Providing quality data in health care - almost perfect inter-rater agreement in the Norwegian tonsil surgery register.

Background: The Norwegian Tonsil Surgery Register (NTSR) was launched in January 2017. The purpose of the register is to present data on tonsil surgery to facilitate improvements in patient care. Data used for evaluating the quality of medical care needs to be of high reliability. This study aims to assess the inter-rater reliability (IRR) of the variables reported to the register by medical professionals.

Methods: The study population consists of the first 137 tonsil surgery patients who were included in the NTSR at St. Olav's University Hospital in Trondheim. An experienced rater completed the register's paper form for all 137 patients based on their electronic medical records, blinded for the data already in the register. To assess the inter-rater reliability between the register and the external rater, we calculated observed agreement, Cohen's kappa and Gwet's AC coefficients with 95% confidence intervals.

Results: All tested variables in the NTSR have almost perfect reliability except for the variable for the cold steel technique, which had a substantial to almost perfect reliability. The inter-rater agreement was substantial to almost perfect for every variable, with substantial (kappa/AC > 0.61) to almost perfect (kappa/AC > 0.81) agreement for all the examined variables.

Conclusion: This study shows that the reliability of the NTSR is high for all variables registered by the professionals at the hospital immediately after surgery.