The Relationship Between Wealth and Frailty
Prof Kenneth Rockwood is Director of Geriatric Medicine Research at Dalhousie University, Canada and serves on the International Advisory Panel of Age and Ageing journal.
It's never good to be frail, but it's worse to be frail and poor, or to be frail in a tough environment. That would be one conclusion from a recent analysis of data from middle-aged and older adults in the Study of Health, Ageing and Retirement in Europe (SHARE). This analysis (by our group) showed that the number of health problems people have (the mean deficit count in a frailty index) was strongly and negatively correlated with national wealth (measured by Gross Domestic Product - GDP). In fact, for the 15 countries evaluated, per capita GDP "explained" about 60% of the variance in the national level of frailty.
We also looked at 2-year death rates. Unsurprisingly, in each country, across every level of the frailty index, frailer people were more likely to die than were fitter people. People who lived in less wealthy countries were more likely to die than those in wealthier countries.
What surprised us was how frailty interacted with GDP. Overall, in frail people, survival reflected national wealth: mortality in the frail was greater in wealthier countries than less wealthy countries.
But this impact of GDP on survival did not extend to non-frail participants: amongst fitter older adults, mortality was not associated with their country’s wealth. That did surprise, because in earlier work from Canada, our group found that even amongst the fittest people, mortality was tied to social vulnerability. Within countries that might still be true, but is beyond what we studied in SHARE.
So what now seems to be clear is that, compared with less wealthy countries, in wealthier countries, the prevalence of frailty is lower, even though frail people live longer. Recalling that prevalence is the product of incidence and survival, the frailty of late life needs to be seen anew. That new focus should also consider a host of social factors (and hospital practices) that might influence frailty. Health relates to wealth, but as we so often see in geriatrics, in any environment it is the most vulnerable who are at greatest risk.