Table 4.

Positive Predictive Values of Algorithms to Identify Composite Endpoints (Stroke/Transient Ischemic Attack and Cerebrovascular Disease)

Citation	Study Population and Time Period	Description of Outcome Studied	Algorithm	Validation/Adjudication Procedure, Operational Definition, and Validation Statistics
Stroke/TIA
Arnason, et al.13	patients discharged from a university-associated teaching hospital in Ottawa, Canada, 1999 to 2000	hospitalizations (stroke/TIA)	inpatient ICD-9-CM codes 433 to 436	Medical record review was conducted (N=179 cases of potential stroke/TIA). Confirmation of ‘acute thromboembolism’ required documentation of at least one of the following: direct visualization or imaging of a new thromboembolism or new clinical signs of a stroke/TIA combined with physician confirmation of newly completed stroke/TIA in the chart or a CT report showing acute or sub-acute cerebral infarct. PPV=57%
Birman-Deych, et al.15	Medicare beneficiaries who were hospitalized with atrial fibrillation identified using the National Registry of Atrial Fibrillation II dataset, 1998 to 1999	hospitalizations (stroke/TIA, prevalent and incident)	inpatient ICD-9-CM codes 433.x1, 434.x1, 435.x, 436, 437.1x, 437.9x, 438.x	Medical record review was conducted. Outcome was confirmed if there was documentation of a history and/or current stroke/TIA. Current or past stroke/TIA: sensitivity=35% specificity=99% PPV=96%
Broderick, et al.17	Black residents of the Greater Cincinnati/Northern Kentucky region, identified by hospitalization discharges from 19 acute-care hospitals, 1993 to 1994	hospitalizations (stroke/TIA including intracerebral hemorrhage and subarachnoid hemorrhage)	inpatient ICD-9-CM codes 430 to 438, 747.81, 674.0, 325	Medical record review was conducted (N=733). The criteria that determined the various diagnostic categories of stroke were adapted from the Classification of Cerebrovascular Diseases III and from epidemiological studies of stroke in Rochester, Minnesota. codes 430–438: PPV=46% codes 430–436: PPV=72% (and would detect 97% of all strokes and TIAs) primary discharge codes 430–436: PPV=83%
Humphries, et al.25	adults identified by the British Columbia Cardiac Registries as having undergone a percutaneous coronary intervention at St. Paul’s Hospital, 1994 to 1995	hospitalizations (cerebrovascular disease: stroke, TIA, or carotid endarterectomy, prevalent or incident)	inpatient ICD-9 codes 430 to 438	Medical record review was conducted (N=817). The outcome was confirmed based upon documentation of a previous history of stroke, TIA, or carotid endarterectomy. sensitivity=42.9% specificity=99.2% PPV=71.4%
Kokotailo, et al.29	patients with inpatient visits or seen at the emergency department identified from hospital discharge abstracts database from 3 acute care hospitals in the Calgary health region, 2000 to 2003	hospitalizations and emergency department visits (stroke/TIA including intracerebral hemorrhage and subarachnoid hemorrhage)	most responsible (primary position) diagnosis ICD-9 codes 430.x, 431.x, 433.x1, 434.x1, 435.x, 436, 362.3; ICD-10 codes I60.x, I61.x, I63.x, I64.x, H34.1, G45.x	Medical record review was conducted on a sample of charts (N=461 identified with ICD-9 codes and N=256 identified with ICD-10 codes). Outcome was confirmed based upon trained research assistant determination, and neurologist determination in ambiguous cases. Assessment of correct coding was based on clinical data alone in 24% of charts and on clinical data and neurovascular imaging reports in 76% of charts. ICD-9 coding: overall: PPV=90% ICD-10 coding: overall: PPV=92%
Lentine, et al.32	kidney transplant patients at Washington University ages ≥ 18 years with Medicare as primary insurer, 1991 to 2002	incident or prevalent (stroke/TIA)	ICD-9-CM codes: 430, 431, 432, 433.x1, 434.x1, 435.x, 997.02; identified with Medicare Part A (institutional) claims and/or Medicare Part B (physician/suppliers) claims	Transplant center’s clinical database was used to confirm stroke or TIA. Definition of stroke included new focal neurologic deficit lasting ≥ 24 hours, confirmed by brain imaging. Definition of TIA included new focal deficit that resolves within 24 hours and was attributed to a central cause by the examining provider. Claims within 30 days from event date recorded in the database: Medicare Part A claims sensitivity = 75.0% (95% CI 53.8 – 96.2%); Medicate Part B claims sensitivity = 81.3% (95% CI 62.1% – 100.0%); Medicare Part A or B claims sensitivity = 87.5% (95%CI 71.3% – 100.0%);
Cerebrovascular Disease
Borzecki, et al.16	Veterans Affairs patients with at least 1 hypertension diagnosis (ICD-9-CM code 401, 402, or 405) and a sample without a hypertension diagnosis Department of Veterans Affairs (VA) databases, 1998 to 1999	incident or prevalent (cerebrovascular disease)	inpatient or outpatient ICD-9-CM codes: 430.x to 438.x	Medical record review was conducted (981 patients with a hypertension diagnosis and 195 without a hypertension diagnosis). Outcome was confirmed based upon documentation of cerebrovascular disease in medical notes. sensitivity=64% specificity=95%
Jollis, et al.27	discharges containing a procedure code for coronary arteriography identified using administrative or insurance claims of Duke University Medical Center, 1985 to 1990	hospitalizations (cerebrovascular disease, incident and prevalent)	discharges with an ICD-9-CM code of 435, 436, 438, 437.1, 434, 38.12, 38.42	Clinical database was compared to coding by medical record technicians (N=12937). Cerebrovascular disease was confirmed based upon documentation in the clinical data. sensitivity= 14% specificity= 99%
Piriyawat, et al.37	residents of Nueces County Texas ≥ 45 years of age, 2000	hospitalizations (acute cerebrovascular events)	primary and secondary ICD-9 discharge codes for 430 to 438, except those with a fifth digit specification of 0 (xxx.x0); also excluded codes 437.0, 437.2, 437.3, 437.4, 437.5, 437.7, 437.8, and 438	Medical record review was conducted (N=815). Acute cerebrovascular events were confirmed based upon criteria specified by Morgenstern et al. Cerebrovascular events resulting from trauma were excluded. sensitivity=89% PPV=72.8%
So, et al.41	patients ≥ 20 years of age hospitalized with acute myocardial infarction at 4 teaching hospitals in Alberta, Canada, 2003	hospitalizations (cerebrovascular disease, incident and prevalent)	inpatient ICD-9-CM codes: 430.x to 438.x; ICD-10 codes: G45.x, G46.x, H34.0, I60.x – I69.x	Medical record review was conducted (N=193) and outcome was confirmed based upon evidence of cerebrovascular disease in chart. ICD-9-CM codes: sensitivity = 100.0% (95% CI 54.1 – 100.0) specificity = 93.6% (89.1 – 96.6) PPV = 33.3% (13.3 – 59.0) ICD-10 codes: sensitivity = 100.0% (54.1 – 100.0) specificity = 95.7% (91.7 – 98.1) PPV = 42.9% (17.7 – 71.1)