Defining emergency department episodes by severity and intensity: A 15-year study of Medicare beneficiaries.

TitleDefining emergency department episodes by severity and intensity: A 15-year study of Medicare beneficiaries.
Publication TypeJournal Article
Year of Publication2010
AuthorsKaskie, B, Obrizan, M, Cook, EA, Jones, MP, Liu, L, Bentler, SE, Wallace, RB, Geweke, JF, Wright, KB, Chrischilles, EA, Pavlik, CE, Ohsfeldt, RL, Rosenthal, GE, Wolinsky, FD
JournalBMC Health Serv Res
Date Published2010 Jun 21
ISSN Number1472-6963
KeywordsAged, Aged, 80 and over, Cohort Studies, Emergency Service, Hospital, Humans, Insurance Claim Review, Medicare, Prospective Studies, Severity of Illness Index, United States

BACKGROUND: Episodes of Emergency Department (ED) service use among older adults previously have not been constructed, or evaluated as multi-dimensional phenomena. In this study, we constructed episodes of ED service use among a cohort of older adults over a 15-year observation period, measured the episodes by severity and intensity, and compared these measures in predicting subsequent hospitalization.

METHODS: We conducted a secondary analysis of the prospective cohort study entitled the Survey on Assets and Health Dynamics among the Oldest Old (AHEAD). Baseline (1993) data on 5,511 self-respondents >or=70 years old were linked to their Medicare claims for 1991-2005. Claims then were organized into episodes of ED care according to Medicare guidelines. The severity of ED episodes was measured with a modified-NYU algorithm using ICD9-CM diagnoses, and the intensity of the episodes was measured using CPT codes. Measures were evaluated against subsequent hospitalization to estimate comparative predictive validity.

RESULTS: Over 15 years, three-fourths (4,171) of the 5,511 AHEAD participants had at least 1 ED episode, with a mean of 4.5 episodes. Cross-classification indicated the modified-NYU severity measure and the CPT-based intensity measure captured different aspects of ED episodes (kappa = 0.18). While both measures were significant independent predictors of hospital admission from ED episodes, the CPT measure had substantially higher predictive validity than the modified-NYU measure (AORs 5.70 vs. 3.31; p < .001).

CONCLUSIONS: We demonstrated an innovative approach for how claims data can be used to construct episodes of ED care among a sample of older adults. We also determined that the modified-NYU measure of severity and the CPT measure of intensity tap different aspects of ED episodes, and that both measures were predictive of subsequent hospitalization.

User Guide Notes

Endnote Keywords

HOSPITALIZATION/emergency department service use/emergency department service use/medicare/predictive validity/predictive validity

Endnote ID


Alternate JournalBMC Health Serv Res
Citation Key7526
PubMed ID20565949
PubMed Central IDPMC2903585
Grant ListU01 AG009740 / AG / NIA NIH HHS / United States
R01 AG-022913 / AG / NIA NIH HHS / United States
R21 AG-031307 / AG / NIA NIH HHS / United States
R21 AG-030333 / AG / NIA NIH HHS / United States