Time trends in ischaemic heart disease incidence and mortality over three decades (1990-2019) in 20 Western European countries: systematic analysis of the Global Burden of Disease Study 2019.

AIMS: To investigate and compare changes in the rates of ischaemic heart disease (IHD) incidence and mortality between 1990 and 2019 in 20 high-income Western European countries with similar public health systems and low cardiovascular risk. METHODS AND RESULTS: The 2020 updated version of the Global Burden of Disease database was searched. Variability and differences in IHD incidence and mortality rates (per 100 000) between countries over time, were calculated. A piecewise linear (join point) regression model was used to identify the slopes of these trends and the points in time at which significant changes in the trends occur. Ischaemic heart disease incidence and mortality rates varied widely between countries but decreased for all between 1990 and 2019. The relative change was greater for mortality than for incidence. Ischaemic heart disease incidence rates declined by approximately 36% between 1990 and 2019, while mortality declined by approximately 60%. Breakpoint analysis showed that the largest decreases in incidence and mortality occurred between 1990 and 2009 (-32%, -52%, respectively), with a much slower decrease after that (-5.9%, -17.6%, respectively), and even a slight increase for some countries in recent years. The decline in both incidence and mortality was lower in the Mediterranean European countries compared to the Nordic and Central European regions. CONCLUSIONS: In the Western European countries studied, the decline in age-standardized IHD incidence over three decades was slower than the decline in age-standardized IHD mortality. Decreasing trends of both IHD incidence and mortality has substantially slowed, and for some countries flattened, in more recent years.

What does validation of cases in electronic record databases mean? The potential contribution of free text.

Electronic health records are increasingly used for research. The definition of cases or endpoints often relies on the use of coded diagnostic data, using a pre-selected group of codes. Validation of these cases, as 'true' cases of the disease, is crucial. There are, however, ambiguities in what is meant by validation in the context of electronic records. Validation usually implies comparison of a definition against a gold standard of diagnosis and the ability to identify false negatives ('true' cases which were not detected) as well as false positives (detected cases which did not have the condition). We argue that two separate concepts of validation are often conflated in existing studies. Firstly, whether the GP thought the patient was suffering from a particular condition (which we term confirmation or internal validation) and secondly, whether the patient really had the condition (external validation). Few studies have the ability to detect false negatives who have not received a diagnostic code. Natural language processing is likely to open up the use of free text within the electronic record which will facilitate both the validation of the coded diagnosis and searching for false negatives.