30-item frailty index may predict post operative delirium in patients undergoing elective surgery

A new study found that frailty defined by a 30-item frailty index (FI) based on the accumulation of deficits is strongly associated with the onset of postoperative delirium among older adults undergoing elective surgery. The study results were published in the journal BMC Geriatrics.  

Delirium is an acute and fluctuating disorder characterized by impaired alertness and reduced consciousness along with worsening of cognitive functions such as attention, memory, orientation, language, and awareness. Frailty is a clinical syndrome of increased vulnerability towards an external stressor leading to an increased risk of adverse outcomes. There is uncertainty on the association between frailty based on the accumulation of deficits with postoperative delirium (POD) in older patients undergoing elective surgery. Hence researchers conducted a study to develop a frailty index (FI) based on the deficits at admission and to analyze the association between this frailty index (FI) and the onset of POD in a middle size population of older adults undergoing cardiac as well as non-cardiac elective surgery. 

Participants recruited from the PAWEL study were used based on their preoperative data and a 30-item frailty index (FI) was built. A combination of I-CAM and chart review were used to define delirium. The association between frailty and POD was analyzed using logistic regression models adjusting for age, sex, smoking, alcohol consumption, education, and type of surgery. 

Key findings: 

• Among 701 participants with a mean age of 77.1 years, 52.4% were male with a median FI was 0.27, with 528 (75.3%) frail participants (FI ≥ 0.2).
• Orthopedic patients exhibited a higher median FI than cardiac surgery patients (0.28 versus 0.23), and it was mostly among women (0.28 versus 0.25 in men).
• A higher POD incidence proportion was shown by frail participants (25.4% versus 17.9% in non-frail).
• An increased odds for POD was observed in frail versus non-frail participants (OR 2.14 [95% CI 1.33, 3.44], c-statistic 0.71).
• A 0.1 increment of FI was associated with OR 1.57 [95% CI 1.30, 1.90] (c-statistic 0.72) for POD.
• No interaction with sex or type of surgery was detected.
• Adding timed-up-and-go-test and handgrip strength to the FI did not improve discrimination. 

Thus, a significant positive association was found between frailty and the POD among older adults undergoing elective surgery through a 30-item FI. Additional functional measures to the frailty index did not improve discrimination. 

Further reading: Steenblock, J., Braisch, U., Brefka, S. et al. Frailty index and its association with the onset of postoperative delirium in older adults undergoing elective surgery. BMC Geriatr 23, 90 (2023). https://doi.org/10.1186/s12877-022-03663-7