Table 1.

Hypertension case ascertainment algorithms from administrative health records (AHRs) and electronic medical records (EMRs)

Data source	Contact frequency, source and duration	ICD 9-CM/10-CA diagnosis codes	ATC medication codes
AHR	1 + H or 2 + P in 2 years	ICD-9-CM: 401–405 ICD-10-CA: I10-I13, I15
EMR	(2 + P in 2 years) or 1 + PL or 1 + Rx ever	ICD-9-CM: 401–405	C07AB04, C09XA02, C03DB01, C08CA01, C07AB03, C07CB03, C09AA07, C09AA01, C07AG02, C03BA04, C09AA08, C09AA02, C09BA02, C09CA02, C09DA02, C08CA02, C09AA09,C03AA03, C03EA01, C03BA11, C09CA04, C09DA04, C09AA03, C09BA03, C09DA01, C02LB01, C03BA08, C09CA07, C07AA06, C09AA10, C03DB02, C09CA03, C08DA01

H Hospital discharge abstract, P Physician billing claim, PL Problem list, Rx Drug codes; ICD-9-CM/10-CA International Classification of Diseases, 9th Revision, Clinical Modification and 10th version of the Canadian version, ATC Anatomic Therapeutic Chemical classification system