Duration of type 2 diabetes mellitus is associated with third-degree atrioventricular block - A Danish nationwide registry study

Abstract Introduction Type 2 diabetes mellitus (T2DM) is associated with third-degree atrioventricular block, but whether duration of T2DM is an important factor of the association is unknown. Aim To investigate the association between duration of T2DM and third-degree atrioventricular block. Method This nested case–control study, based on nation-wide Danish cohort registries, included patients older than 18 years, diagnosed with third-degree atrioventricular block between 1 July 1995 and 31 December 2018. Five controls, from the risk set of each case of third-degree atrioventricular block, were matched on age and sex to fit a conditional logistic regression with time-dependent exposure and time-dependent covariates. Duration of T2DM was split into four groups: 0–5 years, 6–10 years, 11–15 years, and >15 years. Results We included 24 177 cases with third-degree atrioventricular block who were matched 1:5 on sex and birth year with 120 915 controls without third-degree atrioventricular block. Median age was 73.8 years, 62% were males in both cases and controls, whereas 19% of cases and 9.7% of controls had T2DM respectively. After adjusting for atrioventricular nodal blocking agents and comorbidities known to be associated with third-degree atrioventricular block, patients with T2DM duration 0–5 years, 6–10 years, 11-15 years, and >15 years had a higher hazard ratio of third-degree atrioventricular block of 1.24 (95% CI 1.16-1.33), 1.41 (95% CI 1.31-1.52), 1.79 (95% CI 1.64-1.95), and 2.20 (95% CI 2.01-2.40), respectively, compared to patients with no T2DM (Figure 1). Conclusion This study shows a stepwise increase in the hazard ratio of third-degree atrioventricular block along with duration of T2DM, which is independent of atrioventricular nodal blocking agents and comorbidities known to be associated with third-degree atrioventricular block.Figure 1