Differences in spirometry values between US children 6-11 years and adolescents 12-19 years with current asthma, 2007-2010

Background National Asthma Education and Prevention Program (NAEPP) guidelines recommend that periodic spirometry be performed in youth with asthma. NAEPP uses different spirometry criteria to define uncontrolled asthma for children (6-11 years) and adolescents (12+ years). Objective To describe differences in spirometry between US children and adolescents with current asthma. Methods We examined cross-sectional spirometry data from 453 US youth with current asthma age 6-19 years from the 2007-2010 National Health and Nutrition Examination Surveys. The main outcomes were percentage predicted forced expiratory volume at 1 sec (FEV1%) ≤80 and the ratio of FEV1 to forced vital capacity (FEV1/FVC) ≤0.80. We also examined the prevalence of youth with spirometry values consistent with uncontrolled asthma, using NAEPP age-specific criteria, defined for children aged 6-11 years as FEV1% ≤80 or FEV1/FVC ≤0.80, and for adolescents aged 12-19 years as FEV1% ≤80. Results Children 6-11 years and adolescents 12-19 years did not differ in prevalence of FEV1% ≤80 (10.1% vs. 9.0%) or FEV1/FVC ≤0.80 (30.6% vs. 29.8%). However, based on the NAEPP age-specific criteria, 33.0% of children 6-11 years and 9.0% of adolescents 12-19 years had spirometry values consistent with uncontrolled asthma (P < 0.001). Conclusion Children 6-11 years and adolescents 12-19 years with current asthma did not differ in the percentage with FEV1% ≤80 or FEV1/FVC ≤0.80. However, the percent of children and adolescents with spirometry values consistent with uncontrolled asthma did differ. The difference appears to stem mainly from the different spirometry criteria for the two age groups. Pediatr Pulmonol. 2016;51:272-279.