and results in considerable cost savings.

The acquired immune deficiency syndrome: an overview for the emergency physician, Part 1

The acquired immune deficiency syndrome (AIDS) was recognized as a distinct entity in 1981. It began as a medical curiosity affecting only several dozen individuals in a restricted segment of the U.S. population. In the 12 years since its description, AIDS has become a pandemic affecting tens of millions with cases reported from all major countries. The illness is caused by a retrovirus, termed human immunodeficiency virus (HIV). It is a blood-borne disease with sexual, parenteral, and perinatal modes of transmission. Infection with the virus can be determined by a number of serologic techniques as well as viral culture. The pathophysiology of illness is incompletely understood, but is in large part related to destruction of helper, CD4 lymphocytes. This results in immune dysfunction and the development of a variety of opportunistic infections and malignancies. A great deal has been learned over the last decade, with important advances in treatment. Zidovudine (AZT) remains the most important agent in slowing progression of the disease and has resulted in prolonging survival. All organ systems can be affected by HIV, and many clinical manifestations are protein. Fever, weight loss, and diarrhea are often encountered general symptoms. The skin is frequently involved, with Kaposi's Sarcoma the most common malignancy and a variety of fungi and viruses the most frequent cause of infection. The lung is involved in the majority of patients, with Pneumocystis Carinii (PCP) and mycobacteria emerging as the most important pathogens. A variety of treatments have demonstrated efficacy for PCP. The risk of PCP is related to the decay in CD4 lymphocytes so that prophylactic treatment is recommended when CD4 counts fall below 200. Mycobacterial infection with multiresistant organisms has complicated the management of these infections and poses new risks to health care workers. Part 1 of this two-part series on AIDS discusses the pathophysiology and clinical expression, epidemiology, laboratory testing, and the general clinical manifestations of AIDS, as well as dermatologic, pulmonary, and cardiac symptoms. Part 2 will discuss the gastrointestinal, neurologic, and ocular symptoms, as well as the treatment and management of the AIDS patient.

[Effects of the 1987 revision of the definition for an AIDS case in Switzerland]

AIDS cases diagnosed in Switzerland after the revision of 1987 and reported to the Swiss Federal Office of Public Health until 31.12.1992 were categorised according to whether they conformed to the diagnostic criteria valid before the revision (= "pre-87"-group) or only to the new criteria introduced with the revision (= "post-87"-group). Compared to the "pre-87"-group, the proportion of injecting drug users was higher, the proportion of homosexual men was lower, the patients were younger and Pneumocystis carinii pneumonia (PCP) and Kaposi-sarcoma were diagnosed less frequently in the "post-87"-group. The revision of the AIDS case-definition affected the proportion of Aids-diagnoses with PCP over time. It improved the surveillance of AIDS morbidity in Switzerland but its effects must be distinguished from true phenomena of the AIDS-epidemic.

Attitudes to prevention among HIV-infected patients: the case of specific prophylaxis for Pneumocystis carinii pneumonia

Despite a consensus on the need for Pneumocystis carinii pneumonia (PCP) prophylaxis for HIV-infected patients with fewer than 200 CD4+ lymphocytes/mm3, the number of cases of PCP has remained stable, and about 70% involve patients who are not receiving prophylaxis. The aim of this study was to determine why these patients are not covered by prophylaxis. It was based on a retrospective analysis of semidirective interviews with 32 patients who developed PCP while not receiving prophylaxis. The reasons given were a lack of knowledge of risk factors for HIV infection, the fear of HIV testing, unawareness of the existence of PCP prophylaxis, a refusal to see a doctor in the absence of symptoms, unwillingness to be monitored and in four cases a failure of the doctor to prescribe prophylaxis.

A prospective comparison of Porta-sonic and Fisoneb ultrasonic nebulizers for administering aerosol pentamidine

OBJECTIVE

To report patient acceptability and overall therapeutic effectiveness of two different ultrasonic nebulizers, Fisoneb and Porta-sonic, for the administration of aerosol pentamidine for Pneumocysitis carinii prophylaxis in human immunodeficiency virus (hiv)-infected individuals.

DESIGN

Prospective assessment of a random subgroup of 174 individuals from an inception cohort of 1093 patients attending a central aerosol pentamidine treatment centre in Toronto, Ontario.

METHODS

One hundred and seventy-four patients who had been receiving aerosolized pentamidine for more than 10 weeks using Fisoneb at 60 mg every two weeks were switched to Porta-sonic. Subjective evaluation included three standard 10 cm visual analogue scales rating cough/wheeze, aftertaste and overall preference. The individuals were also asked to compare the duration of time spent on the aerosol treatments. Objective evaluation included spirometry performed immediately before and 15 mins after pentamidine administration. Prospective surveillance of the entire cohort was preformed to record and document episodes of breakthrough P carinii pneumonia.

RESULTS

Porta-sonic was the overall preferred nebulizer in 82% of patients. Less time was spent on aerosol treatment using the Porta-sonic nebulizer compared with the Fisoneb in 66% of patients. The Porta-sonic nebulizer system produced less aftertaste compared with Fisoneb. Both nebulizers produced significant but modest reduction in flow rates. During the study period there was no statistically significant difference in the rates of breakthrough P carinii pneumonia between the two groups. A total of 91 episodes occurred, at a rate of 0.5 episodes per patient-month on Porta-sonic compared with 0.7 episodes per patient-month on Fisoneb (P=0.2536).

DISCUSSION

Aerosol pentamidine remains the proven second-line prophylaxis against P carinii pneumonia in hiv/aids for those intolerant to trimethoprim-sulphamethoxazole. Cough, bronchospasm and poor taste are side effects that may limit patient tolerance and acceptability. The results of this study show that the Porta-sonic nebulizer system significantly reduces some of these side effects and increases patient preference.

CONCLUSION

This study suggests that Porta-sonic, the newer nebulizer system, with more ideal in vitro characteristics may become a favoured device in clinical practice.

Danish AIDS patients 1988-1993: a recent decline in Pneumocystis carinii pneumonia as AIDS-defining disease related to the period of known HIV positivity

The frequency of PCP among adult Danish AIDS patients notified in 1988-93 was higher among patients tested HIV-positive less than 4 months prior to AIDS than among those known to be positive for > 1 year. Among the latter, the proportion with PCP decreased significantly over the period, from 45.3% in 1988 to 22.0% in 1993, while no such trend was found among patients tested positive for HIV less than 4 months before AIDS was diagnosed. The incidence of PCP as an AIDS-defining disease has decreased, most likely due to the use of PCP prophylaxis.

Clinical manifestations of AIDS in the era of pneumocystis prophylaxis. Multicenter AIDS Cohort Study

BACKGROUND

Among patients infected with human immunodeficiency virus type 1 (HIV-1), early and widespread use of prophylactic regimens against Pneumocystis carinii is changing the pattern of illnesses related to the acquired immunodeficiency syndrome (AIDS).

METHODS

We conducted a subcohort analysis of 844 men with AIDS (87 percent of whom have since died) from a prospectively followed cohort of 2592 HIV-1-infected homosexual men.

RESULTS

A total of 138 men received prophylaxis before the diagnosis of AIDS, but 39 (28 percent) nevertheless had P. carinii pneumonia at some time. Only four illnesses occurred more frequently in men who received P. carinii prophylaxis before the onset of AIDS: Mycobacterium avium complex disease, which developed in 33.4 percent, as compared with 17.3 percent of the 706 men who did not receive early prophylaxis; wasting syndrome (18.4 percent vs. 6.4 percent); cytomegalovirus disease (44.9 percent vs. 24.8 percent); and esophageal candidiasis (21.3 percent vs. 12.8 percent). Collectively, these four diseases accounted for the initial AIDS-related illness in 42.7 percent of those who received prophylaxis before the onset of AIDS, as compared with 10.7 percent of those who did not. During the three six-month periods before the diagnosis of AIDS (0 to 6, > 6 to 12, and > 12 to 18 months), the geometric mean CD4+ cell counts were 48, 87, and 147 per cubic millimeter, respectively, in men who received prophylaxis against P. carinii, as compared with 118, 211, and 279 per cubic millimeter in those who did not.

CONCLUSIONS

M. avium complex disease, esophageal candidiasis, wasting syndrome, and cytomegalovirus disease are more common in HIV-infected patients who have received prophylaxis against P. carinii than in those who have not. Prophylaxis may delay the first AIDS illness for 6 to 12 months.

Neurotoxic effect of the anti-HIV drug D-aspartate beta-hydroxamate for rat primary neuronal cultures: attenuation by N-methyl-D-aspartate (NMDA) antagonists

The anti-tumor drug D-aspartate beta-hydroxamate (D-A beta H), selectively destroys HIV-1 infected peripheral blood mononuclear cells, but produces anorexia and nausea during prolonged treatment to AIDS patients. Consequently, based on the structural similarity between D-A beta H and the excitotoxins L-aspartate and NMDA, we have investigated the potential neurotoxic action and pharmacology of D-A beta H and of a series of chemically related anti-tumor drugs on rat primary neuronal/glial cultures. In this aim, after a 30 min exposure to D-A beta H (1-2 mM), cortical neurons were selectively destroyed within 24 h. The stereoisomer L-A beta H (0.5-2 mM) was highly neurotoxic for both glial and neuronal cells in mixed cultures but demonstrated no toxicity in glial cell cultures alone. Furthermore, for a series of D-A beta H analogues, VHS.121 and VHS.122 demonstrated a reduced but significant neurotoxicity, whereas VHS.124 and VHS.125 showed no significant neurotoxic effect, and in the case of VHS.125 also prevented D-A beta H and glutamate-mediated neurotoxicity. The related anti-tumor drugs L- or D-glutamate gamma-monohydroxamate or keto-glutamate gamma-monohydroxamate (< or = 2 mM) were not neurotoxic for cortical neurons. The neurotoxic effect of D-A beta H and L-A beta H was attenuated by the NMDA antagonists MK-801, TCP, memantine, ifenprodil, pentamidine and CGS-19755. alpha-Difluoromethylornithine, an inhibitor of polyamine biosynthesis, also protected cultures against the neurotoxicity of L-A beta H and D-A beta H.(ABSTRACT TRUNCATED AT 250 WORDS)

Randomized trial of dapsone and aerosolized pentamidine for the prophylaxis of Pneumocystis carinii pneumonia and toxoplasmic encephalitis

PURPOSE

Pneumocystis carinii pneumonia (PCP) and toxoplasmic encephalitis are the most frequent pulmonary and central nervous system opportunistic infections associated with human immunodeficiency virus (HIV) infection. We designed a prospective study to compare the effects of aerosolized pentamidine and dapsone in the prophylaxis of these infections in HIV-infected persons with CD4+ lymphocyte counts less than 250/mm3.

PATIENTS AND METHODS

Two hundred seventy-eight patients seropositive for HIV who had acquired immunodeficiency syndrome (AIDS) or advanced AIDS-related complex were randomly assigned to receive intermittent dapsone (100 mg twice weekly) or aerosolized pentamidine (100 mg every 2 weeks). The proportion of patients remaining free of PCP or toxoplasmosis was analyzed with the log-rank test as a function of time, as were the effects of zidovudine or prophylaxis on survival.

RESULTS

Dapsone and aerosolized pentamidine demonstrated similar efficacy in the primary and secondary prophylaxis of PCP, with 15 (18%) failures among patients receiving dapsone compared to 15 (14%) among those receiving aerosolized pentamidine (p = 0.4), after a mean length of follow-up of 42 and 44 weeks, respectively. Dapsone was more effective in the primary prophylaxis of toxoplasmic encephalitis, with six toxoplasmic encephalitis events occurring among those receiving aerosolized pentamidine, compared to none among those taking dapsone (p = 0.01). Primary prophylaxis for PCP was more effective than secondary prophylaxis with either therapy. Zidovudine therapy did not prevent PCP yet prolonged the PCP-free interval for those in whom either prophylactic therapy failed. Kaplan-Meier estimates did not show a difference in survival between the patients receiving either therapy, yet zidovudine use was associated with improved survival, independent of race and risk factor (Cox proportional hazards model, p = 0.001). The 1-month survival for patients developing PCP despite prophylaxis was better with those in whom dapsone failed than it was for those in whom aerosolized pentamidine failed (p = 0.08).

CONCLUSION

Dapsone is as effective as aerosolized pentamidine in preventing PCP and has the advantage of a lower cost, easier administration, and possibly an additional preventive effect against toxoplasmosis. Zidovudine prolongs the PCP-free interval for patients receiving prophylaxis, regardless of which prophylactic agent is used.

Diagnostic utility of lactate dehydrogenase levels in patients receiving aerosolized pentamidine

Serum lactate dehydrogenase (LDH) levels are elevated in patients with Pneumocystis carinii pneumonia (PCP). In patients receiving aerosolized pentamidine (AP), PCP may be less severe and present with more localized radiographic infiltrates. We evaluated the diagnostic utility of the serum LDH level in 11 patients developing PCP while receiving AP. Serum LDH levels were increased 72.7 +/- 19.0 percent over mean baseline levels and 76.4 +/- 26 percent over the upper limit of normal value for our laboratory with the development of PCP. An elevated serum LDH value remains a useful diagnostic adjunct in the patient developing PCP while receiving AP. Isolated LDH values must be interpreted with caution given the potential for marked variability in the baseline LDH value.

Factors associated with lack of awareness of HIV infection before diagnosis of AIDS

OBJECTIVE

To identify characteristics of people likely to be unaware of their HIV infection before diagnosis of AIDS defining disease.

DESIGN

Survey of continuing surveillance of voluntarily reported AIDS cases.

SUBJECTS

4127 adults with AIDS diagnosed during 1989-92 and reported to the Public Health Laboratory Service AIDS Centre.

SETTING

England and Wales.

MAIN OUTCOME MEASURE

Lack of prolonged awareness of infection before diagnosis of AIDS, defined as an interval of nine months or less between first positive test result and diagnosis of AIDS.

RESULTS

Of 3556 adults with known dates of first positive HIV test result and AIDS diagnosis, 1742 (49%) had been unaware of their infection for up to nine months before AIDS was diagnosed. Lack of awareness was independently and positively associated with infection through heterosexual contact (odds ratio 4.46, 95% confidence interval 3.15 to 6.33), AIDS reported outside the Thames regions (1.64, 1.38 to 1.96), and being non-white (1.99, 1.51 to 2.61). Women were less likely to be unaware than men (0.50, 0.33 to 0.76), and people diagnosed in 1992 were least likely to be unaware (0.48, 0.39 to 0.60). Those aged 25-49 years at diagnosis were less likely to be unaware than those aged 15-24 years and those aged 50 and over.

CONCLUSIONS

People with certain characteristics are more likely than others to be unaware of their HIV infection before AIDS is diagnosed and are therefore less likely to receive prophylaxis. Methods for educating this heterogeneous group need to be investigated.

Pentamidine, an inhibitor of spinal flexor reflexes in rats, is a potent N-methyl-D-aspartate (NMDA) antagonist in vivo

The present study examined whether the antimicrobial agent pentamidine exerts an antagonistic action at the N-methyl-D-aspartate (NMDA) receptor as tested on spinal reflexes in rats in vivo. After intrathecal injection both the specific NMDA antagonist (-)-2-amino-7-phosphonoheptanoate and pentamidine dose-dependently reduced the magnitude of the polysynaptic flexor reflex without affecting the monosynaptic H-reflex. In contrast, the non-NMDA antagonist 6,7-dinitroquinoxaline-2,3-dione depressed the H-reflex in a dose-dependent manner without affecting the flexor reflex. The depressant effect of pentamidine on the flexor reflex was prevented by coadministration with NMDA but not with the non-NMDA agonist alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid. These data suggest that pentamidine exerts an antagonistic action at the NMDA receptor in vivo.

Involvement of tachykinins in pentamidine-induced airway constriction and microvascular leakage in the guinea pig

We investigated the effects of aerosolized pentamidine isethionate on airway constriction and microvascular leakage in the guinea pig, and the role of tachykinins in these abnormalities. The bronchoconstrictor response to pentamidine was determined in anesthetized, tracheotomized and mechanically ventilated guinea pigs by exposing them to increasing concentrations of aerosolized pentamidine (5 to 30 mg/ml; 60 breaths). Respiratory system resistance was measured by the occlusion method. Airway microvascular permeability was evaluated by measuring the Evans blue dye concentration in the trachea and main bronchi. Aerosolized pentamidine caused a concentration-related increase in respiratory system resistance that was prevented by pretreatment with 50 mg/kg capsaicin given subcutaneously 2 wk before pentamidine and was significantly reduced by pretreatment with 1 mg/kg morphine given intravenously. Pretreatment with 10(-4) M aerosolized phosphoramidon (90 breaths) significantly enhanced the bronchoconstrictor response to pentamidine. Aerosolized pentamidine (50 mg/ml; 90 breaths) increased airway microvascular permeability, as the Evans blue dye concentration was 72.6 +/- 3.7 ng/mg tissue in guinea pigs aerosolized with pentamidine versus 34.2 +/- 3.5 ng/mg tissue in the controls. Capsaicin pretreatment inhibited the increase in microvascular leakage induced by pentamidine. Pretreatment with 5 mg/ml aerosolized albuterol (90 breaths) prevented the bronchoconstrictor response to pentamidine but failed to prevent the pentamidine-induced increase in microvascular permeability. Atropine did not modify the bronchoconstrictor response to pentamidine. These results indicate that in the guinea pig, pentamidine isethionate induces bronchoconstriction and airway microvascular leakage, which are mediated by tachykinins released from sensory nerves. Albuterol, which is used in humans to prevent bronchoconstriction, does not seem able to prevent airway edema.

Dapsone-pyrimethamine compared with aerosolized pentamidine as primary prophylaxis against Pneumocystis carinii pneumonia and toxoplasmosis in HIV infection. The PRIO Study Group

BACKGROUND

Pneumocystis carinii pneumonia and toxoplasmic encephalitis are frequent life-threatening opportunistic infections in patients with human immunodeficiency virus (HIV) infection. Primary prophylaxis against P. carinii pneumonia is now common, but there are few data on regimens for primary prophylaxis against toxoplasmosis.

METHODS

We conducted a randomized trial that compared two prophylactic regimens: dapsone (50 mg per day) plus pyrimethamine (50 mg per week) was compared with aerosolized pentamidine (300 mg per month). The patients had symptomatic HIV infection, no history of P. carinii pneumonia or symptomatic toxoplasmosis, and CD4+ counts below 200 per cubic millimeter (0.2 x 10(9) per liter).

RESULTS

In an intention-to-treat analysis, after a median follow-up of 539 days P. carinii pneumonia developed in 10 patients in each group, whereas toxoplasmosis developed in 32 of 176 patients in the pentamidine group and 19 of 173 patients in the dapsone-pyrimethamine group. Those assigned to pentamidine had a risk of P. carinii pneumonia that was similar to the risk in those assigned to dapsone-pyrimethamine (adjusted relative risk, 1.13; 95 percent confidence interval, 0.44 to 2.92; P = 0.79), but a higher risk of toxoplasmosis (adjusted relative risk, 1.81; 95 percent confidence interval, 1.12 to 2.94; P = 0.02). Among the 262 patients with serologic evidence of past exposure to Toxoplasma gondii, the relative risk of symptomatic toxoplasmosis was 2.37 times higher in those assigned to pentamidine (95 percent confidence interval, 1.3 to 4.4; P = 0.006). More patients discontinued dapsone-pyrimethamine than pentamidine because of toxicity (42 vs. 3; P < 0.001). Survival was similar in the two groups.

CONCLUSIONS

For primary prevention of P. carinii pneumonia, dapsone-pyrimethamine is as effective, though not as well tolerated, as aerosolized pentamidine. Dapsone-pyrimethamine also prevents first episodes of toxoplasmosis.

Differential lobe lavage for diagnosis of acute Pneumocystis carinii pneumonia in patients receiving prophylactic aerosolized pentamidine therapy

The diagnostic yield of bronchoalveolar lavage (BAL) for Pneumocystis carinii pneumonia (PCP) in patients infected with human immunodeficiency virus has been reported to be 95 percent, but falls to 62 percent in patients receiving aerosolized pentamidine. Because aerosolized pentamidine appears to be preferentially deposited in the middle and lower lobes, we postulated that an upper lobe lavage would have a higher diagnostic yield than the standard middle/lower lobe lavage in patients receiving aerosolized pentamidine. Twenty-five patients receiving aerosolized pentamidine suspected of having acute PCP underwent separate BAL of an upper lobe and lower lobe as well as transbronchial biopsy. Fifteen of the 25 (60 percent) were diagnosed as having PCP. Of the 15, one had the samples inadvertently combined. In the remaining 14, BAL was positive for P carinii organisms in 12 lavages of the lower lobe and 14 of the upper lobe. Upper lobe lavage had statistically significantly more P carinii organisms by semiquantitative technique than the lower lobe. In patients receiving aerosolized pentamidine, who develop acute PCP, an upper lobe lavage may have a higher diagnostic yield than the standard middle/lower lobe lavage. In addition, the transbronchial biopsy specimen offered no treatable diagnosis that was not made by lavage alone in the 25 patients. This raises the question of the utility of transbronchial biopsies in these patients.

Lung deposition of nebulised pentamidine in children

BACKGROUND

Nebulised pentamidine is effective for preventing Pneumocystis carinii pneumonia in adults with acquired immunodeficiency syndrome. The nebuliser dose required to produce equivalent lung concentrations of pentamidine in children is unknown. This study was performed to measure pulmonary pentamidine deposition in children and to relate this to age, ventilation pattern, and body size.

METHODS

Nebulised pentamidine (50 mg in 6 ml saline) was administered to 12 children (including one with lymphocytic interstitial pneumonitis) and to six adults with human immunodeficiency virus infection using a Respirgard II nebuliser. Technetium-99m labeled colloidal human serum albumin was used as an indirect marker for pentamidine and deposition in the lungs was detected by a gamma camera.

RESULTS

Absolute deposition of pentamidine was not related to age, height, weight, spirometry, or ventilation characteristics. Deposition, as a mean (SD) percentage of nebuliser output, was similar in children aged 8-11 years (5.5(2.4)%), teenagers aged 12-15 years (7.2(2.2)%) and adults (7.1(2.6)%). Aerosol concentration within the lungs (% nebuliser output deposited/predicted total lung capacity) was therefore higher in children (1.9(1.5)%/1) and teenagers (1.9(0.7)%/1) than in adults (1.0(0.7%)/1), and was negatively correlated with height (r = -0.69) and weight (r = -0.50). Deposition of aerosol in the region of the large central airways was particularly marked in children. Small reductions in forced expiratory volume in one second and forced vital capacity after treatment did not differ significantly between adults and children and visual analogue scores of subjective adverse effects did not vary with age.

CONCLUSIONS

These results suggest that children probably require lower nebuliser pentamidine doses to produce lung pentamidine concentrations equivalent to those found to be effective for preventing P carinii pneumonia in adults using the Respirgard II nebuliser.

Human immunodeficiency virus infection in pregnancy

Human immunodeficiency virus (HIV) infection in women is an increasing problem. World wide, at least 25% of all infections occur in adolescent or adult women, most of whom are of child-bearing age. The commonest modes of acquisition of HIV infection are sexual contact with an HIV-infected male and sharing needles during injecting drug use. Vertical transmission is the major route of HIV infection in infants and children and can occur in utero, intrapartum, through exposure to infected blood or secretions, or post partum, via breast milk. HIV infection has not been demonstrated to affect fertility, or to influence the outcome of pregnancy unless there is evidence of significant immune dysfunction, with CD4 counts below 400/mm3. Though data are limited, pregnancy does not appear to affect the course of HIV infection. Low CD4 counts predispose women to the opportunistic infectious complications of HIV. Pathogens include Candida sp., Mycobacterium tuberculosis, Pneumocystis carinii, Toxoplasma gondii, Cryptococcus neoformans and Cryptosporidium. These pathogens require early recognition and diagnosis if optimal treatment and outcome are to be attained. Treatment with zidovudine and prophylaxis against Pneumocystis carinii are appropriate when CD4 counts are less than 200/mm3, though the safety of zidovudine in early pregnancy is not known. Similarly it is not known whether zidovudine treatment of the mother prevents transmission of HIV infection to her baby. Caesarean section does not prevent peripartum transmission of HIV and should be undertaken only for other appropriate indications. The utility of antenatal screening for HIV depends upon the seroprevalence in the population. Such programmes must be supported by comprehensive clinical care as well as sensitive and non-judgemental counselling.

Long-term results of monthly inhaled pentamidine as primary prophylaxis of Pneumocystis carinii pneumonia in HIV-infected patients

PURPOSE

To evaluate the long-term efficacy and safety of inhaled pentamidine as primary prophylaxis against Pneumocystis carinii pneumonia (PCP) in patients infected with human immunodeficiency virus (HIV).

PATIENTS

Two hundred thirty-two HIV-infected patients with a CD4 cell count below 20% of the total lymphocyte count were given aerosolized pentamidine once every 4 weeks for more than 3 months. Pentamidine aerosols were administered at the hospital under medical supervision. Prevention of bronchospasm was carried out using inhaled salbutamol.

RESULTS

Mean duration of prophylaxis was 15.9 months. Eleven patients (4.7%; [95% confidence interval 2% to 7.4%]) developed PCP. Probability to remain free of PCP is 95.6% at 12 months, 94% at 18 months, and 88% at 24 months. Mean delay between the onset of the prophylaxis and the occurrence of PCP for the 11 patients was 12.9 months (range: 4 to 26 months). No major side effect was observed, and minor side effects (cough, acute dyspnea) were infrequent.

CONCLUSION

The efficacy and tolerance of aerosolized pentamidine as shown in our study support its use as primary prophylaxis against P. carinii in HIV-infected patients.

A controlled trial of aerosolized pentamidine or trimethoprim-sulfamethoxazole as primary prophylaxis against Pneumocystis carinii pneumonia in patients with human immunodeficiency virus infection. The Dutch AIDS Treatment Group

BACKGROUND

Primary prophylaxis against Pneumocystis carinii pneumonia (PCP) is recommended for patients with human immunodeficiency virus (HIV) infection if their CD4 cell counts are below 200 per cubic millimeter (0.2 x 10(9) per liter). Either aerosolized pentamidine or trimethoprim-sulfamethoxazole (co-trimoxazole) is commonly prescribed for prophylaxis, but the relative efficacy and toxicity of these agents are unknown.

METHODS

We conducted a multicenter trial involving 215 HIV-infected patients with no history of PCP but with CD4 cell counts below 200 per cubic millimeter. The patients were randomly assigned to one of three regimens: aerosolized pentamidine once a month, 480 mg of trimethoprim-sulfamethoxazole once a day (80 mg of trimethoprim and 400 mg of sulfamethoxazole), or 960 mg of trimethoprim-sulfamethoxazole once a day (160 mg and 800 mg, respectively). The cumulative incidence of PCP was estimated by Kaplan-Meier survival analysis.

RESULTS

After a mean follow-up of 264 days, 6 of the 71 patients in the pentamidine group had a confirmed first episode of PCP (11 percent), whereas none of the 142 patients in the two trimethoprim-sulfamethoxazole groups had PCP (P = 0.002). However, adverse events that required discontinuation of the medication were much more frequent in the trimethoprim-sulfamethoxazole groups (17 and 18 patients) than in the pentamidine group (2 patients). The adverse reactions occurred significantly sooner in the group given 960 mg of trimethoprim-sulfamethoxazole than in the group given 480 mg (mean time, 16 vs. 57 days; P = 0.02).

CONCLUSIONS

For patients with HIV infection, trimethoprim-sulfamethoxazole taken once a day is more effective as primary prophylaxis against PCP than aerosolized pentamidine administered once a month, although adverse drug reactions are more frequent with trimethoprim-sulfamethoxazole.

Low incidence of Pneumocystis carinii pneumonia in HIV patients receiving 300 mg pentamidine aerosol every 2 weeks

The optimal dosage of pentamidine for prophylaxis of Pneumocystis carinii pneumonia (PcP) is unknown. We assessed the effects of 300 mg pentamidine inhaled every 2 weeks. Salbutamol was added for prevention of bronchoconstriction. A total of 128 consecutive HIV patients were enrolled, 21 of whom were excluded within 8 weeks; the remaining 107 patients, 66 on primary and 41 on secondary prophylaxis, were treated for 39 weeks (median; range 8-133). Two patients developed PcP. Side effects occurred in only 14 of 5082 inhalations. Three patients developed hypoglycemia after inhalations. Blood glucose levels determined in 34 patients before and after inhalation revealed a decline from 89 +/- 23 mg/dl to 79 +/- 23 mg/dl (P < 0.005). A randomized prospective trial is necessary to evaluate the efficacy of 300 mg pentamidine inhaled every 4 or 2 weeks.

A pilot study of prophylactic aerosolized amphotericin B in patients at risk for prolonged neutropenia

Invasive aspergillosis continues to be a significant cause of morbidity and mortality in patients with prolonged neutropenia. We performed a phase I trial of escalating doses of aerosolized amphotericin B given by a face mask nebulizer system with a disposable bacterial exhale filter. Five, 10, 15, and 20 mg of drug were dissolved in sterile water and inhaled over 10 to 15 minutes twice daily. Tolerance was studied in 26 patients (18 transplant recipients, and 8 leukemia patients). No side effects were observed at any dose level. Prophylactic treatment ended for 14 patients (54%) when intravenous (IV) amphotericin B was begun empirically for antifungal coverage following fevers. Eleven patients (43%) continued inhaled amphotericin B until blood counts recovered. One patient was taken off study when she developed cardiogenic pulmonary edema. No patient developed clinically suspicious or pathologically documented infection with invasive aspergillosis. Prophylactic aerosolized amphotericin B is well tolerated at 5, 10, 15, and 20 mg twice daily dosing. In addition, prophylactic aerosolized amphotericin B does not appear to sensitize patients to the subsequent use of IV amphotericin B. Although this study suggests that prophylactic inhaled amphotericin B is well tolerated and effective, a large scale controlled trial is needed.

Human immunodeficiency virus infection in intravenous drug users: a model for primary care

PURPOSE

Intravenous drug users (IVDUs) often encounter barriers to primary care. To improve access, we developed a primary care clinic--Central Medical Unit (CMU)--for substance abusers in drug treatment. We report outcomes for services offered to IVDUs with human immunodeficiency virus (HIV) infection.

PATIENTS AND METHODS

During 1990, 24% (120 of 509) of IVDUs eligible for CMU were HIV positive. Diagnostic therapeutic and preventive goals for IVDUs with HIV infection were evaluated for acceptance and compliance by chart review for these 120 patients.

RESULTS

On admission, 65% (78 of 120) of patients reported having no source of primary care, 64% (77 of 120) were male, and 77% (92 of 120) were in methadone maintenance. All were screened for tuberculosis, syphilis, and hepatitis; 94% (15 of 16) of eligible patients accepted tuberculosis prophylaxis and 83% (5 of 6) accepted syphilis treatment, but only 36% (5 of 14) accepted hepatitis B vaccine. Of those who accepted therapy, 87% (13 of 15) were compliant with tuberculosis prophylaxis, and 100% (5 of 5) were compliant with syphilis treatment. Influenza vaccine was accepted by 49% (59 of 120) and pneumococcal vaccine by 81% (97 of 120). Ninety-eight percent (118 of 120) accepted T-cell testing: 61% had T-helper counts less than 500/mm3 and 25% were less than 200/mm3. Of those eligible, 89% (70 of 79) accepted antiretroviral therapy, and 100% (35 of 35) accepted Pneumocystis carinii pneumonia prophylaxis. Six-month compliance rates for these therapies were 84% (59 of 70) and 77% (27 of 35), respectively.

CONCLUSION

By offering primary care services with drug treatment, the CMU model may be an effective way of providing access to primary care for HIV-infected IVDUs and for facilitating compliance.

AIDS: Part II

Great strides have been made in the therapy of human immunodeficiency virus (HIV) infection. Currently approved drugs include zidovudine and didanosine. A third drug, dideoxycytidine (zalcitibine), has recently been filed for approval with the Food and Drug Administration. All these drugs work through inhibition of the reverse transcriptase enzyme. Zidovudine is the only drug that has shown clinical efficacy against HIV. Treatment of patients with advanced HIV disease (i.e., acquired immune deficiency syndrome [AIDS] or symptomatic infection with < 200 CD4+ lymphocytes per mm3), results in a prolongation and improved quality of life. Zidovudine is the only antiretroviral agent approved for the treatment of asymptomatic patients. Early intervention with zidovudine has been shown to delay progression to AIDS when patients' CD4+ lymphocyte counts decline to less than 500/mm3, irrespective of clinical signs or symptoms of HIV infection. Didanosine is currently indicated for the treatment of patients with advanced HIV disease who are intolerant to or failing zidovudine therapy. The major toxicity of zidovudine is bone marrow suppression with anemia and granulocytopenia (which occurs in from 1% to 45% of patients, depending on the clinical stage of disease and the dose of the drug). Didanosine and zalcitibine have both been associated with a severe peripheral neuropathy, which is generally reversible on cessation of the drug. In addition, didanosine has been implicated as a cause of pancreatitis that has been fatal in a small percentage of cases. The toxicities of didanosine and zalcitibine range from 1% to 10%, depending on dose, duration of therapy, and the presence of underlying HIV-related peripheral neuropathy or a previous history of pancreatitis. The clinical hallmark of HIV infection is the development of opportunistic infections and malignancies, which are a consequence of the profound immunodeficiency. The risk of an opportunistic infection increases significantly as the T-helper lymphocyte count declines to less than 20%, or 200 to 250/mm3. The spectrum of opportunistic infections ranges from viruses to protozoa. Patients with advanced HIV disease are also at increased risk of infection with nonopportunistic, community-acquired pathogens. Primary and secondary prophylaxis against the most common AIDS-defining opportunistic infection, Pneumocystis carinii pneumonia, is now recommended. Studies are currently underway to determine the efficacy of prophylaxis against other opportunistic pathogens. Treatment of opportunistic infections associated with AIDS has improved significantly over the past 5 years as new drugs and combination regimens of antimicrobials have been developed.(ABSTRACT TRUNCATED AT 400 WORDS)

CD4+ cells and CD4+ percent as risk markers for Pneumocystis carinii pneumonia (PCP): implications for primary PCP prophylaxis

The incidence of Pneumocystis carinii pneumonia (PCP) during 2 years in HIV-infected patients with less than or equal to 100 x 10(6)/l CD4+ cells, less than or equal to 200 x 10(6)/l CD4+ cells and less than 20% CD4+ cells of total T lymphocytes were compared. The relative PCP risk in 57 patients with less than or equal to 100 CD4+ cells was more than twice higher than in 120 patients with less than or equal to 200 CD4+ cells. The latter had almost twice higher relative PCP risk than 271 patients with less than or equal to 20% CD4+ cells. Only 3/56 patients who acquired PCP had greater than 200 CD4+ cells and 15/56 patients had greater than 100 CD4+ cells. Centers for Disease Control (CDC) recommends primary PCP prophylaxis in HIV-infected patients when the number of CD4+ cells is less than 200 x 10(6)/l or when the CD4+ is less than 20. On the basis of the presented data we suggest that primary prophylaxis is considered only when CD4+ cells fall below 200 x 10(6)/l.

Effect of the revised CDC case definition of AIDS on the number of AIDS cases in the Sydney AIDS Prospective Study

We sought to evaluate the potential impact of a proposed revision in the case definition of acquired immunodeficiency syndrome (AIDS) (from a clinical case definition to one also including subjects with HIV infection who have an absolute number of peripheral CD4+ cells of less than 200 x 10(6)/L) among 512 HIV-seropositive homosexual/bisexual who were reviewed between 1984 and 1991. According to the current case definition, 151 (30%) of 512 at-risk subjects developed AIDS between 1984 and August 1, 1991. Of the 361 at-risk subjects who were not classified as AIDS by the current definition, 47 (13%; 95% CI 9-17%) were classified as AIDS according to the revised definition. The median time to development of AIDS according to the revised definition was 288 weeks and that according to the current definition was 338 weeks. Data on clinical status were available for 34 of the new cases at the time of their diagnosis according to the proposed case definition: 16 (47%) of these were asymptomatic, 10 (29%) had persistent generalised lymphadenopathy and eight had minor infectious diseases. Of the 151 cases diagnosed according to the current definition, 78 (52%) had an antecedent CD4+ cell count that met the criteria for AIDS under the revised definition a median of 59 weeks before their diagnosis according to the current definition. These data indicate an appreciable increase in the number of cases of AIDS in this cohort when the revised case definition was applied. These findings have important implications for the surveillance, and for the clinical monitoring and treatment, of patients with HIV disease in Australia.

Improved diagnosis of Pneumocystis carinii infection by polymerase chain reaction on induced sputum and blood

Detection of Pneumocystis carinii by the polymerase chain reaction (PCR) may facilitate non-invasive diagnosis of P carinii pneumonia and study of its epidemiology. We have compared the sensitivity and specificity of two PCR methods with those of conventional staining for detection of P carinii in induced sputum, bronchoalveolar lavage fluid (BAL), and blood. Of 71 sputum samples, 17 were from patients with microbiologically confirmed P carinii pneumonia. A nested PCR method correctly identified the presence of P carinii in all 17 (100% sensitive, 95% confidence interval [CI] 81-100%) and found no organisms in 50 of 54 microbiologically negative samples (93% specific, 95% CI 82-98%). PCR with a single primer pair was 71% sensitive (44-90%) and 94% specific (85-99%). The sensitivity of conventional staining methods (direct and indirect fluorescence antibody and toluidine-blue-O tests) was significantly less (38-53%) than that of nested PCR (p less than 0.05). In BAL, neither PCR method was significantly better than the conventional staining methods. P carinii was detected in BAL or sputum from 10 immunocompromised patients without microbiological evidence of P carinii pneumonia, which suggests that symptom-free carriers or subclinical infection can exist. P carinii was detected by nested PCR in blood from 2 of 3 patients with disseminated pneumocystosis but in only 1 of 11 patients with P carinii infection restricted to the lungs. Nested PCR on induced sputum is more sensitive than conventional staining methods for the diagnosis of P carinii pneumonia and provides a non-invasive method of detecting disseminated disease.

Laboratory control values for CD4 and CD8 T lymphocytes. Implications for HIV-1 diagnosis

With the advent of standard flow cytometric methods using two-colour fluorescence on samples of whole blood, it is possible to establish the ranges of CD3, CD4 and CD8 T lymphocyte subsets in the routine laboratory, and also to assist the definition of HIV-1-related deviations from these normal values. In 676 HIV-1-seronegative individuals the lymphocyte subset percentages and absolute counts were determined. The samples taken mostly in the morning. The groups included heterosexual controls, people with various clotting disorders but without lymphocyte abnormalities as well as seronegative homosexual men as the appropriate controls for the HIV-1-infected groups. The stability of CD4% and CD8% values was demonstrated throughout life, and in children CD4 values less than 25% could be regarded as abnormal. The absolute counts of all T cell subsets decreased from birth until the age of 10 years. In adolescents and adults the absolute numbers (mean +/- s.d.) of lymphocytes, CD3, CD4 and CD8 cells were 1.90 +/- 0.55, 1.45 +/- 0.46, 0.83 +/- 0.29 and 0.56 +/- 0.23 x 10(9)/l, respectively. In patients with haemophilia A and B the mean values did not differ significantly. In homosexual men higher CD8 levels were seen compared with heterosexual men and 27% had an inverted CD4/CD8 ratio but mostly without CD4 lymphopenia (CD4 less than 0.4 x 10(9)/l). However, some healthy uninfected people were 'physiologically' lymphopenic without having inverted CD4/CD8 ratios. When the variations 'within persons' were studied longitudinally over a 5-year period, the absolute CD4 counts tended to be fixed at different levels. As a marked contrast, over 60% of asymptomatic HIV-1+ patients exhibited low CD4 counts less than 0.4 x 10(9)/l together with inverted CD4/CD8 ratios. Such combined changes among the heterosexual and HIV-1-seronegative homosexual groups were as rare as 1.4% and 3%, respectively. For this reason, when the lymphocyte tests show less than 0.4 x 10(9)/l CD4 count and a CD4/CD8 ratio of less than unity, the individuals need to be investigated further for chronicity of this disorder, the signs of viral infections such as HIV-1 and other causes of immunodeficiency.

Once-a-week azithromycin in AIDS patients: tolerability, kinetics, and effects on zidovudine disposition

Toxoplasmic encephalitis is one of the leading causes of morbidity in patients with AIDS. Lifelong treatment is needed to prevent relapses, and primary prevention is desirable in high-risk patients, but the available drugs are often poorly tolerated. Azithromycin (AZM) has been considered a drug candidate because of its efficacy in the animal model and its kinetic properties, which would allow intermittent administration. The tolerability and kinetics of AZM and its effect on the disposition of zidovudine (ZVD) were therefore evaluated in a preliminary open study in nine human immunodeficiency virus-infected patients. AZM was administered once weekly for 5 weeks 2 h before the usual morning ZVD dose. The day before and on the first and fifth AZM dosings, blood samples were drawn every 30 min during 5 h for determination of the concentrations of ZVD and its glucuronide metabolite. Blood samples were drawn for AZM measurement over 72 and 360 h on the first and fifth AZM administrations, respectively, as well as before and 3 h after dosing on the second, third, and fourth AZM dosings. After the first and fifth administrations, maximum AZM concentrations in serum were 0.6 +/- 0.1 and 0.8 +/- 0.2 microM (mean +/- standard error of the mean), respectively; times to peak concentration in serum were 3.7 +/- 0.2 and 2.9 +/- 0.4 h, respectively; areas under the plasma concentration-time curves were 9.2 +/- 1.6 and 9.3 +/- 2.0 micrograms.h/ml, respectively; and half-lives were 61.0 +/- 5.4 and 63.8 +/- 6.7 h, respectively. On days -1, 1, and 29, ZVD kinetic parameters were as follows: maximum concentrations in serum, 3.1+/- 0.6, 4.3 +/- 0.6, and 4.2 +/- 0.9 microM, respectively; times to maximum concentrations in serum, 1.1 +/- 0.4, 0.8 +/- 0.2, and 1.2 +/- 0.3 h, respectively: areas under the plasma concentration-time curves, 5.3 +/- 0.9, 5.9 +/- 0.6, and 5.7 +/- 0.8 microgram . h/ml, respectively; and half-lives, 1.3 +/- 0.08, 1.4 +/- 0.04, and 1.3 +/- 0.04 h, respectively. Except for transient mild abdominal cramps that occurred at 2 to 3 h postdose (6 of 45 exposures) and nausea (4 of 45 exposures), neither subjective nor objective side effects were observed. The kinetics of AZM were similar after the first and repeated administrations, and the disposition of ZVD was not altered by this treatment. The efficacy of AZM in preventing cerebral toxoplasmosis can therefore be safely tested in human immunodeficiency virus-infected patients concomitantly treated with zidovudine.

The effects on survival of early treatment of human immunodeficiency virus infection

BACKGROUND

Zidovudine has been shown to prolong survival in patients with the acquired immunodeficiency syndrome (AIDS) and, in persons with human immunodeficiency virus (HIV) infection but not AIDS, to delay the progression to AIDS. However, it is still uncertain whether treatment before the development of AIDS prolongs survival.

METHODS

We analyzed data from a cohort of 2162 high-risk men who were already seropositive for HIV type 1 (HIV-1) and 406 men who seroconverted from October 1986 through April 1991. There were 306 deaths. The probabilities of death were compared among men at similar stages of disease who began zidovudine therapy before the diagnosis of AIDS and among those who did not. Relative risks of death were calculated for each of five initial disease states on the basis of CD4+ cell counts and clinical symptoms and signs appearing over follow-up periods of 6, 12, 18, and 24 months. Adjustments were also made for the use of prophylaxis against Pneumocystis carinii pneumonia (PCP).

RESULTS

After we controlled for CD4+ cell count and symptoms, the use of zidovudine with or without PCP prophylaxis before the development of AIDS significantly reduced mortality in all follow-up periods. The relative risks of death were 0.43 (95 percent confidence interval, 0.23 to 0.78) at 6 months, 0.54 (95 percent confidence interval, 0.38 to 0.78) at 12 months, 0.59 (95 percent confidence interval, 0.44 to 0.79) at 18 months, and 0.67 (95 percent confidence interval, 0.52 to 0.86) at 24 months. After we adjusted for the effects of PCP prophylaxis, zidovudine alone significantly reduced mortality at 6, 12, and 18 months (relative risks, 0.45, 0.59, and 0.70, respectively), but not at 24 months (relative risk, 0.81). Among zidovudine users, those who also used PCP prophylaxis before the development of AIDS had significantly lower mortality at 18 and 24 months than those who did not (relative risks, 0.62 and 0.60, respectively).

CONCLUSIONS

The results of this study support the hypothesis that in HIV-1 infection, early treatment with zidovudine and PCP prophylaxis improves survival in addition to slowing the progression to AIDS.