2-Fold More Cardiovascular Disease Events Decades Before Type 2 Diabetes Diagnosis: A Nationwide Registry Study

Abstract

Background: The risk of cardiovascular disease (CVD) is increased in individuals with type 2 diabetes mellitus (T2DM), but it remains uncertain how long an elevated CVD occurrence precedes diabetes diagnosis.

Objectives: The aim of this study was to investigate CVD occurrence 30 years before, and 5 years after, T2DM diagnosis compared with matched comparisons.

Methods: This combined case-control and cohort study included all individuals diagnosed with T2DM in Denmark between 2010 and 2015, as well as general population comparisons matched by age and sex. CVD was defined as myocardial infarction or ischemic stroke. Conditional logistic regression was used to compute ORs for CVD prevalence in the 30-year period before T2DM diagnosis. Cox proportional hazards regression models were used to compute HRs for 5-year CVD incidence after T2DM diagnosis.

Results: The study included 127,092 individuals with T2DM and 381,023 matched comparisons. In the 30-year period before T2DM diagnosis, 14,179 (11.2%) T2DM individuals and 17,871 (4.7%) comparisons experienced CVD. CVD prevalence was higher in those with T2DM than the comparisons in the entire period before T2DM diagnosis, with ORs ranging from 2.18 (95% CI: 1.91-2.48) in the earliest period (25-30 years before diagnosis) to 2.96 (95% CI: 2.85-3.08) in the latest period (<5 years before diagnosis). After T2DM diagnosis, 5-year CVD incidence was similarly increased in T2DM individuals vs comparisons (HR: 2.20; 95% CI: 2.12-2.27).

Conclusions: Individuals with T2DM had 2-fold more CVD events than matched comparisons starting 3 decades before T2DM diagnosis. This indicates that comprehensive preventive strategies may be initiated much earlier in individuals at risk of T2DM.

Keywords: cardiovascular disease; case-control study; cohort study; epidemiology; primary prevention; type 2 diabetes.