Validation of data quality in the National Swedish Kidney Cancer Register

The National Swedish Kidney Cancer Register (NSKCR) was launched in 2005. It is used for health care quality improvement and research. The aim of this study was to validate the register's data quality by assessing the timeliness, completeness, comparability and validity of the register.

To assess timeliness we evaluated the number of days between date of diagnosis and date of reporting the patient to the NSKCR. For completeness, we used data on number of cancer cases reported to the NSKCR compared to cases reported to the Swedish Cancer Register. Comparability was evaluated by reviewing coding routines and comparing data collected in the NSKCR to national and international guidelines. Validity was assessed by reabstraction of data from medical charts from 431 randomly selected patients diagnosed in 2007, 2010, 2013 and 2016.

Timeliness has improved since the register started. In 2016, 76.9% and 96.5% of the patients were reported within 6 and 12 months respectively. Completeness was high, with a 99.5% coverage between 2008 and 2017. Registration forms and manuals were updated according to national and European guidelines. Improvements have been made continuously to decrease the risk of reporting mistakes and misunderstandings. Validity was high where a majority of the variables demonstrated an exact agreement >90% and few missing values.

Overall, the data quality of the NSKCR is high. Completeness, comparability and validity is high. Timeliness can be further improved, which will make it easier to follow changes and improve the care and research of RCC patients.