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H C Bucher

Publications and source records attributed to H C Bucher.

At least 37 records · Page 2Linked to original sources
PubMed1999

Estimating AIDS-free survival in a severely immunosuppressed asymptomatic HIV-infected population in the era of antiretroviral triple combination therapy. Swiss HIV Cohort Study.

BACKGROUND: Antiretroviral triple combination therapies have been evaluated in randomized controlled trials and cohort studies. Little is known about their impact on asymptomatic, severely immunosuppressed, HIV-infected individuals in a real world population. OBJECTIVES: To describe disease progression in a broad asymptomatic population of HIV-infected individuals with a CD4 count <100 cells/mm3 before and after the introduction of combination triple therapy. DESIGN: Six-month homogenous Markov chain consisting of four recurrent AIDS-free states and one absorbing AIDS state: (1) CD4 count > or =100 cells/mm3, (2) CD4 count 75 to 99 cells/mm3, (3) CD4 count 50 to 74 cells/mm3, (4) CD4 count 0 to 49 cells/mm3, and AIDS. SETTING: Swiss HIV Cohort Study database. PATIENTS: A total of 1027 patients contributed to 2634 pairs of 6-month observations from 1993 to 1995, and 681 patients contributed to 2077 pairs of 6-month observations from 1996 to 1997. MEASUREMENT: AIDS-free survival probabilities and the expected AIDS-free survival time. RESULTS: The expected number of AIDS-free months in a 3-year period was 17 (95% confidence interval [CI], 16-19) for patients starting in state 4 prior to 1996 versus 26 months (95% CI, 24-28) for patients starting in state 4 after 1996. For these two time periods, the corresponding expected numbers of AIDS-free months were 21 (95% CI, 20-22) versus 30 (95% CI, 28-32) for state 3 and 23 (95% CI, 21-24) versus 33 (95% CI, 32-34) for state 2. CONCLUSION: Expected 3-year AIDS-free survival in severely immunosuppressed individuals with CD4 counts <100 cells/mm3 improved significantly between 1993 to 1995 and 1996 to 1997.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Isoniazid prophylaxis for tuberculosis in HIV infection: a meta-analysis of randomized controlled trials.

OBJECTIVES: To evaluate the efficacy of isoniazid for the prevention of tuberculosis in tuberculin skin test-positive and negative individuals with HIV infection. DESIGN: Meta-analysis of randomized controlled trials. SETTING: Seven trials from Mexico, Haiti, the United States, Zambia, Uganda and Kenya. PATIENTS: Individuals free from tuberculosis, 2367 persons in the intervention and 2162 in the control groups. INTERVENTION: Comparison of isoniazid with placebo or no prophylaxis. METHODS: A systematic search of the literature was carried out from 1985 to October 1997 for randomized controlled trials of isoniazid prophylaxis in HIV-infected persons. Two reviewers evaluated the relevance of each candidate study and the validity of eligible trials. Studies were pooled using a random effect model, conducting secondary analyses for tuberculin skin test-positive and negative persons. RESULTS: Mean follow-up in trials varied between 0.4 and 3.2 years. Pooling all seven trials, a risk ratio was found for persons treated with isoniazid for developing tuberculosis of 0.58 [95% confidence interval (CI), 0.43-0.80] and 0.94 (95% CI, 0.83-1.07) for death. In groups of tuberculin skin test-positive and negative persons, the risk ratio of tuberculosis was 0.40 (95% CI, 0.24-0.65) and 0.84 (95% CI, 0.54-1.30), respectively, and the difference in the effectiveness of isoniazid versus placebo between these groups was statistically significant (P = 0.03, for the difference of summary estimates). Consistency of results was found across trials (P > 0.10, heterogeneity value) for all comparisons. CONCLUSIONS: Prophylaxis with isoniazid reduces the risk of tuberculosis in persons with HIV infection. The effect is restricted to tuberculin skin test-positive persons.

AIDS-Related Opportunistic Infections↗
PubMed1999

Rare AIDS-defining diseases in the Swiss HIV Cohort Study.

The objective of this study was to investigate the spectrum and frequency of rare AIDS-defining diseases in the Swiss HIV Cohort Study. AIDS-defining diseases contributing less than 1% to the absolute number of all recorded AIDS-defining diseases in at least one of five periods (1988-1990, 1991-1992, 1993-1994, 1995-1996, 1997) were defined as being rare. A total of 9110 HIV-infected subjects were included in this study. Over the entire 9-year period, the following rare diseases were diagnosed: progressive multifocal leukoencephalopathy (n = 138), disseminated cryptococcosis (n = 67), visceral herpes simplex disease (n = 66), primary cerebral lymphoma (n = 65), indeterminate cerebral lesion (n = 50), cryptococcal meningitis (n = 34), Mycobacterium kansasii disease (n = 32), recurrent Salmonella septicemia (n = 22), intestinal isosporiasis (n = 21), candidiasis of the trachea, bronchi and lungs (n = 19), toxoplasma retinitis (n = 16), disseminated toxoplasmosis (n = 8), invasive cervical carcinoma (n = 8), extrapulmonary Pneumocystis disease (n = 5), disseminated histoplasmosis (n = 1) and disseminated coccidioidomycosis (n = 1). Rare diseases accounted for 7.3% of all AIDS-defining diseases over the entire 9-year period. Physicians should be aware of the likelihood of a broad spectrum of AIDS-defining diseases in HIV-infected patients.

AIDS-Related Opportunistic Infections↗
PubMed1999

The influence of dietary and nondietary calcium supplementation on blood pressure: an updated metaanalysis of randomized controlled trials.

We updated our previous systematic review of the effect of supplemental calcium on blood pressure. We extended our previous searches on MEDLINE and EMBASE to May 1997 and examined citations from relevant articles. We contacted the authors of eligible trials to ensure the accuracy and completeness of data, and to identify unpublished trials. We included any study in which investigators randomized hypertensive or normotensive people to calcium supplementation or alternative therapy and measured blood pressure for at least 2 weeks. In addition to 32 trials included in the prior metaanalysis, 10 new trials contributed to this metaanalysis. Two pairs of independent reviewers abstracted data and assessed the validity of the study data according to six quality criteria. We calculated the differences in blood pressure change between the calcium supplementation and control groups and pooled the estimates with each trial weighted with the inverse of the variance using a random effects model. The predictors of blood pressure reduction that we examined included method of supplementation, baseline blood pressure, and the methodologic quality of the studies. The pooled analysis shows a reduction in systolic blood pressure of -1.44 mm Hg (95% confidence interval -2.20 to -0.68; P < .001) and in diastolic blood pressure of -0.84 mm Hg (95% confidence interval -1.44 to -0.24; P < .001). We found statistically significant heterogeneity of results across trials (P < or = .02), which persisted when we looked at the nondietary trials alone, but not when we restricted our analysis to dietary trials. Although there was a trend toward larger effects with dietary interventions, none of the possible mediators of blood pressure reduction explained differences in treatment effect. We conclude that calcium supplementation leads to a small reduction in systolic and diastolic blood pressure. The effect of supplemental calcium in the diet is at least as great as nondietary supplementation.

Blood Pressure↗
PubMed1999

Systematic validation of disease models for pharmacoeconomic evaluations. Swiss HIV Cohort Study.

Pharmacoeconomic evaluations are often based on computer models which simulate the course of disease with and without medical interventions. The purpose of this study is to propose and illustrate a rigorous approach for validating such disease models. For illustrative purposes, we applied this approach to a computer-based model we developed to mimic the history of HIV-infected subjects at the greatest risk for Mycobacterium avium complex (MAC) infection in Switzerland. The drugs included as a prophylactic intervention against MAC infection were azithromycin and clarithromycin. We used a homogenous Markov chain to describe the progression of an HIV-infected patient through six MAC-free states, one MAC state, and death. Probability estimates were extracted from the Swiss HIV Cohort Study database (1993-95) and randomized controlled trials. The model was validated testing for (1) technical validity (2) predictive validity (3) face validity and (4) modelling process validity. Sensitivity analysis and independent model implementation in DATA (PPS) and self-written Fortran 90 code (BAC) assured technical validity. Agreement between modelled and observed MAC incidence confirmed predictive validity. Modelled MAC prophylaxis at different starting conditions affirmed face validity. Published articles by other authors supported modelling process validity. The proposed validation procedure is a useful approach to improve the validity of the model.

AIDS-Related Opportunistic Infections↗
PubMed1999

Treatment for human immunodeficiency virus with indinavir may cause relevant urological side-effects, effectively treatable by rehydration.

OBJECTIVE: To explore the occurrence of, and diagnostic and therapeutic procedures for urological side-effects (e.g. micro- and macrohaematuria, and kidney stone formation) in individuals treated with indinavir for the human immunodeficiency virus (HIV). PATIENTS AND METHODS: The study comprised a retrospective follow-up of 74 individuals infected with HIV-1 and who were treated with indinavir orally at a daily dose of 2.4 g. Data were collected at the outpatient department of our institution between March 1996 and November 1997. RESULTS: Of the 74 individuals treated with indinavir, 15 (20%) had indinavir-related urological side-effects (19 episodes), most commonly dull flank pain and dysuria. Microhaematuria occurred in 16 of the 19 episodes. Four patients showed urinary tract distension ultrasonographically as a possible indirect sign of urolithiasis and one patient passed a kidney stone. In four patients treatment had to be stopped permanently, but in the remaining 11 patients treatment was continued. Some patients required dose reduction and/or interruption of treatment; only conservative therapeutic measures were required, consisting of rehydration (fluid intake >1.5 L/day) and analgesics. CONCLUSIONS: Urological side-effects of indinavir may be apparent in 20% of patients so treated; some (5%) may require permanent withdrawal. In addition to a history and clinical examination, urine analysis and ultrasonography were the only diagnostic procedures required. Therapy is mainly conservative, using rehydration, analgesics and a brief discontinuation of therapy, according to the severity of the symptoms.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Cost-effectiveness of azithromycin for preventing Mycobacterium avium complex infection in HIV-positive patients in the era of highly active antiretroviral therapy. The Swiss HIV Cohort Study.

We conducted a cost-effectiveness analysis to determine the clinical and economic consequences of Mycobacterium avium complex (MAC) prophylaxis in HIV-infected patients in the era of highly active antiretroviral therapy (HAART) in a health care system with access unrestricted by financial barriers. The analysis was performed from a health care perspective and compared azithromycin (1200 mg/week) with no prophylaxis over a period of 10 years based on data from the Swiss HIV Cohort Study (SHCS) and randomized controlled trials. The main outcome measures were: expected survival; average health care costs; and cost-effectiveness in 1997 Swiss francs ( pound1 corresponds to about 2.3 CHF) per life-year saved. In patients with an initial CD4 count <50 cells/mm(3) and no AIDS, azithromycin increased expected survival by 4 months. In patients with AIDS, HAART durability had a major impact on expected survival and costs. Incremental survival increased from 2 to 4 months if we assumed a 10 year, instead of a 3 year, HAART effect. The cost-effectiveness of azithromycin relative to no prophylaxis in patients without AIDS was between 47,000 CHF (3-year HAART effect) and 60,000 CHF (10-year HAART effect) per life-year saved. The cost-effectiveness ratio increased to 118,000 CHF per life-year saved in patients with symptomatic AIDS. In conclusion, in the era of HAART, MAC prophylaxis with azithromycin increases expected survival and reduces health care costs substantially. Starting MAC prophylaxis in patients without AIDS is more effective and cost-effective than in patients with AIDS.

AIDS-Related Opportunistic Infections↗
PubMed1999

Systematic review on the risk and benefit of different cholesterol-lowering interventions.

Meta-analyses have investigated the efficacy of cholesterol-lowering interventions in relation to the underlying risk of coronary heart disease and the extent and duration of cholesterol reduction. We systematically reviewed the efficacy of antilipidemic interventions on major mortality outcomes in relation to drug classes. We searched MEDLINE and EMBASE from 1966 through October 1996 for randomized, controlled trials of any cholesterol-lowering interventions reporting mortality data. We included 59 trials involving 85 431 participants in the intervention and 87 729 participants in the control groups. We pooled these trials into 7 pharmacological categories of cholesterol-lowering interventions: statins (13 trials), fibrates (12 trials), resins (8 trials), hormones (8 trials), niacin acid (2 trials), n-3 fatty acids (3 trials), and dietary interventions (16 trials). Of the cholesterol-lowering interventions, only statins showed a large and statistically significant reduction in mortality from coronary heart disease (risk ratio, 0.66; 95% confidence interval [CI], 0.54 to 0. 79) and from all causes (risk ratio, 0.75; 95% CI, 0.65 to 0.86). For both all-cause and cardiovascular mortality, the difference between statins and the combined estimate of the other classes of agents was unlikely to be due to chance (P<0.02 for both comparisons). Meta-regression analysis demonstrated that variability in results across trials could be largely explained on the basis of differences in the magnitude of cholesterol reduction. Statins have the largest effect on the reduction of cardiovascular and all-cause mortality, and this result recommends their use in preference to other antilipidemic agents. The greater effect of statins is likely due to the larger reduction in cholesterol.

Anticholesteremic Agents↗
PubMed1999

A randomized trial of interferon-alpha2a and zidovudine versus bleomycin and zidovudine for AIDS-related Kaposi's sarcoma. Swiss HIV Cohort Study.

The efficacy and toxicity of interferon-alpha2a (9MU/d) and bleomycin (15 mg every 2 weeks), each combined with zidovudine (2x250 mg/d), was compared in a randomized study in 26 men with progressing AIDS-related Kaposi's sarcoma (KS). The median CD4 count was 113/microl. Complete or partial response was achieved in one (8%) of 12 evaluable patients on interferon and in 2 (20%) of 10 patients on bleomycin (P = 0.43) during 4.7 and 5.3 months of treatment, respectively. The tolerability was comparable. During extended follow up, survival time was 24 and 13 months in the interferon and bleomycin arm, respectively. In a multivariate Cox regression analysis, CD4 lymphocytes <200/microl (relative risk 3.74; 95% CI: 1.30-10.8) and randomization to interferon (relative risk 0.37; 95% CI: 0.15-0.90) were significantly predictive of mortality. New AIDS-related events occurred more frequently in patients who had received bleomycin. The antiviral activity of interferon-alpha or the chemotherapy-mediated increase in the risk for opportunistic infections may explain these differences.

Acquired Immunodeficiency Syndrome↗
PubMed1998

[Quality aspects in internal medicine--from anamnesis to meta-analysis].

Quality aspects get more important in internal medicine due to novel technical developments and economic constraints. In spite of an extensive research activity in clinical medicine some research aspects of quality control are new. Among these are investigations about symptoms and complaints as well as risk factors. Too much evidence might also blur the view when the necessary data might already be available from existing studies but conclusions have not been drawn to improve quality of patient care. An instrument to this end is metaanalysis compounding the results of single studies to a more meaningful result. Thus further unnecessary trials can be avoided. Finally quality control is characterized by readiness to self-criticism. Its aim is to avoid mistakes and intends to optimize medical actions whenever possible.

Diagnosis↗
PubMed1998

A placebo-controlled trial of didanosine plus stavudine, with and without hydroxyurea, for HIV infection. The Swiss HIV Cohort Study.

OBJECTIVE: To explore the short-term effects on surrogate markers for HIV progression of didanosine (ddl) plus stavudine (d4T), with or without hydroxyurea. DESIGN: Randomized, double-blinded, prospective study. SETTING: Swiss HIV Cohort Study. PATIENTS: A total of 144 patients (75% antiretroviral-naive) were studied (mean baseline HIV-1 RNA, 4.53 log10 copies/ml; mean CD4 cell count, 370 x 10(6)/l). INTERVENTION: Patients received ddl (200 mg twice daily) plus d4T (40 mg twice daily), with additional hydroxyurea (500 mg twice daily) or placebo. MAIN OUTCOME MEASURES: The primary endpoint was a reduction of viraemia below 200 copies/ml after 12 weeks. At that time, patients who did not reach the primary endpoint were withdrawn in the hydroxyurea arm, whereas patients in the placebo group had the option of adding hydroxyurea to ddl and d4T. All patients were followed until week 24. RESULTS: After 12 weeks, 54% of the patients randomized to hydroxyurea had viraemia below 200 copies/ml, compared with 28% on placebo (P < 0.001). Using an ultrasensitive assay with a limit of detection of 20 copies/ml, 19% of patients receiving hydroxyurea had viraemia levels below 20 copies/ml, compared with 8% on placebo (P = 0.05). Mean decrease in HIV-1 RNA was 2.3 and 1.7 log10 copies/ml for hydroxyurea and placebo groups, respectively (P = 0.001). Hydroxyurea was found to induce lymphopenia (-124 x 10(6)/l). Increase in CD4 cell counts was +28 x 10(6)/l during hydroxyurea treatment compared with +107 x 10(6)/l on placebo (P = 0.001). CONCLUSIONS: Hydroxyurea improved the antiviral activity of d4T and ddl over a 12-week period, but was associated with a smaller increase in CD4 cell counts due to hydroxyurea-induced lymphopenia.

Adult↗
PubMed1998

Effect of HMGcoA reductase inhibitors on stroke. A meta-analysis of randomized, controlled trials.

BACKGROUND: Stroke is a leading cause of death in the industrialized world, and hypercholesterolemia may be a risk factor for stroke. OBJECTIVE: To determine whether reducing cholesterol levels with HMGcoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase inhibitors or other antilipidemic interventions reduces risk for nonfatal and fatal stroke. DATA SOURCES: A systematic search in the MEDLINE and EMBASE databases of the English-language and non-English-language literature published from 1966 through October 1996. STUDY SELECTION: All randomized, controlled trials of any cholesterol-lowering intervention that reported data on nonfatal and fatal strokes, on death from coronary heart disease, and on overall mortality were included. Whether treatment effects differed according to the type of cholesterol-lowering intervention used was investigated. DATA EXTRACTION: Trials were reviewed for methods, inclusion and exclusion criteria, and outcomes. DATA SYNTHESIS: 28 trials (for a total of 49,477 study participants in the intervention group and 56,636 participants in the control group) were included. The risk ratio for nonfatal and fatal stroke with HMGcoA reductase inhibitors was 0.76 (95% CI, 0.62 to 0.92; test of heterogeneity, P > 0.2). The risk ratios for nonfatal and fatal stroke with fibrates, resins, and dietary interventions were all close to 1.0, and the difference between the HMGcoA reductase inhibitor effect and the pooled estimate for all other interventions would, under the null hypothesis, be unlikely to occur by chance (P = 0.01). Trials with HMGcoA reductase inhibitors also showed reductions in rates of death from coronary heart disease and overall mortality. CONCLUSION: This meta-analysis of randomized, controlled trials suggests that in hyperlipidemic patients who have not previously had stroke, HMGcoA reductase inhibitors reduce the incidence of stroke.

Cerebrovascular Disorders↗
PubMed1998

Teaching physicians about different measures of risk reduction may alter their treatment preference.

We explored during a postgraduate workshop whether basic teaching about absolute and relative effect measures changed physicians' perceptions of the benefit to be derived from modifying particular cardiovascular risk factors. Before and after instruction physicians were asked about the priority they would give to interventions to reduce four risk factors of coronary heart disease in two male patients, aged 35 and 65 years with multiple risk factors. They were given information about the relative risk (RR), absolute risk reduction (ARR) and the number of patients who need to be treated (NNT) to prevent one event associated with the modification of each risk factor. Ratings of 48 of the 67 participating physicians (71.6%) were evaluated. About half did not change their choices regarding the benefit from a particular intervention. Among those who changed, the new choice was in favor of the patient with the higher ARR for three risk factors (hypertension, p = 0.01; smoking, p = 0.002; non-insulin-dependent diabetes, p = 0.05) but not the fourth (left ventricular hypertrophy, p = 0.82). Teaching basic principles of clinical epidemiology to physicians can have an impact on their perception of treatment effects. However, this will not suffice in itself to guarantee that this new knowledge will become part of their clinical practice.

Adult↗
PubMed1998

"Incomplete resection" in non-small cell lung cancer: need for a new definition. Canadian Lung Oncology Group.

BACKGROUND: This study was designed to determine the prognostic value of positive surgical resection margin or highest nodal station sampled at thoracotomy in patients with non-small cell lung cancer. METHODS: Two reviewers independently examined the surgical records and pathologic reports from a randomized trial comparing computed tomography versus mediastinoscopy for staging of lung cancer. They recorded pathologic findings at the surgical resection margin, the highest mediastinal nodal station sampled at thoracotomy, histologic type, tumor size, N status, and evidence of vascular or lymphatic invasion. These variables formed the independent variables in logistic regression models to predict recurrence. RESULTS: Except for 1 patient, follow-up at 3 years for 399 included patients was complete. Significant predictors of recurrence were tumor size (odds ratio [OR], 1.2 (per centimeter); 99% CI [confidence interval], 1.1 to 1.4), and N status (compared with N0, N1: OR, 1.6; CI, 0.8 to 3.1; N2: OR, 3.2; CI, 1.4 to 7.5). Other variables, including positive surgical resection margin, did not predict early recurrence or death. CONCLUSIONS: In patients with non-small cell lung cancer, surgical resection margin or highest nodal station sampled at thoracotomy that are involved by carcinoma do not predict recurrence. The current definition of incomplete resection has limited prognostic significance.

Aged↗
PubMed1997

Meta-analysis of prophylactic treatments against Pneumocystis carinii pneumonia and toxoplasma encephalitis in HIV-infected patients.

In a meta-analysis, we examined the efficacy of aerosolized pentamidine, trimethoprim-sulfamethoxazole, and dapsone or dapsone/pyrimethamine for the prevention of Pneumocystis carinii pneumonia and toxoplasma encephalitis in patients with HIV infection. Of 22 trials, 13 compared trimethoprim-sulfamethoxazole with aerosolized pentamidine, nine compared dapsone alone or in combination with pyrimethamine with aerosolized pentamidine, and eight compared trimethoprim-sulfamethoxazole with dapsone/pyrimethamine. In total, 1484 patients were treated with trimethoprim-sulfamethoxazole, 1548 patients with dapsone/pyrimethamine or dapsone, and 1800 patients with aerosolized pentamidine. For dapsone/pyrimethamine versus aerosolized pentamidine, the risk ratio for P. carinii pneumonia was 0.90 (95% confidence interval [CI], 0.71-1.15), and for toxoplasma encephalitis it was 0.72 (95% CI, 0.54-0.97). For trimethoprim-sulfamethoxazole versus aerosolized pentamidine, the risk ratio of P. carinii pneumonia was 0.59 (95% CI, 0.45-0.76), and for toxoplasma encephalitis it was 0.78 (95% CI, 0.55-1.11). For trimethoprim-sulfamethoxazole versus dapsone/pyrimethamine, the risk ratio of P. carinii pneumonia was 0.49 (95% CI, 0.26-0.92), and for toxoplasma encephalitis it was 1.17 (95% CI, 0.68-2.04). Although current evidence does not allow a definitive recommendation, administration of trimethoprim-sulfamethoxazole for prophylaxis of P. carinii pneumonia and toxoplasmosis in patients with HIV infection is consistent with the available data.

AIDS-Related Opportunistic Infections↗