Biomedical subjects

S G Humiston

Publications and source records attributed to S G Humiston.

23 records · Page 2Linked to original sources

PubMed1993

Decision rules for predicting vaccination status of preschool-age emergency department patients.

We produced and tested rules to predict undervaccination among preschool-age emergency department (ED) patients. Data were gathered on demographics, vaccination status, health status, and health care utilization from parents, ED physicians, and ED charts at an urban teaching hospital in Rochester, N.Y. Primary care charts were reviewed to verify vaccination status. Using recursive partitioning, we developed decision rules to predict undervaccination. Decision rules were developed on a sample of 602 ED patients 4 to 48 months of age and then prospectively tested on 1832 ED patients aged 6 to 36 months. Factors associated with undervaccination for any vaccine included parental report of vaccination delay (odds ratio = 8.1; p < 0.001), inability to report the receipt of the appropriate number of vaccines (odds ratio = 4.5; p < 0.001), lack of health insurance (odds ratio = 3.6, p < 0.001), elapsed time since the last visit to primary care provider (p < 0.001), household size (p < 0.001), and maternal age (p < 0.01). Eight decision rules were produced that varied in their number of questions (one to six), sensitivity (0.27 to 0.87), and specificity (0.54 to 0.98). No single rule was both highly sensitive and highly specific. The rules' sensitivities and specificities were similar for the validation sample of 1832 patients. Thus a decision rule could not be produced that was both sensitive and specific. Identification of undervaccinated children by means of information available at an ED visit is inherently difficult. Interventions in the ED may be inefficient unless better methods of assessing vaccination status can be developed.

Child↗

PubMed1993

The school-based immunization survey: an inexpensive tool for measuring vaccine coverage.

A school-based immunization survey was conducted among the 36 Rochester, NY, elementary schools (n = 5584 children) to determine (1) the vaccination rates at 2 years of age by type of primary care provider and (2) the accuracy of school immunization records (by comparing them with medical charts for children attending hospital-based clinics). These rates varied by provider type from 58% to 86% and were all below the national goal of 90%. In comparison with medical chart review, the school data had error rates of 15%; however, these errors occurred in both directions and were thus unbiased. School-based surveys include children who lack connections to the primary care system. With minimal effort these surveys can help identify populations in need of intervention.

Bias↗

PubMed1993

Missed opportunities for childhood vaccinations in office practices and the effect on vaccination status.

To determine the rate of childhood under-vaccination, rate and types of missed opportunities (MOs) for vaccinations, and the contribution of MOs to the undervaccination of preschool-age children, the authors conducted a retrospective medical chart review in seven primary care settings in the Rochester, NY, area: a hospital clinic, a neighborhood health center, a group-model health maintenance organization, an urban group practice, a suburban group practice, a rural health center, and a rural private practice. The random sample included 1124 children having birth dates between March 15, 1988, and September 15, 1989. The main outcome measures were cumulative undervaccination rate, defined as the proportion of patients from each practice who were ever > 60 days past-due for a vaccination by 12, 18, or 24 months of age; undervaccination time, defined as the median number of months during which children were undervaccinated; number of MOs; visit types and conditions associated with the MOs; and the duration of undervaccination time attributable to MOs. The cumulative undervaccination rate by 12 months was at least 20% in each practice except for the suburban practice, where it was 4%. The frequency of MOs varied from a high of 1.8 MO per patient per year at the rural private practice to a low of 0.3 MO per patient per year at the suburban practice. More than one quarter of MOs occurred during either health supervision or follow-up visits in all practices. In 28% of visits during which an MO occurred, patients had no fever or acute illness.(ABSTRACT TRUNCATED AT 250 WORDS)

Child Health Services↗

PubMed1993

Is an emergency department visit a marker for undervaccination and missed vaccination opportunities among children who have access to primary care?

The purpose of this study was to determine: (1) whether preschool-age patients who utilize the emergency department (ED) are undervaccinated compared with patients having the same primary care provider and (2) whether reducing missed vaccination opportunities in the primary care office can potentially reduce the differences in undervaccination between the groups. This retrospective cohort study involved two groups: 583 ED patients, aged 4 to 48 months, who had primary care providers; and 583 control subjects randomly selected from primary care sites and matched according to date of birth and primary care site. The major outcome variable was the point prevalence of undervaccination, defined as more than 60 days past due for a vaccine at the time of the ED visit, and for control subjects, at the time of their matched patient's ED visit. Demographic variables, vaccination history, presence of chronic illness, and office utilization history were abstracted from office charts. The mean age of all patients was 20.0 months. Emergency department patients were more likely to be boys (61% vs 50%) and had more chronic illness, but did not differ racially from those in the control group. Primary care sites included a hospital-based clinic (n = 137), neighborhood health centers (n = 172), and private practices (n = 274). The undervaccination rates by primary provider type were for (1) hospital clinic ED patients 21.1%, control subjects 19.7%; (2) neighborhood health center ED patients 29.1%, control subjects 22.7%; and (3) private practice ED patients 26.6%, control subjects 14.9%. Overall, the odds ratio of ED patients' being undervaccinated compared with control subjects was 1.8 (95% confidence interval 1.3 to 2.5).(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Preschool↗

PubMedDate not supplied

ROC curves for classification trees.

A common problem in medical diagnosis is to combine information from several tests or patient characteristics into a decision rule to distinguish diseased from healthy patients. Among the statistical procedures proposed to solve this problem, recursive partitioning is appealing for the easily-used and intuitive nature of the rules it produces. The rules have the form of classification trees, in which each node of the tree represents a simple question about one of the predictor variables, and the branch taken depends on the answer. The authors consider the role of misclassification costs in developing classification trees. By varying the ratio of costs assigned to false negatives and false positives, a series of classification trees are generated, each optimal for some range of cost ratios, and each with a different sensitivity and specificity. The set of sensitivity-specificity combinations define a curve that can be used like an ROC curve.

Child, Preschool↗