Impact of public reporting of coronary artery bypass graft surgery performance data on market share, mortality, and patient selection.

BACKGROUND: The impact of publicly reporting risk-adjusted outcomes for hospitals and surgeons remains controversial, with particular concern about unintended consequences. OBJECTIVES: We evaluated the impact of 3 reports from the voluntary California CABG Mortality Reporting Program (CCMRP) on hospital market share, hospital mortality, and patient selection for coronary artery bypass graft (CABG) surgery. RESEARCH DESIGN AND PARTICIPANTS: We analyzed data from January 2000 to December 2005 for all patients receiving isolated CABG surgery in California. We compared hospital groups based on their quality classification, including low-mortality outliers ("better"), high-mortality outliers ("worse"), and nonoutliers, as well as participation in the CCMRP. MEASURES: We compared changes in market share, risk-adjusted mortality, and hospital caseload of high-risk patients for isolated CABG surgeries before and after the public release of 3 CCMRP reports (July 2001, August 2003, and February 2005). RESULTS: Low-mortality outlier hospitals experienced significantly increased market share for isolated CABG surgery in the first 6 months after the public release of the CCMRP reports (relative change in adjusted mean market share=8.9%, P=0.002). We found no evidence to suggest reduced risk adjusted mortality after the release of the CCMRP reports, but high-mortality outlier hospitals, on average, operated on less sick patients (relative change in mean expected mortality=25%, P=0.02). CONCLUSIONS: The release of public CABG hospital performance reports in California was associated with increased volume at low-mortality hospitals, and may have reduced referrals of high-risk patients to high-mortality hospitals (or risk avoidance).

The CABG surgery volume-outcome relationship: temporal trends and selection effects in California, 1998-2004.

OBJECTIVE: To investigate the temporal trends in the volume-outcome relationship in coronary artery bypass graft (CABG) surgery in California from 1998 to 2004, and to assess the selection effects on this relationship by using data from periods of voluntary and mandatory hospital reporting. DATA SOURCES: We used patient-level clinical data collected for the California CABG Mortality Reporting Program (CCMRP, a voluntary reporting program with between 68 and 81 hospitals) from 1998 to 2002 and the California CABG Outcomes Reporting Program (CCORP, a mandatory reporting program with 121 and 120 hospitals) from 2003 to 2004. STUDY DESIGN: The patient was the primary unit of analysis, and in-hospital mortality was the primary outcome. We used hierarchical logistic regression models (generalized linear mixed models) to assess the association of hospital annual volume with hospital mortality while controlling for detailed patient-level covariates in each of the 7 years. DATA COLLECTION METHODS: All data were systematically collected, reviewed for accuracy, and validated by the State of California's Office of Statewide Health Planning and Development (OSHPD). PRINCIPAL FINDINGS: We found that during the period of voluntary hospital reporting (1998-2002), with the exception of 1998, higher volume hospitals had significantly lower risk-adjusted in-hospital mortality rates, on average, than lower volume hospitals (1998 odds ratio [OR] per 100 operations performed = 0.962, 95 percent confidence interval [CI]: 0.912-1.015; 1999 OR=0.955, 95 percent CI: 0.920-0.991; 2000 OR=0.942, 95 percent CI: 0.897-0.989; 2001 OR=0.935, 95 percent CI: 0.887-0.986; 2002 OR=0.946, 95 percent CI: 0.899-0.997). We also found that in the period of mandatory reporting (2003 and 2004) there was no volume-outcome relationship (2003 OR=0.997, 95 percent CI: 0.939-1.058; 2004 OR=0.984, 95 percent CI: 0.915-1.058) and that this lack of association was not due to a reporting bias from the addition of data from hospitals that did not originally contribute during the voluntary program. CONCLUSIONS: In California, where no state regulations support regionalization of CABG surgeries, a weak volume-outcome relationship was present from 1998 to 2002, but was absent in 2003 and 2004. The disappearance of the volume-outcome association was temporally related to the implementation of a statewide mandatory CABG surgery reporting program.

Dimension reduction for classification with gene expression microarray data.

An important application of gene expression microarray data is classification of biological samples or prediction of clinical and other outcomes. One necessary part of multivariate statistical analysis in such applications is dimension reduction. This paper provides a comparison study of three dimension reduction techniques, namely partial least squares (PLS), sliced inverse regression (SIR) and principal component analysis (PCA), and evaluates the relative performance of classification procedures incorporating those methods. A five-step assessment procedure is designed for the purpose. Predictive accuracy and computational efficiency of the methods are examined. Two gene expression data sets for tumor classification are used in the study.