Towards improving the accuracy of diagnosing asthma in early childhood

Evidence for overdiagnosis in noncancer conditions was assessed: a metaepidemiological study using the 'Fair Umpire' framework

OBJECTIVES

To evaluate the strength of the evidence for, and the extent of, overdiagnosis in noncancer conditions.

STUDY DESIGN AND SETTING

We systematically searched for studies investigating overdiagnosis in noncancer conditions. Using the 'Fair Umpire' framework to assess the evidence that cases diagnosed by one diagnostic strategy but not by another may be overdiagnosed, two reviewers independently identified whether a Fair Umpire-a disease-specific clinical outcome, a test result or risk factor that can determine whether an additional case does or does not have disease-was present. Disease-specific clinical outcomes provide the strongest evidence for overdiagnosis, follow-up or concurrent tests provide weaker evidence, and risk factors provide only weak evidence. Studies without a Fair Umpire provide the weakest evidence of overdiagnosis.

RESULTS

Of 132 studies, 47 (36%) did not include a Fair Umpire to adjudicate additional diagnoses. When present, the most common Umpire was a single test or risk factor (32% of studies), with disease-specific clinical outcome Umpires used in only 21% of studies. Estimates of overdiagnosis included 43-45% of screen-detected acute abdominal aneurysms, 54% of cases of acute kidney injury, and 77% of cases of oligohydramnios in pregnancy.

CONCLUSION

Much of the current evidence for overdiagnosis in noncancer conditions is weak. Application of the framework can guide development of robust studies to detect and estimate overdiagnosis in noncancer conditions, ultimately informing evidence-based policies to reduce it.

Outpatient management of asthma in children age 5-11 years: guidelines for practice

PURPOSE

To increase awareness among nurse practitioners (NPs) regarding diagnostic and treatment guidelines for asthma for the 5-11 year age group recently updated by the National Asthma Education Prevention Program-Expert Panel 3 (NAEPP-EPR3).

DATA SOURCES

NAEPP-EPR3 guidelines for the diagnosis and management of asthma released from the National Heart, Lung, and Blood Institute in August 2007, selected clinical trials, meta-analyses, and clinical reviews.

CONCLUSIONS

Recent research has revealed that children suffering from asthma in the United States are underdiagnosed and their asthma is poorly controlled. Compelling evidence supports that children classified as having persistent asthma following NAEPP-EPR3 guidelines benefit from daily inhaled corticosteroid therapy, yet many are misclassified and undertreated.

IMPLICATIONS FOR PRACTICE

With application of current guidelines from NAEPP-EPR3, NPs can more effectively assess, diagnose, treat, and foster a collaborative self-management plan for children age 5-11 years. These interventions will result in an improved quality of life and decreased health risks for this young population.

Persistence of asthma medication use in preschool children

OBJECTIVE

In young children with asthmatic symptoms diagnostic difficulties lead to use of trials of asthma medication as a diagnostic tool. Our aim is to quantify the persistent use of asthma medication, initiated in the first year of life and identify determinants of this persistent use.

PATIENTS AND METHODS

We identified 165 children within the PIAMA (Prevention and Incidence of Asthma and Mite Allergy) birth cohort who used asthma medication before the age of one. Persistent use was investigated during three years after the first prescription. A Cox regression analysis was performed to identify factors associated with persistent use.

RESULTS

A total of 58.8% of children continued using asthma medication after the first prescription and 10.3% continued during three years. Children with doctor-diagnosed asthma (Hazard ratio of discontinuation (HR)=0.64, 95% CI: 0.45-0.91) or prescribed inhaled corticosteroids in the first year of life (HR of discontinuation=0.59, 95% CI: 0.40-0.86) were 1.6-1.7 times more likely to continue using asthma medication.

CONCLUSIONS

Persistence of asthma medication, prescribed in the first year of life is very low and is positively associated with doctor-diagnosed asthma and use of inhaled corticosteroids. Characterizing persistent users of asthma medication is important to understand prescribing of asthma medication in this age group.

Asthma history and presentation

Asthma is suspected from a history of key symptoms, including cough, wheezing, dyspnea, chest tightness, and increased mucus production. A positive family or personal history of atopic diseases and diseases that are comorbid with asthma, such as allergic rhinitis and rhinosinusitis, is also important. The differential diagnosis of asthma is broad and includes potentially life-threatening diseases. Pediatric asthma and psychiatric mimics require special attention to prevent misdiagnosis. Differentiating asthma from these other disease states by history alone is not always possible. Because accurate diagnosis is critical to successful treatment, objective testing by spirometry and methacholine challenge should be employed.

Infant frequent wheezing correlated to Clara cell protein 10 (CC10) polymorphism and concentration, but not allergy sensitization, in a perinatal cohort study

BACKGROUND

Wheezing episodes are common in young infants. However, the molecular mechanism of wheezing is unclear, and very few therapeutic regimens are effective.

OBJECTIVE

This study investigated the genetic and environmental factors predisposing to infant wheezing in a birth cohort study.

METHODS

A cohort of 1211 pregnant women was recruited for this study. Infant wheezing episodes during the first 18 months of life were correlated to parental atopic history, parental smoking, prematurity, CB IgE levels, and the sequence variant (G+38A) of the Clara cell protein 10 (CC10) gene encoding a secretary anti-inflammatory CC10 protein.

RESULTS

Nine hundred eighty-three infants completed umbilical cord blood collection, and 813 infants completed the 18-month postnatal follow-up. Twenty-two percent of the infants experienced at least 1 wheezing episode, and 6.6% of the infants experienced frequent wheezing (> or =3 episodes). Multivariate logistic regression showed that male sex and the CC10 G+38A polymorphism, but not prematurity, CB IgE level, passive smoking, or parental atopy, were predictors of frequent wheezing. Further studies found that infant frequent wheezing was significantly associated with the CC10 +38AA genotype and lower plasma CC10 levels at 18 months of age (P = .046), and infants with acute wheezing episodes had significantly lower CC10 levels than those without (P = .023). No association of wheezing episodes with allergic sensitization was observed in this cohort population.

CONCLUSION

Infant frequent wheezing is associated with the CC10 G+38A polymorphism and lower CC10 levels but not infant atopy.

CLINICAL IMPLICATIONS

Lower CC10 expression, but not allergy sensitization, is involved in the pathogenesis of infant frequent wheezing.

Diagnosing asthma in young children

PURPOSE OF REVIEW

Asthma is defined by the 1997 National Asthma Education and Prevention Program guideline as a chronic inflammatory disorder of the airways which leads to an increase in bronchial hyperresponsiveness to a variety of stimuli or triggers. Since it is difficult to determine whether an individual patient has the above pathophysiology, particularly in young children, it is essential that clinically useful criteria be identified that can serve as proxies for the presence of asthma.

RECENT FINDINGS

There are three reasons for making a diagnosis: to identify the most effective treatment to alleviate symptoms and prevent mortality; to educate the parent or primary caregiver to manage symptoms and avoid triggers; and to estimate the prognosis. A diagnostic test is a procedure which gives a rapid, convenient and inexpensive indication of whether a patient has a certain disease. The likelihood ratio incorporates both the sensitivity and specificity of the test and provides a direct estimate of how much a test result will change the odds of having a disease.

SUMMARY

By applying the principles of evidence-based medicine to define likelihood ratios for each criterion, it should be possible to define the probability of asthma and to identify the best treatment. Future research should permit accurate correlations to be drawn between the underlying pathophysiology and the clinical condition commonly known as asthma.