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ICD Code: 493. Asthma



ICD Code: 493. Article Review
Title: Akinbami LJ et al; "Trends in Childhood Asthma: Prevalence, Health Care Utilization, and Mortality." Pediatrics; V.110; No.2; 8/02; p315
      STUDY DESIGN: The objective of this study was to use national data to produce a comprehensive description of trends in childhood asthma prevalence, health care utilization, and mortality to assess changes in the disease burden among U.S. children. This analysis used data from 1980 through the most recent year for which data were available from four National Center for Health Statistics (NCHS) data systems: the National Health Interview Survey (NHIS; in 1997 this survey was redesigned to improve data quality, simplify the survey, and reduce the questionnaire length), the National Ambulatory Medical Care Survey (NAMCS), the National Hospital Discharge Survey (NHDS), and the Mortality Component of the National Vital Statistics System. A fifth NCHS data set, the National Hospital Ambulatory Medical Care Survey (NHAMCS), provided data on ambulatory care in hospitals beginning in 1992. Children aged 0 to 17 years were included, and the sample from each data source was stratified by age group (0 to 4 years, 5 to 10 years, and 11 to 17 years) and by race/ethnicity when possible (white non-Hispanic, black non-Hispanic, and Hispanic).
      PREVALENCE IN CHILDREN: The average annual prevalence of asthma (per 1000) for 1985 to 1986 was reported as follows: overall prevalence, 49.4; white non-Hispanics, 51.0; black non-Hispanics, 59.8; Hispanics, 31.5; 0 to 4 years old, 31.9; 5 to 10 years old, 54.5; 11 to 17 years old, 58.0.
      The average annual prevalence of asthma (per 1000) for 1990 to 1991 was reported as follows: overall prevalence, 60.1; white non-Hispanics, 59.6; black non-Hispanics, 72.6; Hispanics, 51.2; 0 to 4 years old, 43.0; 5 to 10 years old, 62.7; 11 to 17 years old, 71.4.
      The average annual prevalence of asthma (per 1000) for 1995 to 1996 was reported as follows: overall prevalence, 68.6; white non-Hispanics, 65.3; black non-Hispanics, 82.1; Hispanics, 76.1; 0 to 4 years old, 50.3; 5 to 10 years old, 74.3; 11 to 17 years old, 77.4.
      For children younger than 18 years, the asthma attack prevalence (per 1000) during the previous 12 months was reported in 1997 as follows: overall prevalence, 54.4; white non-Hispanics, 52.2; black non-Hispanics, 67.5; Hispanics, 51.3; 0 to 4 years old, 41.2; 5 to 10 years old, 58.5; 11 to 17 years old, 60.4.
      For children younger than 18 years, the asthma attack prevalence (per 1000) during the previous 12 months was reported in 1998 as follows: overall prevalence, 53.1; white non-Hispanics, 52.1; black non-Hispanics, 68.1; Hispanics, 47.4; 0 to 4 years old, 46.5; 5 to 10 years old, 53.0; 11 to 17 years old, 58.0.
      For children younger than 18 years, the asthma attack prevalence (per 1000) during the previous 12 months was reported in 1999 as follows: overall prevalence, 52.7; white non-Hispanics, 49.9; black non-Hispanics, 74.1; Hispanics, 44.5; 0 to 4 years old, 42.1; 5 to 10 years old, 57.2; 11 to 17 years old, 56.2.
      For children younger than 18 years, the asthma attack prevalence (per 1000) during the previous 12 months was reported in 2000 as follows: overall prevalence, 55.3; white non-Hispanics, 53.4; black non-Hispanics, 76.8; Hispanics, 42.1; 0 to 4 years old, 43.5; 5 to 10 years old, 57.5; 11 to 17 years old, 61.5.
      Asthma prevalence among 0- to 17-year-old children increased from 36 per 1000 children to 75 per 1000 from 1980 to 1995 but then decreased 17% to 62 per 1000 children in 1996. The 1997 estimate of childhood asthma attack prevalence from the redesigned questionnaire, 54 per 1000 children, and subsequent estimates cannot be compared directly with previous estimates and should be considered the first point of a new trend. Because the redesigned asthma questions measure asthma attack prevalence (individuals who had previously received a diagnosis of asthma and who had 1 or more asthma attacks in the past 12 months) as opposed to asthma prevalence in the past 12 months, it is not surprising that the post-1997 estimates are lower than previous estimates. Asthma attack prevalence from 1997 to 2000 remained level with no statistically significant difference between estimates during this time period.
      In 2000, black non-Hispanic children had an asthma attack prevalence rate 44% higher than that of white non-Hispanic children. From 1985/1986 to 1995/1996, asthma prevalence increased dramatically among Hispanic children. However, from 1997 to 2000, asthma attack prevalence among Hispanic children remained below that for white non-Hispanic children. Within the 3 pediatric age groups, prevalence increased over time. Children aged 0 to 4 years had the most rapid growth in asthma prevalence from 1980/1981 to 1995/1996. From 1997 to 2000, asthma attack prevalence remained fairly level among all age groups.
      HEALTH SERVICE USE: Among children younger than 18 years, the average annual number of office visits for asthma (per 1000) for 1995-1996 and 1998-1999, respectively, was reported by visit type as follows. Private physician offices: overall, 48.7, 61.4; white patients, 48.1, 59.3; black patients, 55.1, 71.7; patients age 0 to 4 years, 54.9, 67.0; patients age 5 to 10 years, 50.8, 71.4; patients age 11 to 17 years, 42.2, 48.5. Hospital emergency department (ED) visits: overall, 10.4, 11.4; white patients, 7.5, 9.0; black patients, 25.8, 26.2; patients age 0 to 4 years, 14.8, 15.6; patients age 5 to 10 years, 11.4, 12.0; patients age 11 to 17 years of age, 6.2, 8.0. Hospital outpatient department (OPD): overall, 6.7, 7.7; white patients, 4.7, 5.5; black patients, 17.4, 19.3; patients age 0 to 4 years, 7.7, 10.9; patients age 5 to 10 years, 8.7, 7.2; patients age 11 to 17 years, 4.0, 5.9. Total ambulatory asthma visits: overall, 65.7, 80.5; white patients, 60.3, 73.9; black patients, 98.2, 117.1; patients age 0 to 4 years, 77.4, 92.5; patients age 5 to 10 years, 70.9, 90.6; patients age 11 to 17 years, 52.4, 62.4.
      The rate for annual visits to private physician offices for childhood asthma followed an increasing trend during 1989 to 1999, the period for which annual data are available, and rose by an average of 3.8 per year. However, before this period, the asthma office visit rate declined by a total of 27% during the 9-year period from 1980 to 1989. Compared with white children, the asthma office visit rate in 1998 to 1999 for black children was 1.2 times higher. Asthma office visit rates were higher in younger children and almost doubled among children 0 to 4 years of age between 1980/1981 and 1998/1999 compared with more modest increases among older children.
      Black children had visit rates to OPDs and EDs about 3 times higher than those for white children in 1998 to 1999. When all sources of data for ambulatory visits for asthma are combined (ED, OPD, and private physician office visits), black children had a visit rate 1.6 times higher than white children in 1998 to 1999. As with office visits to private physician offices, rates of hospital ED and OPD visits in 1995 to 1999 were higher among younger children compared with those aged 11 to 17 years.
      The childhood asthma hospitalization rate grew slowly from 1980 to 1999, by an average of 1.4% per year. However, the hospitalization rate seems to have plateaued since the mid-1990s. Asthma hospitalization rates increased to a much greater extent among black children than white children. In 1998 to 1999, the asthma hospitalization rate among black children was 3.6 times the rate for white children. The results of a sensitivity analysis show that if hospitalizations with unknown race are assumed to be for children of white race, then the hospitalization rate for black children in 1998 to 1999 was 3.2 times that for white children and hospitalization rates for black and white children increased 25% and 11%, respectively, from 1980/1981 to 1998/1999. Although asthma prevalence was lowest among the youngest children, hospitalization rates were substantially higher among 0- to 4-year-olds and increased more rapidly compared with older children. After 1995 to 1996, asthma hospitalization rates plateaued among all age groups.
      MORTALITY: Among children younger than 18 years, the annual asthma mortality (per 1,000,000) for 1990-1991, 1995-1996, and 1997-1998, respectively, was reported as follows: overall mortality, 3.1, 3.8, 3.3; white non-Hispanic, 2.0, 2.4, 2.2; black non-Hispanic, 8.5, 11.7, 10.1; Hispanic, 1.9, 2.0, 1.6; patients age 0 to 4 years, 2.2, 2.7, 2.5; patients age 5 to 10 years, 2.3, 2.7, 2.7; patients age 11 to 17 years, 4.4, 5.6, 4.4. Asthma death rates increased by an average of 3.4% per year from 1980 to 1998. After reaching a peak of 3.8 per 1,000,000 children in 1996, the childhood asthma death rate declined 18% in 1997 to 3.1% per 1,000,000 children. However, asthma mortality rose again in 1998 to 3.5 per 1,000,000 children. Black non-Hispanic children had the highest asthma death rates and the greatest increase over time. In 1985 to 1986, the death rate among black non-Hispanic children was 4.1 times higher than the death rate for white non-Hispanic children and in 1997 to 1998 was 4.6 times higher. Hispanic children had asthma death rates similar to those of white non-Hispanic children. Asthma mortality trends over time were generally similar among all ages groups, but 11- to 17-year-old children had asthma death rates about twice those of younger children.
      DISCUSSION: The hospitalization rate for bronchitis and bronchiolitis increased by 0.7% per year from 1980 to 1999, whereas that for asthma increased by 1.4%. However, the pneumonia hospitalization rate decreased by 1.3% per year during the same period. Thus, there is an inverse relationship between trends in asthma office visits and hospitalizations and those for pneumonia, bronchitis, and bronchiolitis.
      The burden of asthma on the pediatric population as measured by asthma prevalence, ambulatory visits, and mortality increased dramatically during the past 2 decades. The childhood asthma hospitalization rate increased more slowly but was still rising during a period when pediatric hospitalization rates for other causes were declining. The factors behind the increasing asthma burden remain unclear.
      Just as puzzling as the prolonged increase in asthma prevalence, health care utilization, and mortality is the recent plateauing of some indicators and the apparent decrease of asthma prevalence after 1995. The interpretation of trends in asthma prevalence has been complicated by the redesign of the NHIS in 1997. Although the redesign will improve the validity of asthma surveillance by requiring a diagnosis by a health professional, it created a break in the trend of asthma prevalence and generated uncertainty about how to interpret the drop in asthma prevalence in 1996. The 1996 sample was reduced by 40% as a result of pilot testing of the 1997 redesigned survey, and the impact of this decreased sample size on prevalence estimates is unclear. Although asthma hospitalizations and mortality have plateaued since 1995, these recent trends cannot be used to "confirm" a change in the prevalence trends because multiple factors affect asthma morbidity and mortality. For example, changes in hospitalization rates may also reflect changes in medical practice, asthma therapy, and access to and utilization of care. Mortality may reflect availability and utilization of health care, access to and correct use of medication and prevention strategies, and severity of disease. Therefore, additional years of data are necessary to determine whether the pattern of increasing asthma prevalence during the past 2 decades has changed.
      One possible reason for the recent plateauing of hospitalizations and deaths may be the impact of clinical and public health intervention and prevention efforts. Although it is difficult to evaluate the efficacy of specific or local prevention programs with national data, the impact of nationwide programs, such as the State Children's Health Insurance Program that was passed as part of the Balanced Budget Act of 1997, may be discerned. A large nationwide increase in enrollment of children in insurance programs (2,684,300 children were enrolled by September 1998) may be partly responsible for the large jump in asthma office visits in 1998. Another recent nationwide development is the dissemination of the National Asthma Education and Prevention Program Guidelines in 1997. It has been theorized that adoption of these guidelines by medical practitioners was responsible for the recent decline in asthma mortality among all ages in the United States in 1997.
      The burden of pediatric asthma has increased substantially during the past 2 decades and has been borne disproportionately by black children. Although recent data suggest that the burden from childhood asthma may have recently plateaued after several years of increasing, additional years of data collection are necessary to confirm a change in trend.

Search Criteria: Text - Pediatrics; V.110; No.2; 8/02; p315