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ICD Code: 493. Asthma

ICD Code: 493. Article Review
Title: Yawn BP et al; "A Longitudinal Study of the Prevalence of Asthma in a Community Population of School-Age Children." Journal of Pediatrics; V.140; No.5; 5/02; p576
      STUDY DESIGN: This U.S. study used medical records to study physician diagnoses of asthma in a population-based cohort of children currently in kindergarten through 12th grade. The longitudinal design made it possible to assess the age at first diagnosis of asthma and to calculate age- and sex-specific incidence and prevalence rates, as well as time trends in rates of new physician diagnoses of asthma. The authors used a 50% random sample of children in one of the three public school clusters in Rochester, Minnesota. For all children, nurse abstractors reviewed all medical records for all children, including those from all three hospitals and emergency departments in Olmsted County, as well as records from all ambulatory care sites affiliated with the three medical care providers in the county. Previous work has shown that the three sites provide more than 98% of all care to all Olmsted County residents.
      Data were abstracted from the time of the child's birth in Olmsted County or from the time of the child's first visit to any Olmsted County medical care facility through October 31, 1999. The median duration of follow-up was 6.78 years for children younger than 10 years and 11.53 years for children older than 10 years at the time of the study. All diagnoses were based on physicians', nurse practitioners', or physician's assistants' notes. No attempt to confirm the diagnosis or record diagnostic criteria was made. Therefore, the information presented does not assess the accuracy of the diagnoses. The cohort included 1370 (48.7%) girls and 1446 (51.3%) boys.
      CUMULATIVE INCIDENCE: Overall, 496 (17.6%) of the children had one or more recorded diagnosis of asthma. 41 (1.6% of the total cohort) children had only a single visit with a diagnosis of asthma. Overall, 16% of the children had multiple diagnoses consistent with chronic asthma. The cumulative incidence of physician-diagnosed asthma was estimated as follows in boys versus girls: age 5 years, 10% vs 6%; age 10 years, 18% vs 9%; age 15 years, 27% vs 17%.
      Asthma diagnoses were 1.5 times more common in boys than in girls (21% versus 13.9%). The mean age at first diagnosis of asthma was 6.1 years (median, 5.2 years; range, 9 days to 17.7 years).
      CURRENT PREVALENCE: To allow comparison with cross-sectional studies reporting "current prevalence" of asthma (usually defined as asthma symptoms within the past 1 to 2 years), the authors identified children with a visit in which asthma was documented between November 1, 1997 and October 31, 1999. The prevalence of "current" asthma was 364 of 2816 children or 12.9% (10.4% in girls and 15.3% in boys).
      DISCUSSION: On the basis of data from multiple studies in several regions of the U.S., it may be time to update the commonly reported childhood "current" asthma prevalence rates in the U.S. from 7% to 8% to a broader range of 7% to 13%. The reasons for the sex-related difference in rate and pattern of acquiring asthma are unknown.
      Although this study had the benefit of being community-based, using actual medical records to identify physician diagnoses of asthma and following children for 5 to 18 years has weaknesses. Although about 17% of the student population of Rochester, Minnesota represent children of racial or ethnic minorities, these results may not be generalizable to a community with greater or lesser diversity. However, the high prevalence rates seen in this population compared with inner-city populations support the assertion that the increasing prevalence of asthma is not just a concern for large cities, inner-city communities, or communities of color.

Search Criteria: Text - Journal of Pediatrics; V.140; No.5; 5/02; p576