Nils Skajaa

TY - JOUR

T1 - Venous Thromboembolism in Denmark

T2 - Seasonality in Occurrence and Mortality

AU - Skajaa, Nils

AU - Horváth-Puhó, Erzsébet

AU - Adelborg, Kasper

AU - Prandoni, Paolo

AU - Rothman, Kenneth J

AU - Sørensen, Henrik Toft

PY - 2019/4

Y1 - 2019/4

N2 - Background  Many cardiovascular conditions exhibit seasonality in occurrence and mortality, but little is known about the seasonality of venous thromboembolism. Methods  Using Danish registries, we identified all patients with deep vein thrombosis, pulmonary embolism, splanchnic vein thrombosis, cerebral vein thrombosis, and retinal vein thrombosis during 1977-2016. We tallied monthly deaths occurring within 90 days of the venous thromboembolism diagnosis. We estimated peak-to-trough ratios and timing of the peak of both diagnoses and deaths summed over all years of the study period. The departure from 1.0 of the peak-to-trough ratio measures the intensity of any seasonal pattern. Results  We estimated a peak-to-trough ratio of 1.09 (95% confidence interval: 1.07-1.11) for deep vein thrombosis and 1.22 (1.19-1.24) for pulmonary embolism occurrence. The peak-to-trough ratios for splanchnic vein thrombosis, cerebral vein thrombosis, and retinal vein thrombosis occurrence were 1.10 (1.01-1.20), 1.19 (1.00-1.40), and 1.12 (1.07-1.17), respectively. The occurrence of all conditions peaked during winter or fall. In time trend analyses, the peak-to-trough ratio increased considerably for splanchnic vein thrombosis, cerebral vein thrombosis, and retinal vein thrombosis occurrence. In associated mortality, the peak-to-trough ratio for deep vein thrombosis was larger (1.15, 1.07-1.23) than that for pulmonary embolism (1.04, 1.01-1.08). Discussion  Excess winter risks were modest, but more marked for pulmonary embolism occurrence than for deep vein thrombosis occurrence. The seasonal pattern intensified throughout the study period for splanchnic vein thrombosis, cerebral vein thrombosis, and retinal vein thrombosis. The winter peak in mortality following pulmonary embolism was smaller than that for deep vein thrombosis.

AB - Background  Many cardiovascular conditions exhibit seasonality in occurrence and mortality, but little is known about the seasonality of venous thromboembolism. Methods  Using Danish registries, we identified all patients with deep vein thrombosis, pulmonary embolism, splanchnic vein thrombosis, cerebral vein thrombosis, and retinal vein thrombosis during 1977-2016. We tallied monthly deaths occurring within 90 days of the venous thromboembolism diagnosis. We estimated peak-to-trough ratios and timing of the peak of both diagnoses and deaths summed over all years of the study period. The departure from 1.0 of the peak-to-trough ratio measures the intensity of any seasonal pattern. Results  We estimated a peak-to-trough ratio of 1.09 (95% confidence interval: 1.07-1.11) for deep vein thrombosis and 1.22 (1.19-1.24) for pulmonary embolism occurrence. The peak-to-trough ratios for splanchnic vein thrombosis, cerebral vein thrombosis, and retinal vein thrombosis occurrence were 1.10 (1.01-1.20), 1.19 (1.00-1.40), and 1.12 (1.07-1.17), respectively. The occurrence of all conditions peaked during winter or fall. In time trend analyses, the peak-to-trough ratio increased considerably for splanchnic vein thrombosis, cerebral vein thrombosis, and retinal vein thrombosis occurrence. In associated mortality, the peak-to-trough ratio for deep vein thrombosis was larger (1.15, 1.07-1.23) than that for pulmonary embolism (1.04, 1.01-1.08). Discussion  Excess winter risks were modest, but more marked for pulmonary embolism occurrence than for deep vein thrombosis occurrence. The seasonal pattern intensified throughout the study period for splanchnic vein thrombosis, cerebral vein thrombosis, and retinal vein thrombosis. The winter peak in mortality following pulmonary embolism was smaller than that for deep vein thrombosis.

U2 - 10.1055/s-0039-1692399

DO - 10.1055/s-0039-1692399

M3 - Journal article

C2 - 31259300

VL - 3

SP - e171-e179

JO - TH Open

JF - TH Open

SN - 2567-3459

IS - 2

ER -