Predictive factors for a shortened methacholine challenge protocol in children

Area of Science:

• Pediatric Pulmonology
• Respiratory Medicine
• Clinical Diagnostics

Background:

• The methacholine challenge test is crucial for asthma diagnosis in children but is often time-consuming.
• Quadrupled concentration protocols shorten testing in adults, but their safety and efficacy in children are not well-established.
• Predictors for safely using a quadrupled concentration protocol in pediatric patients are currently unidentified.

Purpose of the Study:

• To identify clinical predictors associated with the preclusion of a quadrupled concentration protocol in children undergoing methacholine challenge testing.
• To establish criteria for safely omitting lower methacholine concentrations in pediatric asthma diagnosis.

Main Methods:

• A derivation cohort (n=399) and a validation cohort (n=195) of subjects under 18 years were analyzed.
• Eligibility to omit 0.5 mg/ml and 2.0 mg/ml methacholine concentrations was determined by PC20 values.
• Bivariate analysis identified baseline characteristics associated with precluding the quadrupled protocol; an algorithm was derived and validated.

Main Results:

• Specific pulmonary function measures, including baseline FEV1 ≤90% predicted, FEV1/FVC ≤0.8, FEF25-75 ≤70% predicted, and a ≥10% FEV1 decrease with prior concentration, precluded omitting 0.5 mg/ml.
• Baseline FEF25-75 ≤70% predicted and a ≥10% FEV1 drop with the previous concentration precluded omitting 2.0 mg/ml.
• The derived criteria achieved 74.0% sensitivity and 84.6% specificity in the validation cohort.

Conclusions:

• Objective pulmonary function measures were identified as predictors for safely shortening the pediatric methacholine challenge test.
• These findings support personalizing and expediting the methacholine challenge protocol in children by quadrupling concentrations.
• This approach has the potential to improve the efficiency of asthma diagnosis in pediatric populations.