Cause-specific mortality after spousal bereavement in a Danish register-based cohort

Spousal bereavement is associated with increased all-cause mortality, but less is known for cause-specific mortality. We estimated the average effect of bereavement on cause-specific mortality. Furthermore, we developed and evaluated the performance of prediction models estimating individualized mortality risks. This matched cohort study leveraged nationwide registry data on 223,500 married Danish individuals aged ≥ 65 years. Individuals were followed from bereavement date until death, emigration, or 3-year end of follow-up. G-estimation was used to estimate the average effect of bereavement on cause-specific mortality. Risk prediction models were developed and internally validated using logistic regression and Extreme Gradient Boosting utilizing information on sociodemographic factors and healthcare expenditures prior to bereavement. Among males, bereavement was associated with increased 3-year mortality from cardiovascular disease (CVD) (Risk Difference: 8 deaths/1000 individuals [95% confidence intervals (CI) 3;13]), digestive diseases (3 [95% CI 1;5]), psychiatric diseases/suicide (3 [95% CI 1;5]), and respiratory diseases (4 [95% CI 1;8]) and decreased 3-year mortality for dying from dementia/Parkinson's disease (-4 [95% CI -6;-2]). Among females, bereavement was only associated with increased 3-year mortality from CVD (5 [95% CI 3;7 ]) and from psychiatric diseases/suicide (1 [95% CI 1;2]). The prediction models developed using sociodemographic information and healthcare expenditures showed limited accuracy in identifying cause-specific mortality risk. On average, spousal bereavement slightly elevated the risk for most causes of death for males and less so for females. Despite incorporating comprehensive healthcare and sociodemographic data, accurately predicting individual cause-specific mortality remains challenging.