Minimally important difference of the Child Oral Health Impact Profile for children with orofacial anomalies

BACKGROUND The Child Oral Health Impact Profile (COHIP) is an instrument designed to measure the self-reported oral health-related quality of life of children between the ages of 8 and 15, including domains for oral health, functional well-being, social-emotional well-being, school environment and self-image. The purpose of this study was to estimate the minimally important difference (MID) of the COHIP for patients with cleft lip/palate. METHODS Data from a 6-year, prospective, longitudinal cohort study of children with cleft lip/palate were analyzed to estimate the MID. Analysis was restricted to patients with data at baseline and first follow-up and not receiving a surgical intervention in the intervening years (N = 281). MIDs were estimated via the anchor-based method, using the Global Assessment of Change, and the effect size distribution method. RESULTS Based on the distributional method, the minimally important differences were 0.16 (oral health), 0.12 (functional), 0.22 (social-emotional), 0.21 (school environment) and 0.19 (self-image). MID anchor estimates for COHIP domains ranged from -0.32 to 0.84. The anchor-based and effect size MID estimates for the overall COHIP score were 2.95 and 0.25, respectively. CONCLUSION The minimally important difference of the Child Oral Health Impact Profile is recommended for interpreting clinically meaningful change in patients with cleft lip/palate.