Social connection and end-of-life outcomes among older people in 19 countries: a population-based longitudinal study.

Background: Social connection is a key determinant of health, but its role in shaping end-of-life outcomes is poorly understood. We examined changes in structure, function, and quality components of social connection in older people's last years of life, and the extent to which social connection predicts end-of-life outcomes (ie, symptoms, health-care utilisation, and place of death).

Methods: This study used longitudinal data of representative samples from across 18 European countries and Israel in the Survey of Health, Ageing, and Retirement in Europe (SHARE), the largest European cohort study of people aged 50 years or older. We included deceased participants of waves 4 and 6 (which contained social network modules) for whom a proxy provided an end-of-life interview. We did paired sample t-tests (for continuous variables), Wilcoxon signed-rank tests (for ordinal variables), and McNemar's tests (for non-ordinal categorical variables) to assess changes in structure, function, and quality components of social connection between waves 4 and 6. To examine social connection as a predictor of end-of-life outcomes, we used social connection data from wave 6 core interviews and end-of-life interviews from wave 7, conducted with a proxy respondent covering the deceased participant's last year of life. End-of-life outcomes included symptoms (pain, breathlessness, and anxiety or sadness) in the last month of life, health-care utilisation in the last year of life, and place of death. We conducted a mixed-effects logistic regression analysis per social connection measure, for each end-of-life outcome.

Findings: Data were collected in 2011-12 for wave 4, 2015-16 for wave 6, and 2017-18 for wave 7. We studied 3356 individuals (mean age at death was 79·7 years [SD 10·2]), with interviews conducted, on average, 4·6 (1·2) years (wave 4) and 1·1 (0·7) years (wave 6) before death. From wave 4 to wave 6, the following changes in social connection were observed: proportion of married or partnered participants (from 1406 [60·9%] of 2310 to 1438 [57·1%] of 2518; p<0·0001), receiving personal care or practical help (from 781 [37·2%] of 2099 to 1334 [53·1%] of 2512; p<0·0001), loneliness (from mean 1·4 [SD 0·5] to 1·5 [0·6]; p<0·0001; scale 1-3), satisfaction with social network (from 8·8 [1·67] to 8·7 [1·7]; p=0·037; scale 0-10), and emotional closeness to social network (eg, from 1883 [88·8%] of 2121 to 1710 [91·3%] of 1872 participants who indicated being either very close or extremely close to social network members; p<0·0001). Higher levels of loneliness at wave 6 predicted a greater likelihood of experiencing symptoms in the last month of life (odds ratio range across symptoms: 1·29 [95% CI 1·08-1·55] to 1·58 [1·32-1·89]). Being married (1·32 [1·03-1·68]) or receiving personal care or practical help (1·25 [1·04-1·49]) predicted death in hospital.

Interpretation: Social connection undergoes multifaceted changes towards older people's end of life, countering prevalent ideas of generally declining social trajectories. Loneliness in the final months of life might be a risk factor for end-of-life symptoms. Further research is needed to substantiate a causal relationship and to identify underpinning mechanisms, which could inform screening and prevention measures.

Funding: Research Foundation-Flanders and European Union.