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Research on Heart Disease

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Likelihood of heart attack in symptomatic patients who visit the ER is twice as great for men as for women

Women who arrive at a hospital emergency department (ED) with chest pain or other heart attack symptoms are much less likely than men with similar symptoms to actually have a heart attack. The exception is women who have ST-segment elevation on electrocardiogram (ECG) or signs of congestive heart failure (CHF), according to a study supported in part by the Agency for Health Care Policy and Research (HS07360 and NRSA training grant T32 HS00060).

This study involved more than 10,500 men and women 30 years of age or older who visited the EDs of 10 hospitals with heart attack symptoms during a 7-month period in 1993. Women and men typically had different symptoms. Although chest pain was reported in 76 percent of men and 75 percent of women, with men more frequently citing it as the "chief complaint," a greater proportion of women had nausea or vomiting, shortness of breath, and findings consistent with CHF, such as fluid in the lung on chest x-ray. Women's histories more often included hypertension and diabetes, while more men had histories of previous heart attack, angina pectoris, and peptic ulcer disease. Men more often than women had Q waves and ST-segment elevations on their ECG tracings.

Of the women in the study with CHF, 8 percent also had diabetes, 38 percent had hypertension, and 30 percent had both diabetes and hypertension. Independent of the increased risk of heart attack due to a history of diabetes mellitus or hypertension, the presence of CHF should be given substantial weight in assessing the likelihood of heart attack in symptomatic women presenting to the ED, suggest Deborah R. Zucker, M.D., Ph.D., and her colleagues from New England Medical Center and Tufts University School of Medicine.

See "Presentations of acute myocardial infarction in men and women," by Dr. Zucker, John L. Griffith, Ph.D., Joni R. Beshansky, R.N., M.P.H., and Harry P. Selker, M.D., M.S.P.H., in the Journal of General Internal Medicine 12, pp. 79-87, 1997.

Heart attack studies document patients' reluctance to go to the hospital and undertreatment of some severely ill patients

Research consistently shows that heart attack victims who arrive at the hospital early and receive thrombolytic (clot-busting) therapy have a much better chance for long-term survival than those who don't. However, two new articles, resulting from a dissemination research project funded by the Agency for Health Care Policy and Research (HS07357), show that heart attack victims often delay going to the hospital, and those with severe mental or physical illnesses are less apt to receive thrombolytics and aspirin (which also thins the blood) than other patients. These articles, authored by researchers at Harvard Medical School, are summarized here.

Gurwitz, J.H., McLaughlin, T.J., Willison, D.J., and others (1997, April). "Delayed hospital presentation in patients who have had acute myocardial infarction." Annals of Internal Medicine 126(8), pp. 593-599.

The authors report that 40 percent of patients in this study with acute myocardial infarction (AMI or heart attack) didn't arrive at the hospital until more than 6 hours after the onset of heart attack symptoms. This is later than the ideal time within which thrombolytic therapy can be most effective in preventing further heart damage. What's more, only 42 percent of all patients hospitalized with AMI used emergency medical transport services to get to the hospital. Patients most apt to delay going to the hospital were older and female and those with a history of hypertension. Time of day also made a difference, with the highest risk of delay being from 6 p.m. to 6 a.m.

Persons who felt chest pressure or pain and those who had a history of revascularization surgery (coronary bypass surgery or angioplasty) were significantly less likely to prolong departure for the hospital. Most patients in this study had public (Medicare or Medicaid) or private health insurance coverage, and there was no association between income and prolonged delay.

The researchers recommend educational interventions that encourage prompt use of emergency medical transport services and target specific patient populations—such as elderly persons, women, and those with cardiac risk factors—and encourage them not to hesitate to go to the hospital at the first signs of a possible heart attack. These findings are based on examination of factors affecting delayed arrival of more than 2,400 patients who were hospitalized for AMI at 37 Minnesota hospitals.

McLaughlin, T.J., Soumerai, S.B., Willison, D.J., and others (1997). "The effect of comorbidity on use of thrombolysis or aspirin in patients with acute myocardial infarction eligible for treatment." Journal of General Internal Medicine 12(1), pp. 1-6.

In this article, the researchers review the medical records of the same group of Minnesota patients with AMI to investigate a correlation between patients' coexisting medical illnesses and receipt of thrombolytic or aspirin therapy. These lifesaving treatments are widely underused in all patients with AMI. But the odds of treatment among patients with severe mental and physical conditions in addition to AMI (comorbidity), who were otherwise eligible to receive thrombolytic therapy or aspirin, were about 0.5 when compared with patients without these problems, according to this study. Patients with mild or moderate comorbidity received therapy as often as those without any coexisting illness.

These findings suggest that undertreatment of eligible patients with AMI may be influenced by the physicians judgment about the patient's prognosis, which takes into account serious coexisting illnesses, such as mental impairment, malignancies, kidney impairment, hypertension, diabetes, and respiratory dysfunction. Thus, not following treatment recommendations for AMI patients may not be due to a gap in physician knowledge or lack of acceptance of the recommendations. Undertreatment in this case may reflect conscious or unconscious considerations to withhold standard therapeutic options given the expected prognosis of certain patients.

Non-insulin-dependent diabetics frequently have heart disease, but high blood sugar is not the culprit

More than half of persons with non-insulin-dependent diabetes mellitus (NIDDM) die from cardiovascular disease. Since the hyperglycemia (high blood sugar levels) of diabetes is clearly related to diabetic microvascular complications, it has been suggested that high blood sugar may play a role in large-vessel cardiovascular disease as well. However, a recent study by the NIDDM Patient Outcomes Research Team (PORT) suggests otherwise. It found that the prevalence of cardiovascular disease did not climb with rising blood sugar levels, but it did increase significantly in the presence of the established risk factors of advancing age, cigarette smoking, and high blood pressure (hypertension).

Diabetics with cardiovascular disease were significantly older (67 vs. 59 years), more likely to have hypertension (66 percent vs. 54 percent), to currently smoke cigarettes (17 percent vs. 13 percent), to have high total/HDL cholesterol ratios (5.9 vs. 5.6), and to have had NIDDM significantly longer (11 vs. 8 years) than their counterparts in the study who did not have cardiovascular disease. However, cardiovascular disease prevalence remained constant across increasing blood sugar levels for both men and women.

Thus, intensive management of hypertension and hyperlipidemia, as well as smoking cessation, continue to be the most promising strategies to reduce cardiovascular complications in persons with NIDDM, conclude the PORT researchers.

The NIDDM PORT, which completed its work in 1996, was supported by the Agency for Health Care Policy and Research (HS06665). For this study, the researchers analyzed the association between blood sugar control and prevalent cardiovascular disease in 1,539 patients at one site, who were enrolled in a longitudinal observational study of effectiveness and outcomes of care for people with NIDDM ranging in age from 31 to 91 years.

Details are in "Metabolic control and prevalent cardiovascular disease in non-insulin-dependent diabetes mellitus (NIDDM): The NIDDM patient outcomes research team," by James B. Meigs, M.D., M.P.H., Daniel E. Singer, M.D., Lisa M. Sullivan, and others, in the January 1997 issue of The American Journal of Medicine 102, pp. 38-47.

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Outcomes/Effectiveness Research

Researchers continue to question value of annual prostate cancer screening for men over 50

Available evidence does not yet support the American Cancer Society's recommendation of annual digital rectal exam and prostate-specific antigen (PSA) measurement for men over 50 years of age, concludes a study by the Patient Outcomes Research Team (PORT) for Prostatic Diseases, supported by the Agency for Health Care Policy and Research (HS08397). Indeed, this approach results in as many as 15 percent of men in their 50's and 40 percent of men in their 70's requiring further invasive evaluation with biopsy (following suspicious PSA results) with a meager net benefit of 6 days to 2.5 weeks of prolonged life per man screened if the ensuing radical prostatectomy (surgical removal of the prostate) for localized cancer is assumed to be effective.

If the assumptions about curative treatment are less favorable, older men may be harmed by aggressive treatment, explains team leader Michael J. Barry, M.D., of Harvard Medical School. The team constructed a model to estimate the risks and maximum benefits (based on data from large studies and meta analyses) as well as the cost-effectiveness of one-time screening of a hypothetical group of 100,000 men in their 50's, 60's, and 70's using both digital rectal exams and PSA measurements.

The team estimated that early detection would result in the following results per 100,000 men: many biopsies of the prostate (10,752 to 27,046 men, depending on age), few surgical deaths (8 to 23 men), and the onset of impotence (657 to 1,594 men), or incontinence (131 to 317 men), or both (196 to 476 men). Over time, the model predicts that 407 men 50 to 59 years of age, 653 men aged 60 to 69, and 427 men aged 70 to 79 would develop metastatic prostate cancer in the absence of an early detection program but would die of something other than prostate cancer if screening were implemented. The net benefit of early detection would be 17, 17, and 6 days per man screened, respectively, for the three age groups if treatment cured all prostate cancers still confined to the prostate gland. These men also would lose about 200 life-years from surgical death and have more than 20,000 life-years with incontinence, impotence, or both. The researchers conclude that the lack of direct evidence showing a net benefit of screening for prostate cancer mandates more clinician-patient discussion for this procedure than for many other routine tests.

Details are in "Early detection of prostate cancer: Part I: Prior probability and effectiveness of tests," and "Early detection of prostate cancer: Part II: Estimating the risks, benefits, and costs," by Christopher M. Coley, M.D., Dr. Barry, Craig Fleming, M.D., and others, in the March 1 and 15, 1997, Annals of Internal Medicine 126(5), pp. 394-406, and 126(6), pp. 468-479.

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Health Care Marketplace

Hospital mergers are driven primarily by local merger opportunities

During the 1980's, a large number of freestanding hospitals dotted the U.S. landscape. But by 1991, 195 formal mergers and consolidations had taken place, most involving not-for-profit hospitals in the same community. Hospitals were more apt to merge with one another if there was considerable market overlap—that is, they were competing with similar facilities and services for the same patients, and they had similar performance levels, according to a study supported in part by the Agency for Health Care Policy and Research (National Research Service Award training grant T32 HS00009).

For the study, researchers analyzed State, hospital, and other data collected on 76 acute care hospitals in the San Francisco Bay area and identified 17 hospital mergers from 1983 to 1992.

Based on the findings of this study, the likelihood of a merger between a particular pair of hospitals is positively related to the degree of market overlap that exists between them, and market overlap and performance difference interact in their effect on merger likelihood. In an analysis of individual hospitals, however, conditions of rivalry, hospital market share, and hospital size were not found to influence the likelihood that a hospital will engage in a merger.

The researchers point out, in particular, that mergers were not driven directly by considerations of market power or efficiency as much as they were by the existence of specific merger opportunities in the hospitals' local markets. Nevertheless, such mergers do offer opportunities for increasing market presence as well as for improving efficiency, explain Geoffrey R. Brooks, Ph.D., and V. Grace Jones, M.P.H., of the University of Pennsylvania.

For instance, a merged hospital system may be able to exercise market power in setting prices, particularly with respect to patients who pay out-of-pocket and indemnity insurers who pay posted prices. They also may have better bargaining power with large payers if such payers cannot provide access for their beneficiaries without contracting through the system. These mergers also may provide economies of scale for specialized services, such as open heart surgery and obstetrics, which have high fixed labor costs and substantial capital requirements.

Finally, specialized expertise can be shared between merged hospitals. To the extent that national or State policies on health insurance generate increased buyer concentration, the pressures on hospitals with higher market overlap to merge may increase so that they can bargain more effectively with suppliers, insurance companies, and others, conclude the researchers.

See "Hospital mergers and market overlap," by Dr. Brooks and Ms. Jones in the February 1997 Health Services Research 31(6), pp. 701-722.

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Dental Research

Higher dental prices often denote higher quality of care

If you're paying higher prices for dental services, you are probably getting better quality dental care than someone who is paying less, according to a study supported by the Agency for Health Care Policy and Research (HS06554). It shows that dentists who charge higher prices are more apt to have quality office practices such as staff vaccinated against Hepatitis B and trained in CPR, and quality of care practices such as head and neck exam, written treatment plans, autoclaving of handpieces, and use of rubber dams.

According to the participating dentists' self-reported data, the price of services increased by $21.38 for each quality policy implemented in the practice. Thus, for dentists who provided three of six quality office practices, the price of services would be almost $64.14 more than a practice that did not implement any of the practices. Also, each incremental increase in the standard of care, such as use of rubber dams, increased the overall price of services by $42.93.

Higher-priced dentists also were less likely to make patients wait a long time for an initial appointment or to wait in the dental office after arriving for an appointment. For instance, the cost of services decreased by $4.86 per day for each days wait for a new-patient appointment and by $5.20 per minute spent in the office waiting to be seen. Since dentists do seem to be compensated for higher quality of care and reduced patient time, regulatory intervention to restrict dental fees may have the unintended side effect of reducing quality of dental care, concludes Peter Milgrom, D.D.S., of the University of Washington.

Dr. Milgrom and his colleagues surveyed a random sample of 3,048 dentists in private practice, drawn from the 1991-1992 American Dental Association's Distribution of Dentists census of U.S. dentists, to examine dentist demographic characteristics, dental practice characteristics, practice finances, and insurance.

For more information, see "The relationship between price of services, quality of care, and patient time costs for general dental practice," by Coralyn W. Whitney, Ph.D., Dr. Milgrom, Douglas Conrad, M.H.A., M.B.A., Ph.D., and others, in the February 1997 Health Services Research 31(6), pp. 773-790.

Consistency of dentists' treatment recommendations for restoring teeth is questioned

Most dental schools teach that a crown is the preferred treatment for substantially compromised posterior teeth with extensive caries, fractures, or large defective restorations (fillings), as opposed to a direct metal alloy (amalgam) or composite resin filling. But older patients are significantly more likely to receive crowns than young patients, resulting in as much as a 33 percent increase in the mean per tooth cost of treatment in the oldest group. And regional variation in provision of crowns appears to contribute to a 31 percent difference in the mean per tooth treatment cost between the highest and lowest cost regions.

The ratio of crowns to their alternatives varies beyond that accounted for by the patient and practice factors that were measurable through the claims data used in this study, raising questions about the consistency of dentists' treatment recommendations. These are the findings of a study supported by the Agency for Health Care Policy and Research (HS06786) and conducted by William J. Hayden, D.D.S., M.P.H., of the University of Missouri, Kansas City, School of Dentistry, and his colleagues. They used data from an electronic insurance claims clearinghouse to examine claims submitted by dental practices in 48 States from May 1991 through April 1994.

For this study, the researchers selected general practices with claims for 10 or more posterior restorations (covering more than three surfaces) during the study period. Across the entire sample, the average cost of restoring a tooth requiring either a crown or its alternative was $225. The most notable differences in average cost per tooth were between the 18 to 34 age group ($181) and the 50 and older group ($269) and when comparing the Northeast ($173) and the West ($251).

Since crowns can cost up to six times as much as the alternative, seemingly small differences in crown utilization can have profound effects on overall costs. The variation found in the provision of crowns at the practice level also raises concerns about the appropriateness of care, note the researchers. They conclude that if a substantial portion of the variation noted in this study is indeed due to dentists' idiosyncratic use of crowns, the profession has a clear indication of the need to improve knowledge among practitioners of treatment outcomes.

In fact, Dr. Hayden points out in a related article that the dental profession lacks basic evidence that many of the treatments provided are even effective. He also suggests that soon payers and consumers will no longer accept anecdotal stories about quality; they will want measurement and quantification instead.

Dr. Hayden argues that dental schools are the logical site for the development of valid, reliable, and acceptable health services research methods and databases. He describes the actual development of an insurance claims database to demonstrate the types of investigations possible with it. This database was used to conduct the study described here on practice variations in the use of crowns.

More details are in "Variation in the use of crowns and their alternatives," by Daniel A. Shugars, D.D.S., Ph.D., M.P.H., Dr. Hayden, James J. Crall, D.D.S., M.S., Sc.D., and Mark S. Scurria, D.D.S., and "Dental health services research utilizing comprehensive clinical databases and information technology," by Dr. Hayden, in the January 1997 Journal of Dental Education 61(1), pp. 22-28 and 47-55.

Use of dental services by the elderly grows, especially among city-dwelling blacks covered by Medicare

With more elderly persons having discretionary income and retaining their natural teeth, demand for dental services among the elderly has grown. But this demand can be substantially influenced by financial barriers and other health concerns, according to a study supported by the Agency for Health Care Policy and Research (HS07661).

The study found that poor, black elderly persons living in the city are twice as likely to use dental services that are reimbursed by a Medicare waiver program than their white counterparts. This suggests that eliminating financial barriers among less affluent and less-educated minority elderly persons does affect their use of oral health care services, comments Michael S. Strayer, D.D.S., M.S., of Ohio State University College of Dentistry.

The researchers analyzed dental and medical claims data from 1983 to 1992 for individuals over 62 years of age who visited two Cincinnati health care facilities and participated in a Medicare-waiver program that reimbursed for dental services (not usually covered by Medicare). They compared demographic variables, medical use, and pharmaceutical use among dental and nondental medical users. Nondental medical users had twice as many medical visits and more than twice the monthly medical charges in the program than the dental users (.99 compared with .56 visit and $43 vs. $21 in charges per month).

Dental users were more likely to be younger (born after 1910) and black (63 percent vs. 36 percent white) than nondental users, with twice as many blacks participating in the dental waiver program than whites. The decrease in oral health care services associated with increased use of medical services would suggest that as health declines, persons are less inclined or able to seek dental care. This could indicate a decrease in the priority given to oral health care, a decreased ability to access oral health care services, or both.

See "Predictors of dental use for low-income, urban elderly persons upon removal of financial barriers," by Dr. Strayer, Raymond A. Kuthy, D.D.S., M.P.H., Robert J. Caswell, Ph.D., and Melvin L. Moeschberger, Ph.D., in The Gerontologist 37(1), pp. 110-116, 1997.

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