Outpatient Complex Case Management: Health System-Tailored Risk Stratification Taxonomy to Identify High-Cost, High-Need Patients

J Gen Intern Med. 2018 Nov;33(11):1921-1927. doi: 10.1007/s11606-018-4616-2. Epub 2018 Aug 3.


Background: U.S. health systems, incentivized by financial penalties, are designing programs such as case management to reduce service utilization among high-cost, high-need populations. The major challenge is identifying patients for whom targeted programs are most effective for achieving desired outcomes.

Objective: To evaluate a health system's outpatient complex case management (OPCM) for Medicare beneficiaries for patients overall and for high-risk patients using system-tailored taxonomy, and examine whether OPCM lowers service utilization and healthcare costs.

Design: Retrospective case-control study using Medicare data collected between 2012 and 2016 for Ochsner Health System.

Participants: Super-utilizers defined as Medicare patients with at least two hospital/ED encounters within 180 days of the index date including the index event.

Intervention: Outpatient complex case management.

Main measures: Propensity score-adjusted multivariable logistic regression analysis was conducted for primary outcomes (90-day hospital readmission; 90-day ED re-visit). A difference-in-difference analysis was conducted to examine changes in per membership per month (PMPM) costs based on OPCM exposure.

Key results: Among 18,882 patients, 1197 (6.3%) were identified as "high-risk" and 470 (2.5%) were OPCM participants with median enrollment of 49 days. High-risk OPCM cases compared to high-risk controls had lower odds of 90-day hospital readmissions (0.81 [0.40-1.61], non-significant) and lower odds of 90-day ED re-visits (0.50 [0.32-0.79]). Non-high-risk OPCM cases compared to non-high-risk controls had lower odds of 90-day hospital readmissions (0.20 [0.11-0.36]) and 90-day ED re-visits (0.66 [0.47-0.94]). Among OPCM cases, high-risk patients compared to non-high-risk patients had greater odds of 90-day hospital readmissions (4.44 [1.87-10.54]); however, there was no difference in 90-day ED re-visits (0.99 [0.58-1.68]). Overall, OPCM cases had lower total cost of care compared to controls (PMPM mean [SD]: - $1037.71 [188.18]).

Conclusions: Use of risk stratification taxonomy for super-utilizers can identify patients most likely to benefit from case management. Future studies must further examine which OPCM components drive improvements in select outcome for specific populations.

Keywords: Medicare; case management; health services research; utilization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Ambulatory Care / economics*
  • Ambulatory Care / methods
  • Ambulatory Care / trends
  • Case Management / economics*
  • Case Management / trends
  • Case-Control Studies
  • Female
  • Health Care Costs* / trends
  • Health Services Needs and Demand / economics*
  • Health Services Needs and Demand / trends
  • Humans
  • Male
  • Medicare / economics*
  • Medicare / trends
  • Retrospective Studies
  • Risk Assessment
  • United States / epidemiology