Registration and validity of surgical complications in colorectal cancer surgery

BACKGROUND: Population-based quality registers have become an important tool in quality assessment during the past decade. For registers to be reliable, however, data must be checked carefully for validity. METHODS: The present study describes the validity of surgical complications registered in a national register run by the National Board of Health and Welfare (NBH), a register run by Regional Oncological Centres (ROC) and, for comparison, a local quality assurance system at Uppsala University Hospital (UUH). A specialized, independent surgeon checked 10 per cent of patient records against datasheets from the registers. RESULTS: The local quality assurance system at UUH showed the best validity for surgical complications. Data for complications of colonic cancer surgery were more valid than those for rectal cancer surgery. Registration of serious complications was more valid than that of wound infections. The calculated proportion of missed surgical complications was 0.69, 0.64, 0.40, 0.22 and 0.07 for rectal and colonic cancer in the NBH register, rectal and colonic cancer in the ROC register, and the UUH register respectively. Corresponding figures for reoperation were 0.45, 0.48, 0.04, 0.09 and 0.21. CONCLUSION: Local interest and routine use of data for quality assurance are crucial factors for valid registers. Careful monitoring of validity is necessary for use of registry data in structured systems for improvement of surgical results.