Population-based screening or case detection for asthma: are we ready?

Strategies for Identifying Students in Need of School-Based Asthma Services

Charlotte-Mecklenburg Schools (CMS), with assistance from the Centers for Disease Control and Prevention (CDC), conducted an evaluation of the CMS Asthma Program. Data were collected during the 2007-2008 school year through surveys of students with asthma (n = 286), interviews with school nurses (n = 11), and reviews of administrative records that included service provision and nurse ratings of the need for asthma services (based on a set of clinical indicators and symptom frequencies) for each student with asthma. Ninety percent of high-need students, 75.8% of medium-need students, 45.3% of low-need students, and 21.4% of nonrated students were enrolled in student-level services. Given the large number of students without a nurse rating for need, asthma management difficulties (AMD; a set of questions completed by all students on the student survey) were examined as a proxy indicator of need for student-level services. When looking only at need based on AMD, 46.0% of high-need students, 48.0% of medium-need students, and 35.2% of low-need students were enrolled in any student-level service. A Pearson χ2 revealed that nurse ratings of need and need based on AMD were not significantly related (χ2 = 4.1888, df = 4, P = .381); of students with nurse ratings for need, more were classified as medium and high need based on AMD than were rated medium and high need by school nurses. This suggests that many students were experiencing AMD but not coming to the attention of school nurses. Among students with asthma, additional resources and systematic procedures are needed to identify those who need student-level services, particularly for students who do not otherwise present with symptoms to the school nurse.

Asthma morbidity among children evaluated by asthma case detection

OBJECTIVE

Population-based asthma detection is a potential strategy to reduce asthma morbidity in children; however, the burden of respiratory symptoms and health care use among children identified by case detection is not well known.

METHODS

Data come from a school-based asthma case detection validation study of 3539 children. Respiratory symptoms, emergency department (ED) visits, and hospitalizations were assessed by questionnaire for children whose case detection result and physician study diagnosis agreed.

RESULTS

Physician evaluation of 530 case detection results yielded 420 cases of agreement (168 children with previously diagnosed asthma, 39 with undiagnosed asthma, and 213 without asthma). Children with previously diagnosed asthma were more likely to be male (P < .0001). No differences in severity were observed in children with previously and undiagnosed asthma (P = .31). Children with undiagnosed asthma reported less frequent daytime and nighttime symptoms than children with previously diagnosed asthma but more than those without asthma (P < .0001). The proportion of children with at least 1 respiratory-related ED visit in the past year was 32%, 3%, and 3% for those with previously diagnosed, undiagnosed, and no asthma, respectively (P < .0001). The proportion with at least 1 respiratory-related hospitalization was 8%, 0%, and 0%, respectively (P < .0001). There were no differences in nonrespiratory ED visits (P = .93).

CONCLUSIONS

Despite similar physician-rated severity, children with undiagnosed asthma reported significantly less frequent respiratory symptoms and health care use than children with previously diagnosed asthma. These findings suggest that the potential health gains from case detection may be smaller than expected.

Peak flow measurements in children with asthma: what happens at school?

BACKGROUND

Self-monitoring of symptoms or peak flow monitoring (PFM) is recommended for all asthma patients and is commonly included in asthma management plans. Limited data are available documenting PFM outcomes in school settings.

METHOD

Three hundred twenty-three urban children with persistent asthma were enrolled in a school-based study that implemented an internet-based asthma monitoring and data collection system. The mean age of the children was 10.0 (SD 2.1) years; 57% were male and 91% were African American. Children logged in daily to an internet-based program to record their asthma symptoms and PFM reading. Teachers logged in daily to confirm the PFM readings. School staff responsible for student health reported actions taken for low PFM readings.

RESULTS

A total of 12,245 child reports were completed; 98% (n = 11,974) had corresponding teacher reports, confirming the peak flow meter readings reported by the children. The prevalence of reported asthma symptoms varied across PFM readings; the highest prevalence occurred in the setting of red zone readings, with intermediate prevalence in the setting of yellow zone readings, and lowest prevalence in the setting of green zone readings. The actions reported in response to children's symptoms and peak flow results similarly varied; however, instances of no action were reported in the setting of yellow and red zone readings. When comparing the "worst days" of children who had ever had a red or yellow PFM reading with those of children who only had exhibited green, there was a nonsignificant trend toward fewer symptoms in the green-only group. Additionally, there was a nonsignificant trend toward a greater likelihood of being sent to the office or school nurse with greater symptoms in the setting of a yellow or red zone reading.

CONCLUSIONS

On the whole, peak flow readings tended to correspond to asthma disease activity. However, the data indicate that school staff may be more inclined to take action based on their own perceptions of a child's asthma or respond to children's subjective reports of asthma symptoms rather than using a more objective measure of disease activity provided by a peak flow meter.

School-based asthma programs

Asthma is prevalent in school-age children and contributes to school absenteeism and limitation of activity. There is a sizable literature on school-based interventions for asthma that attempt to identify children with asthma and improve outcomes. The purpose of this review is to describe and discuss limitations of screening tools and school-based asthma interventions. Identification of children with asthma may be appropriate in schools located in districts with a high prevalence of children experiencing significant morbidity and a high prevalence of undiagnosed asthma, provided there is access to high-quality asthma care. We review strategies for improving access to care, for teaching self-management skills in schools, and for improving school personnel management skills. Although studies indicate that school-based programs have the potential to improve outcomes, competing priorities in the educational system present challenges to their implementation and emphasize the need for practical, targeted, and cost-effective strategies.

Identification and education of adolescents with asthma in an urban school district: results from a large-scale asthma intervention

Asthma is a leading cause of hospitalizations, acute care utilization, health care costs, and school absences in children. Asthma morbidity is disproportionately high in inner city populations. In general, community-based public health interventions to reduce asthma morbidity have had modest success due in part to their limited reach and low participation by the targeted population. Adolescents have been especially difficult to reach. A coalition of community organizations developed a school-based, population-level system to identify, prioritize, and provide interventions for middle school children with asthma in a large urban school district in Oakland, CA. Nearly 92% (n = 8,326) of students in the targeted schools took an asthma case identification survey. Of those students who took the survey, 17.5% (n = 1,458) had active asthma and were eligible for services. Among those identified with active asthma, 83% (n = 1,217) voluntarily attended asthma self-management classes at school. The 4-week curriculum previously has been shown to significantly improve several indicators of asthma control in this population. Retention was high-72% of students who enrolled attended at least three of the four curriculum sessions. Many higher-risk students were subsequently referred to and enrolled in off-site asthma services. Large school districts with incomplete or inadequate health records, high asthma prevalence, and internal or external services available for students with asthma may benefit from a similar model. A system such as the one described may be an effective public health strategy for school districts, health departments, and community coalitions addressing asthma or other conditions with high childhood prevalence.

Identifying students with self-report of asthma and respiratory symptoms in an urban, high school setting

Strategies for identifying urban youth with asthma have not been described for high school settings. African-American high school students are rarely included in asthma studies, despite a high risk of asthma mortality when compared to other age and race groups. Identification and follow-up of children with uncontrolled respiratory symptoms are necessary to reduce the burden of asthma morbidity and mortality, especially in underserved areas. We describe a process used to identify high school students who could benefit from intervention based on self-report of asthma and/or respiratory symptoms, and the costs associated with symptom-identification. Letters announcing a survey were mailed to parents of 9th-11th graders by an authorized vendor managing student data for the school district. Scan sheets with student identifiers were distributed to English teachers at participating schools who administered the survey during a scheduled class. Forms were completed by 5,967 of the 7,446 students assigned an English class (80% response). Although prevalence of lifetime asthma was 15.8%, about 11% of students met program criteria for enrollment through report of an asthma diagnosis and recent symptoms, medication use, or health care utilization. Another 9.2% met criteria by reported symptoms only. Cost of symptom-identification was $5.23/student or $32.29/program-eligible student. There is a need for school-based asthma programs targeting urban adolescents, and program initiation will likely require identification of students with uncontrolled symptoms. The approach described was successfully implemented with a relatively high response rate. Itemized expenses are presented to facilitate modifications to reduce costs. This information may benefit providers, researchers, or administrators targeting similar populations.

Validating an asthma case detection instrument in a Head Start sample

Although specific tests screen children in preschool programs for vision, hearing, and dental conditions, there are no published validated instruments to detect preschool-age children with asthma, one of the most common pediatric chronic conditions affecting children in economically disadvantaged communities of color. As part of an asthma education intervention, a 15-item Brief Respiratory Questionnaire (BRQ) was developed to detect children with probable asthma in Head Start and subsidized preschool settings in communities with high asthma prevalence and associated morbidity. Preschool personnel administered the BRQ to consenting parents of 419 enrolled children. Trained interviewers administered validation interviews (VALs) to parents of 149 case-positive children and 51 case-negative children. Three physicians independently assessed deidentified summaries of the VALs that captured responses about signs and symptoms of asthma, diagnosis and treatment, and use of medical services. The physicians' assessments of the summarized VALs were the validated standard to which the BRQ classifications were compared. A simple algorithm of 4 items was identified that can be administered and scored by nonmedical preschool personnel in less than 5 minutes. The chance-corrected agreement between these 4 items of the BRQ and the VAL was good: kappa, .73 (95% confidence interval, 0.62-0.84); specificity, 96%; sensitivity, 73%; and positive predictive value, 97%. The BRQ appears to be a valid instrument for detecting children with probable asthma in Head Start and other subsidized preschool settings in communities with high prevalence of asthma.

Comparison of parent and student responses to asthma surveys: students grades 1-4 and their parents from an urban public school setting

This study compared parent and child responses to a symptom questionnaire as a means of determining whether child and parent responses are equally valuable in case-detection procedures. We completed a study validating a multistage case-detection procedure. The case-detection procedure classified students into 3 categories based on their parents' questionnaire responses (probable asthma, possible asthma, and negative for asthma). Those who were classified as possible asthma by questionnaire underwent further testing, including spirometry and exercise challenge. The children with abnormal testing results were considered to have probable asthma. McNemar's test and kappa coefficients were used to examine parent-child agreement. Sensitivity and specificity of the case-detection procedure were compared using either the parent's or the child's responses to the questionnaire. The data indicated moderate agreement between parent and child responses to questions regarding previous diagnosis of asthma and past asthma therapy (p < .001, kappa coefficients of 0.6030 and 0.5966, respectively). Sensitivity, specificity, and predictive values in the multistage case-detection procedure were similar when using either parent or child responses to the questionnaire. Among the false negatives, the distribution of asthma severity was consistent whether using child or parent responses. Parent-child agreement did not differ significantly by gender or age of the child or whether the child had a previous diagnosis of asthma. These results suggest that the use of child responses is a viable option for case detection, particularly in identifying those with a previous diagnosis of asthma

Effect of asthma intervention on children with undiagnosed asthma

OBJECTIVE

To measure the effect of an asthma intervention on the functional status and morbidity of children with undiagnosed asthma.

STUDY DESIGN

Data from a randomized trial were used to compare outcomes at baseline and follow-up for children with undiagnosed and diagnosed asthma. We studied 510 symptomatic children with diagnosed asthma (diagnosed) and 299 children with symptoms but no diagnosis (undiagnosed). Baseline functioning and morbidity were similar for undiagnosed and diagnosed patients classified as moderate-severe.

RESULTS

There were fewer undiagnosed reported allergies, seasonal symptoms, and other respiratory diagnoses (all P < 0.01). Among the moderate-severe, functional status, for example, symptom-days ( P = .02), symptom-nights ( P < .01), and days of restricted activity ( P < .01), was significantly reduced at follow-up for the undiagnosed in the intervention group but not for undiagnosed control subjects. Findings were similar for children with diagnosed asthma.

CONCLUSIONS

Children with undiagnosed asthma were generally nonatopic, although some had symptoms at a level comparable to children with a diagnosis. The intervention successfully improved functional status for children with undiagnosed asthma as well as for children with diagnosed asthma. These results can be applied to ongoing discussions related to case detection.

Validation of a multistage asthma case-detection procedure for elementary school children

OBJECTIVE

The purpose of this study was to validate a 3-stage asthma case-detection procedure for elementary school-aged children.

METHODS

The study was performed in 10 elementary schools in 4 inner-city school systems, with a total enrollment of 3539 children. Results of the case-detection procedure were compared with the diagnosis of an asthma specialist study physician, to determine the sensitivity and specificity of the case-detection procedure.

RESULTS

Ninety-eight percent of children returned the asthma symptoms questionnaires, and 79% of those children consented to additional testing. Results indicated that the 3-stage procedure had good validity, with sensitivity, specificity, and predictive value of 82%, 93%, and 93%, respectively. A 2-stage procedure using questionnaires and spirometry had similar validity, with sensitivity, specificity, and predictive value of 78%, 93%, and 93%, respectively. However, given the time and expense associated with the 2- or 3-stage procedure and the difficulty of obtaining physician follow-up evaluation of the case-detection diagnosis, schools may prefer to use a 2-item questionnaire that has a lower sensitivity (66%) but higher specificity (96%) and predictive value (95%).

CONCLUSIONS

Case-detection programs are generally well received by school personnel and can identify children with unrecognized or undiagnosed disease, as well as those with a current diagnosis but poorly controlled disease. This study yields substantial information regarding the validity, yield, and specific types of children who might be identified with the use of such procedures. For the choice of the method of case detection used in a school, the strengths and weaknesses of each procedure, as well as the resources available for case detection, physician referral, and follow-up procedures, must be considered.