Would better adherence to guidelines improve childhood immunization rates?

OBJECTIVE: To evaluate the contribution of three provider practices to underimmunization of children with financial coverage for vaccines. DESIGN: Retrospective cohort study of children in a large health maintenance organization, based on computerized databases and chart review. SETTING: Large health maintenance organization in northern California. PATIENTS: The population included 24,268 children who had at least one immunization recorded in the health plan tracking system and had continuous health plan membership between 15 and 24 months of age in 1992 through 1993. The study group (N = 4691) were those who had missed one or more of the immunizations due during their second year. RESULTS: Most (57%) of the underimmunized children had made at least one clinic visit between 15 and 24 months of age. Among those underimmunized children who made well care visits, 90% had been partially immunized at the visit but had not been simultaneously given all vaccines for which they were eligible. When a provider did not give all possible vaccines simultaneously, there was a 9% chance that the child would go on to miss the remaining immunization. Simultaneous administration alone would have achieved full second year coverage of 30% of the underimmunized children in this population. Most underimmunized children (53%), including 35% of those children who had not made any well care visits, had made urgent visits between 15 and 24 months of age. Chart review of randomly sampled patients showed no obstacle or contraindication to immunization at 79% of urgent visits and at 71% of well care visits at which vaccines were withheld. A policy to use weekday urgent visits to promote immunization could potentially reach 27% of the underimmunized children. CONCLUSIONS: Provider practices play an important role in underimmunization of children who have insurance coverage for vaccines. Of the three guidelines evaluated, simultaneous administration of all possible vaccines has the greatest potential effectiveness to improve coverage rates in this population. Other guidelines, such as immunizing at urgent visits, are potentially effective but their costs and logistics need further study.

Cost-effectiveness of varicella serotesting versus presumptive vaccination of school-age children and adolescents.

OBJECTIVE: To evaluate the cost-effectiveness of presumptive vaccination versus serological testing of school-age children (6 to 12 years) and adolescents (13 to 17 years) with a negative or uncertain history of varicella. DESIGN: Decision analysis model based on published and unpublished probabilities and costs. PATIENTS: Hypothetical cohorts of 10,000 school-age children and 10,000 adolescents. MAIN OUTCOME MEASURES: Number of chicken pox cases prevented and cost per chicken pox case prevented. RESULTS: For school-age children, presumptively vaccinating would prevent 95% of the predicted chicken pox cases, would result in net savings when long-term and work loss costs were included, and would have a similar cost per case prevented as routinely testing before vaccination. For adolescents, presumptively vaccinating would be the most effective policy, and would prevent 99% of the projected chicken pox cases. A policy of routinely testing before vaccination would be the least effective policy for adolescents, preventing 81% of the predicted cases. However, even when long-term and work loss costs were taken into account, presumptively vaccinating adolescents had a relatively high cost of $329 per chicken pox case prevented and extremely high incremental costs per chicken pox case prevented compared with policies that involved serological testing. Results for school-age children were sensitive to the probability of previously having had chicken pox given a negative or uncertain history, to the rate of adherence to follow-up visits, and to vaccine price and test price. Results for adolescents were sensitive only to the rate of adherence to the first follow-up visit. CONCLUSIONS: Presumptively vaccinating all patients with a negative or uncertain history of varicella is projected to be a relatively cost-effective policy for school-age children but not for adolescents. However, further empirical studies of the accuracy of a negative or uncertain history of chicken pox in these age groups are needed.

Outpatient management practices associated with reduced risk of pediatric asthma hospitalization and emergency department visits.

OBJECTIVES: Effective outpatient care is believed to prevent hospitalization and emergency department (ED) visits resulting from childhood asthma. The aim of this study was to suggest priority areas for intervention by identifying outpatient management practices associated with the risk of these adverse outcomes in a large population. METHODS: This case-control study included children aged 0 to 14 years with asthma who were members of a regional health maintenance organization. Cases were children undergoing either a hospitalization or an ED visit for asthma during the study period. Control subjects were children with asthma without a hospitalization or an ED visit during the study period who were matched to patients on age, gender, and number of asthma-related hospitalizations in the past 24 months. Data on provider and parent asthma management practices were collected using chart review, closed-ended telephone interviews with parents, and computerized use databases. Multivariate analyses were conducted using conditional logistic regression models. RESULTS: Data were collected on 508 cases and 990 control subjects. A total of 43% of cases were reported by their parents to have moderately severe or severe asthma, compared with 20% of control subjects. Parents of cases with hospitalization were less likely than control subjects to have a written asthma management plan (44% vs 51%) and to report washing bedsheets in hot water at least twice a month (77% vs 86%). Cases with hospitalization were more likely to have a nebulizer (74% vs 56%). In the final multivariate model, race/ethnicity was not associated with having had either a hospitalization or an ED visit, as was lower socioeconomic status. Having a written asthma management plan [odds ratio (OR): 0.54; 95% confidence interval (CI): 0.30, 0.99] and washing bedsheets in hot water at least twice a month (OR: 0.45; 95% CI: 0.21, 0.94) were associated with reduced odds of hospitalization. Having a written asthma management plan (OR: 0.45; 95% CI: 0.27, 0.76) and starting or increasing medications at the onset of a cold or flu were associated with reduced odds of making an ED visit. CONCLUSIONS: Practices that support early intervention for asthma flare-ups by parents at home, particularly written management plans, are strongly associated with reduced risk of adverse outcomes among children with asthma.

The association between asthma, asthma, therapeutic classes and hepatic enzyme elevation among adult HMO members.

The results of this case-control study conducted at a large HMO support the notion that severe asthma may be associated with transient hepatic enzyme elevation. Conversely, we found no evidence of associations between asthma therapeutic classes and hepatic enzyme elevation.

Computer-based models to identify high-risk children with asthma.

Effective management of populations with asthma requires methods for identifying patients at high risk for adverse outcomes. The aim of this study was to develop and validate prediction models that used computerized utilization data from a large health-maintenance organization (HMO) to predict asthma-related hospitalization and emergency department (ED) visits. In this retrospective cohort design with split-sample validation, variables from the baseline year were used to predict asthma-related adverse outcomes during the follow-up year for 16,520 children with asthma-related utilization. In proportional-hazard models, having filled an oral steroid prescription (relative risk [RR]: 1.9; 95% confidence interval [CI]: 1.3 to 2.8) or having been hospitalized (RR: 1.7; 95% CI: 1.1 to 2.7) during the prior 6 mo, and not having a personal physician listed on the computer (RR: 1.6; 95% CI: 1.1 to 2.3) were associated with increased risk of future hospitalization. Classification trees identified previous hospitalization and ED visits, six or more beta-agonist inhalers (units) during the prior 6 mo, and three or more physicians prescribing asthma medications during the prior 6 mo as predictors. The classification trees performed similarly to proportional-hazards models, and identified patients who had a threefold greater risk of hospitalization and a twofold greater risk of ED visits than the average patient. We conclude that computer-based prediction models can identify children at high risk for adverse asthma outcomes, and may be useful in population-based efforts to improve asthma management.