How Valid Is the ICD-9-CM Based AHRQ Patient Safety Indicator for Postoperative Venous Thromboembolism?

Med Care. 2009 Dec;47(12):1237-43. doi: 10.1097/MLR.0b013e3181b58940.


Background: Hospital administrative data are being used to identify patients with postoperative venous thromboembolism (VTE), either pulmonary embolism (PE) or deep-vein thrombosis (DVT). However, few studies have evaluated the accuracy of these ICD-9-CM codes across multiple hospitals.

Methods and materials: The Agency for Healthcare Research and Quality (AHRQ) Patient Safety Indicator (PSI)-12 was used to identify cases with postoperative VTE in 80 hospitals that volunteered for either an AHRQ or University HealthSystem Consortium (UHC) validation project. Trained abstractors using a standardized tool and guidelines retrospectively verified all coded VTE events.

Results: In the combined samples, the positive predictive value of the set of prespecified VTE codes for any acute VTE at any time during the hospitalization was 451 of 573 = 79% (95% CI: 75%-82%). However, the positive predictive value for acute lower extremity DVT or PE diagnosed after an operation was 209 of 452 = 44% (95% CI: 37%-51%) in the UHC sample and 58 of 121 = 48% (95% CI: 42-67%) in the AHRQ sample. Fourteen percent of all cases had an acute upper extremity DVT, 6% had superficial vein thrombosis and 21% had no acute VTE, however, 61% of the latter had a documented prior/chronic VTE. In the UHC cohort, the sensitivity for any acute VTE was 95.5% (95% CI: 86.4%-100%); the specificity was 99.5% (95% CI: 99.4%-99.7%).

Conclusion: Current PSI 12 criteria do not accurately identify patients with acute postoperative lower extremity DVT or PE. Modification of the ICD-9-CM codes and implementation of "present on admission" flags should improve the predictive value for clinically important VTE events.

Publication types

  • Multicenter Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • Female
  • Humans
  • International Classification of Diseases / statistics & numerical data*
  • Male
  • Middle Aged
  • Postoperative Complications / epidemiology*
  • Quality Indicators, Health Care / statistics & numerical data*
  • Reproducibility of Results
  • Retrospective Studies
  • Sex Factors
  • United States
  • United States Agency for Healthcare Research and Quality / statistics & numerical data*
  • Venous Thromboembolism / epidemiology*