Recurrence after hospitalization for acute coronary syndrome among HIV-infected and HIV-uninfected individuals

OBJECTIVES

We evaluated the association of HIV infection and immunodeficiency with acute coronary syndrome (ACS) recurrence, and with all-cause mortality as a secondary outcome, after hospitalization for ACS among HIV-infected and HIV-uninfected individuals.

METHODS

We conducted a retrospective cohort study within Kaiser Permanente Northern California of HIV-infected and HIV-uninfected adults discharged after ACS hospitalization [types: ST-elevation myocardial infarction (STEMI), non-STEMI, or unstable angina] during 1996-2010. We compared the outcomes of ACS recurrence and all-cause mortality within 3 years, both overall by HIV status and stratified by recent CD4 count, with HIV-uninfected individuals as the reference group. Hazard ratios (HRs) were obtained from Cox regression models with adjustment for age, sex, race/ethnicity, year, ACS type, smoking, and cardiovascular risk factors.

RESULTS

Among 226 HIV-infected and 86 321 HIV-uninfected individuals with ACS, HIV-infected individuals had a similar risk of ACS recurrence compared with HIV-uninfected individuals [HR 1.08; 95% confidence interval (CI) 0.76-1.54]. HIV infection was independently associated with all-cause mortality after ACS hospitalization overall (HR 2.52; 95% CI 1.81-3.52). In CD4-stratified models, post-ACS mortality was higher for HIV-infected individuals with CD4 counts of 201-499 cells/μL (HR 2.64; 95% CI 1.66-4.20) and < 200 cells/μL (HR 5.41; 95% CI 3.14-9.34), but not those with CD4 counts ≥ 500 cells/μL (HR 0.67; 95% CI 0.22-2.08), compared with HIV-uninfected individuals (P trend < 0.001).

CONCLUSIONS

HIV infection and immunodeficiency were not associated with recurrence of ACS after hospitalization. All-cause mortality was higher among HIV-infected compared with HIV-uninfected individuals, but there was no excess mortality risk among HIV-infected individuals with high CD4 counts.

Correlation between pulse wave velocity and other measures of arterial stiffness in chronic kidney disease

AIM

Pulse wave velocity (PWV), augmentation index (AIx) and time to first wave reflection (Tr) are all measures of arterial stiffness, but whether these parameters behave similarly in different populations is not well-understood. Given the large burden of cardiovascular disease in individuals with chronic kidney disease (CKD), assessing the relationship between vascular stiffness parameters in this population is important.

METHOD

A subset of 152 participants enrolled in the Chronic Renal Insufficiency Cohort Study had vascular stiffness parameters (aortic PWV, central AIx, and Tr) measured using the SphygmoCor system. Linear association between these parameters was assessed using Pearson correlation coefficients. Reproducibility across operators of the device was also tested within individuals.

RESULTS

Association was largest between PWV and heart rate-adjusted AIx (AIx-75). The correlation coefficient was 0.371 (p = 0.0003) for ideal studies and 0.305 (p = 0.0001) for all technically acceptable studies. The association between ideal PWV and AIx-75 measurements was 0.361 (p = 0.005) for men and 0.423 (p = 0.01) for women. Bland-Altman plots comparing the mean value of PWV (n = 31) or AIx-75 (n = 21) when measured by 2 different individuals against the difference in their respective values demonstrate that both measures of arterial stiffness are reproducible across multiple technicians.

CONCLUSIONS

Thus, we conclude that PWV and AIx-75, despite measuring different quantities in different units, are related measures of arterial stiffness and are reproducible across multiple operators in the population with CKD.

Community-based incidence of acute renal failure

There is limited information about the true incidence of acute renal failure (ARF). Most studies could not quantify disease frequency in the general population as they are hospital-based and confounded by variations in threshold and the rate of hospitalization. Earlier studies relied on diagnostic codes to identify non-dialysis requiring ARF. These underestimated disease incidence since the codes have low sensitivity. Here we quantified the incidence of non-dialysis and dialysis-requiring ARF among members of a large integrated health care delivery system - Kaiser Permanente of Northern California. Non-dialysis requiring ARF was identified using changes in inpatient serum creatinine values. Between 1996 and 2003, the incidence of non-dialysis requiring ARF increased from 322.7 to 522.4 whereas that of dialysis-requiring ARF increased from 19.5 to 29.5 per 100,000 person-years. ARF was more common in men and among the elderly, although those aged 80 years or more were less likely to receive acute dialysis treatment. We conclude that the use of serum creatinine measurements to identify cases of non-dialysis requiring ARF resulted in much higher estimates of disease incidence compared with previous studies. Both dialysis-requiring and non-dialysis requiring ARFs are becoming more common. Our data underscore the public health importance of ARF.

Hormone therapy and in-hospital survival after myocardial infarction in postmenopausal women

BACKGROUND

Although postmenopausal hormone therapy (HRT) commonly is used in hope of preventing coronary heart disease, the effect of HRT on case fatality of myocardial infarction has never been studied. We evaluated HRT as a predictor of survival after MI in postmenopausal women.

METHODS AND RESULTS

The present study was performed with 114 724 women of age >/=55 years with confirmed myocardial infarction who presented between April 1998 and January 2000 to 1 of 1674 hospitals participating in the National Registry of Myocardial Infarction-3. Presenting characteristics, treatment, and clinical outcome data were obtained by chart review. At time of hospitalization, 7353 (6.4%) women reported current use of HRT, defined as use of estrogen, progestin, or estrogen/progestin for reasons other than contraception. Unadjusted mortality was 7.4% in users of HRT and 16.2% in nonusers (odds ratio 0.41, 95% confidence interval 0.36 to 0.43). After adjustments were made for prior medical history, clinical characteristics, treatments received in-hospital, and likelihood of receiving HRT, HRT remained associated with an improved rate of survival (odds ratio 0.65, 95% confidence interval 0.59 to 0.72). Significant association of HRT with decreased mortality after myocardial infarction was observed in all age strata.

CONCLUSIONS

Postmenopausal HRT appears to be associated with reduced mortality after myocardial infarction. This finding could be caused by therapeutic effect of HRT, selection and adherence bias, or some combination of both.

Hormone therapy and the risk of stroke after acute myocardial infarction in postmenopausal women

OBJECTIVES

We examined the association of hormone therapy (HRT) with hemorrhagic and ischemic stroke among postmenopausal women with acute myocardial infarction (AMI).

BACKGROUND

Hemorrhagic and ischemic strokes are common complications of AMI, and women are at increased risk for hemorrhagic stroke after thrombolytic therapy. This risk may be related to female hormones.

METHODS

Using data from the National Registry of Myocardial Infarction-3, we studied 114,724 women age 55 years or older admitted to the hospital for AMI, of whom 7,353 reported HRT use on admission. We determined rates of in-hospital hemorrhagic and ischemic stroke stratified by HRT use and estimated the independent association of HRT with each stroke type using multivariable logistic regression.

RESULTS

The HRT users were younger than non-users, had fewer risk factors for stroke including diabetes and prior stroke, and received more pharmacologic and invasive therapy including cardiac catheterization. A total of 2,152 (1.9%) in-hospital strokes occurred, with 442 (0.4%) hemorrhagic, 1,017 (0.9%) ischemic and 693 (0.6%) unspecified. Among HRT users and non-users, the rates of hemorrhagic stroke (0.40% vs. 0.42%, p = 1.00) and ischemic stroke (0.80% vs. 0.96%, p = 0.11) were similar. Among 13,328 women who received thrombolytic therapy, the rate of hemorrhagic stroke was not significantly different for users and non-users (1.6% vs. 2.1%, p = 0.22). After adjustment for baseline and treatment differences, HRT was not associated with hemorrhagic (odds ratio [OR], 0.88; 95% confidence intervals [CI], 0.58 to 1.35) or ischemic stroke (OR, 0.89; CI, 0.66 to 1.18).

CONCLUSIONS

Acute myocardial infarction is a high-risk setting for stroke among postmenopausal women, but HRT does not appear to modify that risk. Clinicians should not alter their approach to thrombolytic therapy based on HRT use.

Clinical predictors of prolonged delay in return of the international normalized ratio to within the therapeutic range after excessive anticoagulation with warfarin

BACKGROUND

An elevated international normalized ratio (INR) increases the risk for major hemorrhage during warfarin therapy. Optimal management of patients with asymptomatic elevations in INR is hampered by the lack of understanding of the time course of INR decay after cessation of warfarin therapy.

OBJECTIVE

To identify predictors of the rate of INR normalization after excessive anticoagulation.

DESIGN

Retrospective cohort study.

SETTING

Outpatient anticoagulant therapy unit.

PATIENTS

Outpatients with an INR greater than 6.0 were identified from August 1993 to September 1998. Patients in whom two doses of warfarin were withheld and a follow-up INR was obtained on the second calendar day were enrolled. No patient received vitamin K(1).

MEASUREMENTS

The INR was measured 2 days after an INR greater than 6.0 was recorded.

RESULTS

Of 633 study patients with an initial INR greater than 6.0, 232 (37%) still had an INR of 4.0 or greater after two doses of warfarin were withheld. Patients who required larger weekly maintenance doses of warfarin were less likely to have an INR of 4.0 or greater on day 2 (adjusted odds ratio per 10 mg of warfarin, 0.87 [95% CI, 0.79 to 0.97]). Other risk factors for having an INR of 4.0 or greater on day 2 included age (odds ratio per decade of life, 1.18 [CI, 1.01 to 1.38]), index INR (odds ratio per unit, 1.25 [CI, 1.14 to 1.37]), decompensated congestive heart failure (odds ratio, 2.79 [CI, 1.30 to 5.98]), and active cancer (odds ratio, 2.48 [CI, 1.11 to 5.57]).

CONCLUSIONS

Steady-state warfarin dose, advanced age, and extreme elevation in INR are risk factors for prolonged delay in return of the INR to within the therapeutic range. Decompensated congestive heart failure and active cancer greatly increase this risk.

Congestive heart failure with preserved systolic function in a statewide sample of community hospitals

BACKGROUND

The importance of congestive heart failure (CHF) in patients with preserved left ventricular systolic function is increasingly recognized, but most studies have been conducted at a single, usually academic, medical center. The aim of this study was to determine the prognosis, readmission rate, and effect of ACE inhibitor therapy in a Medicare cohort with CHF and preserved systolic function.

METHODS AND RESULTS

We examined a statewide, random sample of 1,720 California Medicare patients hospitalized with an ICD-9 diagnosis of CHF confirmed by a decreased left ventricular ejection fraction (EF) or chest radiograph from July 1993 to June 1994 and January 1996 to June 1996. Among the 782 patients with confirmed CHF and an in-hospital left ventricular EF measurement, 45% had reduced systolic function (ReSF) (EF < 40%) and 55% had preserved systolic function (PrSF) (EF > 40%). The PrSF group had a lower 1-year mortality rate but similar hospital readmission rates for both CHF and all causes. In patients with ReSF, ACE inhibitor treatment was associated with a lower mortality rate (P =.04) and a trend toward a lower CHF readmission rate (P =.13). In contrast, ACE inhibition therapy was associated with neither a lower rate of mortality nor CHF readmission in PrSF patients (P =.61 and.12, respectively). In multivariate analyses treatment with ACE inhibitors in PrSF patients was not associated with either a reduction in mortality (hazard ratio, 1.15; 95% CI, 0.79-1.67) or CHF readmission (hazard ratio, 1.21; 95% CI, 0.92-1.58).

CONCLUSIONS

CHF with PrSF seems to be associated with high mortality and morbidity rates, but ACE inhibitors may not produce comparable benefit in this group as in patients with ReSF.

The prognostic value of troponin in patients with non-ST elevation acute coronary syndromes: a meta-analysis

OBJECTIVES

This study was designed to compare the prognostic value of an abnormal troponin level derived from studies of patients with non-ST elevation acute coronary syndromes (ACS).

BACKGROUND

Risk stratification for patients with suspected ACS is important for determining need for hospitalization and intensity of treatment.

METHODS

We identified clinical trials and cohort studies of consecutive patients with suspected ACS without ST-elevation from 1966 through 1999. We excluded studies limited to patients with acute myocardial infarction and studies not reporting mortality or troponin results.

RESULTS

Seven clinical trials and 19 cohort studies reported data for 5,360 patients with a troponin T test and 6,603 with a troponin I test. Patients with positive troponin (I or T) had significantly higher mortality than those with a negative test (5.2% vs. 1.6%, odds ratio [OR] 3.1). Cohort studies demonstrated a greater difference in mortality between patients with a positive versus negative troponin I (8.4% vs. 0.7%, OR 8.5) than clinical trials (4.8% if positive, 2.1% if negative, OR 2.6, p = 0.01). Prognostic value of a positive troponin T was also slightly greater for cohort studies (11.6% mortality if positive, 1.7% if negative, OR 5.1) than for clinical trials (3.8% if positive, 1.3% if negative, OR 3.0, p = 0.2)

CONCLUSIONS

In patients with non-ST elevation ACS, the short-term odds of death are increased three- to eightfold for patients with an abnormal troponin test. Data from clinical trials suggest a lower prognostic value for troponin than do data from cohort studies.

Multicenter epidemiologic and health services research on therapeutics in the HMO Research Network Center for Education and Research on Therapeutics

Research and education programs in therapeutics that combine the data, organizational capabilities, and expertise of several managed care organizations working in concert can serve an important role when a single organization is not large enough to address a question of interest, when diversity in populations or delivery systems is required, and when it is necessary to establish consistency of results in different settings. Nine members of the HMO Research Network, a consortium of health maintenance organizations (HMOs) that perform public domain research, have formed a Center for Education and Research on Therapeutics (CERT), sponsored by the Agency for Healthcare Research and Quality, to conduct multicenter research in therapeutics. The CERT uses a distributed organizational model with shared leadership, in which data reside at the originating organization until they are needed to support a specific study. Extraction of data from the host computer systems, and some manipulation of data, is typically accomplished through computer programs that are developed centrally, then modified for use at each site. For complex studies, pooled analysis files are created by a coordinating center, and then analysed by investigators throughout the HMOs. It is also possible to contact HMO members when necessary. This multicenter environment has several benefits, addressing: (1) a wide array of questions about the safety and effectiveness of therapeutics, (2) the impact of efforts to change clinicians' and patients' behavior, and (3) pharmacoeconomic and pharmacogenetic questions.

Glycemic control and heart failure among adult patients with diabetes

BACKGROUND

Glycemic control is associated with microvascular events, but its effect on the risk of heart failure is not well understood. We examined the association between hemoglobin (Hb) A(Ic) and the risk of heart failure hospitalization and/or death in a population-based sample of adult patients with diabetes and assessed whether this association differed by patient sex, heart failure pathogenesis, and hypertension status.

METHODS AND RESULTS

A cohort design was used with baseline between January 1, 1995, and June 30, 1996, and follow-up through December 31, 1997 (median 2.2 years). Participants were 25 958 men and 22 900 women with (predominantly type 2) diabetes, >/=19 years old, with no known history of heart failure. There were a total of 935 events (516 among men; 419 among women). After adjustment for age, sex, race/ethnicity, education level, cigarette smoking, alcohol consumption, hypertension, obesity, use of beta-blockers and ACE inhibitors, type and duration of diabetes, and incidence of interim myocardial infarction, each 1% increase in Hb A(Ic) was associated with an 8% increased risk of heart failure (95% CI 5% to 12%). An Hb A(Ic) >/=10, relative to Hb A(Ic) <7, was associated with 1.56-fold (95% CI 1.26 to 1.93) greater risk of heart failure. Although the association was stronger in men than in women, no differences existed by heart failure pathogenesis or hypertension status.

CONCLUSIONS

These results confirm previous evidence that poor glycemic control may be associated with an increased risk of heart failure among adult patients with diabetes.

Prevalence of diagnosed atrial fibrillation in adults: national implications for rhythm management and stroke prevention: the AnTicoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study

CONTEXT

Atrial fibrillation is the most common arrhythmia in elderly persons and a potent risk factor for stroke. However, recent prevalence and projected future numbers of persons with atrial fibrillation are not well described.

OBJECTIVE

To estimate prevalence of atrial fibrillation and US national projections of the numbers of persons with atrial fibrillation through the year 2050.

DESIGN, SETTING, AND PATIENTS

Cross-sectional study of adults aged 20 years or older who were enrolled in a large health maintenance organization in California and who had atrial fibrillation diagnosed between July 1, 1996, and December 31, 1997.

MAIN OUTCOME MEASURES

Prevalence of atrial fibrillation in the study population of 1.89 million; projected number of persons in the United States with atrial fibrillation between 1995-2050.

RESULTS

A total of 17 974 adults with diagnosed atrial fibrillation were identified during the study period; 45% were aged 75 years or older. The prevalence of atrial fibrillation was 0.95% (95% confidence interval, 0.94%-0.96%). Atrial fibrillation was more common in men than in women (1.1% vs 0.8%; P<.001). Prevalence increased from 0.1% among adults younger than 55 years to 9.0% in persons aged 80 years or older. Among persons aged 50 years or older, prevalence of atrial fibrillation was higher in whites than in blacks (2.2% vs 1.5%; P<.001). We estimate approximately 2.3 million US adults currently have atrial fibrillation. We project that this will increase to more than 5.6 million (lower bound, 5.0; upper bound, 6.3) by the year 2050, with more than 50% of affected individuals aged 80 years or older.

CONCLUSIONS

Our study confirms that atrial fibrillation is common among older adults and provides a contemporary basis for estimates of prevalence in the United States. The number of patients with atrial fibrillation is likely to increase 2.5-fold during the next 50 years, reflecting the growing proportion of elderly individuals. Coordinated efforts are needed to face the increasing challenge of optimal stroke prevention and rhythm management in patients with atrial fibrillation.

Antithrombotic therapy in atrial fibrillation

Atrial fibrillation is a common condition affecting elderly individuals; as many as 10% of people older than age 80 years have AF. AF is also a potent risk factor for ischemic stroke, raising the risk of stroke fivefold. A set of consistent randomized controlled trials has demonstrated that long-term anticoagulation can largely reverse the risk of stroke attributable to AF. In these trials, anticoagulation generally proved quite safe, raising the risk of intracranial hemorrhage by less than 0.5% per year. The anticoagulation target for AF is INR 2 to 3 with INR 2.5 as the specific goal. The trials were much less consistent about the efficacy of aspirin, although it seems that aspirin has a small stroke-preventive effect. The recommended dose of aspirin is 325 mg per day. Because it raises the risk of hemorrhage and adds the burden of frequent monitoring of INR values, anticoagulation is recommended for those patients with AF at higher risk of stroke. Such higher risk is conferred by the following risk factors: (1) a history of a prior stroke, TIA, or other systemic embolic event; (2) a history of hypertension; (3) diabetes mellitus; (4) left ventricular dysfunction; (5) mitral stenosis; and (6) older age. The exact age threshold conferring sufficiently increased risk is uncertain, with some research indicating the threshold should be age 65 years, and other research indicating the threshold should be age 75 years. For lower-risk patients, aspirin is recommended. Future research should focus on the oldest patients with AF. These individuals face the highest risk of ischemic stroke without anticoagulation and the highest risk of major hemorrhage with anticoagulation. Only small numbers of such elderly patients were included in the randomized trials. Future research should also focus on improved risk stratification, allowing better targeting of anticoagulation. Discoveries of new antithrombotic agents and new drugs and devices for preservation of sinus rhythm could radically improve stroke-preventive strategies for AF.

Clinical symptoms and myocardial infarction in left bundle branch block patients

In patients with left bundle branch block (LBBB) and acute chest pain, the association between the clinical presentation and the diagnosis of myocardial infarction has not been investigated. We sought to identify features in the clinical history of patients with LBBB and acute cardiopulmonary symptoms that predict myocardial infarction among candidates for reperfusion therapy. We retrospectively studied a consecutive cohort of 75 patients (94 presentations) who presented to a university emergency department from 1994 to 1997 with LBBB on initial electrocardiogram (ECG) and acute chest pain of >/=20 min duration or acute pulmonary edema. Among the 94 presentations meeting criteria for the cohort, 26 (28%) had confirmed myocardial infarction. Coronary heart disease risk factors, past cardiac history, prior LBBB on the ECG, and presenting symptoms did not predict whether patients were having myocardial infarction. The clinical history was not effective at distinguishing LBBB patients with myocardial infarction among patients who appeared to be candidates for acute reperfusion therapy.

Treatment and outcomes of left bundle-branch block patients with myocardial infarction who present without chest pain. National Registry of Myocardial Infarction 2 Investigators

OBJECTIVES

We sought to determine the importance of chest pain on presentation as a predictor of in-hospital treatment and mortality in myocardial infarction (MI) patients with left bundle-branch block (LBBB).

BACKGROUND

Left bundle-branch block patients have a high mortality after MI but are unlikely to receive reperfusion therapy despite evidence from clinical trials demonstrating the efficacy of thrombolytic therapy. Nearly half of MI patients with LBBB present without chest pain.

METHODS

We studied the clinical features, treatment and in-hospital survival of 29,585 patients with LBBB enrolled in the National Registry of MI 2 June 1994 through March 1998). Multivariate logistic regression was used to assess the independent effect of chest pain on reperfusion decisions and in-hospital mortality.

RESULTS

Left bundle-branch block patients with chest pain were greater than five-fold more likely to receive reperfusion therapy (13.6% vs. 2.6%) than LBBB patients without chest pain; they were also more likely to receive aspirin, beta-adrenergic blocking agents, heparin and nitrates (all p < 0.0001). Unadjusted in-hospital mortality was 18% in patients with chest pain and 27% in patients without chest pain. Adjusting for patient characteristics reduced the odds ratio associated with the absence of chest pain from 1.47 (95% confidence interval: 1.41 to 1.54) to 1.21 (95% confidence interval: 1.12 to 1.30). The remainder of the mortality difference was caused by the undertreatment of patients without chest pain, particularly the low utilization of aspirin and beta-blockers.

CONCLUSIONS

Left bundle-branch block patients with MI who present without chest pain are less likely to receive optimal therapy and are at increased risk of death. Prompt recognition and treatment of this high-risk subgroup should improve survival.

Implications of stroke risk criteria on the anticoagulation decision in nonvalvular atrial fibrillation: the Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) study

BACKGROUND

Warfarin dramatically reduces the risk of stroke in patients with nonvalvular atrial fibrillation (NVAF) but increases the likelihood of bleeding. Accurately identifying patients who need anticoagulation is critical. We assessed the potential impact of prominent stroke risk classification schemes on this decision in a large sample of patients with NVAF.

METHODS AND RESULTS

We used clinical and electrocardiographic databases to identify 13 559 ambulatory patients with NVAF from July 1996 through December 1997. We compared the proportion of patients classified as having a low enough stroke risk to receive aspirin using published criteria from the Atrial Fibrillation Investigators (AFI), American College of Chest Physicians (ACCP), and the Stroke Prevention in Atrial Fibrillation Investigators (SPAF). In this cohort, AFI criteria classified 11% as having a low stroke risk, compared with 23% for ACCP and 29% for SPAF (kappa range, 0.44 to 0.85). This 2- to-3-fold increase in low stroke risk patients by ACCP and SPAF criteria primarily resulted from the inclusion of many older subjects (65 to 75 years+/-men >75 years) with no additional clinical stroke risk factors.

CONCLUSIONS

The age threshold for assigning an increased stroke risk has a dramatic impact on whether to recommend warfarin in populations of patients with NVAF. Large, prospective studies with many stroke events are needed to precisely determine the relationship of age to stroke risk in AF and to identify which AF subgroups are at a sufficiently low stroke risk to forego anticoagulation.

A systematic review of the effects of physician specialty on the treatment of coronary disease and heart failure in the United States

PURPOSE

To assess the effects of physician specialty on the knowledge, management, and outcomes of patients with coronary disease or heart failure.

MATERIALS AND METHODS

We performed a systematic search of MEDLINE from 1980 to 1997, as well as bibliographic references to articles about the effects of physician specialty on the knowledge, treatment, and outcomes of patients with coronary disease or heart failure in the United States.

RESULTS

Twenty-four articles met our criteria for inclusion (including eight that involved knowledge or self-reported practices, 14 that described actual practice patterns, and six that measured clinical outcomes). Cardiologists were more knowledgeable than generalist physicians about the optimal evaluation and management of coronary disease but not about the use of angiotensin-converting enzyme (ACE) inhibitors for heart failure. Patients with unstable angina or myocardial infarction were more likely to receive proven medical therapies, and possibly had improved outcomes, if they were treated by cardiologists. The use of lipid-lowering drugs after myocardial infarction was also more common among patients of cardiologists. ACE inhibitor use for heart failure was probably greater, and short-term readmission rates were lower, with cardiology care.

CONCLUSIONS

Patients with coronary disease or heart failure in the United States who are treated by cardiologists appear more likely to receive evidence-based care and probably have better outcomes. Investigation of collaborative models of care and innovative efforts to improve the use of proven therapies by physicians are needed.

Warfarin use among ambulatory patients with nonvalvular atrial fibrillation: the anticoagulation and risk factors in atrial fibrillation (ATRIA) study

BACKGROUND

Warfarin dramatically reduces the risk for ischemic stroke in nonvalvular atrial fibrillation, but its use among ambulatory patients with atrial fibrillation has not been widely studied.

OBJECTIVE

To assess the rates and predictors of warfarin use in ambulatory patients with nonvalvular atrial fibrillation.

DESIGN

Cross-sectional study.

SETTING

Large health maintenance organization.

PATIENTS

13428 patients with a confirmed ambulatory diagnosis of nonvalvular atrial fibrillation and known warfarin status between 1 July 1996 and 31 December 1997.

MEASUREMENTS

Data from automated pharmacy, laboratory, and clinical-administrative databases were used to determine the prevalence and determinants of warfarin use in the 3 months before or after the identified diagnosis of atrial fibrillation.

RESULTS

Of 11082 patients with nonvalvular atrial fibrillation and no known contraindications, 55% received warfarin. Warfarin use was substantially lower in patients who were younger than 55 years of age (44.3%) and those who were 85 years of age or older (35.4%). Only 59.3% of patients with one or more risk factors for stroke and no contraindications were receiving warfarin. Among a subset of "ideal" candidates to receive warfarin (persons 65 to 74 years of age who had no contraindications and had previous stroke, hypertension, or both), 62.1% had evidence of warfarin use. Among our entire cohort, the strongest predictors of receiving warfarin were previous stroke (adjusted odds ratio, 2.55 [95% CI, 2.23 to 2.92]), heart failure (odds ratio, 1.63 [CI, 1.51 to 1.77]), previous intracranial hemorrhage (odds ratio, 0.33 [CI, 0.21 to 0.52]), age 85 years or older (odds ratio, 0.35 [CI, 0.31 to 0.40]), and previous gastrointestinal hemorrhage (odds ratio, 0.47 [CI, 0.40 to 0.57]).

CONCLUSIONS

In a large, contemporary cohort of ambulatory patients with atrial fibrillation who received care within a health maintenance organization, warfarin use was considerably higher than in other reported studies. Although the reasons why physicians did not prescribe warfarin could not be elucidated, many apparently eligible patients with atrial fibrillation and at least one additional risk factor for stroke, especially hypertension, did not receive anticoagulation. Interventions are needed to increase the use of warfarin for stroke prevention among appropriate candidates.

Warfarin use among ambulatory patients with nonvalvular atrial fibrillation: the anticoagulation and risk factors in atrial fibrillation (ATRIA) study

BACKGROUND

Warfarin dramatically reduces the risk for ischemic stroke in nonvalvular atrial fibrillation, but its use among ambulatory patients with atrial fibrillation has not been widely studied.

OBJECTIVE

To assess the rates and predictors of warfarin use in ambulatory patients with nonvalvular atrial fibrillation.

DESIGN

Cross-sectional study.

SETTING

Large health maintenance organization.

PATIENTS

13428 patients with a confirmed ambulatory diagnosis of nonvalvular atrial fibrillation and known warfarin status between 1 July 1996 and 31 December 1997.

MEASUREMENTS

Data from automated pharmacy, laboratory, and clinical-administrative databases were used to determine the prevalence and determinants of warfarin use in the 3 months before or after the identified diagnosis of atrial fibrillation.

RESULTS

Of 11082 patients with nonvalvular atrial fibrillation and no known contraindications, 55% received warfarin. Warfarin use was substantially lower in patients who were younger than 55 years of age (44.3%) and those who were 85 years of age or older (35.4%). Only 59.3% of patients with one or more risk factors for stroke and no contraindications were receiving warfarin. Among a subset of "ideal" candidates to receive warfarin (persons 65 to 74 years of age who had no contraindications and had previous stroke, hypertension, or both), 62.1% had evidence of warfarin use. Among our entire cohort, the strongest predictors of receiving warfarin were previous stroke (adjusted odds ratio, 2.55 [95% CI, 2.23 to 2.92]), heart failure (odds ratio, 1.63 [CI, 1.51 to 1.77]), previous intracranial hemorrhage (odds ratio, 0.33 [CI, 0.21 to 0.52]), age 85 years or older (odds ratio, 0.35 [CI, 0.31 to 0.40]), and previous gastrointestinal hemorrhage (odds ratio, 0.47 [CI, 0.40 to 0.57]).

CONCLUSIONS

In a large, contemporary cohort of ambulatory patients with atrial fibrillation who received care within a health maintenance organization, warfarin use was considerably higher than in other reported studies. Although the reasons why physicians did not prescribe warfarin could not be elucidated, many apparently eligible patients with atrial fibrillation and at least one additional risk factor for stroke, especially hypertension, did not receive anticoagulation. Interventions are needed to increase the use of warfarin for stroke prevention among appropriate candidates.

Outcome following acute myocardial infarction: are differences among physician specialties the result of quality of care or case mix?

BACKGROUND

Studies to determine whether care by cardiologists improves the survival of patients with acute myocardial infarction (MI) have produced conflicting results, and it is not known what accounts for differences in patient outcome by physician specialty.

OBJECTIVES

To evaluate whether cardiologists provide more recommended therapies to elderly patients with acute MI and, if so, to determine whether variations in processes of care account for differences in patient outcome.

DESIGN

Retrospective cohort study using medical chart data and administrative data files.

SETTING

All nonfederal acute care hospitals in California.

PATIENTS

A cohort of 7663 Medicare beneficiaries 65 years and older directly admitted to the hospital with a confirmed acute MI from April 1994 to July 1995 with complete data regarding potential contraindications to recommended therapies.

MAIN OUTCOME MEASURES

Percentage of "good" and "ideal" candidates for a given acute MI therapy who actually received that therapy, percentage who received exercise stress testing or coronary angiography, percentage who underwent revascularization, and 1-year mortality, stratified by specialty of the attending physician.

RESULTS

During hospitalization, good candidates for aspirin were more likely to receive aspirin if they were treated by cardiologists (87%) than by medical subspecialists (73%; P<.001), general internists (84%; P = .003), or family practitioners (81%; P<.001). Cardiologists were also more likely to treat good candidates with thrombolytic therapy (51%) than were medical subspecialists (29%; P<.001), general internists (40%; P<.001), or family practitioners (27%; P<.001). Patients of cardiologists were 2- to 4-fold more likely to undergo a revascularization procedure. Despite these differences in utilization, we found similar 30-day mortality rates across physician specialties. However, 1-year mortality rates were greater for patients treated by medical subspecialists (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.6-2.3), general internists (OR, 1.4; 95% CI, 1.3-1.6), and family practitioners (OR, 1.7; 95% CI, 1.4-1.9) than for those treated by cardiologists. Adjusting for differences in patient and hospital characteristics markedly reduced the ORs for those treated by medical subspecialists (OR, 1.2; 95% CI, 0.9-1.4), general internists (OR, 1.1; 95% CI, 1.0-1.3), and family practitioners (OR, 1.3; 95% CI, 1.1-1.6), whereas further adjustment for medication use and revascularization procedures had little effect.

CONCLUSIONS

Differences in the use of recommended therapies by physician specialty are generally small and do not explain differences in patient outcome. In comparison, differences among patients treated by physicians of various specialties (case mix) have a large impact on patient outcome and may account for the residual survival advantage of patients treated by cardiologists. With the exception of the in-hospital use of aspirin, recommended MI therapies are markedly underused, regardless of the specialty of the physician.

Should the electrocardiogram be used to guide therapy for patients with left bundle-branch block and suspected myocardial infarction?

CONTEXT

Recently, an algorithm based on the electrocardiogram (ECG) was reported to predict myocardial infarction (MI) in patients with left bundle-branch block (LBBB), but the clinical impact of this testing strategy is unknown.

OBJECTIVE

To determine the diagnostic test characteristics and clinical utility of this ECG algorithm for patients with suspected MI.

DESIGN

Retrospective cohort study to which an algorithm was applied, followed by decision analysis regarding thrombolysis made with or without the algorithm.

SETTING

University emergency department, 1994 through 1997.

PATIENTS

Eighty-three patients with LBBB who presented 103 times with symptoms suggestive of MI.

MAIN OUTCOME MEASURES

Myocardial infarction determined by serial cardiac enzyme analyses and stroke-free survival.

RESULTS

Of 9 ECG findings assessed, none effectively distinguished the 30% of patients with MI from those with other diagnoses. The ECG algorithm indicated positive findings in only 3% of presentations and had a sensitivity of 10% (95% confidence interval, 2%-26%). The decision analysis showed that among 1000 patients with LBBB and chest pain, 929 would survive without major stroke if all received thrombolysis compared with 918 if the ECG algorithm was used as a screening test.

CONCLUSIONS

The ECG is a poor predictor of MI in a community-based cohort of patients with LBBB and acute cardiopulmonary symptoms. Acute thrombolytic therapy should be considered for all patients with LBBB who have symptoms consistent with MI.

Bundle-branch block and in-hospital mortality in acute myocardial infarction. National Registry of Myocardial Infarction 2 Investigators

BACKGROUND

Left bundle-branch block (BBB) is considered an important predictor of poor outcome in patients with acute myocardial infarction, but the consequences of right BBB are not well understood.

OBJECTIVES

To 1) estimate the prevalence of left and right BBB in patients with myocardial infarction; 2) compare the clinical characteristics of and treatments received by patients with left, right, or no BBB; and 3) determine the independent association of left BBB and right BBB with in-hospital death.

DESIGN

Retrospective cohort study.

SETTING

Multicenter registry of 1571 U.S. hospitals.

PATIENTS

297,832 patients with acute myocardial infarction who had left, right, or no BBB on initial electrocardiography.

MEASUREMENTS

Presence and type of BBB, clinical characteristics of patients, therapies given, and in-hospital death.

RESULTS

Patients with left BBB (n = 19,967; 6.7%) or right BBB (n = 18,354; 6.2%) were older and had more comorbid illness and congestive heart failure than patients with no BBB. Among patients for whom thrombolytic therapy was clearly indicated, fewer patients with left or right BBB (16.6% and 32.0%, respectively) than patients with no BBB (66.5%) received this therapy (P < 0.001). Fewer patients with left or right BBB (60.6% and 67.3%, respectively) than patients with no BBB (75.6%) received aspirin within the first 24 hours (P < 0.001), and fewer patients with left or right BBB (23.9% and 31.8%, respectively) than patients with no BBB (40.4%) received beta-blockers within the first 24 hours (P < 0.001). Unadjusted in-hospital mortality rates were almost twice as high for patients with left or right BBB (22.6% and 23.0%, respectively) as for patients with no BBB (13.1%) (P < 0.001). Compared with no BBB and no ST-segment elevation, left BBB was associated with a 34% increase (odds ratio, 1.34 [95% CI, 1.28 to 1.39]) and right BBB was associated with a 64% increase (odds ratio, 1.64 [CI, 1.57 to 1.71]) in the risk for in-hospital death, after adjustment for potential confounders.

CONCLUSIONS

In patients with acute myocardial infarction, prevalences of right and left BBB are similar. Patients with BBB have more comorbid conditions, are less likely to receive therapy, and have an increased risk for in-hospital death compared with patients with no BBB. Compared with left BBB, right BBB seems to be a stronger independent predictor of in-hospital death.

HIV-1 entry into quiescent primary lymphocytes: molecular analysis reveals a labile, latent viral structure

Productive infection of human T lymphocytes by HIV-1 is dependent upon proliferation of the infected cell. Nonproliferating quiescent T cells can be infected by HIV-1 and harbor the virus in an inactive state until subsequent mitogenic stimulation. We use a modification of the polymerase chain reaction method, which is both sensitive and quantitative, to demonstrate that HIV-1 DNA synthesis is initiated in infected quiescent T cells at levels comparable with those of activated T cells. However, unlike that of activated T cells, the viral genome is not completely reverse transcribed in quiescent cells. Although this viral DNA structure can persist in quiescent cells as a latent form, it is labile. We discuss the lability of this HIV-1 DNA structure in relation to a "self-restricting persistent infection" by HIV-1 and propose that this may explain the low percentage of infected cells in the circulation of AIDS patients.