Burden and prevalence of prognostic factors for severe covid-19 disease in Sweden

Katalin Gemes; Mats Talback; Karin Modig; Anders Ahlbom; Anita Berglund; Maria Feychting; Anthony Matthews

The number of people living with cardiovascular disease in 2015 in Sweden was 492,943 according to the Global Burden of Diseases studies, which is higher than the 389,774 we reported in the one year look back estimate in Appendix 2. [18] However, previous studies suggest the specificity and sensitivity of diagnoses of specific cardiovascular diagnoses such as acute myocardial infarction, heart failure and atrial fibrillation from the National Patient Registers are high. [19] The National Cancer Register reported that there were 214,000 individual tumors reported in 3 years prior to 31 st December 2016, while we report 129, 155 individuals in our study population with at least one tumor in 3 years prior to 1 st January 2016. [20] The prevalence of COPD is estimated at around 4-10% in Sweden, which is higher than the 0.8% we calculated. However, only 30% of COPD cases are diagnosed by healthcare professionals, which are often the most severe cases. The low observed prevalence of COPD in our study may therefore be due to us only capturing severe disease that is recorded in the Patient Register, and we were unable to capture moderate and mild COPD diagnosed and treated exclusively in primary care. [21] [22] [23] We have also underestimated the prevalence of asthma in Sweden, which is known to be between 8-10%, as we were only able to identify severe cases that required hospital admission. [19, 24, 25] However, more severe asthma is likely to exacerbate more severe COVID-19 disease, meaning we have identified those at the greatest risk. Finally, a study calculated a diabetes prevalence of 4.6% in Stockholm using survey data from the Stockholm Public Health Cohort, which is slightly higher than our estimate of 4.0%. [26] However, a report from the National Diabetes Register suggests that 22.6% of diabetes cases do not require pharmaceutical therapies, and only can be identified from primary care or quality registers, for which we did not have access. [27, 28]