Effect of nesiritide in patients with acute decompensated heart failure

BACKGROUND

Nesiritide is approved in the United States for early relief of dyspnea in patients with acute heart failure. Previous meta-analyses have raised questions regarding renal toxicity and the mortality associated with this agent.

METHODS

We randomly assigned 7141 patients who were hospitalized with acute heart failure to receive either nesiritide or placebo for 24 to 168 hours in addition to standard care. Coprimary end points were the change in dyspnea at 6 and 24 hours, as measured on a 7-point Likert scale, and the composite end point of rehospitalization for heart failure or death within 30 days.

RESULTS

Patients randomly assigned to nesiritide, as compared with those assigned to placebo, more frequently reported markedly or moderately improved dyspnea at 6 hours (44.5% vs. 42.1%, P=0.03) and 24 hours (68.2% vs. 66.1%, P=0.007), but the prespecified level for significance (P≤0.005 for both assessments or P≤0.0025 for either) was not met. The rate of rehospitalization for heart failure or death from any cause within 30 days was 9.4% in the nesiritide group versus 10.1% in the placebo group (absolute difference, -0.7 percentage points; 95% confidence interval [CI], -2.1 to 0.7; P=0.31). There were no significant differences in rates of death from any cause at 30 days (3.6% with nesiritide vs. 4.0% with placebo; absolute difference, -0.4 percentage points; 95% CI, -1.3 to 0.5) or rates of worsening renal function, defined by more than a 25% decrease in the estimated glomerular filtration rate (31.4% vs. 29.5%; odds ratio, 1.09; 95% CI, 0.98 to 1.21; P=0.11).

CONCLUSIONS

Nesiritide was not associated with an increase or a decrease in the rate of death and rehospitalization and had a small, nonsignificant effect on dyspnea when used in combination with other therapies. It was not associated with a worsening of renal function, but it was associated with an increase in rates of hypotension. On the basis of these results, nesiritide cannot be recommended for routine use in the broad population of patients with acute heart failure. (Funded by Scios; ClinicalTrials.gov number, NCT00475852.).

Association of intradialytic blood pressure changes with hospitalization and mortality rates in prevalent ESRD patients

The relationship between blood pressure (BP) and clinical outcomes among hemodialysis patients is complex and incompletely understood. This study sought to assess the relationship between blood pressure changes with hemodialysis and clinical outcomes during a 6-month period. This study is a secondary analysis of the Crit-Line Intradialytic Monitoring Benefit Study, a randomized trial of 443 hemodialysis subjects, designed to determine whether blood volume monitoring reduced hospitalization. Logistic regression was used to estimate the association between BP changes with hemodialysis (Deltasystolic blood pressure=postdialysis-predialysis systoic BP (SBP) and the primary outcome of non-access-related hospitalization and death. Subjects whose systolic blood pressure fell with dialysis were younger, took fewer blood pressure medications, had higher serum creatinine, and higher dry weights. After controlling for baseline characteristics, lab variables, and treatment group, subjects whose SBP remained unchanged with hemodialysis (N=150, DeltaSBP -10 to 10 mm Hg) or whose SBP rose with hemodialysis (N=58, DeltaSBP > or =10 mm Hg) had a higher odds of hospitalization or death compared to subjects whose SBP fell with hemodialysis (N=230, DeltaSBP < or =-10 mm Hg) (odds ratio: 1.85, confidence interval: 1.15-2.98; and odds ratio: 2.17, confidence interval: 1.13-4.15). Subjects whose systolic blood pressure fell with hemodialysis had a significantly decreased risk of hospitalization or death at 6 months, suggesting that hemodynamic responses to dialysis are associated with short-term outcomes among a group of prevalent hemodialysis subjects. Further research should attempt to elucidate the mechanisms behind these findings.

Initial experience with factor-Xa inhibition in percutaneous coronary intervention: the XaNADU-PCI Pilot

BACKGROUND

Direct factor (F)Xa inhibition is an attractive method to limit thrombotic complications during percutaneous coronary intervention (PCI).

OBJECTIVES

To investigate drug levels achieved, effect on coagulation markers, and preliminary efficacy and safety of several doses of DX-9065a, an intravenous, small molecule, direct, reversible FXa inhibitor during PCI.

PATIENTS AND METHODS

Patients undergoing elective, native-vessel PCI (n = 175) were randomized 4 : 1 to open-label DX-9065a or heparin in one of four sequential stages. DX-9065a regimens in stages I-III were designed to achieve concentrations of > 100 ng mL-1, > 75 ng mL-1, and > 150 ng mL-1. Stage IV used the stage III regimen but included patients recently given heparin.

RESULTS

At 15 min median (minimum) DX-9065a plasma levels were 192 (176), 122 (117), 334 (221), and 429 (231) ng mL-1 in stages I-IV, respectively. Median whole-blood international normalized ratios (INRs) were 2.6 (interquartile range 2.5, 2.7), 1.9 (1.8, 2.0), 3.2 (3.0, 4.1), and 3.8 (3.4, 4.6), and anti-FXa levels were 0.36 (0.32, 0.38), 0.33 (0.26, 0.39), 0.45 (0.41, 0.51), and 0.62 (0.52, 0.65) U mL-1, respectively. Stage II enrollment was stopped (n = 7) after one serious thrombotic event. Ischemic and bleeding events were rare and, in this small population, showed no clear relation to DX-9065a dose.

CONCLUSIONS

Elective PCI is feasible using a direct FXa inhibitor for anticoagulation. Predictable plasma drug levels can be rapidly obtained with double-bolus and infusion DX-9065a dosing. Monitoring of DX-9065a may be possible using whole-blood INR. Direct FXa inhibition is a novel and potentially promising approach to anticoagulation during PCI that deserves further study.

Time-based risk assessment after myocardial infarction. Implications for timing of discharge and applications to medical decision-making

AIMS

We evaluated timing of adverse cardiac events after thrombolysis to guide length of stay after ST-segment elevation myocardial infarction.

METHODS AND RESULTS

Kaplan-Meier survival curves described timing of major postinfarction complications in 41021 fibrinolytic-treated patients in GUSTO-I. Using model-fitting, these data were best explained by a mixed-exponential survival model: an acute curve describing most adverse events and a chronic curve describing a lower background rate. We replicated this strategy in 15059 fibrinolytic-treated patients in GUSTO-III. From the relation between time and events described by the model's acute curve in GUSTO-III, we proposed times for hospital discharge. The acute curve explained 97% of deaths and 68%-96% of various event composites. Of complications within 10 days, 90% of deaths and 70% of acute curve death, stroke, shock, heart failure, or reinfarction occurred by 24 h. By 2.7 days, 95% of deaths, stroke, shock, heart failure, or reinfarction occurred. Most major ventricular arrhythmias occurred within 24 h, after which the hazard curve was flat.

CONCLUSIONS

Mixed-exponential survival modelling describes timing of post-infarction complications and supports discharge 4 days after uncomplicated infarction. Such time-based risk assessment could guide decision-making in other settings in which randomized studies are impractical.

A randomized, placebo-controlled trial of enoxaparin after high-risk coronary stenting: the ATLAST trial

OBJECTIVES

We performed a multicenter, double-blind placebo-controlled trial to examine the efficacy and safety of enoxaparin in patients at high risk for stent thrombosis (ST).

BACKGROUND

The optimal antithrombotic regimen for such patients is unknown.

METHODS

We randomized 1,102 patients with clinical, angiographic or ultrasonographic features associated with an increased risk of ST to receive either twice-daily injections of weight-adjusted enoxaparin or placebo for 14 days after stenting. All patients received aspirin and ticlopidine. The primary end point was a 30-day composite end point of death, myocardial infarction (MI) or urgent revascularization.

RESULTS

The target enrollment for the study was 2,000 patients. However, the trial was terminated prematurely at 1,102 patients after interim analysis revealed an unexpectedly low event rate. The primary outcome occurred in 1.8% enoxaparin-treated patients versus 2.7% treated with placebo (odds ratio [OR] 0.66; 95% confidence interval [CI] 0.29 to 1.5, p = 0.30); for death or MI the rates were 0.9% vs. 2.2%, respectively (OR 0.41, 95% CI 0.14 to 1.2, p =0.13); and for MI, 0.4% vs. 1.6%, respectively (OR 0.22, 95% CI 0.05 to 0.99, p = 0.04). The groups had comparable rates of major bleeding (3.3% for enoxaparin, 1.6% for placebo, p =0.08), but minor nuisance bleeding was increased with enoxaparin (25% vs. 5.1%, p < 0.001).

CONCLUSIONS

The clinical outcomes of patients at increased risk of ST are more favorable than previously reported, rendering routine oral antiplatelet therapy adequate for most. However, given its relative safety and potential to reduce the risk of subsequent infarction, a 14-day course of enoxaparin may be considered for carefully selected patients.

Prognostic usefulness of the six-minute walk in patients with advanced congestive heart failure secondary to ischemic or nonischemic cardiomyopathy

Clinicians have relied on history and results from physical examinations to guide treatment of patients with advanced congestive heart failure, but these results may not reflect disease severity or hemodynamic status. We assessed how the distance walked in 6 minutes relates to clinical outcomes and symptoms of such patients. We compared the rates of death, hospitalization, and their composite at 1 year by the distance walked in 6 minutes at baseline and at 1 month, and by the change in distance between baseline and 1 month in 440 patients enrolled in a randomized trial. We also assessed the relations of baseline distance walked to symptom score and New York Heart Association class. The median distance increased from 218 m at baseline to 280 m at 1 month. Of 365 patients able to perform the baseline walk, 121 (33%) died and 217 (60%) were hospitalized compared with 46 (61%) and 34 (45%) of 75 patients unable to walk at baseline. Baseline distance significantly predicted mortality (hazard ratio 0.58/100-m increase, 95% confidence interval 0.50 to 0.68, p <0.001), even after adjustment. Baseline distance also significantly predicted hospitalization and the composite end point, as did the 1-month distance walked. The change in distance walked from baseline to 1 month did not predict any end point. Baseline distance correlated only moderately with symptom score (r = -0.385, p <0.001) and New York Heart Association class (r = -0.468, p <0.001). Distance walked during 6 minutes independently and strongly predicts mortality and hospitalization in patients with advanced congestive heart failure. This may be a simple, noninvasive, objective way to risk-stratify these patients and standardize their treatment.

Relationship between transferrin saturation and iron stores in the African American and US Caucasian populations: analysis of data from the third National Health and Nutrition Examination Survey

In previous analyses of transferrin saturation data in African Americans and Caucasians from the second National Health and Nutrition Examination Survey (NHANES II), subpopulations were found consistent with population genetics for common loci that influence iron metabolism. The goal of this new study was to determine if these transferrin saturation subpopulations have different levels of iron stores. Statistical mixture modeling was applied to transferrin saturation data for African Americans and Caucasians from the third National Health and Nutrition Examination Survey (NHANES III), and then the mean serum ferritin concentrations were determined for the transferrin saturation subpopulations that were identified. After adjustment for diurnal variation, 3 subpopulations of transferrin saturation were identified in each racial group. Satisfying Hardy-Weinberg conditions for major locus effects, in both racial groups the sum of the square roots of the proportion with the lowest mean transferrin saturation and the proportion with the highest mean transferrin saturation was approximately 1. When weighted to reflect the US adult population as a whole, these subpopulations of increasing transferrin saturations had progressively increasing mean age-adjusted serum ferritin concentration values in each ethnic grouping as stratified by sex (trend test, P <.002 for all). These results are consistent with the concept that population transferrin saturation subpopulations reflect different levels of storage iron.

Epoetin treatment of anemia associated with cancer therapy: a systematic review and meta-analysis of controlled clinical trials

Epoetin treatment offers an attractive but costly alternative to red blood cell transfusion for managing anemia associated with cancer therapy. The goal of this review is to facilitate more efficient use of epoetin by 1) quantifying the effects of epoetin on the likelihood of transfusion and on quality of life in patients with cancer treatment-related anemia and 2) evaluating whether outcomes are superior when epoetin treatment is initiated at higher hemoglobin thresholds. Two independent reviewers followed a prospective protocol for identifying studies. Outcomes data were combined with the use of a random-effects meta-analysis model. Double-blind, randomized, controlled trials that minimized patient exclusions were defined as higher quality for sensitivity analysis; randomized but unblinded trials and trials with excessive exclusions were included in the meta-analysis but were defined as lower quality. Twenty-two trials (n = 1927) met inclusion criteria, and 12 (n = 1390) could be combined for estimation of odds of transfusion. Epoetin decreased the percentage of patients transfused by 9%-45% in adults with mean baseline hemoglobin concentrations of 10 g/dL or less (seven trials; n = 1080), by 7%-47% in those with hemoglobin concentrations greater than 10 g/dL but less than 12 g/dL (seven trials; n = 431), and by 7%-39% in those with hemoglobin concentrations of 12 g/dL or higher (five trials; n = 308). In sensitivity analysis, the combined odds ratio for transfusion in epoetin-treated patients as compared with controls was 0.45 (95% confidence interval [CI] = 0.33 to 0.62) in higher quality studies and 0.14 (95% CI = 0.06 to 0.31) in lower quality studies. The number of patients needed to treat to prevent one transfusion is 4.4 for all studies, 5.2 for higher quality studies, and 2.6 for lower quality studies. Only studies with mean baseline hemoglobin concentrations of 10 g/dL or less reported statistically significant effects of epoetin treatment on quality of life; quality-of-life data were insufficient for meta-analysis. No studies addressed epoetin's effects on anemia-related symptoms. We conclude that epoetin reduces the odds of transfusion for cancer patients undergoing therapy. Evidence is insufficient to determine whether initiating epoetin earlier spares more patients from transfusion or results in better quality of life than waiting until hemoglobin concentrations decline to nearly 10 g/dL.

Assessing the clinical and economic burden of coronary artery disease: 1986-1998

BACKGROUND

The acute phase of coronary artery disease (CAD) is dramatic and receives much attention because of its high mortality and associated treatment cost. However, the acute phase typically resolves within 30 days whereas CAD is a chronic disease, which most patients will live with for more than a decade. We compared the clinical and economic burden of CAD during the acute phase (first 30 days) with that in the postacute phase (31st day through 10 years).

METHODS

We included acute coronary syndrome (ACS) patients with significant CAD receiving an initial cardiac catheterization at Duke University Medical Center between 1986 and 1997 with follow-up continuing through 1998. Inpatient medical costs were estimated from ACS clinical trial and economic study data. Costs were adjusted to 1997 values and discounted at 3% per annum.

RESULTS

Our study included 9,876 ACS patients (5,557 with an acute myocardial infarction [MI] and 4,319 with unstable angina [UA]). Acute MI patients had higher 30-day mortality than UA patients (5.6% vs. 2.3%, P <0.001). In addition, acute MI and UA patients had significant 10-year unadjusted and adjusted survival differences (both P <0.001). For patients who survived to 30 days, there was no difference in 10-year survival between acute MI and UA patients before adjustment (P = 0.472). After adjustment, however, unstable angina patients who survived to 30 days had greater survival than myocardial infarction patients (P = 0.011). Mean 10-year discounted ACS inpatient medical costs were $45,253 ($23,510 acute phase and $21,819 postacute phase, P = 0.002). Ten year costs for unstable angina patients were $46,423 ($21,824 acute phase and $24,599 postacute phase, P = 0.003); ten year costs for myocardial infarction patients were $44,663 ($24,823 acute phase and $19,840 postacute phase, P <0.001).

CONCLUSIONS

We found that the clinical and economic burden of CAD continues long after a patient's acute event has resolved and that postacute CAD cardiac event rates and inpatient medical costs may be higher than previously estimated. With much of all medical costs occurring in the postacute phase, the potential for effective secondary prevention therapies is substantial.

Benefit of glycoprotein IIb/IIIa inhibition in patients with acute coronary syndromes and troponin t-positive status: the paragon-B troponin T substudy

BACKGROUND

Troponin T (TnT) is valuable for short- and long-term risk stratification of patients with acute coronary syndromes (ACS). It also may predict which ACS patients will benefit from glycoprotein (GP) IIb/IIIa blockade.

METHODS AND RESULTS

We prospectively studied 1160 patients with non-ST-segment elevation ACS randomized in PARAGON-B to receive lamifiban, an intravenous GP IIb/IIIa antagonist, or placebo. TnT levels were obtained before study treatment began and 24 to 72 hours later; assays were performed by a blinded core laboratory. At baseline, 40.2% of patients were TnT-positive (>/=0.1 ng/mL); these patients were older and more often male or smokers. Patients positive at baseline had a significantly higher rate of the primary end point (composite of death, myocardial [re]infarction, or severe recurrent ischemia at 30 days; odds ratio, 1.5; 95% CI, 1.1 to 2.1) than those who were TnT-negative. Lamifiban was associated with significant reduction in the primary end point (from 19.4% to 11.0%, P=0.01) among TnT-positive patients but not among TnT-negative patients (11.2% for placebo versus 10.8% for lamifiban, P=0.86; P=0.08 for test of interaction between TnT status and treatment assignment). This pattern held for the end points of death alone and death or myocardial (re)infarction at 30 days. Peak TnT level at 48 hours did not differ with lamifiban treatment.

CONCLUSIONS

TnT predicts poor short-term outcomes in non-ST-segment elevation ACS. Treatment benefit with lamifiban is limited almost exclusively to TnT-positive patients, reducing 30-day adverse outcomes to a rate nearly identical to that of negative patients.

Hemodynamic profiles of advanced heart failure: association with clinical characteristics and long-term outcomes

BACKGROUND

Classifying patients with advanced congestive heart failure (CHF) by baseline measures of congestion and perfusion has been used to estimate hemodynamic status and to select and titrate therapy. We describe clinical characteristics of 4 hemodynamic profiles-wet/cold, wet/warm, dry/cold, and dry/warm-in patients with advanced CHF and assess relations between symptoms, physical signs, and outcomes with each profile.

METHODS AND RESULTS

We retrospectively assessed baseline symptoms, physical-examination variables, and 1-year outcomes of 440 patients in a randomized trial. With univariable and multivariable logistic regression, we examined relations of physical-examination variables to hemodynamic profiles. We also assessed the rates of death and death or readmission by profile. Severity of CHF symptoms did not predict the wet-versus-dry profile or cold-versus-warm status, despite significant differences in hemodynamics among groups. Of the physical-examination variables, only a lower proportional pulse pressure was a significant multivariable predictor of the wet category. Among wet patients (n = 348), this same variable was the only significant multivariable predictor of the cold category. For dry patients (n = 92), the cold category was predicted in multivariable analysis by supine heart rate and hepatomegaly. Survival was similar among profiles: wet/cold, 54.2% (n = 91); wet/warm, 58.3% (n = 105); dry/cold, 78.9% (n = 15); and dry/warm, 67.1%, P =.13 (n = 49). Event-free survival also was similar among profiles: wet/cold, 22.0% (n = 37); wet/warm, 29.4% (n = 53); dry/cold, 42.1% (n = 8); and dry/warm, 31.5%, P =.44 (n = 23).

CONCLUSIONS

The patient's history and physical examination alone may lead to inaccurate estimation of hemodynamic status and thus suboptimal management for patients with advanced CHF.

Platelet glycoprotein IIb/IIIa integrin blockade with eptifibatide in coronary stent intervention: the ESPRIT trial: a randomized controlled trial

CONTEXT

The Enhanced Suppression of the Platelet IIb/IIIa Receptor with Integrilin Therapy (ESPRIT) trial showed the efficacy of adjunctive, double-bolus eptifibatide therapy in reducing ischemic complications of nonurgent coronary stent implantation at 48 hours and at 30 days.

OBJECTIVE

To determine whether the beneficial effects of eptifibatide persist at 6 months after treatment.

DESIGN

Follow-up study of a randomized, double-blind, placebo-controlled, crossover-permitted trial conducted from June 1999 through February 2000.

SETTING

Ninety-two tertiary care centers in the United States and Canada.

PARTICIPANTS

A total of 2064 patients scheduled to undergo nonurgent percutaneous coronary intervention with stent implantation.

INTERVENTION

Patients were randomly assigned to receive placebo or eptifibatide (two 180-microg/kg boluses 10 minutes apart and continuous infusion of 2.0 microg/kg per minute), started immediately before stent implantation and continued for 18 to 24 hours. Complete follow-up data were available for 988 (95.0%) of 1040 patients given eptifibatide and 977 (95.4%) of 1024 patients given placebo.

MAIN OUTCOME MEASURES

Composite rates of death or myocardial infarction (MI); death, MI, or target vessel revascularization; and their individual components 6 months after enrollment, compared between the 2 groups.

RESULTS

By 6 months, the composite end point of death or MI had occurred in 7.5% of eptifibatide-treated patients and in 11.5% of placebo-treated patients (hazard ratio [HR], 0.63; 95% confidence interval [CI], 0.47-0.84; P =.002). The composite of death, MI, or target vessel revascularization was 14.2% in eptifibatide-treated patients vs 18.3% in placebo-treated patients (HR, 0.75; 95% CI, 0.60-0.93; P =.008). Most of this benefit accrued early (<48 hours after initiation of therapy) and was maintained through 6 months. Six-month mortality in the eptifibatide group was 0.8% vs 1.4% in the placebo group (HR, 0.56; 95% CI, 0.24-1.34; P =.19) and target vessel revascularization occurred in 8.6% of the eptifibatide group vs 9.4% of the placebo group (HR, 0.91; 95% CI, 0.68-1.22; P =.51).

CONCLUSION

Adjunctive eptifibatide therapy during coronary stent implantation provides benefit through 6-month follow-up.

Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE): design and rationale

BACKGROUND

There is little information about how to adjust pharmacologic agents in the treatment of patients with advanced congestive heart failure (CHF). Some studies have suggested that use of pulmonary artery catheterization to guide reductions in filling pressures may improve outcomes for patients with heart failure who are hospitalized with evidence of elevated filling pressures. However, there is no consensus regarding the true utility of this strategy. A randomized clinical trial is needed to test the safety, efficacy, and treatment benefit of pulmonary artery catheterization in patients with advanced CHF.

STUDY DESIGN

The Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) trial is a multicenter, randomized trial designed to test the long-term safety and efficacy of treatment guided by hemodynamic monitoring and clinical assessment versus that guided by clinical assessment alone in patients hospitalized with New York Heart Association class IV CHF. Five hundred patients will be randomly assigned to receive either medical therapy guided by a combination of clinical assessment and hemodynamic monitoring (PAC arm) or medical therapy guided by clinical assessment alone (CLIN arm). The primary end point of ESCAPE will be the number of days that patients are hospitalized or die during the 6-month period after randomization. Secondary end points will include changes in mitral regurgitation, peak oxygen consumption, and natriuretic peptide levels. Other secondary end points will be pulmonary artery catheter-associated complications, resource utilization, quality of life measures, and patient preferences regarding survival.

IMPLICATIONS

The primary goal of ESCAPE will be to provide information about the utility of the pulmonary artery catheter in patients with advanced heart failure, independent of various treatment approaches used by individual physicians. In addition, this study will define current outcomes for this severely compromised population.

Reactivation of ischemic events in acute coronary syndromes: results from GUSTO-IIb. Gobal Use of Strategies To Open occluded arteries in acute coronary syndromes

OBJECTIVES

We sought to determine the incidence of and risk factors for thrombotic events early after discontinuing antithrombin therapy in patients with acute coronary syndromes.

BACKGROUND

Discontinuation of treatment with heparin and other thrombin inhibitors in patients with unstable coronary syndromes has related to clinical and biochemical evidence of early reactivation of thrombosis.

METHODS

We studied 8,943 of the 12,142 patients with acute coronary syndromes enrolled in the Global Use of Strategies To Open occluded arteries in acute coronary syndromes trial of hirudin versus heparin. We excluded patients who received no study drug, lacked timing data, died or had myocardial (re)infarction [(re)MI] during study-drug infusion, or began heparin treatment within 2 h after treatment with the study drug was stopped. We assessed the incidence and timing of (re)MI by type and timing of antithrombin treatment.

RESULTS

In all, 215 patients (2.4%) suffered (re)MI, 49 within 12 h of antithrombin therapy discontinuation and 166 between hour 12 and hospital discharge. The duration of infusion did not differ between the hirudin and heparin groups. The rate of early re(MI) after drug therapy discontinuation was significantly higher in patients given heparin versus hirudin (0.8% vs. 0.3%, p = 0.002). Patients with (re)MI had higher mortality at 30 days (23.6% vs. 2.4%, p = 0.001) and 1 year (35.2% vs. 6.7%, p = 0.001) compared with patients without (re)MI.

CONCLUSIONS

The incidence of (re)MI was clustered within 12 h of heparin therapy discontinuation, with the greatest risk within 4 h. There was no evidence of early reactivation of thrombotic events after hirudin. Patients who had (re)infarction had worse outcomes. Better understanding of the mechanism and possible prevention of recurrent thrombosis is needed.

Accuracy of the Papanicolaou test in screening for and follow-up of cervical cytologic abnormalities: a systematic review

PURPOSE

To evaluate the accuracy of conventional and new methods of Papanicolaou (Pap) testing when used to detect cervical cancer and its precursors.

DATA SOURCES

Systematic search of English-language literature through October 1999 using MEDLINE, EMBASE, other computerized databases, and hand searching.

STUDY SELECTION

All studies that compared Pap testing (conventional methods, computer screening or rescreening, or monolayer cytology) with a concurrent reference standard (histologic examination, colposcopy, or cytology).

DATA EXTRACTION

Two reviewers independently reviewed selection criteria and completed 2 x 2 tables for each study.

DATA SYNTHESIS

94 studies of the conventional Pap test and three studies of monolayer cytology met inclusion criteria. No studies of computerized screening were included. Data were organized by cytologic and histologic thresholds used to define disease. For conventional Pap tests, estimates of sensitivity and specificity varied greatly in individual studies. Methodologic quality and frequency of histologic abnormalities also varied greatly between studies. In the 12 studies with the least biased estimates, sensitivity ranged from 30% to 87% and specificity ranged from 86% to 100%.

CONCLUSIONS

Insufficient high-quality data exist to estimate test operating characteristics of new cytologic methods for cervical screening. Future studies of these technologies should apply adequate reference standards. Most studies of the conventional Pap test are severely biased: The best estimates suggest that it is only moderately accurate and does not achieve concurrently high sensitivity and specificity. Cost-effectiveness models of cervical cancer screening should use more conservative estimates of Pap test sensitivity.

Single-therapy androgen suppression in men with advanced prostate cancer: a systematic review and meta-analysis

PURPOSE

To compare luteinizing hormone-releasing hormone (LHRH) agonists with orchiectomy or diethylstilbestrol, and to compare antiandrogens with any of these three alternatives.

DATA SOURCES

A search of the MEDLINE, Cancerlit, EMBASE, and Cochrane Library databases from 1966 to March 1998 and Current Contents to 24 August 1998 for articles comparing the outcomes of the specified treatments. The search was limited to studies on prostatic neoplasms in humans. Total yield was 1477 studies.

STUDY SELECTION

Reports of efficacy outcomes were limited to randomized, controlled trials. Twenty-four trials involving more than 6600 patients, phase II studies that reported on withdrawals from therapy (the most reliable indicator of adverse effects), and all studies reporting on quality of life were abstracted.

DATA EXTRACTION

Two independent reviewers abstracted each article by following a prospectively designed protocol. The meta-analysis combined data on 2-year overall survival by using a random-effects model and; reported results as a hazard ratio relative to orchiectomy.

DATA SYNTHESIS

Ten trials of LHRH agonists involving 1908 patients reported no significant difference in overall survival. The hazard ratio showed LHRH agonists to be essentially equivalent to orchiectomy (hazard ratio, 1.1262 [corrected] [95% CI, 0.915 to 1.386]). There was no evidence of difference in overall survival among the LHRH agonists, although CIs were wider for leuprolide (hazard ratio, 1.0994 [CI, 0.207 to 5.835]) and buserelin (hazard ratio, 1.1315 [CI, 0.533 to 2.404]) than for goserelin (hazard ratio, 1.1172 [CI, 0.898 to 1.390]). Evidence from 8 trials involving 2717 patients suggests that nonsteroidal antiandrogens were associated with lower overall survival. The CI for the hazard ratio approached statistical significance (hazard ratio, 1.2158 [CI, 0.988 to 1.496]). Treatment withdrawals were less frequent with LHRH agonists (0% to 4%) than with nonsteroidal antiandrogens (4% to 10%).

CONCLUSIONS

Survival after therapy with an LHRH agonist was equivalent to that after orchiectomy. No evidence shows a difference in effectiveness among the LHRH agonists. Survival rates may be somewhat lower if a nonsteroidal antiandrogen is used as monotherapy.

Does primary intraocular lens implantation prevent "aphakic" glaucoma in children?

PURPOSE

Open-angle glaucoma may develop after surgery for congenital or developmental cataract with an incidence ranging from 3% to 41%. The pathogenesis of "aphakic" (open-angle) glaucoma remains unknown. Despite numerous reported clinical series (>1000 eyes), we are unaware of any reported case of open-angle glaucoma after primary intraocular lens (IOL) implantation for congenital or developmental cataract. We decided to test the hypothesis that primary posterior chamber IOL implantation might decrease the incidence of open-angle glaucoma in children.

METHODS

Pseudophakic eyes were collected from surgeons who contributed data to a refractive study and who monitored intraocular pressure on a regular basis. IOL implantation was commonly performed in eyes with a corneal diameter >10 mm. Comparable primary data on aphakic eyes were included from 2 published studies on aphakic glaucoma, which included corneal diameters and the patient's age at surgery. Glaucoma-free survival estimates for each cohort were estimated.

RESULTS

Only 1 case of glaucoma was found among 377 eyes with primary pseudophakia (mean age of patient, 5.1 +/- 4.7 years; mean follow-up, 3.9 +/- 2.7 years). There were 14 eyes (11.3%) with glaucoma among 124 aphakic eyes (mean age of patient, 2.7 +/- 2.6 years; mean follow-up time, 7.2 +/- 3.9 years).

CONCLUSIONS

We report a decreased incidence of open-angle glaucoma among eyes rendered primarily pseudophakic compared with those that remained aphakic after cataract surgery. We propose 2 theories on the possible mechanism of reduction in the incidence of glaucoma in pseudophakic eyes.

Clinical outcomes of bivalirudin for ischemic heart disease

BACKGROUND

Current treatment strategies for percutaneous coronary revascularization and acute coronary syndromes incorporate thrombin inhibition with either unfractionated or fractionated heparin. The peptide bivalirudin (Hirulog) is a direct thrombin inhibitor whose pharmacological properties differ from those of heparin. We conducted a systematic overview (meta-analysis) to assess the effect of bivalirudin on 4 end points: death, myocardial infarction, major hemorrhage, and the composite of death or infarction.

METHODS AND RESULTS

Six trials (5674 patients) represent the randomized, controlled bivalirudin experience, including 4603 patients undergoing elective percutaneous coronary revascularization and 1071 patients with acute coronary syndromes. ORs for the 4 clinical end points were calculated for each trial. Four trials (4973 patients) that compared bivalirudin with heparin were combined with the use of a random-effects model. In these trials, bivalirudin was associated with a significant reduction in the composite of death or infarction (OR 0.73, 95% CI 0.57 to 0.95; P=0.02) at 30 to 50 days, or 14 fewer events per 1000 patients so treated. There also was a significant reduction in major hemorrhage for the same trials (OR 0.41, 95% CI 0. 32 to 0.52; P<0.001, or 58 fewer events per 1000 patients so treated). A similar analysis combined 2 dose-ranging trials (701 patients) that compared therapeutic (activated partial thromboplastin time more than twice the control time) with subtherapeutic bivalirudin anticoagulation (activated partial thromboplastin time less than twice the control time).

CONCLUSIONS

Bivalirudin is at least as effective as heparin, with clearly superior safety. Thus, it provides an unprecedented net clinical benefit over heparin in patients with ischemic heart disease.

Assessment of human exposure to ambient particulate matter

Recent epidemiological studies have consistently shown that the acute mortality effects of high concentrations of ambient particulate matter (PM), documented in historic air pollution episodes, may also be occurring at the low to moderate concentrations of ambient PM found in modern urban areas. In London in December 1952, the unexpected deaths due to PM exposure could be identified and counted as integers by the coroners. In modern times, the PM-related deaths cannot be as readily identified, and they can only be inferred as fractional average daily increases in mortality rates using sophisticated statistical filtering and analyses of the air quality and mortality data. The causality of the relationship between exposure to ambient PM and acute mortality at these lower modern PM concentrations has been questioned because of a perception that there is little significant correlation in time between the ambient PM concentrations and measured personal exposure to PM from all sources (ambient PM plus indoor-generated PM). This article shows that the critical factor supporting the plausibility of a linear PM mortality relationship is the expected high correlation in time of people's exposure to PM of ambient origin with measured ambient PM concentrations, as used in the epidemiological time series studies. The presence of indoor and personal sources of PM masks this underlying relationship, leading to confusion in the scientific literature about the strong underlying temporal relationship between personal exposure to PM of ambient origin and ambient PM concentration. The authors show that the sources of PM of non-ambient origin operate independently of the ambient PM concentrations, so that the mortality effect of non-ambient PM, if any, must be independent of the effects of the ambient PM exposures.

Reduction in heart failure events by the addition of a clinical pharmacist to the heart failure management team: results of the Pharmacist in Heart Failure Assessment Recommendation and Monitoring (PHARM) Study

BACKGROUND

The multidisciplinary approach to managing heart failure has been shown to improve outcomes. The role of a clinical pharmacist in treating heart failure has not been evaluated.

METHODS

One hundred eighty-one patients with heart failure and left ventricular dysfunction (ejection fraction <45) undergoing evaluation in clinic were randomized to an intervention or a control group. Patients in the intervention group received clinical pharmacist evaluation, which included medication evaluation, therapeutic recommendations to the attending physician, patient education, and follow-up telemonitoring. The control group received usual care. The primary end point was combined all-cause mortality and heart failure clinical events. All clinical events were adjudicated by a blinded end point committee.

RESULTS

Baseline characteristics were similar except for slightly higher age in the intervention group. Median follow-up was 6 months. All-cause mortality and heart failure events were significantly lower in the intervention group compared with the control group (4 vs 16; P= .005). In addition, patients in the intervention group received higher angiotensin-converting enzyme inhibitor doses as reflected by the median fraction of target reached (25th and 75th percentiles), 1.0 (0.5 and 1) and 0.5 (0.1875 and 1) in the intervention and control groups, respectively (P<.001). The use of other vasodilators in angiotensin-converting enzyme inhibitor-intolerant patients was higher in the intervention group (75% vs 26%; P= .02).

CONCLUSIONS

Outcomes in heart failure can be improved with a clinical pharmacist as a member of the multidisciplinary heart failure team. This observation may be due to higher doses of angiotensin-converting enzyme inhibitors and/or closer follow-up.

Patient Outcomes Research Teams: contribution to outcomes and effectiveness research

This paper describes the key methodological and substantive findings of Patient Outcomes Research Teams, the first outcomes and effectiveness research centers funded by the Agency for Health Care Policy and Research. Patient Outcomes Research Teams contributed to our increased understanding of how to perform meta analysis on nontrial data, use administrative data to characterize patterns of care, develop general and disease-specific outcome measures, and disseminate important outcome information to patients and physicians to reduce practice variation. Patient Outcomes Research Teams also influenced the development of outcomes measurement in the private sector.

Relative effectiveness and cost-effectiveness of methods of androgen suppression in the treatment of advanced prostate cancer

OBJECTIVES

With 184,500 new cases and 39,200 deaths anticipated in 1998, prostate cancer is second only to lung cancer in cancer mortality for men. This report is a systematic review of the evidence from randomized controlled trials on the relative effectiveness of alternative strategies for androgen suppression as treatment of advanced prostate cancer. Three key issues are addressed: (1) the relative effectiveness of the available methods for monotherapy (orchiectomy, luteinizing hormone-releasing hormone [LHRH] agonists, and antiandrogens), (2) the effectiveness of combined androgen blockade compared to monotherapy, and (3) the effectiveness of immediate androgen suppression compared to androgen suppression deferred until clinical progression. Outcomes of interest are overall, cancer-specific, and progression-free survival; time to treatment failure; adverse effects; and quality of life. Two supplementary analyses were conducted for each key question: (1) meta-analysis of overall survival at 2 years (questions 1 and 2) and 5 years (questions 2 and 3), and (2) cost-effectiveness analysis.

SEARCH STRATEGY

The MEDLINE, CANCERLIT, and EMBASE databases were searched from 1966 to March 1998, and Current Contents to August 24, 1998, for the terms: leuprolide (Lupron); goserelin (Zoladex); buserelin (Suprefact); flutamide (Eulexin); nilutamide (Anandron, Nilandron); bicalutamide (Casodex); cyproterone acetate (Androcur); diethylstilbestrol (DES); and orchiectomy (castration, orchidectomy). The search was then limited to human studies indexed under the MeSH term "prostatic neoplasms" and by the UK Cochrane Center search strategy for randomized controlled trials. Total yield was 1,477 references.

SELECTION CRITERIA

We Reports of efficacy outcomes were limited to randomized controlled trials. Phase II studies that reported on withdrawals from therapy and all studies reporting on quality of life were also included.

DATA COLLECTION AND ANALYSIS

The systematic review used a prospectively designed protocol conducted by two independent reviewers, with disagreements resolved by consensus. The meta-analysis combined data on overall survival using a random effects model. The cost-effectiveness analysis used a decision analysis model of advanced prostate cancer with health states and transitions derived from the literature and estimates of effectiveness derived from the meta-analysis. The cost-effectiveness analysis is conducted from a societal perspective, consistent with the guidelines of the U.S. Public Health Service Panel on Cost-Effectiveness in Health and Medicine.

MAIN RESULTS

Survival after treatment with an LHRH agonist is equivalent to survival after orchiectomy. The available LHRH agonists are equally effective, and no LHRH agonist is superior to the other when adverse effects are considered. Survival may be somewhat lower with use of a nonsteroidal antiandrogen. There is no statistically significant difference in survival at 2 years between patients treated with combined androgen blockade or monotherapy. Meta-analysis of the limited data available shows a statistically significant difference in survival at 5 years that favors combined androgen blockade. However, the magnitude of this difference is of questionable clinical significance. For the subgroup of patients with good prognosis, there is no statistically significant difference in survival. Adverse effects leading to withdrawal from therapy occurred more often with combined androgen blockade. No evidence is yet available from randomized controlled trials of androgen suppression initiated at prostate-specific antigen (PSA) rise after definitive therapy for clinically localized disease. For patients who are newly diagnosed with locally advanced or asymptomatic metastatic disease, the evidence is insufficient to determine whether primary androgen suppression initiated at diagnosis improves outcomes. (ABSTRACT TRUNCATED)

Hormone replacement therapy and the risk of colorectal cancer: a meta-analysis

OBJECTIVE

To review systematically the association between hormone replacement therapy (HRT) and the risk of developing or dying from colorectal cancer.

DATA SOURCES

We searched the English-language literature using MEDLINE, Current Contents, CancerLit, and bibliographies of selected studies.

METHODS OF STUDY SELECTION

We included studies that specifically addressed the association of HRT with colorectal cancer, had adequate controls, and had retrievable risk estimates. We excluded letters, reviews, and multiple publications of the same data.

TABULATION, INTEGRATION, AND RESULTS

Studies were evaluated independently by two of the authors. The exposures of interest were ever, recent, or former use of HRT, and the main outcome measures were colon and rectal cancer incidence and mortality. To reduce the risk of a "healthy estrogen user" bias, we defined recent HRT use as either at time of assessment or within the previous year. The most adjusted risk estimates were extracted. We used a random-effects model to calculate summary relative risks (RRs) and confidence intervals (CIs). Recent use of HRT was associated with a 33% reduction in the risk of colon cancer (RR = 0.67; 95% CI 0.59, 0.77). Protection was limited to recent users; the risk of colon cancer with ever use of HRT was 0.92 (95% CI 0.79, 1.08). Duration of use was not significant. Three studies addressed the risk of fatal colon cancer; the summary RR for death from colon cancer in HRT users was 0.72 (95% CI 0.64, 0.81) compared with nonusers. Rectal cancer incidence was not associated with HRT.

CONCLUSION

The risk of colon cancer may be decreased among recent postmenopausal HRT users. Although data are limited, the risk of fatal colon cancer also may be lower in HRT users.

Clinical outcomes of therapeutic agents that block the platelet glycoprotein IIb/IIIa integrin in ischemic heart disease

BACKGROUND

Several platelet glycoprotein (GP) IIb/IIIa receptor antagonists have been evaluated in clinical trials. We conducted a systematic overview (meta-analysis) to assess the effect of these compounds on death, myocardial infarction (MI), and revascularization.

METHODS AND RESULTS

ORs were calculated for 16 randomized, controlled trials of GP IIb/IIIa inhibitors. An empirical Bayesian random-effects model combined the outcomes of 32 135 patients. There was a significant mortality reduction by GP IIb/IIIa inhibitors at 48 to 96 hours, with an OR of 0.70 (95% CI, 0. 51 to 0.96; P<0.03), equivalent to a reduction of 1 death per 1000 patients treated. Mortality benefits at 30 days (OR, 0.87; 95% CI, 0. 74 to 1.02; P=0.08) and 6 months (OR, 0.97; 95% CI, 0.86 to 1.10; P=0.67) were not statistically significant. For the combined end point of death or MI, there was a highly significant (P<0.001) benefit for GP IIb/IIIa inhibitors at each time point. The 30-day OR was 0.76 (95% CI, 0.66 to 0.87), or 20 fewer events per 1000 patients treated. For the composite end point of death, MI, or revascularization, there was also a highly significant (P<0.001) benefit for GP IIb/IIIa inhibitors. At 30 days, the OR was 0.77 (95% CI, 0.68 to 0.86), or 30 fewer events per 1000 patients treated. The risk differences for death, death or MI, and composite outcomes were similar at 6 months, indicating a sustained absolute improvement. Similar benefit was seen when trials were subgrouped by therapeutic indication (percutaneous intervention versus acute coronary syndromes).

CONCLUSIONS

Application of this new therapeutic class to clinical practice promises substantial benefit for both indications.

Diagnostic efficiency of home pregnancy test kits. A meta-analysis

OBJECTIVE

To assess the diagnostic efficiency of home pregnancy test (HPT) kits.

DATA SOURCES

A literature search of English-language studies was performed with MEDLINE and a review of bibliographies.

STUDY SELECTION

Studies were included if HPT kits were compared with a criterion standard (laboratory testing), if they used appropriate controls, and if data were available to determine sensitivity and specificity.

DATA EXTRACTION

Two investigators independently extracted data, and disagreement was resolved by consensus. Sensitivity, specificity, and an effectiveness score (a measure of the discriminatory power of the test, with higher scores implying greater effectiveness) were calculated.

DATA SYNTHESIS

Five studies evaluating 16 HPT kits met the inclusion criteria. The range of sensitivities for HPT kits was 0.52 to 1.0. In studies where urine samples obtained by the investigators were tested by volunteers, sensitivity was 0.91 (95% confidence interval [CI], 0.84-0.96). However, the sensitivity was less in studies where subjects were actual patients who performed the test on their own urine samples (sensitivity, 0.75 [95% CI, 0.64-0.85]). The test effectiveness score was 2.75 (95% CI, 2.3-3.2) for studies where subjects were volunteers but deteriorated to 0.82 (95% CI, 0.4-1.2) for studies with actual patients.

CONCLUSIONS

The diagnostic efficiency of HPT kits is greatly affected by characteristics of the users. Despite the popularity of these kits, the relatively low effectiveness scores of these kits when used by actual patients are of concern. We suggest that manufacturers of HPT kits publish results of trials in actual patients before marketing them to the general public.

The Agency for Health Care Policy and Research Smoking Cessation Clinical Practice Guideline. Findings and implications for psychologists

Smoking is the leading cause of preventable morbidity and mortality in the United States, and the health benefits of quitting smoking are substantial. Nevertheless, over 25% of American adults (48 million individuals) continue to smoke, and the vast majority of quit attempts are unsuccessful. The Agency for Health Care Policy and Research recently addressed the smoking problem by conducting a 2-year research project that was published as the Smoking Cessation Clinical Practice Guideline (Fiore et al., 1996). This article reviews methods, analyses, and results from the Guideline project, and highlights major Guideline recommendations. Guideline findings and recommendations are discussed with respect to their implications for psychology.

Is optimal angiotensin-converting enzyme inhibitor dosing neglected in elderly patients with heart failure?

BACKGROUND

The benefit of angiotensin-converting enzyme (ACE) inhibitors on mortality in heart failure has been proved in randomized controlled trials.

METHODS

We prospectively evaluated the prescribing of ACE inhibitors and the prescribing of target ACE inhibitor doses in 43 ambulatory patients with heart failure to identify differences in ACE inhibitor utilization among elderly and nonelderly patients. The prescribed ACE inhibitor dose and other variables were assessed by direct patient interview and information contained in the medical record. Telephone calls were conducted at 3 months to identify the occurrence of clinical events.

RESULTS

Fewer elderly patients were prescribed target ACE inhibitor doses compared with nonelderly patients (21.4% vs 68.8%; p = 0.0136). Elderly patients were more likely to experience an event than nonelderly patients (11 vs 4; p = 0.0074). Elderly patients not receiving target ACE inhibitor doses demonstrated a trend toward more events than elderly patients who were at target doses.

CONCLUSION

The data suggest that this group of elderly patients with heart failure who received lower ACE inhibitor doses appeared to be at higher risk for clinical events.

The Agency for Health Care Policy and Research Smoking Cessation Clinical Practice Guideline. Findings and implications for psychologists

Smoking is the leading cause of preventable morbidity and mortality in the United States, and the health benefits of quitting smoking are substantial. Nevertheless, over 25% of American adults (48 million individuals) continue to smoke, and the vast majority of quit attempts are unsuccessful. The Agency for Health Care Policy and Research recently addressed the smoking problem by conducting a 2-year research project that was published as the Smoking Cessation Clinical Practice Guideline (Fiore et al., 1996). This article reviews methods, analyses, and results from the Guideline project, and highlights major Guideline recommendations. Guideline findings and recommendations are discussed with respect to their implications for psychology.

Failure of the mandatory domestic violence reporting law to increase medical facility referral to police

STUDY OBJECTIVE

To assess the effect of California's 1994 mandatory domestic violence reporting law on Los Angeles Sheriff's Department dispatches to medical facilities for domestic violence incidents.

METHODS

This ecological time-trend study analyzed data from the Los Angeles Sheriff's Department for the period January 1, 1993, to December 31, 1995. All 26,051 dispatches for domestic violence offenses during the study period were analyzed. The outcome measures were changes in biweekly department dispatches for domestic violence offenses resulting from the implementation of the mandatory domestic violence reporting law adjusted for seasonal variation and the Simpson/Goldman murders.

RESULTS

The percentage of biweekly dispatches to medical facilities for domestic violence offenses did not increase in response to the law (beta = -.0072, P = .095). Total domestic violence dispatches increased significantly after the Simpson/Goldman murders but not after passage of the law (beta = 82.7, P < .0001 versus beta = -10.1, P = .2205).

CONCLUSION

The mandatory domestic violence reporting law in California did not increase medical personnel reporting of domestic violence situations to the Sheriff's Department during the 2 years after its implementation.

Predicting the cost of illness: a comparison of alternative models applied to stroke

Predictions of cost over well-defined time horizons are frequently required in the analysis of clinical trials and social experiments, for decision models investigating the cost-effectiveness of interventions, and for macro-level estimates of the resource impact of disease. With rare exceptions, cost predictions used in such applications continue to take the form of deterministic point estimates. However, the growing availability of large administrative and clinical data sets offers new opportunities for a more general approach to disease cost forecasting: the estimation of multivariable cost functions that yield predictions at the individual level, conditional on intervention(s), patient characteristics, and other factors. This raises the fundamental question of how to choose the "best" cost model for a given application. The central purpose of this paper is to demonstrate how to evaluate competing models on the basis of predictive validity. This concept is operationalized according to three alternative criteria: 1) root mean square error (RMSE), for evaluating predicted mean cost; 2) mean absolute error (MAE), for evaluating predicted median cost; and 3) a logarithmic scoring rule (log score), an information-theoretic index for evaluating the entire predictive distribution of cost. To illustrate these concepts, the authors conducted a split-sample analysis of data from a national sample of Medicare-covered patients hospitalized for ischemic stroke in 1991 and followed to the end of 1993. Using test and training samples of about 500,000 observations each, they investigated five models: single-equation linear models, with and without log transform of cost; two-part (mixture) models, with and without log transform, to directly address the problem of zero-cost observations; and a Cox proportional-hazards model stratified by time interval. For deriving the predictive distribution of cost, the log transformed two-part and proportional-hazards models are superior. For deriving the predicted mean or median cost, these two models and the commonly used log-transformed linear model all perform about the same. The untransformed models are dominated in every instance. The approaches to model selection illustrated here can be applied across a wide range of settings.

Distribution of transferrin saturations in the African-American population

To determine if transferrin saturations in African Americans may reflect the presence of a gene that influences iron metabolism, we analyzed the distribution of these values in 808 African Americans from the second National Health and Nutrition Survey. We tested for a mixture of three normal distributions consistent with population genetics for a major locus effect in which the proportion of normal homozygotes is p2; of heterozygotes, 2pq; of affected homozygotes, q2; and in which p+q = 1. Three subpopulations based on transferrin saturation were present (P < .0001) and the fit to a mixture of three normal distributions was good (P = .2). A proportion of .009 was included in a subpopulation with a mean +/- standard deviation transferrin saturation of 63.4% +/- 5.7% (postulated homozygotes for a gene that influences iron metabolism), while a proportion of .136 had an intermediate saturation of 38.0% +/- 5.7% (postulated heterozygotes) and .856 a saturation of 24.6% +/- 5.7% (postulated normal homozygotes). These proportions were consistent with population genetics because the sum of the square roots of the proportions with the lowest mean transferrin saturation (P = .925) and the highest (q = 0.093) was approximately 1 (1.018). The results are consistent with the presence in African Americans of a common locus that influences iron metabolism.

Meta-analysis of multitreatment studies

Studies comparing more than two competing therapies are common in several fields, but standard meta-analytic methods can make only pairwise comparisons. The methods proposed in this article, a generalization of current meta-analytic methods, allow for any number of competing therapies and include both fixed- and random-effects models.

Cost-effectiveness of the clinical practice recommendations in the AHCPR guideline for smoking cessation. Agency for Health Care Policy and Research

CONTEXT

The Agency for Health Care Policy and Research (AHCPR) published the Smoking Cessation: Clinical Practice Guideline in 1996. Based on the results of meta-analyses and expert opinion, the guideline identifies efficacious interventions for primary care clinicians and smoking cessation specialty providers.

OBJECTIVE

To determine the cost-effectiveness of clinical recommendations in AHCPR's guideline.

DESIGN

The guideline's 15 recommended smoking cessation interventions were analyzed to determine their relative cost-effectiveness. Then, using decision probabilities, the interventions were combined into a global model of the guideline's overall cost-effectiveness.

PATIENTS

The analysis assumes that primary care clinicians screen all presenting adults for smoking status and advise and motivate all smokers to quit during the course of a routine office visit or hospitalization. Smoking cessation interventions are provided to 75% of US smokers 18 years and older who are assumed to be willing to make a quit attempt during a year's time.

INTERVENTION

Three counseling interventions for primary care clinicians and 2 counseling interventions for smoking cessation specialists were modeled with and without transdermal nicotine and nicotine gum.

MAIN OUTCOME MEASURE

Cost (1995 dollars) per life-year or quality-adjusted life-year (QALY) saved, at a discount of 3%.

RESULTS

The guideline would cost $6.3 billion to implement in its first year. As a result, society could expect to gain 1.7 million new quitters at an average cost of $3779 per quitter, $2587 per life-year saved, and $1915 for every QALY saved. Costs per QALY saved ranged from $1108 to $4542, with more intensive interventions being more cost-effective. Group intensive cessation counseling exhibited the lowest cost per QALY saved, but only 5% of smokers appear willing to undertake this type of intervention.

CONCLUSIONS

Compared with other preventive interventions, smoking cessation is extremely cost-effective. The more intensive the intervention, the lower the cost per QALY saved, which suggests that greater spending on interventions yields more net benefit. While all these clinically delivered interventions seem a reasonable societal investment, those involving more intensive counseling and the nicotine patch as adjuvant therapy are particularly meritorious.

The Stroke Prevention Policy Model: linking evidence and clinical decisions

Simulation models that support decision and cost-effectiveness analysis can further the goals of evidence-based medicine by facilitating the synthesis of information from several sources into a single comprehensive structure. The Stroke Prevention Policy Model (SPPM) performs this function for the clinical and policy questions that surround stroke prevention. This paper first describes the basic structure and functions of the SPPM, concentrating on the role of large databases (broadly defined as any database that contains many patients, regardless of study design) in providing the SPPM inputs. Next, recognizing that the use of modeling continues to be a source of some controversy in the medical community, it discusses the philosophical underpinnings of the SPPM. Finally, it discusses conclusions in the context of both stroke prevention and other complex medical decisions. We conclude that despite the difficulties in developing comprehensive models (for example, the length and complexity of model development and validation processes, the proprietary nature of data sources, and the necessity for developing new software), the benefits of such models exceed the costs of continuing to rely on more conventional methods. Although they should not replace the clinician in decision making, comprehensive models based on the best available evidence from large databases can support decision making in medicine.

Assessing uncertainty in cost-effectiveness analyses: application to a complex decision model

A framework for quantifying uncertainty about costs, effectiveness measures, and marginal cost-effectiveness ratios in complex decision models is presented. This type of application requires special techniques because of the multiple sources of information and the model-based combination of data. The authors discuss two alternative approaches, one based on Bayesian inference and the other on resampling. While computationally intensive, these are flexible in handling complex distributional assumptions and a variety of outcome measures of interest. These concepts are illustrated using a simplified model. Then the extension to a complex decision model using the stroke-prevention policy model is described.

Pediatric Vesicoureteral Reflux Guidelines Panel summary report on the management of primary vesicoureteral reflux in children

PURPOSE

The American Urological Association convened the Pediatric Vesicoureteral Reflux Guidelines Panel to analyze the literature regarding available methods for treating vesicoureteral reflux diagnosed following a urinary tract infection in children and to make practice policy recommendations based on the treatment outcomes data insofar as the data permit.

MATERIALS AND METHODS

The panel searched the MEDLINE data base for all articles from 1965 to 1994 on vesicoureteral reflux and systematically analyzed outcomes data for 7 treatment alternatives: 1) intermittent antibiotic therapy, 2) bladder training, 3) continuous antibiotic prophylaxis, 4) antibiotic prophylaxis and bladder training, 5) antibiotic prophylaxis, anticholinergics and bladder training, 6) open surgical repair and 7) endoscopic repair. Key outcomes identified were probability of reflux resolution, likelihood of developing pyelonephritis and scarring, and possibility of complications of medical and surgical treatment.

RESULTS

Available outcomes data on the various treatment alternatives were summarized in tabular form and graphically, and the relative probabilities of possible outcomes were compared for each alternative. Treatment recommendations were based on scientific evidence and expert opinion. The panel concluded that only a few recommendations can be derived purely from scientific evidence of a beneficial effect on health outcomes.

CONCLUSIONS

For most children the panel recommended continuous antibiotic prophylaxis as initial treatment. Surgery was recommended for children with persistent reflux and other indications, as specified in the document.

A metaanalysis of predischarge risk stratification after acute myocardial infarction with stress electrocardiographic, myocardial perfusion, and ventricular function imaging

We assessed the relation of abnormal predischarge non-invasive test results to outcomes in postmyocardial infarction patients. We included series published from 1980 to 1995 containing only myocardial infarction patients, enrolling most patients after 1980, testing within 6 weeks of infarction, having follow-up rates > 80%, and having 2 x 2 frequency outcome rates for test results, that were the latest of multiple reports. Sensitivity, specificity, and predictive values were calculated for test results for 1-year outcomes (cardiac death, cardiac death or reinfarction). Univariable and summary odds were calculated for test results. Reports (n = 54) included a total of 19,874 patients and were primarily retrospective (76%) and small series (35% of reports included < 5 deaths). One-year mortality ranged from 2.5% for pharmacologic stress echocardiography to 9.3% for exercise radionuclide angiography. Positive predictive values for most noninvasive risk markers were < 0.10 for cardiac death and < 0.20 for death or reinfarction. Electrocardiographic, symptomatic, and scintigraphic risk markers of ischemia (ST-segment depression, angina, a reversible defect) were less sensitive (< or = 44%) for identifying morbid and fatal outcomes than markers of left ventricular dysfunction or heart failure (exercise duration, impaired systolic blood pressure response, and peak left ventricular ejection fraction). The positive predictive value of predischarge noninvasive testing is low. Markers of left ventricular dysfunction appear to be better predictors than markers of ischemia. Limitations of the literature-small samples and widely varying event rates-impede our ability to discern the accuracy of pre-discharge noninvasive testing. More rigorous, controlled trials are required to elucidate the relative value of these tests for risk stratification.

A clinical approach for the diagnosis of diabetes mellitus: an analysis using glycosylated hemoglobin levels. Meta-analysis Research Group on the Diagnosis of Diabetes Using Glycated Hemoglobin Levels

OBJECTIVE

To determine whether a glycosylated hemoglobin level can be used in place of an oral glucose tolerance test (OGTT) to diagnose diabetes.

DATA SOURCES/STUDY SELECTION

An augmented MEDLINE search was performed to identify all reports from 1966 through June 1994 in which glycosylated hemoglobin levels were measured concurrently with performance of OGTTs in the same study. The corresponding authors were contacted and asked to provide individual data for all subjects tested. A total of 31 investigators representing 34 possible studies responded, and 18 were able to provide us with the data requested. Overall fasting plasma glucose concentrations, 2-hour postdextrose glucose concentrations, and glycosylated hemoglobin levels were available from 11 276 individuals.

DATA EXTRACTION

To define normal glucose tolerance, impaired glucose tolerance (IGT), and diabetes, modified World Health Organization criteria were used.

DATA SYNTHESIS

An analysis of the methods used for measurement of glycosylated hemoglobin levels revealed that the HbA1c assay showed the least variance in normal subjects. Therefore, only data from the 8984 subjects who had HbA1c levels measured were used. When we used the mean HbA1c level plus 4 SDs as a cutpoint, the sensitivity was 36% and specificity was 100% compared with the results of the OGTT. Because of the lack of agreement between OGTT results and HbA1c levels, models were created to analyze the distribution of HbA1c levels in each study. Using these models, we identified 3 subpopulations. The third subpopulation was likely to represent subjects with diabetes. When we applied an HbA1c level of 7.0% as a cutpoint, the sensitivity was 99.6% for the third subpopulation. When this cutpoint was reapplied to the OGTT results, of those subjects with an HbA1c level of at least 7.0%, 89% had diabetes, 7% had IGT, and 4% were normal.

CONCLUSIONS

Although the OGTT is the "gold standard" for diagnosing diabetes, it is known to be poorly reproducible and is often not performed. Not only is use of an HbA1c level to diagnose diabetes more convenient, but therapeutic decisions are based on this value, regardless of the findings on the OGTT. An HbA1c level of 7.0% or higher often requires pharmacological intervention and is most often associated with the diagnosis of diabetes by World Health Organization standards. An HbA1c level below 7.0% would generally be treated with diet and exercise, regardless of the diagnosis of IGT or diabetes by OGTT. Thus, measurement of HbA1c levels may represent a reasonable approach to identifying treatment-requiring diabetes.

Comparison and meta-analysis of randomized trials of endarterectomy for symptomatic carotid artery stenosis

OBJECTIVE

Comparison and meta-analysis of randomized trials of carotid endarterectomy for symptomatic stenosis of the extracranial carotid artery.

BACKGROUND

Randomized trials (North American Symptomatic Carotid Endarterectomy Trial [NASCET], the European Carotid Surgery Trial [ECST], and the VA Cooperative Study [VACS]) each show that carotid endarterectomy improves outcomes in selected symptomatic patients with high-grade extracranial carotid artery stenosis. Direct comparisons among the studies have not been possible because of differing methodologies, endpoints, and formats of data reporting.

DESIGN/METHODS

Data for specified endpoints and corresponding person-years at risk were obtained for each trial. The rates of nonfatal stroke, nonfatal myocardial infarction, or death for surgically or medically treated patients in the perioperative period (30 days) and thereafter were compared (both including and excluding perioperative events) and then combined using meta-analytic techniques. Data from NASCET and ECST were also analyzed for differences in outcomes by sex.

RESULTS

Event rate estimates (with 95% confidence intervals [95% CI]) for the first 30 days (events per person-year, primarily nonfatal stroke) for medically treated patients were 0.44 (0.22 to 0.76) for NASCET, 0.15 (0.04 to 0.38) for ECST, and 0.27 (0.03 to 0.96) for VACS. For surgically treated patients, the corresponding rates (per person-year) were 0.78 (0.49 to 1.19), 0.63 (0.41 to 0.94), and 1.27 (0.58 to 2.43). Event rates per year after 30 days were higher for medically treated patients (0.20 [0.16 to 0.25] versus 0.08 [0.05 to 0.11] for NASCET; 0.12 [0.10 to 0.15] versus 0.07 [0.06 to 0.09] for ECST; and 0.15 [0.07 to 0.25] versus 0.07 [0.03 to 0.16] for VACS). There were no significant differences among the trials, with an overall benefit for surgical therapy (risk ratio estimate, RR = 0.67, 95% CI = 0.54 to 0.83). There were no significant sex-based differences between NASCET and ECST and the overall benefit was not significantly different for men and women (RR = 0.58, 95% CI = 0.45 to 0.74 for men; RR = 0.84, 95% CI = 0.57 to 1.25 for women).

CONCLUSIONS

Adjusting for primary endpoints and duration of follow-up, carotid endarterectomy has a similar benefit for symptomatic patients across trials and a similar benefit for men and women.

Prevalence of heterozygotes for hemochromatosis in the white population of the United States

In previous studies, the prevalence of HLA-linked hemochromatosis, thought to be the most common genetic illness in whites, has been estimated by identifying homozygotes in the population. Because not all homozygotes express the disease phenotypically, the accuracy of these estimates is uncertain. We analyzed the distribution of transferrin saturation values in the second National Health and Nutrition Examination Survey to estimate the prevalence of hemochromatosis heterozygotes in the US population. After removing values for possible homozygotes, two populations were present (P < .01 for each gender). When weighted to reflect the US adult white male population as a whole, a proportion of 850 per 1,000 (95% confidence interval, 0.81 to 0.89) were included in a population with a lower mean saturation of 29.7% (29.1% to 30.3%), whereas 150 per 1,000 (0.11 to 0.19) comprised a population with a higher mean saturation of 47.0% (45.1% to 49.0%). Similar results were found for the female population. The gene frequencies were estimated to be 0.081 from the male population and 0.070 from the female population corresponding to prevalences of homozygotes of 6.6 and 4.8 per 1,000, respectively. Our results confirm that the gene for hemochromatosis is common.