Frailty and multimorbidity at the oldest ages

Most of the life expectancy still to be gained in high-income countries lies at the oldest ages, and those are the ages the data describe worst. Mortality above 85 has improved more slowly than mortality at 65 in most countries since 2010, and above 95 it is barely measured: ages are misreported, populations are estimated rather than counted between censuses, and the exceptional cases — the centenarians whose numbers double every decade — are validated in a few countries and assumed in the rest. Whether there is a ceiling to human lifespan, and whether the slowing of improvement at the top means it is near, is argued in the demographic literature without resolution.

How well people live at those ages is measured by two families of tools. Frailty — a loss of reserve, scored from deficits or from physical performance — predicts death and hospital admission better than age does and is now recorded routinely in some health systems. Multimorbidity, the presence of several long-term conditions, is the norm above 75 and begins a decade or more earlier in deprived areas than in affluent ones. Both are rising in prevalence because more people reach the ages where they occur; whether they are rising at a given age — whether morbidity is being compressed into fewer years or spread across more — differs by country, by measure, and by whether the condition counted is diagnosed more or present more.

The best evidence comes from the countries that can follow whole populations: Denmark, Sweden and the Netherlands from registers; Japan, with the largest and best-measured oldest-old population in the world, from surveys. Elsewhere the oldest ages are studied through cohorts that under-represent the frail, the institutionalised and the poor.

Status

building

Direction

mixed

Would change our view

A consistent frailty measure adopted in national surveys and linked to deaths; cohort evidence of compression or expansion of morbidity above 85 in more than one country; or a country in which improvement above 90 clearly accelerates.

Trackers

Gaps

Age validation above 100 outside a handful of countries; frailty in official statistics anywhere; care-home populations, which most surveys exclude; comparable data for Japan and Europe.