Identifying breastfeeding-sensitive conditions by expert consensus

Background: Infant feeding-related health outcomes need to be consistently defined prior to inclusion in health services research. Objective: To categorize conditions common in infants under 12 months old by their association with breastfeeding for use as outcome measures in a randomized, controlled trial of breastfeeding promotion. Methods: A modified Delphi consensus method synthesized opinions of 13 physician experts on breastfeeding's association with ICD-9 infant diagnosis codes derived from literature review and medical center experience. A pilot round and 2 subsequent Delphi rounds were used. For the first round, consensus was achieved when more than 80% of experts agreed on a classification for a particular condition, with a predetermined level of certainty based on a 7-point Likert scale. For the second round, consensus was achieved when a majority of experts agreed on the classification from Round 1. Results: An initial 68 diagnosis codes were identified for evaluation by the expert panel. After a pilot round, the codes were refined and condensed, which resulted in 38 diagnoses for categorization into 1 of 3 categories: (1) breastfeeding protects against the condition; (2) breastfeeding may cause or worsen the condition; and (3) breastfeeding is unrelated to the condition. At the conclusion of the process, consensus was achieved on the classification of 31 conditions, and 7 conditions remained unclassified because of a lack of consensus. Conclusions: This study provides a list of conditions common in infants under 12 months of age classified based on relationship to infant feeding method and validated by expert consensus. These conditions, based on readily available insurance claims data, contribute to the standardization of outcome measures used for health services research related to breastfeeding promotion.