Validity of Diagnostic Codes for Acute Stroke in Administrative Databases: A Systematic Review

PLoS One. 2015 Aug 20;10(8):e0135834. doi: 10.1371/journal.pone.0135834. eCollection 2015.


Objective: To conduct a systematic review of studies reporting on the validity of International Classification of Diseases (ICD) codes for identifying stroke in administrative data.

Methods: MEDLINE and EMBASE were searched (inception to February 2015) for studies: (a) Using administrative data to identify stroke; or (b) Evaluating the validity of stroke codes in administrative data; and (c) Reporting validation statistics (sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), or Kappa scores) for stroke, or data sufficient for their calculation. Additional articles were located by hand search (up to February 2015) of original papers. Studies solely evaluating codes for transient ischaemic attack were excluded. Data were extracted by two independent reviewers; article quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool.

Results: Seventy-seven studies published from 1976-2015 were included. The sensitivity of ICD-9 430-438/ICD-10 I60-I69 for any cerebrovascular disease was ≥ 82% in most [≥ 50%] studies, and specificity and NPV were both ≥ 95%. The PPV of these codes for any cerebrovascular disease was ≥ 81% in most studies, while the PPV specifically for acute stroke was ≤ 68%. In at least 50% of studies, PPVs were ≥ 93% for subarachnoid haemorrhage (ICD-9 430/ICD-10 I60), 89% for intracerebral haemorrhage (ICD-9 431/ICD-10 I61), and 82% for ischaemic stroke (ICD-9 434/ICD-10 I63 or ICD-9 434&436). For in-hospital deaths, sensitivity was 55%. For cerebrovascular disease or acute stroke as a cause-of-death on death certificates, sensitivity was ≤ 71% in most studies while PPV was ≥ 87%.

Conclusions: While most cases of prevalent cerebrovascular disease can be detected using 430-438/I60-I69 collectively, acute stroke must be defined using more specific codes. Most in-hospital deaths and death certificates with stroke as a cause-of-death correspond to true stroke deaths. Linking vital statistics and hospitalization data may improve the ascertainment of fatal stroke.

Publication types

  • Research Support, Non-U.S. Gov't
  • Systematic Review

MeSH terms

  • Cerebral Hemorrhage / diagnosis
  • Cerebral Hemorrhage / pathology
  • Cerebrovascular Disorders / diagnosis
  • Cerebrovascular Disorders / pathology
  • Clinical Coding / methods
  • Databases, Factual
  • Death Certificates
  • Hospitalization
  • Humans
  • International Classification of Diseases
  • Ischemic Attack, Transient / diagnosis
  • Ischemic Attack, Transient / pathology
  • Stroke / diagnosis*
  • Stroke / pathology*
  • Subarachnoid Hemorrhage / diagnosis
  • Subarachnoid Hemorrhage / pathology

Grants and funding

This study was funded by the Canadian Arthritis Network ( Natalie McCormick is supported by a Doctoral Research Award from the Canadian Institutes of Health Research. J. Antonio Avina-Zubieta held a salary award from the Canadian Arthritis Network and The Arthritis Society of Canada. He is currently the British Columbia Lupus Society Scholar and holds a Scholar Award from the Michael Smith Foundation for Health Research. Diane Lacaille holds the Mary Pack Chair in Arthritis Research from UBC and The Arthritis Society of Canada. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.