Optimising Use of Electronic Health Records to Describe the Presentation of Rheumatoid Arthritis in Primary Care: A Strategy for Developing Code Lists

Abstract

BackgroundResearch using electronic health records (EHRs) relies heavily on coded clinical data. Due to variation in coding practices, it can be difficult to aggregate the codes for a condition in order to define cases. This paper describes a methodology to develop ‘indicator markers’ found in patients with early rheumatoid arthritis (RA); these are a broader range of codes which may allow a probabilistic case definition to use in cases where no diagnostic code is yet recorded.MethodsWe examined EHRs of 5,843 patients in the General Practice Research Database, aged ≥30y, with a first coded diagnosis of RA between 2005 and 2008. Lists of indicator markers for RA were developed initially by panels of clinicians drawing up code-lists and then modified based on scrutiny of available data. The prevalence of indicator markers, and their temporal relationship to RA codes, was examined in patients from 3y before to 14d after recorded RA diagnosis.FindingsIndicator markers were common throughout EHRs of RA patients, with 83.5% having 2 or more markers. 34% of patients received a disease-specific prescription before RA was coded; 42% had a referral to rheumatology, and 63% had a test for rheumatoid factor. 65% had at least one joint symptom or sign recorded and in 44% this was at least 6-months before recorded RA diagnosis.ConclusionIndicator markers of RA may be valuable for case definition in cases which do not yet have a diagnostic code. The clinical diagnosis of RA is likely to occur some months before it is coded, shown by markers frequently occurring ≥6 months before recorded diagnosis. It is difficult to differentiate delay in diagnosis from delay in recording. Information concealed in free text may be required for the accurate identification of patients and to assess the quality of care in general practice.

Rheumatoid arthritis is getting less frequent—results of a nationwide population-based cohort study

“…Definition of RA RA was defined using a previously published medical Read code list [23] Case definition Prevalent cases of RA were participants 518 years of age on 1 July of each calendar year who had a medical Read code that had been used previously to identify cases with RA [23]. Information about RF, anti-CCP antibodies and DMARD prescriptions were not used for identifying RA cases, as serological testing and DMARD prescription rates vary over time and affect temporal trends in the epidemiology of RA.…”

Dental consultations in UK general practice and antibiotic prescribing rates: a retrospective cohort study

“…13,14 Comorbid conditions were identified using Read Codes identified by previously published studies. [15][16][17] A comorbidity was considered to be present if a patient had been recorded as having a consultation with a disease-specific Read Code on, or before, the event date of the dental consultation.…”

Intelligent use and clinical benefits of electronic health records in rheumatoid arthritis

“…Another method applied support vector machines, a machine learning technique[48], to ICD9 codes, NLP results, and medication records with similar performance[47]. Another group of researchers has investigated non-diagnosis code lists and keywords in early identification of RA[49,50]. …”