The relationship between choice of outcome measure and hospital rank in general surgical procedures: implications for quality assessment.

OBJECTIVE: Institutional complication rates are often used to assess hospital quality of care, particularly for conditions and procedures where mortality rates are not useful because deaths are rare. The objective of this study was to assess the correlation among hospital quality assessment rankings based on adjusted mortality, complication and failure-to-rescue rates.
DESIGN: This study used a clinically detailed administrative data set to compare severity and case-mix adjusted hospital outcome rankings for three different measures of quality of care: in-hospital death, complication and failure-to-rescue (in-hospital death following a complication). SETTING AND PATIENTS: Analysis of 74,647 patients who underwent general surgical procedures included in the 1991 and 1992 MedisGroups National Comparative Data Base. MEASUREMENTS: Adjusted outcomes of death, complication and failure to rescue based on multivariable logistic regression models.
RESULTS: For 142 hospitals, the correlation between hospital rankings based on the death rate and those ranked by the complication rate was only 0.208 (P = 0.013). A similarly low correlation was present between the complication and failure rate rankings, r = -0.090 (P = 0.287). A higher correlation was observed between the death and failure rate rankings, r = 0.90 (P < 0.001).
CONCLUSIONS: For general surgical procedures, hospital rank using the complication rate is poorly correlated with rankings using the death or failure rate. Complication rates should be used with great caution and should not be used in isolation when assessing hospital quality of care.