Association between Pre-operative frailty and Post Operative Delirium and Cognitivedysfunction in elderly patients undergoing major surgery under general anaesthesia : Prospective Observational Study

With advances in medical care and technology, the world is currently facing a growth in the

aging population of above 60 years of age seen as a 56% rise from 901 million to a projected 1.4

billion between 2015 and 2030 (1), which is in turn associated with a rise in the comorbidities

associated with the same. In India, compared to 1951 national survey when elderly population

was 5.4%, there has been an increase up to 7.4% in the 2001 national survey. This rising trend

seen in the average life span of the population is inadvertently associated with increase in

incidence of pathologies and hence, demand for surgical procedures to manage them which in

turn pushes health care system to deal with expectant comorbidities of old age to begin with in

all these cases(2). It has been studied that a significant proportion of previously cognitively well

patients undergoing surgery and anaesthesia have been developing symptoms of cognitive

dysfunction after their procedure (34). This could be linked to the identification of surgery as an

iatrogenic stress-generating condition with far reaching effects on patient care, morbidity, care

giver stress and the dependent population burden on the society at large(3).

As we talk about the different comorbidities, elderly population is associated with risk of frailty

and sarcopenia. Frailty is a geriatric syndrome rendering the patient more vulnerable to any kind

of stressors and poor homeostatic reserve (4). Due to increased vulnerability to stress, physical

frailty describes the impact of medical comorbidities on a patient’s overall state of health. In

2001, Fried et al defined frailty by the presence of three or more of the following criteria:

unintentional weight loss, weakness as measured by grip strength, self-reported exhaustion, slow

walking speed and low physical activity level. Sarcopenia is defined as loss of skeletal muscle

and strength which causes age-related functional and physical impairment. It is featured by a

poor hand grip strength and slow walking pace. The similarity in the features associated with

both frailty and sarcopenia reflects in their similar association with poor outcomes post-surgery

like increased length of hospital stay, higher 30-day readmission rates and mortality(5).

Of the various morbidities noticed in elderly individuals after surgery, delirium, defined as

disturbance in attention and awareness that develops over a short period of time, typically

evolves within 72 hours following surgery(6,7,8). Mild Cognitive Impairment (MCI) converts to

dementia at a rate of 10% per year and has been linked with both delirium and POCD(35).

Makary et al. showed that preoperative frailty using the Fried criteria was associated with

increased risk for postoperative complications for patients undergoing cardiac surgery like a

higher risk of postoperative delirium (POD). POD is the most common postsurgical complication

in older adults and occurs in 14%–60% of older surgical patients (9) with an incidence ranging

from 5 to 51% in major surgeries(10). The incidence of POD in elderly patients after total joint

arthroplasty differs significantly among reports, ranging from 10% to 70% (11,12).

In about 30-50% cases, even after delirium is resolved, elderly patients are additionally affected

by post-operative cognitive dysfunction (POCD) (13). Other than as sequelae to post-operative

delirium, it can independently occur after surgeries up to 3 months. POCD refers to deterioration

in cognition temporally associated with surgery as quantified by neurophysiological tests. Its

incidence among patients older than 65 years is about 25.8% at ne week and 9.9% at three

months following surgery (14).

Although aetiology of both these are not completely understood, a multicausal association of

neuroinflammation, brain network dysfunction, endocrine stress response and neurotransmitter

imbalance is described in literature (15). Frailty has been found to have strong association with

post-operative delirium (POD), and to a lesser extent with cognitive dysfunction (POCD)(16).

However there is no established data regarding the same in non-cardiac surgery in Indian

population.

Since detection of MCI can be difficult, this study aims at observing a correlation between

presence of frailty in pre-operative period in the elderly Indian population undergoing all major

surgeries with the occurrence of delirium and cognitive dysfunction in the post-operative period.

We also try to determine if the presence of frailty and sarcopenia is associated with increased

incidence of postoperative morbidity such as cardiac, pulmonary, renal complications, deep vein

thrombosis, surgical site infection, length of hospital stay, length of ICU stay, readmission rates

and mortality rates.