Agreement between survey data and Régie de l'assurance maladie du Québec (RAMQ) data with respect to the diagnosis of asthma and medical services use for asthma in children.

INTRODUCTION The goal of this study was to assess the agreement between the results of a respiratory health survey conducted in Montréal on children aged 6 months to 12 years and the Régie de l'assurance maladie du Québec (RAMQ, Quebec health insurance board) database in terms of the diagnosis of asthma and medical services use. A secondary aim was to evaluate the effect of the survey method used (Internet-based survey or telephone survey). METHODS We assessed whether a diagnosis of asthma was made for 7922 children. In addition, we compared the use of medical services for asthma (emergency department visits and hospitalizations) in the 12 months preceding the survey for the 402 children considered to have asthma, using 2 groups of respiratory diagnoses and 2 data linkage periods. The agreement between the 2 data sources was evaluated using the kappa statistic (κ) and sensitivity and specificity, as well as percentages of agreement, overreporting and under-reporting with respect to health services use. RESULTS Moderate agreement was found between the 2 data sources (survey and RAMQ data) in terms of the diagnosis of asthma (κ = 0.54 and κ = 0.60 depending on the definition used). Specificity was high (93% and 96%), but sensitivity varied (50% and 65%). Respondents over-reported health services use, resulting in moderate kappa values (0.49 for emergency department visits and 0.48 for hospitalizations). However, when more diagnoses were included in the definition and when the linkage period was extended (15 rather than 12 months), the kappa values increased (0.59 for emergency department visits and 0.64 for hospitalizations) and sensitivity and specificity were high. Slightly higher agreement was obtained for the Internet-based survey relative to the telephone survey. CONCLUSION The findings validate the use of survey data with respect to the diagnosis of pediatric asthma and major health services use for this disease.