Consistency between the National Patient Register and the Swedish Cancer Register.

PURPOSE: The Swedish National Patient Register (NPR) is widely used as a data source in epidemiological studies, but the consistency of all cancer diagnoses compared to the Swedish Cancer Register (SCR) remains unclear. Using NPR supplementary for detecting safety signals is beneficial due to shorter data extraction delays compared to using SCR alone. This study aims to evaluate the consistency of NPR for cancer diagnoses compared to SCR and its potential use in pharmacoepidemiology. METHODS: Patients with a cancer diagnosis recorded in SCR during 2018-2020 were included. To measure the consistency of NPR diagnoses with SCR as the gold standard, positive predictive value (PPV), and sensitivity were calculated. As an empirical example showing differences in identification of cancer diagnoses in NPR and SCR, two nested case-control studies for the association between antidiabetic medications and pancreatic cancer were repeated using the two registers. Conditional logistic regression was performed and the 95% confidence intervals (CIs) for the odds ratios (ORs) were checked for overlaps. RESULTS: For breast, male genital organs, and oral cancers consistency was high (PPV: 87.5%-97.4%, sensitivity: 82.2%-91.0%), while for female genital organs, thyroid, and ill-defined, secondary, and unspecified sites cancers it was low (PPV: 8.8%-90.0%, sensitivity: 19.9%-32.3%). All the CIs for the ORs from the nested case-control studies overlapped when pancreatic cancer was identified in NPR or SCR. CONCLUSION: Consistency of cancer diagnoses in NPR when compared to SCR depends on cancer type with higher consistency for some cancers and lower for others. Differences in diagnostic processes for different cancer types and coding of cancer in the two registers may explain part of the inconsistent results.

Cardiometabolic disease, cognitive decline, and brain structure in middle and older age.

INTRODUCTION: The presence of multiple cardiometabolic diseases (CMDs) has been linked to increased dementia risk, but the combined influence of CMDs on cognition and brain structure across the life course is unclear. METHODS: In the UK Biobank, 46,562 dementia-free participants completed a cognitive test battery at baseline and a follow-up visit 9 years later, at which point 39,306 also underwent brain magnetic resonance imaging. CMDs (diabetes, heart disease, and stroke) were ascertained from medical records. Data were analyzed using age-stratified (middle age [< 60] versus older [≥ 60]) mixed-effects models and linear regression. RESULTS: A higher number of CMDs was associated with significantly steeper global cognitive decline in older (ß = -0.008; 95% confidence interval: -0.012, -0.005) but not middle age. Additionally, the presence of multiple CMDs was related to smaller total brain volume, gray matter volume, white matter volume, and hippocampal volume and larger white matter hyperintensity volume, even in middle age. DISCUSSION: CMDs are associated with cognitive decline in older age and poorer brain structural health beginning already in middle age. Highlights: We explored the association of CMDs with cognitive decline and brain MRI measures.CMDs accelerated cognitive decline in older (≥60y) but not middle (<60) age.CMDs were associated with poorer brain MRI parameters in both middle and older age.Results highlight the connection between CMDs and cognitive/brain aging.