2.1 Age

Age alone is a good but clinically insufficient predictor of life expectancy with consistent trends of decreasing life expectancy as a person ages [2]. A 65-year-old man in the United States will live an average of 18 more years compared to nearly 21 years for the typical 65-year-old woman. By age 85, life expectancy drops to 6.1 and 7.3 years for men and women in the US, respectively. Despite these general estimates, there is a wide distribution in the life expectancy at any given age [3]. For example, life expectancy for 85-year-old men can range as much as fourfold, from about 2 to 8 years. To further refine patient-specific estimates of life expectancy, it is important to also consider a patient′s comorbidities and personal functional trajectory.

2.2 Comorbidities

As expected, patients with more comorbidities have lower life expectancies and experience more surgical complications. The Charlson Comorbidity Index (CCI) [4] is a well-known example of a pure comorbidity scale used for prognostication. The CCI assigns a weighted point value to a number of common diseases and can also be age-stratified by assigning a point for age for every decade after 40 (see Table 1.5-1 ).

Higher scores correlate with higher mortality. A hospitalized patient with a score of 0 will have a 1-year predicted mortality of 12%; patients with scores of 3–4 have a 1 year mortality of 52%, and scores greater than 5 predict an 85% 1-year mortality [4].

In hip fracture patients, a CCI is also an independent predictor of 30-day mortality; patients with a CCI > 6 are more than twice as likely to die during this time frame [5].

2.3 Functional status

It addition to age and comorbidity assessment, it has been increasingly recognized that function is an important independent prognostic indicator in older adults. Functional debility is a common pathway for any disease, as it increases in severity and is typically easy to assess. The most common geriatric functional scale is the Barthel Index of Activities of Daily Living [6], in which patients are assessed for independence in the following daily abilities: toileting, continence (bowel and bladder), transferring, mobility, stair use, feeding, grooming, bathing and dressing. Lower scores reflect increased dependency, which is also an independent predictor of mortality ( Table 1.5-2, Table 1.5-3 ).

Functional assessment is most important in the oldest patients. Function correlates more closely with mortality than comorbidities for those older than 80 years, while for those younger than 70 years comorbidities are better at predicting mortality [9]. Other studies have used function to predict survival in cancer, heart failure, surgeries and dementia [10–14].

The most valid predictors of postsurgical outcomes come from comprehensive tools that incorporate elements of age, comorbidity and function. The best studied of these in the hip fracture population is the Nottingham Hip Fracture Score (NHFS), which assigns points for age, gender, number of comorbidities, cognitive impairment, anemia, institutionalization and malignancy [15]. Patients can be grouped as low risk (NHFS ≤ 4) or high risk (NHFS > 5) with differences in survival at 30 days (96.5% versus 86.3%) and 1 year (84.1% versus 54.5%) [16]. Table 1.5-4 summarizes the NHFS scoring.

Despite the presence of procedure-specific outcome estimates, it is critical to recognize that individual older adults will have a wide range of responses to medical and surgical treatments. Assessing age, comorbidities and function allows for a more individualized assessment and care plan.

Without individualizing care based on prognosis and frailty, the clinician is at great risk for overtreatment of some patients, and undertreatment in others. Individualizing care based on patient-specific assessment allows for a treatment plan that is tolerable, purposeful, effective, and consistent with a patient′s goals of care.