The validity of the diagnosis of inflammatory arthritis in a large population-based primary care database

Markus Mj Nielen,François G Schellevis,Joke C Korevaar,Jennie Ursum

doi:10.1186/1471-2296-14-79

Abstract

BackgroundLarge population-based databases based on electronic medical records (EMRs) of patients in primary care are a useful data source to investigate morbidity and health care utilization. Diagnoses recorded in EMRs are doctor-defined, but their validity can be disputed. In this study we investigated the validity of the diagnosis inflammatory arthritis (IA), a group of chronic rheumatic diseases, including rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis, in primary care based EMRs.MethodsIn five general practices, participating in the Netherlands Information Network of General Practice (LINH), EMRs of 219 patients with a diagnostic code of IA were systematically reviewed on characteristics which are not routinely extracted for the LINH database. The diagnosis IA was confirmed when we found, based on a correspondence with a medical specialist, the following diagnoses in the free text fields of the EMR: oligoarthritis, polyarthritis, rheumatoid arthritis and/or spondyloarthropathy. These results were used to determine the validity of the diagnosis IA in EMRs and to develop an algorithm to improve diagnostic validity.ResultsFrom the 219 patients diagnosed as IA in the database, the diagnosis IA was confirmed in 155 patients (70.8%). The algorithm, which resulted in a group of patients with as many as possible confirmed IA-diagnosed patients without excluding too many patients from our dataset, was when patients fulfilled at least one of the following three criteria: 1) a repeat prescription for a disease-modifying antirheumatic drug (DMARD) and/or biological agent, 2) ≥ four contacts or one episode with a diagnostic code for IA, combined with at least two IA-related prescriptions (excluding DMARDs/biological agents), and 3) age at diagnosis ≥ 61 years. After applying this algorithm, the percentage of correctly diagnosed IA patients increased from 71% to 78% reducing the size of our study population by 36%.ConclusionsBased on additional diagnostic information, the diagnosis IA from EMRs of patients in primary care is sufficiently valid when using the proposed algorithm. After applying the algorithm, the percentage of correctly diagnosed IA patients increased from 71% to 78%.

Highlights

Large population-based databases based on electronic medical records (EMRs) of patients in primary care are a useful data source to investigate morbidity and health care utilization
general practitioners (GPs) have a gatekeeper role for access to specialized care, and their EMRs include a complete record of all morbidity of their patients using a uniform methodology
Validity of the diagnosis inflammatory arthritis The diagnosis IA was confirmed when we found, based on a correspondence with a medical specialist, the following diagnoses in the free text fields of the EMR: oligoarthritis, polyarthritis, rheumatoid arthritis and/or spondyloarthropathy

Summary

Introduction

Large population-based databases based on electronic medical records (EMRs) of patients in primary care are a useful data source to investigate morbidity and health care utilization. In this study we investigated the validity of the diagnosis inflammatory arthritis (IA), a group of chronic rheumatic diseases, including rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis, in primary care based EMRs. A major advantage of using electronic medical records (EMRs) from general practitioners (GPs) is the possibility to study large numbers of patients over a long period. A major advantage of using electronic medical records (EMRs) from general practitioners (GPs) is the possibility to study large numbers of patients over a long period This makes it, for example, possible to investigate diseases with a low prevalence, or monitor disease course over time. Patients from primary care, in countries where the GP acts as gatekeeper and where inhabitants are listed in a practice, are representative for the total population, including the whole range of disease severity. According to the guidelines of the Dutch College of GPs, GPs are expected to record diagnostic information from their patients routinely in EMRs, using the International Classification of Primary Care version 1 (ICPC-1) [1]

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