Concordance between survey reported childhood asthma and linked Medicaid administrative records.

OBJECTIVE: Agreement between administrative and survey data has been shown to vary by the condition of interest and there is limited research dedicated to parental report of asthma among children. The current study assesses the concordance between parent-reported asthma from the National Health Interview Survey (NHIS) with Medicaid administrative claims data among linkage eligible children from the NHIS.

METHODS: Medicaid Analytic eXtract (MAX) files from the Centers for Medicare & Medicaid Services (CMS) (years 2000-2005) were linked to participants of the NHIS (years 2001-2005). Concordance measures were calculated to assess overall agreement between a claims-based asthma diagnosis and a survey-based asthma diagnosis. Structural equation modeling was used to assess the association between demographic, service utilization, and co-occurring conditions factors and agreement.

RESULTS: Percent agreement between the two data sources was high (90%) with a prevalence-adjusted bias-adjusted kappa of 0.80 and Cohen's kappa of 0.55. Agreement varied by demographic characteristics, service utilization characteristics, and the presence of allergies and other health conditions. Structural equation modeling results found the presence of a series of co-occurring conditions, namely allergies, resulted in significantly lower agreement after controlling for demographics and service utilization.

CONCLUSIONS: There was general agreement between asthma diagnoses reported in the NHIS when compared to medical claims. Discordance was greatest among children with co-occurring conditions.