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Media Advisory Date: November 18, 1999
The Agency for Health Care Policy and Research (AHCPR) works to improve the quality of health care, reduce costs, and broaden access to essential services. Here are some of the findings described in the October issue of AHCPR's Research Activities.
Beta Blockers May Be Most Effective First-line Treatment for Stable Angina
Stable angina, marked by crushing chest pain, affects more than 7 million people in the United States. Long-term drug therapy to prevent anginal symptoms has consisted of beta blockers, calcium antagonists (also called calcium channel blockers), long-acting nitrates, and their combinations. However, physicians currently don't treat the condition with beta blockers, even though several clinical guidelines recommend them as the first line of treatment. A new AHCPR-supported study bolsters these recommendations, and adds evidence supporting these guidelines. It shows that compared with calcium antagonists and long-acting nitrates, beta blockers are equally well or better tolerated and provide equivalent angina relief. A team of researchers at the University of California, Stanford, led by Paul A. Heidenreich, M.D., M.S., based their findings on a meta-analysis of 90 studies from 1966 to 1997 that directly compared these three types of medication in patients with stable angina. They found that calcium antagonists were associated with a greater number of adverse events, but they did not provide greater angina relief (measured by number of angina episodes, nitroglycerine use, and exercise time) than beta blockers. For example, there were 0.31 fewer episodes of angina per week with beta blockers, and they were discontinued 28 percent less often because of adverse events than calcium antagonists (odds ratio, OR 0.72).
["Meta-analysis of trials comparing -blockers, calcium antagonists, and nitrates for stable angina," by Dr. Heidenreich, Kathryn M. McDonald, M.M., Trevor Hastie, Ph.D., and others, in the May 26, 1999 Journal of the American Medical Association 281(20), pp. 1927-1936.]
Multiple Drug Therapy for HIV Clinic Patients is Only Half as Successful as it is for Clinical Trial Patients
Highly active antiretroviral therapy (HAART), an intense combination drug therapy for patients who have HIV infection, is only half as successful in reducing HIV viral load in patients treated at a typical urban HIV clinic compared with similar patients enrolled in clinical trials. Failure to keep clinic appointments is the primary reason for the lack of success in suppressing HIV levels, according to an AHCPR-supported study. Missed appointments may simply be a marker for poor compliance with drug therapy, which is more easily controlled in clinical trials, suggests Richard D. Moore, M.D., M.H.Sc., of Johns Hopkins University School of Medicine. He and colleagues analyzed the success of a broad range of multiple drug therapies, which usually included a protease inhibitor and one or two other antiretroviral drugs, in 273 patients at an urban HIV clinic. They found that 37 percent of patients receiving HAART had undetectable HIV levels 1 year after starting therapy and only 23 percent experienced viral suppression in the three time periods studied: 1 to 90 days, 3 to 7 months,
and 7 to 14 months. This was half the rate of viral suppression seen in clinical trial patients receiving similarly potent therapy.
["Highly active antiretroviral therapy in a large urban clinic: Risk factors for virologic failure and adverse drug reactions," by Gregory M. Lucas, M.D., Richard E. Chaisson, M.D., and Dr. Moore, in the July 20, 1999 Annals of Internal Medicine 131(2), pp. 81-87.]
Costs Pose a Barrier to Timely Immunization of Children
A National priority for the year 2000 is full immunization of at least 90 percent of U.S. children by age 2. Yet the vaccination rate for children ages 19-35 months was only 78 percent in 1996. A recent study supported by AHCPR places part of the blame on economic barriers to timely immunization. Richard K. Zimmerman, M.D., M.P.H., of the University of Pittsburgh and his colleagues interviewed 29 primary care physicians in Minnesota about their likelihood of vaccinating a child in a particular clinical situation. They then correlated physicians' stated practices with actual immunization practices. They found that children are vaccinated later in the practices of providers who do not receive free vaccine supplies, those who tend to refer uninsured children to a public vaccine clinic rather than do the vaccinations themselves, and providers who over-interpret contraindications to vaccination. Clearly, providing free vaccines to providers through the federal Vaccines for Children Program can increase immunization rates, concludes Dr. Zimmerman.
["Are vaccination rates higher if providers receive free vaccines and follow contraindication guidelines?" Dr. Zimmerman, Tammy A. Mieczkowski, Ph.D., and Matthew Michel, in the May 1999 Family Medicine 31(5), pp. 317-323]
Dialysis Patients' Quality-of-Life Concerns Deserve Greater Attention from Providers
Patients with end stage renal disease (ESRD), or chronic kidney failure, apparently have concerns about the impact of their dialysis treatment on the quality of their lives that are not fully appreciated by health care professionals, according to a study supported by AHCPR. These patients usually receive hemodialysis (HD) for 3 to 4 hours three times a week at a dialysis center or peritoneal dialysis (PD) four times per day. Dialysis functions like a kidney to remove waste products from the body and regulate chemical and water balance. In HD a machine filters impurities out of the blood from an arm or leg artery. The filtered blood is then returned to the body via an adjacent vein. PD involves inserting a catheter in the patient's abdomen to run dialysis fluid into the abdomen. The fluid is then drawn out along with excess water and waste products.
Researchers conducted separate focus groups with adult patients and health care professionals. The patients said that dialysis affected 10 different areas of quality of life compared with only 5 mentioned by health care professionals. For instance, patients mentioned that they became depressed, had problems with body image, were weak and tired, and believed they did not think clearly. Providers did not mention these issues, even though the providers had a good sense of the loss of freedom and control felt by dialysis patients.
"Use of focus groups to identify concerns about dialysis," by Neil R. Powe, M.D., M.P.H., M.B.A., Eric B. Bass, M.D., Mollie W. Jenckes, M.H.Sc., Nancy E. Fink, M.P.H., and others, July 1999 Medical Decision Making 19, pp. 287-295]
Other articles in Research Activities include findings on:
- Incidence of serious mental illness among HIV/AIDS patients.
- Response of the hemophiliac community to blood safety issues.
- Improving prenatal care programs for poor women.
- High cesarean delivery rates at private hospitals.
- Benefits of early tube feeding of bowel resection patients.
- Factors affecting doctors' adoption of clinical guidelines.
- Effect of disabilities on receipt of preventive care.
- Role of depression in self-assessments of health status.
- Expansion of rural communities into managed care.
- Use of incentives to improve pediatric preventive care in HMOs.
- Influence of gatekeeping on pediatric referral rates.
- Care for heart attack patients in HMOs.
- Physician/patient interaction during initial and return visits.
- Effects of managed care on use of ICU services.
- Hospital length of stay and costs for pneumonia patients.
For additional information, contact the AHCPR Press Office, (301) 427-1364: Salina Prasad, (301) 427-1864 (SPrasad@ahrq.gov).