Possible effect of DRGs on the classification of stroke: Implications for epidemiological surveillance

Carol A. Derby, Kate L. Lapane, Henry A. Feldman, Richard A. Carleton

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Background and Purpose - Accurate data on the distribution of stroke subtypes are essential for understanding the forces driving recent morbidity and mortality trends. The introduction of diagnosis-related groups (DRGs) in the 1980s may have affected the distribution of stroke subtypes as defined by International Classification of Diseases, Ninth Revision (ICD-9), discharge diagnosis codes. Methods - The Pawtucket Heart Health Program cardiovascular surveillance data were used to examine trends in stroke classification for 1980 to 1991 in relation to the introduction of DRGs in 2 communities in Massachusetts and Rhode Island, where DRGs were implemented 2 years apart. Included were all hospital discharges for residents aged 35 to 74 with a primary ICD-9 diagnosis of 431 to 432, 434, or 436 to 437 (N = 1386 in Rhode Island, N = 1839 in Massachusetts). Results - In each state, concurrently with the introduction of DRGs, the proportion of strokes classified as cerebral occlusion (ICD-9 434.0 to 434.9) increased, and the proportion classified as acute but ill-defined (ICD-9 436.0 to 436.9) decreased. Before DRGs, 30.0% of strokes in Rhode Island and 26.6% in Massachusetts were classified as cerebral occlusion, whereas 51.8% in Rhode Island and 51.7% in Massachusetts were classified as acute ill defined. After DRGs were instituted, the proportions of cerebral occlusion and acute, ill-defined stroke, respectively, were 70.9% and 8.5% in Rhode Island and 74.1% and 7.7% in Massachusetts (Χ2, all P < 0.001). The proportions of strokes classified as intracerebral hemorrhage or transient cerebral ischemia remained constant. Conclusions - The implementation of DRGs may have influenced coding of strokes to the ICD-9. Findings highlight the limitations of hospital discharge data for evaluating stroke subtypes and demonstrate the need for community-based surveillance for monitoring specific trends in stroke.

Original languageEnglish (US)
Pages (from-to)1487-1491
Number of pages5
Issue number7
StatePublished - 2001
Externally publishedYes


  • Cerebrovascular disorders
  • Diagnostic-related groups
  • Population surveillance
  • Stroke

ASJC Scopus subject areas

  • Clinical Neurology
  • Cardiology and Cardiovascular Medicine
  • Advanced and Specialized Nursing


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