Neuropathic pain in a primary care electronic health record database.

BACKGROUND: Neuropathic pain (NP) is common in the adult population but is difficult to study in electronic health record (EHR) databases because it is a symptom rather than a pathologic diagnosis. The first step in studying NP in EHR databases is to develop methods for identifying patients with NP. The objectives of this study were to develop estimates of the prevalence of NP among patients in a primary care EHR database and describe these patients' demographic characteristics and health-care utilization. METHODS: This was a retrospective cohort study of de-identified data from a 5-year period (2005-2010) from 23 general practitioners (GPs) in 10 primary care practices in southwestern Ontario, Canada. International Classification of Diseases version 9 (ICD-9) diagnostic codes and medication prescriptions were used to identify patients with certain and probable NP. RESULTS: Different methods produced prevalence estimates ranging from 1.5% (for certain NP in the epidemiologically rigorous period cohort) to 11.2% (for certain NP + probable NP in the more inclusive database cohort). Patients in the NP groups had more GP visits, specialist referrals and analgesic prescriptions than patients without NP. CONCLUSION: This study represents a step towards being able to utilize EHR databases to study NP by proposing methods to identify patients with certain and probable NP in a primary care EHR database. Validation against a gold standard is the next step.