BackgroundProlongation of the corrected QT (QTc) interval has been associated with increased long-term mortality; however, little is known about short-term mortality. This knowledge gap represents a clinical dilemma, because determining the disposition of patients with QTc prolongation is difficult. ObjectiveTo estimate the short-term (7-day and 30-day) all-cause mortality risk in patients with moderately and severely prolonged QTc. MethodsThe study-design was a Retrospective international multi-center observational cohort study, which took place in four emergency departments in Denmark and Sweden. Participants were all adult patients who received an ECG on arrival. QTc intervals were calculated with the Framingham formula. Associations between QTc duration and mortality were estimated with univariable and multivariable analyses, propensity score matching, and cubic splines analyses. ResultsAmong 103,075 ECGs, we identified 6672 (6.5%) patients with moderate and 587 (0.6%) with severe QTc prolongation. The crude hazard ratios (HRs) for moderate QTc prolongation (450/460−499 ms (men/women) were 2.2 (1.8-2.6) for 7-day and 2.1 (1.9-2.4) for 30-day mortality; HRs for severe QTc prolongation (≥500 ms) were 3.7 (2.4-5.7) and 3.4 (2.5-4.7), respectively. Adjustments led to attenuated estimates, with fully adjusted HRs for moderate QTc prolongation of 1.7 (1.4-2.0) for 7-day and 1.6 (1.4-1.8) for 30-day mortality; fully adjusted HRs for severe QTc prolongation were 2.6 (1.9-4.3) and 2.6 (1.9-3.5), respectively. Only a minority of patients with moderate (8.7% in Denmark and 15.1% in Sweden) and severe QTc prolongation (20.0% in Denmark and 22.7% in Sweden) died of possible, but not confirmed, cardiac cause.Our limitations were that we used the first ECG measured and an automated QTc calculation. We could not adjust for treatments carried out during admission. ConclusionsModerate and severe QTc prolongation was strongly associated with short-term mortality. However, QTc prolongation is likely a proxy for underlying disease rather than a direct contributor to mortality.

Knowledge on utilization patterns of non-insulin antidiabetic drugs in childhood and youth is limited. Therefore, we conducted a population-based drug utilization study using publicly available aggregate data on use of non-insulin antidiabetics from 2010 to 2019 in Scandinavia (Denmark, Norway and Sweden) in individuals aged up to 24 years. For each non-insulin antidiabetic drug, we calculated the annual prevalence