Abstract Number: OC 65.1
Meeting: ISTH 2021 Congress
Background: It is unclear whether cancer adds to the risk of arterial thromboembolism (ATE) in atrial fibrillation (AF). This is especially relevant for low-intermediate CHA2DS2VASc scores, where risk-benefit ratios between ATE and bleeding are delicately balanced.
Aims: Evaluate ATE risk in AF patients with a low-intermediate CHA2DS2VASc score, with/without cancer.
Methods: A population-based historical cohort study of the Clalit Health Services (CHS) database (1.1.2005–31.12.2020). Patients ≥20 years, with CHA2DS2VASc ≤2, not receiving anticoagulation at study index, were included. Experimental groups included patients with atrial fibrillation/flutter (ICD-9 codes) at/prior study index. The study exposure was newly diagnosed cancer (ICD-9 codes). Patients with embolic ATE or cancer, prior study index, were excluded.
Patients were classified into 4 cohorts: “AF&cancer” (exposed), “AF&no-cancer” (unexposed), “cancer&no-AF” (positive control) and “no-AF&no-cancer” (negative control). Cohorts were matched for multinomial distribution of age, sex, index year, AF duration, CHA2DS2VASc score and low/high/undefined ATE-risk cancer. Cancers were classified as high ATE risk if 12-month ATE incidence was ≥5% in prior studies. Patients were followed from study index (date of cancer or matched date) until primary outcome or death.
The primary outcome was acute embolic ATE (ischemic stroke, transient ischemic attack (TIA) or systemic ATE), using ICD-9 codes from hospitalization. Cox proportional hazards multivariate regression was used to calculate the hazard ratio (HR) for the primary outcome at 12 months (death as competing risk).
Results: The study included 28420 patients. Table 1 shows baseline characteristics. The ATE incidence is shown in Figure 2. The risk of embolic ATE was highest in AF&cancer, compared to AF&no-cancer (HR 2.86 [95% CI: 1.75-4.69]) and to cancer&no-AF (2.86 [1.86-4.39]).
|Table 1: Patient characteristics|
|Variable (at index)||AF & Cancer, n (%) (n=1490)||AF & no-cancer, n (%) (n=4368)||Cancer & no-AF, n (%) (n=2908)||no-AF & no-cancer, n (%) (n=19654)|
|Age (years), median (IQR)||65 (60-71)||64 (59-70)||65 (59-70)||64 (59-71)|
|Male sex||1110 (74.5)||3228 (73.9)||2148 (73.9)||14489 (73.7)|
|BMI, median (IQR)||27.1 (24.2-30.3)||27.3 (24.6-30.7)||26.6 (23.9-29.7)||27.1 (24.4-30.1)|
|Dyslipidemia||728 (48.9)||2067 (47.3)||1324 (45.5)||7991 (40.7)|
|CHADS2VASc2 = 2||865 (58.1)||2493 (57.1)||1658 (57.0)||11152 (56.7)|
|Chronic cardiovascular disease||124 (8.3)||306 (7.0)||137 (4.7)||698 (3.6)|
|Aspirin||646 (43.4)||1869 (42.8)||707 (24.3)||4267 (21.7)|
|Duration of AF prior index (months), median (IQR)||26.1 (1.9-60.1)||21.0 (1.5-59.7)||Not relevant||Not relevant|
|Antiarrhythmic medication||317 (21.3)||937 (21.5)||9 (0.3)||66 (0.3)|
Conclusions: Cancer patients with AF and low-intermediate CHA2DS2VASc score have a higher risk of stroke, TIA or systemic ATE than non-cancer patients with AF. Risk/benefit of anticoagulation in this population should be studied.
To cite this abstract in AMA style:Leader A, Mendelson Cohen N, Afek S, Jaschek R, Frajman A, Itzhaki Ben Zadok O, Raanani P, Lishner M, Tanay A, Spectre G. Cancer is Associated with an Increased Stroke Risk in Patients with Atrial Fibrillation and CHA2DS2VASc Score ≤ 2 [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 1). https://abstracts.isth.org/abstract/cancer-is-associated-with-an-increased-stroke-risk-in-patients-with-atrial-fibrillation-and-cha2ds2vasc-score-%e2%89%a4-2/. Accessed September 24, 2021.
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