As we age, it is natural to become more concerned about our longevity, especially if we have experienced health challenges or engaged in unhealthy behaviors earlier in life. One way to assess probabilistic near-term (under five years) and long-term (10–25 years) mortality risk is to use an assessment known as the Deficit Index, also called the Frailty Index. Essentially, the index evaluates health across many different domains. Each item is scored as 0 (not present), 0.5 (a mild or partial problem), or 1 (a severe or fully present problem). The individual deficit scores are added together and then divided by the total number of items assessed (61 in this example) to produce a final index value between 0 and 1. Below are commonly included deficit domains:

• Chronic Medical Conditions: Hypertension, diabetes mellitus, coronary artery disease, stroke or TIA, osteoarthritis, osteoporosis, chronic lung disease, chronic kidney disease, cancer (current or past)
• Activities of Daily Living (ADLs): Difficulty bathing, dressing, transferring, using the bathroom, feeding, shopping, managing medications, managing finances, preparing meals, using transportation
• Mobility & Physical Performance: Difficulty walking one block, difficulty climbing stairs, slow walking speed, poor balance, use of cane/walker/wheelchair, fall/s within previous year
• Symptoms & Somatic Complaints: Chronic pain, fatigue or low energy, shortness of breath, dizziness, poor appetite, sleep problems, urinary incontinence
• Cognitive Function: Memory complaints, difficulty concentrating, diagnosed mild cognitive impairment, dementia, difficulty following instructions
• Psychological & Emotional Health: Depressive symptoms, anxiety, low mood most days, anhedonia, high perceived stress, poor coping skills
• Sensory Impairments: Poor vision (even with correction), poor hearing, difficulty communicating due to sensory loss
• Nutrition & Body Composition: Unintentional weight loss, low BMI, sarcopenia or muscle weakness, difficulty chewing or swallowing
• Social & Environmental Factors: Living alone, social isolation, limited social support, financial strain, low physical activity, limited access to care
• Laboratory & Physiological Abnormalities: Anemia, elevated inflammatory markers, abnormal glucose regulation, low vitamin D, reduced kidney function markers

In population studies, scores below 0.10 are considered robust and associated with low mortality risk over the next 10–20+ years; scores of 0.10–0.15 are considered pre-frail and associated with low five-year mortality but increased 10–20 year risk; scores of 0.15–0.25 indicate moderate frailty and a substantially elevated 5–10 year mortality risk, with many studies showing a roughly 50–70% chance of death within the next decade; scores of 0.25–0.40 indicate severe frailty and high near-term mortality, with up to a 50% chance of death within ~3 years and very high five-year mortality; and scores of 0.40 or higher indicate extreme frailty and are associated with very high 1–3 year mortality and markedly shortened survival.

Importantly, this assessment and others like it are not intended to predict exactly how many years any one individual has left. Rather, they help visualize how multiple health factors combine to reflect overall biological aging and vulnerability. The goal is not fatalism, but insight, so that efforts to improve strength, nutrition, mobility, mental health, sleep, and social connection can reduce frailty, improve quality of life, and potentially extend both lifespan and health span.