Anticoagulant treatment and COVID‐19 mortality among older adults living in nursing homes in Sweden

BACKGROUND: Anticoagulants (AC) were introduced in March 2020 as standard of care in nursing home (NH) residents affected with COVID‐19 in the Stockholm region, Sweden. ACs are proven to reduce the risk of complications and mortality from COVID‐19 among patients of other ages and settings, but there is limited scientific evidence underpinning this practice in the NH setting. METHODS: This matched cohort study included 182 NH residents in the Stockholm Region diagnosed with COVID‐19 in March–May 2020. The main exposure was any AC treatment. Exposed (n = 91), 49% prevalent (pre‐COVID‐19 diagnosis) AC and 51% incident AC were compared with unexposed controls (n = 91). The outcome was 28‐days all‐cause mortality after COVID‐19 infection. The mortality odds ratios (OR) were assessed using logistic regression, adjusted for age, sex, multimorbidity, and mobility, also stratified by incident or prevalent AC‐type, age group, and sex. RESULTS: Of the 182 individuals diagnosed with COVID‐19 (median age 88 years, 68% women), 39% died within 28 days after diagnosis. Use of either incident or prevalent AC was associated with a reduced, adjusted 28‐day mortality (OR[95% CI]: 0.31[0.16–0.62]). In stratified analyses, the association was significant in both age groups: 70–89 (OR: 0.37 [0.15–0.89]) and 90–99 years of age (OR: 0.22 [0.07–0.65]. In sex‐stratified analysis, the AC‐lowering effect was significant in women only (OR: 0.28[0.11–0.67]). In the analyses stratified by AC type, the mortality‐lowering effect was observed for both prevalent AC (OR: 0.35[0.12–0.99]) and incident AC (OR: 0.29[0.11–0.76]). CONCLUSIONS: Both prevalent and incident use of ACs in prophylactic dosing was associated with reduced 28‐day mortality among older individuals with COVID‐19 in a NH setting. The effect was seen across age‐strata and in women. The findings present new insight in best practice for individuals diagnosed with COVID‐19 in the NH setting.