Validation of data quality in the National Swedish Kidney Cancer Register.

INTRODUCTION: 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. MATERIAL AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

The renal cell cancer database Sweden (RCCBaSe) - a new register-based resource for renal cell carcinoma research.

Introduction: In 2005, the National Swedish Kidney Cancer Register (NSKCR) was set up to collect data on newly diagnosed patients with renal cell carcinoma (RCC). In 2015, the NSKCR was linked to a number of national healthcare and demographic registers to construct the Renal Cell Cancer Database Sweden (RCCBaSe). The aim was to facilitate research on trends in incidence, effects of treatment and survival, with detailed data on tumour characteristics, treatment, pharmaceutical prescriptions, socioeconomic factors and comorbidity.Material and methods: All patients registered in the NSKCR between 2005 and 2014 were included. For each case, ten controls and first-degree relatives for cases and controls were identified. The RCCBaSe was created linking all cases, controls and first-degree relatives to a number of national registers with information on co-morbidity, socioeconomic factors and pharmaceutical prescriptions.Results: Between 2005 and 2014, a total of 9,416 patients with RCC were reported to the NSKCR. 94,159 controls and a total cohort of 575,007 individuals including cases, controls and first-degree relatives were identified. Linkage to the Swedish cancer register resulted in 106,772 matches. When linked to the National patient register, 432,677 out-patient and 471,359 in-patient matches were generated. When linked to the Swedish renal registry 1,778 matches were generated. Linkage to the Prescribed drug register resulted in 448,084 matches and linkage to the The Longitudinal integration database for health insurance and labour market studies database resulted in 450,017 matches.Conclusion: By linking the NSKCR to several Swedish national databases, a unique database for RCC research has been created.

Overweight and obesity during adolescence increases the risk of renal cell carcinoma.

While overweight among adults has been linked with renal cell carcinoma (RCC) risk, little is known about the potential influence of overweight and obesity during adolescence. To ascertain if adolescent body mass index is associated with subsequent risk of RCC, we identified a cohort of 238,788 Swedish men who underwent mandatory military conscription assessment between 1969 and 1976 at a mean age of 18.5 years. At the time of conscription assessment, physical and psychological tests were performed including measurements of height and weight. Participants were followed through linkage to the Swedish Cancer Registry to identify incident diagnoses of RCC. The association between body mass index (BMI, kg/m2 ) at conscription assessment and subsequent RCC was evaluated using multivariable Cox regression. During a follow-up of up to 37 years, 266 men were diagnosed with RCC. We observed a trend for higher RCC risk with increasing BMI during adolescence, where one-unit increase in BMI conferred a 6% increased risk of RCC (95% CI 1.01-1.10). compared to normal weight men (BMI 18.5- < 25), men with overweight (BMI 25- < 30) or obesity (BMI ≥30) had hazard ratios for RCC of 1.76 (95% CI 1.16-2.67) and 2.87 (95% CI 1.26-6.25), respectively. The link between overweight/obesity and RCC appear to be already established during late adolescence. Prevention of unhealthy weight gain during childhood and adolescence may thus be a target in efforts to decrease the burden of RCC in the adult population.