Volume 46 | Number 3 | June 2011

Abstract List

Hui Zheng, Wei Zhang Ph.D., John Z. Ayanian, Lawrence B. Zaborski, Alan M. Zaslavsky Ph.D.


To profile hospitals by survival rates of colorectal cancer patients in multiple periods after initial treatment.

Data Sources

California Cancer Registry data from 50,544 patients receiving primary surgery with curative intent for stage I–III colorectal cancer in 1994–1998, supplemented with hospital discharge abstracts.

Study Design

We estimated a single Bayesian hierarchical model to quantify associations of survival to 30 days, 30 days to 1 year, and 1–5 years by hospital, adjusted for patient age, sex, race, stage, tumor site, and comorbidities. We compared two profiling methods for 30‐day survival and four longer‐term profiling methods by the fractions of hospitals with demonstrably superior survival profiles and of hospital pairs whose relative standings could be established confidently.

Principal Findings

Interperiod correlation coefficients of the random effects are (95 percent credible interval 0.27, 0.85), (0.20, 0.76), and (0.19, 0.82). The three‐period model ranks 5.4 percent of pairwise comparisons by 30‐day survival with at least 95 percent confidence, versus 3.3 percent of pairs using a single‐period model, and 15–20 percent by weighted multiperiod methods.


The quality of care for colorectal cancer provided by a hospital system is somewhat consistent across the immediate postoperative and long‐term follow‐up periods. Combining mortality profiles across longer periods may improve the statistical reliability of outcome comparisons.