Use of Payer as a Proxy for Health Insurance Status on Admission Results in Misclassification of Insurance Status among Pediatric Trauma Patients

The purpose of this study was to quantify health insurance misclassification among children treated at a pediatric trauma center and to determine factors associated with misclassification. Demographic, medical, and financial information were collected for patients at our institution between 2008 and 2010. Two health insurance variables were created: true (insurance on hospital admission) and payer (source of payment). Multivariable logistic regression was used to determine which factors were independently associated with health insurance misclassification. The two values of health insurance status were abstracted from the hospital financial database, the trauma registry, and the patient medical record. Among 3630 patients, 123 (3.4%) had incorrect health insurance designation. Misclassification was highest in patients who died: 13.9 per cent among all deaths and 30.8 per cent among emergency department deaths. The adjusted odds of misclassification were 6.7 (95% confidence interval: 1.7, 26.6) among patients who died and 16.1 (95% confidence interval: 3.2, 80.77) among patients who died in the emergency department. Using payer as a proxy for health insurance results in misclassification. Approaches are needed to accurately ascertain true health insurance status when studying the impact of insurance on treatment outcomes.