Introduction

The marked heterogeneity in how ageing is experienced between individuals means that chronological age alone is insufficient for clinicians to identify patients who are at risk of a poor clinical outcome when they become unwell.1 Frailty describes vulnerability to poor resolution of homeostasis after a stressor event.1 It results from cumulative decline in multiple physiological systems, and is observed in 12%–24% of older adults.1 2 Frailty is particularly common in those with cardiovascular disease, and a combination of population ageing and increased survivorship of cardiovascular disease means that cardiologists will be caring for increasingly complex patients, who are living with varying degrees of frailty.3–5 Recognising that frailty is not a dichotomous variable is crucial; without that, frailty can become the polite face of ageism.

Understanding the degree of frailty present in individuals helps clinicians to estimate how much a new condition is likely to affect their patient, allowing them to better estimate the likely prognosis for people of the same age.6 It is useful in guiding individualised treatment of people with cardiovascular disease, including weighing up risks and benefits with greater precision, guiding person-oriented decisions in what levels of intervention are appropriate. By understanding the size of the gap between what the patients look like when ill and their baseline health, it also signals the need for rehabilitation and other follow-up care (figure 1).7