Panelists' views of 68 NIH consensus conference.

OBJECTIVES: To analyze the response patterns and trends of 68 surveys of successive NIH consensus panels' views on the NIH consensus process. METHODS: Each panel's responses were compared to an "average" panel's responses calculated by determining the mean response for each survey question across panels. RESULTS: The results show a stable pattern of panelists' generally positive views. However, several conferences were judged very positively and some very negatively compared to the norm. Most negatively viewed conferences occurred early in the consensus program's history. CONCLUSIONS: The disparate perceptions are discussed and interpreted as reflecting favorable panels' views of recent changes in the NIH Consensus Development Program.

Curative and population medicine: bridging the great divide.

There are gaps in understanding between practicing physicians (curative medicine) and those trained in public health and epidemiology (population medicine). In the last century, these groups were closer, as physicians played a role in public health, sanitation and in the prevention of the spreading of infection. However, with the recent extraordinary successes of the biomedical model in explaining disease, and the ensuing explosion of remarkable - and expensive - medical procedures and treatments, public health, preventive medicine and the population approach in general have been overshadowed. In this essay, I try to explain how the training of physicians and the daily care of patients may hinder their appreciation of the population model. For instance, for many of the myriad decisions involved in patient care in daily practice, there is little evidence, population derived or otherwise. What little evidence there is may be dominated by personal experiences, opinions and values. Additionally, the statistical and epidemiologic approach necessary for the maintenance of health and prevention of illness may not be valued by practitioners whose training and focus is on treating sick people one by one. To illustrate these disparities in understanding, examples are given from the NIH Consensus Conference on mammography screening for women aged 40-49, and from the use of science in the courtroom in adjudicating toxic tort cases. Understanding population medicine requires an appreciation of the concepts of chance, probability and statistics and of epidemiologic principles, difficult areas for many - including the general public. These topics play a small to nonexistent role in the formal training of most physicians. Some closing of the gap in understanding may be occurring. It is hoped this essay will help.

Influence of the NIH Consensus Conference on Helicobacter pylori on physician prescribing among a Medicaid population.

OBJECTIVES: In February 1994, an National Institutes of Health (NIH) Consensus Development Conference panel unequivocally recommended antimicrobial therapy to eradicate Helicobacter pylori in the treatment of peptic ulcer disease. The goal of this study was to determine if these recommendations resulted in a change in physician prescribing among an underserved population. METHODS: Computerized Pennsylvania Medicaid data from January 1993 through February 1996 were used to evaluate prescribing patterns in the year before and 2 years after the NIH conference. An interrupted time series model, based on 12,737 outpatient peptic ulcer disease encounters, assessed the impact of the conference in influencing physician prescribing. RESULTS: The prescription of antimicrobial agents for the treatment of peptic ulcer disease significantly increased across the study period, from 6.5% in January 1993 to 10.2% in February 1996. Similarly, the prescription rate for the proton pump inhibitor, omeprazole, significantly increased from 9.4% in January 1993 to 25.6% in February 1996. Neither trend, however, could be attributed to the NIH Consensus Development Conference. Stratification by physician specialty, ulcer type, nonsteroidal anti-inflammatory drug use, and patient demographics did not affect these results. The traditional treatment approach, using H2-receptor antagonists, remained the preferred pharmacotherapy (72% of all prescriptions). CONCLUSIONS: Two years after the highly publicized NIH conference on the eradication of Helicobacter pylori, antimicrobial agents were not widely prescribed among the Pennsylvania Medicaid population. In treating this underserved population, physicians do not appear to be using recommendations developed by an NIH expert panel based on recent scientific advances.

The NIH Consensus Development Program. The evolution of guidelines.

The U.S. National Institutes of Health (NIH) Consensus Development Program (CDP) Guidelines have undergone some modifications over the program's 18-year history. They have never been published in archival form. This article reviews the evolution of the NIH CDP Guidelines and then presents the complete 1995 version.

The NIH consensus development program.

The NIH CDCs are a highly visible, public forum to evaluate controversial medical technologies by synthesizing current medical science data. The consensus statements, although not intended as medical practice guidelines, may form part of the database preceding guideline formulation. It is difficult to assess the effect of the conferences on physician practice, in part reflecting the interference of the many other influences, medical and nonmedical, on physician behavior. Yet the program has had some success in influencing reimbursement policy for some technologies here and abroad and in influencing specialty organization policy, thereby indirectly affecting physician behavior. On the other hand, OMAR's dissemination activities have apparently been so successful that demand for CDC statements has more than doubled over the past five years, prompting OMAR to establish an information service (including fax and the Internet). And finally, the program has spawned consensus conferences throughout the world, including Canada, Western Europe, and Israel (Goodman & Baratz 1990).

Ambulatory blood pressure monitoring during pregnancy. Establishment of standards of normalcy.

Ambulatory blood pressure monitoring (ABPM) was used as an effective methodology by a primary care physician to assess normalcy of blood pressure (BP) and heart rate during pregnancy. One hundred fifty pregnant women in one of three periods (18 to 22, 30 to 32, and 36 to 38 weeks) of gestation and 30 age-matched nonpregnant women participated in this study. The study was designed to establish ABPM standards of normalcy during critical times of gestation. Twenty-four-hour BP (systolic and diastolic BP) values monitored during gestational weeks 18 to 22 and 30 to 32 were similar to each other and lower than the same values recorded in nonpregnant women. Blood pressures monitored during gestational weeks 36 to 38 were significantly higher than similar values observed during the two earlier gestational periods but not significantly higher than nonpregnancy BP values. Heart rates were significantly elevated during all gestational periods when compared with nonpregnancy heart rates. The results of this study established normalcy BP curves during three different gestational periods. Mean 24-h, daytime, and nighttime BPs were significantly elevated during weeks 36 to 38 when compared with BPs recorded during gestational weeks 18 to 22 and 30 to 32. Ambulatory blood pressure monitoring is a useful tool for the measurement and treatment of BP abnormalities during pregnancy.

Court-ordered reimbursement for unproven medical technology. Circumventing technology assessment.

OBJECTIVE--Because we found examples where courts of law ruled against insurance carriers that had been sued for reimbursement for unproven medical procedures, we conducted a case study to determine the reasoning behind these decisions that run counter to accepted medical science. Such actions circumvent health technology assessment and could contribute to escalating health care costs and poorer quality health care. DATA SOURCES--A literature search identified 17 cases between 1980 and 1989 in which an insurance company was sued to reimburse a patient who had received an unproven or questionable health technology; 14 of these suits were decided in favor of the plaintiff, and the insurance company was ordered to pay. Discussed in this article are six of these cases, two involving Laetrile (amygdalin), two involving immunoaugmentative therapy, and two involving thermography, technologies that had previously been assessed as not safe, not effective, or inadequately evaluated. DATA SYNTHESIS AND CONCLUSIONS--The circumstances determining how the courts arrive at these "unscientific" decisions fall into three general categories: (1) for legal reasons, the insurance contract is interpreted in favor of the insured; (2) the reluctance and/or inability, legal or otherwise, of the courts to use published scientific literature; and (3) the use of adversarial "expert" witnesses with potential conflicts of interest. To address this situation, we first urge the legal and insurance industries to cooperate in improving the contract language and process in a way that would be both legally and scientifically appropriate. Second, we encourage the courts to use and foster the use of published peer-reviewed scientific material as evidence whenever possible. Third, we recommend that the courts choose their own unbiased expert witnesses to interpret scientific material.

The effective diagnosis and treatment of hypertension by the primary care physician: impact of ambulatory blood pressure monitoring.

BACKGROUND: Ambulatory blood pressure monitoring (ABPM) has been described as an effective method for the diagnosis and formulation of the treatment of hypertension by the primary care physician. METHODS: Sixty patients selected from a suburban private primary care practice participated in a study that compared measurements of office blood pressures using a mercury sphygmomanometer with the same pressures recorded by ABPM. RESULTS: Blood pressures and blood pressure loads measured by ABPM were significantly lower than blood pressures and pressure loads recorded in the office setting. CONCLUSIONS: Blood pressure recorded by ABPM differed from the same measurements made by office or casual sphygmomanometry. Use of ABPM changed diagnosis or treatment of hypertension in borderline and antihypertensive drug-treated patients. Ambulatory blood pressure monitoring is a useful tool for the diagnosis and treatment of hypertension by the primary care physician. It can be used to identify white-coat hypertension in various patient populations.

The Consensus Development Program. Detecting changes in medical practice following a consensus conference on the treatment of prostate cancer.

The treatment of prostate cancer was reviewed at a U.S. National Institutes of Health Consensus Development Conference in June 1987. Data from the U.S. National Cancer Institute's Surveillance, Epidemiology, and End Results tumor registries were analyzed and showed that the proportion of eligible prostate cancer patients receiving the recommended therapies did not increase at a faster rate after the conference than before.

Analysis of the National Institutes of Health Medicare coverage assessment.

The National Institutes of Health (NIH) is periodically asked to conduct assessments of new medical technologies to assist in coverage decisions made at the Office of Health Technology Assessment (OHTA) for the Health Care Financing Administration coverage policy. Analysis of NIH assessments indicates that even though most NIH assessments rely only on expert opinion, OHTA agreed with NIH recommendations in over 90%.

Scaling the physiological effects of exposure to radiofrequency electromagnetic radiation: consequences of body size.

We have demonstrated that a comparative analysis of the physiological effects of exposure of laboratory mammals to radiofrequency electromagnetic radiation (RFR) may be useful in predicting exposure thresholds for humans if the effect is assumed to be due only to heating of tissue. The threshold specific absorption rate (SAR) necessary to affect a thermoregulatory parameter shows an inverse and linear relationship to body mass. The inverse relationship between threshold SAR and body mass is attributed to a surface area: body mass relationship. In comparison to small mammals, relatively large mammals have a reduced capacity to dissipate an internal heat load passively, and are therefore physiologically more sensitive to RFR exposure. The threshold for a thermoregulatory response depends on the type of response measured, species, ambient temperature, etc. By extrapolation, it can be shown that a SAR of only 0.2-0.4 W/kg is required to promote a thermoregulatory response in a mammal with a body mass of 70 kg (e.g. weight of adult human). The specific absorption rate bioeffects data collected from laboratory mammals can be related by means of a simple power formula: threshold SAR (W/kg) = aMb, where M is body mass in kg, a is a constant and b is equal to approximately -0.5. Through this equation we have illustrated that a threshold SAR measured in a species weighing 100 g would be 10 times greater than that of a species weighing 10 000 g. Accordingly, a relatively low SAR that is physiologically ineffective in small mammals may be stressful to larger species.

Oxygen storage capacity and tolerance of submergence of a non-aquatic reptile and an aquatic reptile.

The oxygen storage capacities and the tolerance to submergence of an aquatic snake, Natrix sipedon, and a non-aquatic snake, Crotalus viridis, were determined and compared. C. viridis was found to have a larger oxygen storage capacity, hemoglobin content and blood volume than N. Sipedon. The submergence time for C. viridis was 30.13 min which was less than the estimated time for submergence based on the oxygen storage capacity. N. sipedon exceeded its estimated dive time of 24.00 min and remained submerged for 65.57 min without signs of stress. During submergence, the heart rate of N. sipedon fell to 9% (5 beats/min) of the resting rate, while the heart rate of C. viridis fell to only 75% (27 beats/min) of the resting rate during this activity. These data indicate that N. sipedon responds to submergence via a typical diving reflex and extends its oxygen stores beyond that expected of a non-diver such as C. viridis.

Passive joint position sense after total hip replacement surgery.

Passive joint position sense was tested in 10 subjects after unilateral total hip replacement surgery (which included capsulectomy). Varied initial limb position, amplitude, and velocity of movement were used. The unoperated side was used as a control. Statistically barely significant errors (p less than 0.025) on the operated side were detected at 0.6 degrees per second but not at 2 degrees per second. No significant differences were noted among the different hip positions. The results indicate that the ability to detect passive hip joint position sense remains largely, but not completely, intact after hip joint replacement. The joint capsule, ligaments, and joint surfaces, although not essential for kinesthesia, may provide some limb movement and position information, the absence of which is not now clinically apparent.