Problematic Risk Adjustment in National Healthcare Safety Network Measures.

Area of Science:

• Healthcare Quality and Safety
• Health Services Research
• Epidemiology

Background:

• The National Healthcare Safety Network (NHSN) utilizes risk-adjustment models to calculate standardized infection ratios (SIRs).
• These models incorporate various patient and hospital factors to account for differences in patient populations and care settings.
• Hospital intensive care unit (ICU) designation is a key variable used in several NHSN risk-adjustment models.

Purpose of the Study:

• To review the risk-adjustment models used by the NHSN for standardized infection ratios.
• To critically evaluate the role and impact of hospital intensive care unit (ICU) designation within these models.
• To assess the consistency of ICU utilization reporting across different hospitals using Medicare fee-for-service claims data.

Main Methods:

• Described the risk-adjustment models employed by the NHSN.
• Focused analysis on hospital intensive care unit (ICU) designation as a risk-adjustment variable.
• Compared the risk-adjusted frequency of ICU service reporting in Medicare fee-for-service claims data across hospitals.

Main Results:

• Identified extreme variation in the reporting of ICU utilization among hospital admissions, particularly for conditions like congestive heart failure.
• Observed ICU utilization reporting ranging from 25% in the lowest quartile to 95% in the highest quartile of hospitals.
• Found that this wide variation in reported ICU utilization was not associated with differences in patient severity.

Conclusions:

• The significant and unexplained variation in reported ICU utilization across hospitals is a major concern.
• The NHSN's reliance on nursing unit designation, specifically ICU status, within its risk-adjustment models may compromise the accuracy of SIRs.
• Further investigation and potential model revision are warranted to address the inconsistencies in ICU utilization reporting.