A cost-effectiveness analysis of prevaccination testing for hepatitis B in adolescents and preadolescents.

OBJECTIVE: To study the clinical effectiveness and cost-effectiveness of prevaccination testing for hepatitis B virus in adolescents and preadolescents. DESIGN: Decision analysis model comparing (1) prevaccination testing for hepatitis B surface antibodies, (2) no testing, and (3) testing at the same time as the first vaccine dose. Sensitivity analyses of the first two strategies were performed varying the seroprevalence of hepatitis B surface antibodies, compliance with follow-up, and costs of testing. SETTING: Charges for testing and vaccination were obtained from Children's Hospital and Medical Center in Seattle, Wash. Vaccination compliance, hepatitis B surface antibodies seroprevalence, and vaccine response rates are from published literature. PATIENTS: A hypothetical cohort of 100,000 11-year-old children presenting for well-child care. MAIN OUTCOME MEASURES: Rate of complete vaccination, cost of testing and vaccination for each cohort, and cost per patient protected from hepatitis B virus. RESULTS: No testing was the most cost-effective strategy. Prevaccination testing elevated costs by $2.9 million for every 100,000 patients and lowered the rate of complete vaccination by 22% compared with vaccination without testing. For prevaccination testing to be cost-effective, the seroprevalence of hepatitis B surface antibodies needed to be greater than 40%. As the seroprevalence of hepatitis B surface antibodies decreased, the ratio of testing costs to vaccination costs had to decrease for prevaccination testing to remain cost-effective. Even with perfect compliance, prevaccination testing required high seroprevalence rates to be cost-effective. CONCLUSIONS: For most populations of preadolescents and adolescents, prevaccination testing for hepatitis B virus is not effective in terms of cost or rate of complete vaccination.

One-year experience with an inpatient asthma clinical pathway.

OBJECTIVE: To study the effects of an inpatient asthma clinical pathway on the processes and outcomes for children who were admitted to a hospital for the treatment of asthma. DESIGN: Before-and-after study. SETTING: A private nonprofit academic children's hospital in Seattle, Wash. PATIENTS AND METHODS: Three hundred forty-two admissions of 297 patients in the first year of the asthma clinical pathway were compared with 353 admissions of 292 similar patients in the previous year. Patients who required intensive care, were younger than 2 years, or had a major chronic disease were excluded. INTERVENTION: Asthma was chosen for the development of a clinical pathway because of its large number of admissions, involvement of multiple health care providers (nurses, physicians, and respiratory therapists), predictable hospital course, and variable lengths of hospital stay. The pathway was a consensus-based guideline for patient management that was intended to be adapted to the care of an individual patient. Prior to the implementation of the clinical pathway, nurses, attending physicians, house staff, and respiratory therapists were trained in its use. The main hospital chart of each patient who was admitted to the pathway had a flowchart that outlined day-to-day guidelines for monitoring and care. Nursing staff were responsible for documenting when a patient's care varied from the pathway, and these variances were entered into a computer database. OUTCOME MEASURES: Use of peak flowmeters, steroids, laboratory studies, radiological studies, and respiratory therapy was assessed by analyzing the patients' electronic billing records. For patients enrolled in the pathway, additional data on process of care were obtained by analyzing the variance database. For both groups, the total charges, length of stay, and rate of readmission to the hospital were measured by use of the billing records. RESULTS: There were no significant differences in the use of steroids or peak flowmeters, average lengths of stay, or total charges between the 2 groups. However, patients in the "pathway group" had significantly lower average charges for laboratory ($26 vs $39; P < .05) and radiology ($32 vs $55; P < .001) services. Variances from the pathway guidelines were most often related to the patients' responses to therapy. CONCLUSIONS: The asthma clinical pathway had no effect on clinical outcomes and small effects on the use of resources. Further development, including physician and nurse training, computer and administrative support, and clinical severity scales, are needed to develop the potential utility of the clinical pathway as a research and quality assurance tool.

The mechanism of low-frequency sound production in muscle.

Frog gastrocnemius muscles stimulated isometrically in a saline bath at 20 degrees C were found to produce a single ringing sound event beginning just before the tension record began to rise. The sound event was substantially over by the time the isometric tension began to fall. Results from studies correlating the spatial pattern of the sound, the amplitude and frequency of the sound as a function of the muscle length, and the response of both the passive and active muscle to a transverse pluck were found to be consistent with the conclusion that the sounds in these muscles are caused primarily by transverse resonant vibrations. As the muscle develops force, its lack of cylindrical symmetry gives rise to lateral motions, which are most likely the initiators of the bending vibrations detected as sound.

Is household antibiotic use a risk factor for antibiotic-resistant pneumococcal infection?

We used microbiology and pharmacy data from health-maintenance organizations to determine whether antibiotic use by a household member increases the risk of penicillin-non-susceptible pneumococcal disease. Though it has been well established that an individual's antibiotic use increases one's risk of antibiotic-resistant infection, it is unclear whether the risk is increased if a member of one's household is exposed to antibiotics. We therefore conducted a case-control study of patients enrolled in health maintenance organizations in Western Washington and Northern California. Cases were defined as individuals with penicillin-non-susceptible pneumococcal infection; controls were individuals with penicillin-susceptible pneumococcal infection. Socioeconomic variables were obtained by linking addresses with 1997 census block group data. One-hundred and thirty-four cases were compared with 798 controls. Individual antibiotic use prior to diagnosis increased the odds of penicillin non-susceptibility, with the strongest effect seen for beta-lactam use within 2 months (OR 1.8, 95% CI 1.2, 2.8). When household antibiotic use by persons other than the patient were considered, at 4 months prior to diagnosis there was a trend towards an association between penicillin non-susceptibility and beta-lactam antibiotic use, and a possible association in a small subgroup of patients with eye and ear isolates. However, no significant overall pattern of association was seen. We conclude that though antibiotic use of any kind within 2 months prior to diagnosis is associated with an increased risk of penicillin-non-susceptible pneumococcal disease, there is no significant overall pattern of association between household antibiotic use and penicillin-non-susceptible pneumococcal infection.

Meeting clinician information needs by integrating access to the medical record and knowledge resources via the Web.

MINDscape is a web based integrated interface to diverse sources of clinical information including both patient specific information (electronic medical record) as well as medical knowledge (the "digital library") to provide "just in time" information at the point of care. It was developed at the University of Washington to meet clinical information needs both as identified locally and by a review of the literature. Beta testing by over 600 clinicians is in progress and medical centers wide access scheduled for Fall 1997. We describe the information needs we sought to meet and the ongoing evaluation approach we are taking to ensure the information needs of a diverse group of clinicians are met. The iterative evolution of the interface from prototype, to alpha to large scale beta testing is reported. Integration of information occurs at three levels: integration of information by patient, integration of information by provider, and integration of patient specific information with medical reference material and decision support tools.