Sex-related differences in pulmonary physiologic outcome measures in a high-risk birth cohort.

BACKGROUND: Sex influences the risk of wheezing illnesses and the prevalence of asthma throughout childhood. OBJECTIVE: To better understand the mechanisms of these effects, we analyzed longitudinal relationships between sex, lung physiology, and asthma in the Childhood Origins of ASThma birth cohort study. METHODS: Childhood Origins of ASThma birth cohort study children were followed prospectively from birth and assessed annually. Results of spirometry, fractional exhaled nitric oxide (Feno), mannitol provocation testing, and (3)He gas magnetic resonance imaging were assessed by sex using multivariate models including age, asthma diagnosis, and wheezing histories. RESULTS: Girls had higher prebronchodilator forced expiratory volume in 0.5 seconds/forced vital capacity values than did boys (mean difference, 0.017; 95% CI, 0.000-0.034; P = .05) of equivalent age. Postbronchodilator findings were more pronounced, with boys demonstrating reduced forced expiratory volume in 0.5 seconds/forced vital capacity values than did girls of equivalent age (mean difference, 0.032; 95% CI, 0.014-0.049; P = .0005). Conversely, girls were noted to have higher ventilation defects on (3)He magnetic resonance imaging than did boys (P = .01). No differences were noted in the rate of positive responses to mannitol provocation or Feno measurements. CONCLUSIONS: Lower airflow values are present by spirometry for prepubertal boys than for age-matched girls; however, greater (3)He ventilation defects were noted in girls. This could represent a greater degree of subclinical air trapping in prepubertal girls because residual volumes are not detected on standard spirometric readings. No differences were noted between the 2 sexes with airway hyperresponsiveness (mannitol provocation testing) or inflammation (Feno). Prospective peripubertal follow-up will determine whether these differences persist or change with the de novo expression and remission of asthma based on sex and age.

Daily diaries vs retrospective questionnaires to assess asthma control and therapeutic responses in asthma clinical trials: is participant burden worth the effort?

BACKGROUND: Presently, there is insufficient information to compare the value of daily diaries vs retrospective questionnaires for assessing symptoms in relationship to asthma control in clinical trials. Daily symptom diaries are often burdensome to gather, incomplete, susceptible to fabrication, and of questionable reliability. There is also concern that retrospective symptom questionnaires may be subject to poor recall and may be insensitive. METHODS: To compare these two methods of assessing symptoms reporting, we analyzed data collected during the Best Add-on Therapy Giving Effective Responses (BADGER) trial. During the trial, asthma control in 182 children aged 6 to 17 years was assessed in two ways: (1) by asthma control days (ACDs) determined by manually recorded daily diary symptom and rescue medication use scores and (2) by monthly retrospective report of symptoms embedded within the age-appropriate version of the Asthma Control Test (ACT). Correlations between ACDs and ACT scores were analyzed, and the sensitivity of each method for measuring asthma control and determining the differential response among the three BADGER treatments was evaluated. RESULTS: Although validated using a 4-week recall period, ACT correlated better with daily diary information from the last 2 weeks of the 4-week recall (r = 0.46) than from the first 2 weeks (r = 0.34). In addition, clinically significant differential treatment responses were detected using ACDs but not ACT scores . CONCLUSIONS: The results of this study indicate that daily diaries used to determine ACDs can be a more sensitive tool than ACT for assessing differential treatment responses with respect to asthma control.