Comparing regression-adjusted mortality to standardized mortality ratios for trauma center profiling

Area of Science:

• Trauma care quality assessment
• Health services research
• Biostatistics

Background:

• Trauma center profiling commonly uses Standardized Mortality Ratios (SMRs).
• Comparing SMRs across centers with varying case mixes can lead to confounding and biased performance rankings.
• Regression-Adjusted Mortality (RAM) is proposed as a more valid alternative.

Purpose of the Study:

• To compare trauma center performance rankings derived from RAM estimates versus SMRs.
• To evaluate the validity of SMRs for trauma center profiling.

Main Methods:

• Utilized data from a provincial Trauma Registry (1999-2006; n = 88,235).
• Calculated SMRs using internal and external standards (US National Trauma Data Bank).
• Derived RAM estimates using a hierarchical logistic regression model.

Main Results:

• Significant rank changes were observed when comparing SMRs and RAM: 49/59 centers changed rank using internal SMRs, and 55/59 centers changed rank using external SMRs.
• 17 centers shifted by more than five ranks when comparing external SMRs and RAM.
• Crude mortality varied significantly across the 59 trauma centers.

Conclusions:

• SMRs may be a misleading metric for ranking trauma centers based on mortality.
• RAM estimates present a more valid and reliable approach for trauma center profiling and performance evaluation.