Incident Gout: Risk of Death and Cause-specific Mortality in Western Sweden – a Nested Case Control Study

Abstract BackgroundExcess mortality in gout has mainly been attributed to cardiovascular disease (CVD). In the light of decreased CVD-mortality in general we wanted to evaluate the risk of overall mortality in gout and cause-specific contributions to mortality beyond CVD as well as temporal trends of it.MethodsAll incident cases of gout between 2006-2015 in western Sweden were identified in the healthcare database VEGA. Up to 5 population controls per case matched on age, sex and county were identified. Relevant comorbidities were identified for 5 years preceding index date in VEGA. Follow-up until the first of death, migration or study end 31 of December 2017. Cause of death was identified and cause-specific mortality grouped as: cardiovascular disease (CVD), renal disease (RD), dementia (DEM), infections, diabetes, diseases of the digestive system (DDS), lung diseases, cancer (CA) and other. Effect of gout on risk of death was calculated using COX regression on whole population and stratified by sex, adjusted for demographics and comorbidities. Death incidence rate were compared between the two time periods, 2006-2010 and 2011-2015.ResultsWe identified 22055 cases of incident gout and 98 946 controls, mean age (SD) 67.3-66.3 (15.3-15.4) years and 67.6-66.5% males. All comorbidities were more common at baseline among gout cases except for dementia which was more common in controls. Overall risk for death in incident gout was increased with 3%. Gout cases had a significantly increased risk for death by CVD, RD and DDS and a significantly decreased risk for death by DEM and CA. Similar results were found when stratifying for sex. There were no significant differences in incident death rate ratios in total, and subdivided into CVD and non CVD cause of death, between cases and controls in the two time periods examined.ConclusionsA 3% increase in all-cause death in patients with gout highlights the importance in addressing not only CVD risk factors in the management of gout patients. Furthermore, gout was associated with reduced mortality from dementia and these findings calls for further study, not least because of possible effects of urate lowering therapy on risk of dementia.