Validation of diagnostic codes for outpatient-originating sudden cardiac death and ventricular arrhythmia in Medicaid and Medicare claims data.
OBJECTIVE
Sudden cardiac death (SD) and ventricular arrhythmias (VAs) caused by medications have arisen as an important public health concern in recent years. The validity of diagnostic codes in identifying SD/VA events originating in the ambulatory setting is not well known. This study examined the positive predictive value (PPV) of hospitalization and emergency department encounter diagnoses in identifying SD/VA events originating in the outpatient setting.


METHODS
We selected random samples of hospitalizations and emergency department claims with principal or first-listed discharge diagnosis codes indicative of SD/VA in individuals contributing at least 6 months of baseline time within 1999-2002 Medicaid and Medicare data from five large states. We then obtained and reviewed medical records corresponding to these events to serve as the reference standard.


RESULTS
We identified 5239 inpatient and 29 135 emergency department events, randomly selected 100 of each, and obtained 119 medical records, 116 of which were for the requested courses of care. The PPVs for an outpatient-originating SD/VA precipitating hospitalization or emergency department treatment were 85.3% (95% confidence interval [CI] = 77.6-91.2) overall, 79.7% (95%CI = 68.3-88.4) for hospitalization claims, and 93.6% (95%CI = 82.5-98.7) for emergency department claims.


CONCLUSIONS
First-listed SD/VA diagnostic codes identified in inpatient or emergency department encounters had very good agreement with clinical diagnoses and functioned well to identify outpatient-originating events. Researchers using such codes can be confident of the PPV when conducting studies of SD/VA originating in the outpatient setting.
Center for Clinical Epidemiology & Biostatistics, Department of Biostatistics & Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
Sean
S
Hennessy
Charles E
CE
Leonard
Cristin P
CP
Freeman
Rajat
R
Deo
Craig
C
Newcomb
Stephen E
SE
Kimmel
Brian L
BL
Strom
Warren B
WB
Bilker
D000553:Ambulatory Care / Q000379:methods; D001145:Arrhythmias, Cardiac / Q000139:chemically induced / Q000175:diagnosis* / Q000453:epidemiology; D016208:Databases, Factual; D016757:Death, Sudden, Cardiac / Q000453:epidemiology / Q000209:etiology*; D064420:Drug-Related Side Effects and Adverse Reactions; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D038801:International Classification of Diseases; D008484:Medicaid / Q000706:statistics & numerical data; D008499:Medical Records / Q000706:statistics & numerical data; D006278:Medicare / Q000706:statistics & numerical data; D011237:Predictive Value of Tests; D014481:United States