Diagnostic codes for sudden cardiac death and ventricular arrhythmia functioned poorly to identify outpatient events in EPIC's General Practice Research Database.
OBJECTIVE
To examine the validity of OXMIS/Read diagnoses of hospitalization for sudden cardiac death and ventricular arrhythmia (SD/VA) for use in studies of arrhythmogenic effects of outpatient medications in the General Practice Research Database (GPRD).


METHODS
We identified putative occurrences of hospitalization for SD/VA in patients receiving outpatient prescriptions for cisapride, domperidone, or metoclopramide. We then administered a questionnaire to general practitioners (GPs) caring for these patients, requested hospital discharge consult letters, and examined the positive predictive value (PPV) of diagnostic codes in identifying outpatient events precipitating hospitalization.


RESULTS
We identified 84 putative events, 38 (45%) of which occurred in patients cared for by GPs participating in the follow-up scheme. Thirty of 38 questionnaires (79%) were completed. The PPV for the occurrence of any SD/VA was 93% (95% CI, 78-99%). However, the PPV for SD/VA occurrence in an outpatient setting precipitating a hospitalization was only 23% (95% CI, 10-42%). The majority of inpatient diagnostic codes reflected events occurring after hospital admission, not precipitating it.


CONCLUSIONS
While computerized codes for SD/VA agreed well with physician diagnosis, they operated poorly to identify events occurring in an outpatient setting. Studies of SD/VA in the GPRD should verify events on a case-by-case basis.
Hennessy
Sean
S
Center for Clinical Epidemiology & Biostatistics, Department of Biostatistics & Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6021, USA. hennessy@mail.med.upenn.edu
Leonard
Charles E
CE
Palumbo
Cristin M
CM
Bilker
Warren B
WB
Newcomb
Craig
C
Kimmel
Stephen E
SE
D001145:Arrhythmias, Cardiac / Q000139:chemically induced / Q000175:diagnosis* / Q000453:epidemiology; D020117:Cisapride / Q000008:administration & dosage / Q000009:adverse effects; D015331:Cohort Studies; D016208:Databases, Factual / Q000706:statistics & numerical data*; D016757:Death, Sudden, Cardiac / Q000453:epidemiology / Q000209:etiology; D004294:Domperidone / Q000008:administration & dosage / Q000009:adverse effects; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology / Q000209:etiology; D005194:Family Practice / Q000592:standards / Q000706:statistics & numerical data; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D038801:International Classification of Diseases / Q000592:standards*; D008499:Medical Records / Q000592:standards; D008787:Metoclopramide / Q000008:administration & dosage / Q000009:adverse effects; D011237:Predictive Value of Tests; D011795:Surveys and Questionnaires
D004294:Domperidone; D008787:Metoclopramide; D020117:Cisapride