INTRODUCTION
The global geriatric population aged ≥60 years is increasing faster than the other age groups and expected to triple from 600 million in 2000 to 2 billion in 2050 due to an increase in life expectancy and decrease in birth rates.1) For example, in Indonesia, the life expectancy of the population reached 67.8 years in 2000–2005 and 73.6 years in 2020–2025.2) By 2050, one-quarter of the Indonesian population will be classified as older adults, compared with one-twelfth of the current Indonesian population.3) With the increasing population of older adults, developing strategic plans for healthcare providers to increase the functional capacity and quality of life (QOL) of geriatric patients has become necessary.
In older people, aging causes a progressive decline in physiological and cognitive functions and an increased susceptibility to illness.4,5) In the geriatric population, cognitive function is related to perception, reasoning, creativity, problem-solving, and intuition.6) Postoperative cognitive dysfunction is characterized by a significant decline in cognitive performance, memory function, attention, verbal ability, orientation, and executive function.7) Changes in cognitive function tend to be significantly associated with increased depression and decreased QOL in patients.8) Geriatric patients also tend to have more comorbidities accompanied by decreased physiological and cognitive function.9) Moreover, aging contributes to physiological changes in the nervous system, cognition, memory, learning and intelligence, sensory and musculoskeletal systems, body composition, and body mass.10) The physiological changes also affect organ systems, resulting in decreased cardiac output, increased blood pressure, arteriosclerosis, decreased vital capacity, and slower lung expiratory flow rate. Additionally, older people often experience decreased creatinine clearance, changes in motility, atrophic gastritis, and changes in drug metabolism in the liver.11) These changes have important practical implications for the clinical management of older patients. Morphological and physiological changes in these degenerative processes in geriatrics also alter drug responses,12) which are influenced by interactions between pharmacokinetic and pharmacodynamic responses.12)
Geriatric characteristics, such as aging, affect perioperative outcomes and the quality of postoperative recovery, which, in turn, affect the QOL in patients.9) QOL in geriatric patients is associated with their perception of their life situation, including life goals, norms, and interests. QOL also represents the life expectancy of older adults. In older adults, QOL should also be considered to achieve dynamic aging.13) Moreover, QOL is important for analyzing postoperative outcomes. Generally, postoperative outcomes of geriatric patients differ from those of patients in other age groups. More than 10% of geriatric patients aged ≥80 years have a postoperative disability.14) Therefore, patient postoperative function must be assessed, including QOL.15)
To achieve positive postoperative outcomes in geriatric patients, clinicians should consider preoperative factors. For example, the anesthesia technique requires full consideration due to the increased risk of negative drug responses in geriatric patients.16) Ideally, the medical profiles of patients, as well as physical, cognitive, psychological, logistical, financial, and social factors are assessed preoperatively. Intraoperative decision-making is more difficult because of decreased cognitive function.17) The choice of anesthesia in geriatrics is influenced by factors including the medical condition of the patient, surgery type and duration, and anesthesiologist and surgeon skills. However, evidence regarding the appropriate anesthesia for geriatric patients is insufficient. General anesthesia techniques potentially depress cardiovascular and respiratory functions as well as consciousness. Regional anesthesia has several advantages over general anesthesia, such as reducing the need for sedatives and analgesics, maintaining spontaneous ventilation, and reducing postoperative complications.16,18) A recent study suggested that regional anesthesia is more beneficial than general anesthesia as the primary anesthetic modality. However, this finding remains controversial due to the quality of the study and lack of consideration of the risk of neuraxial block.19,20)
To date, no study has assessed the outcomes of changes in cognitive function and QOL in geriatric patients after elective surgery in Indonesia or other regions. Therefore, this study investigated the relationships between patient characteristics, anesthetic management, and changes in postoperative cognitive function and QOL in geriatric patients undergoing elective surgery at an Indonesian hospital.
MATERIALS AND METHODS
Study Population
This prospective, observational, multicenter study was conducted in Indonesia by the Indonesian College of Anesthesiology and Intensive Therapy (KATI) between February and April 2021 and was approved by the Research Ethics Committee of the Dr. Saiful Anwar General Hospital (No. 400/025/K.3/302/201).
The study population comprised geriatric patients undergoing elective surgery under regional or general anesthesia during the study period. The study participants were recruited from 14 national educational hospitals in Indonesia. We used the multiple regression analysis sample formula to perform minimum sampling with a study power of 95%, as follows:
where Z α 2
According to the minimum sample formula, this study required 95 participants to be enrolled. Assuming a 10% dropout rate, a minimum of 106 patients was required. Consecutive samples were collected during the study period.
We recruited participants who met the inclusion criteria, including geriatric patients aged ≥60 years undergoing elective surgery and requiring anesthesia in the operating room. The inclusion of participants >60 years was based on the World Health Organization (WHO) definition of older adults as being within 60–80 years of age and 60 years as the commonly used benchmark for old age. We excluded patients and their families who refused to participate, those who did not undergo follow-up 30 days after surgery, and those with missing data.
Variable Measurement
The study variables were geriatric preoperative characteristics, including age, sex, body mass index (BMI), comorbidities, American Society of Anesthesiologists (ASA) physical status, anesthetic management, preoperative cognitive function, and QOL. The BMI measurement was then categorized as underweight (<18.5 kg/m2), normoweight (18.5 - <25 kg/m2), overweight (25 - <30 kg/m2), obese I (30 - <35 kg/m2), and obese II (35 - <40 kg/m2). The recorded cognitive functions included orientation to time, place, attention, recall, language, repetition, and the ability to follow complex instructions. We assessed cognitive impairment using the Mini-Mental State Examination (MMSE), in which normal cognition, and mild, moderate, and severe cognitive impairment were defined as scores of 27–30, 21–26, 11–20, and 0–10, respectively. We assessed QOL using the WHOQOL tool by measuring four aspects: physical, psychological, social, and environmental.
We recorded participant characteristics preoperatively. Data on the anesthetic characteristics were recorded when the patient underwent surgery. We assessed cognitive function and QOL 1 day preoperatively and 30 days postoperatively. The MMSE and QOL scores were assessed by study personnel. Multicenter data were collected using Research Electronic Data Capture (REDCap; Vanderbilt University, Nashville, TN, USA).
Statistical Analysis
Patient characteristics were presented on numerical and categorical scales. Data were presented as frequencies and percentages. This study used one-tailed statistical analysis. We analyzed the difference between two categories using bivariate chi-square tests and the influence of geriatric factors on cognitive function and QOL using a multivariate logistic regression test. Before analyzing the bivariate chi-square tests, we performed receiver operating characteristic (ROC) curve test analysis to determine the cut-off QOL value based on the WHOQOL tool. All analyses used α=5% with p<0.05. The statistical analyses and 95% confidence intervals (CIs) were calculated using IBM SPSS Statistics for Windows, version 18.0 (IBM Corp., Armonk, NY, USA).
RESULTS
This study included a total of 933 geriatric patients. Their characteristics are presented in Table 1. Approximately 49.1% of the participants were aged 60–65 years and most were females (55.0%). Approximately 65.3% of the patients had comorbidities, most commonly hypertension (n=394; 39.7%), followed by diabetes (n=131; 13.2%) and tumors (n=127; 12.8%). Most patients were classified as obese (23.3%) or overweight (23.0%) and had an ASA physical status of II (n=643; 64.8%). A total of 594 (59.8%) and 399 (41.2%) patients, respectively, received general and regional anesthesia.
Bivariate analysis of the characteristics and cognitive function of the geriatric patients showed that age (p=0.000), BMI (p=0.012), comorbidities (cerebrovascular disease [p=0.035], dementia [p=0.026], chronic obstructive pulmonary disease [COPD; p=0.023], and hemiplegia [p=0.047]), and ASA physical status (p=0.002) differed significantly between patients with impaired and normal cognitive function. More than half of the geriatric patients (54.1%) with normal cognitive function were aged 60–65 years, 37.2% were aged 66–74 years, and 8.7% were aged 77–90 years (p<0.05). Among patients with impaired cognitive function, 18.2% were 77–90 years of age (old), 37.5% were 66–74 years of age (young-old), and 44.3% were 60–65 years of age (older). Among these patients, 44.9%, 24.2%, and 18.6% were classified as having normal weight, overweight, and obesity I, respectively. Among patients with normal cognitive function, 38.4% had normal weight, 21.7% were overweight, and 28.0% were categorized as obese (obesity I). We observed comorbidities such as cerebrovascular disease, dementia, COPD, and hemiplegia significantly more often in patients with cognitive impairment than in those with normal cognition . In addition, most patients in both the impaired (59.7%) and normal (69.9%) cognitive function groups had ASA physical status II (Table 2).
Before performing the bivariate chi-square tests, we performed ROC curve analysis to determine the cutoff value for QOL based on the WHOQOL tool. The cutoff value was 65.4 (area under the curve [AUC]=0.591; 95% CI, 0.566–0.616). Meanwhile, the cutoff for changes in QOL (ΔWHOQOL) was 2.94 (AUC=0.757; 95% CI, 0.728–0.787). The results of the ROC analysis showed that WHOQOL changes <2.95 were unfavorable, whereas changes >2.95 were considered good (Fig. 1).
The results of the bivariate chi-square test of geriatric patient characteristics and changes in QOL showed that age (p=0.035), BMI (p=0.000), and cognitive function (p=0.004) were significantly associated with changes in patient QOL. We defined ΔWHOQOL as the difference between pre- and postoperative QOL. Based on the cutoff value, 619 patients (66.3%) experienced unfavorable changes in their QOL and 374 (33.7%) experienced improved QOL. Approximately 46.4% of patients with a low QOL were aged 55–65 years, 40.4% were aged 66–74 years, and 13.2% were aged 75–90 years. Among patients with a good QOL, 53% were classified as older, 32% as young-old, and 13.9% as old. Among patients with low QOL, most were of normal weight (43.9%), whereas 23.6% and 18.6% were overweight and obese, respectively. Among these patients, 38.0% were normoweight, 31% were obese I, and 21.9% were overweight. Approximately 63.3% of geriatric patients who experienced unfavorable changes in QOL experienced impaired cognitive function, compared with 54.0% of those who experienced positive changes in QOL (Table 3).
Based on the preoperative MMSE scores, 49.5% of patients had normal cognitive function, 42.5% had mild cognitive impairment, and 7.8% had moderate cognitive impairment. 50.5% of geriatric patients had impaired cognitive function. Postoperative assessment showed that 49.4% of patients had impaired cognitive function, and 50.6% had normal cognitive function (Fig. 2). Preoperative assessment of patient QOL showed that 44.0% of geriatric patients were classified as having good QOL. Postoperatively, patients with good QOL increased to 56.0% (Fig. 3).
A multivariate logistic regression test was performed to determine the effect of patient characteristics (age, sex, BMI, presence or absence of comorbidities, ASA physical status, and general and regional anesthesia management) on the cognitive function of geriatric patients. The Nagelkerke R2 coefficient was 0.052 (5.2%), indicating that 5.2% of the variation in cognitive function was influenced by patient characteristics. The regression analysis identified age, BMI, and ASA physical status as factors affecting cognitive function in geriatric patients. Regarding age, older patients had a 0.688-fold higher probability of cognitive dysfunction, compared with younger patients (odds ratio [OR]=0.688; 95% CI, 1.005–1.288). Patients with a higher BMI had a 1.138-fold higher probability of experiencing cognitive changes, compared with patients with a lower BMI (OR=1.138; 95% CI, 1.005–1.288). Finally, a higher ASA physical status indicated a 0.633-fold higher probability of experiencing cognitive changes, compared with a lower ASA physical status (95% CI, 0.483–0.828) (Table 4).
BMI, presence or absence of comorbidities, regional anesthesia, and cognitive function affected the postoperative QOL in geriatric patients in the present study. The Nagelkerke R2 coefficient value was 0.062, indicating that the characteristics of geriatric patients influenced 6.2% of the variation in the postoperative QOL. Patients with a higher BMI had a 1.244-fold higher risk of changed QOL, compared with patients with a lower BMI (95% CI, 1.094–1.413). The presence of comorbidities decreased the QOL of geriatric patients by 0.734-fold, compared with the QOL of patients without comorbidities (95% CI, 0.543–0.987). Patients with normal cognitive function had a 1.334-fold higher probability of a better QOL change, compared with patients with impaired cognitive function (95% CI, 1.020–1.743). Regional anesthesia had a regression coefficient of 0.606 and an OR of 1.833. Patients who received regional anesthesia were 1.833-fold more likely to experience a good QOL than those who did not receive regional anesthesia (Table 5).
DISCUSSION
Cognitive impairment and reduced QOL in geriatric patients may increase disability and mortality.21) This study investigated the relationship between patient characteristics and anesthetic management and changes in cognitive function and QOL in geriatric patients undergoing elective surgery. The geriatric characteristics included age, sex, BMI, ASA physical status, and type of anesthesia used. In this study, most of the geriatric patients were aged between 60–65 years, were female, and had comorbidities. The BMI of geriatric patients was most often classified as normal. The most common ASA physical status was ASA II, and general anesthesia was more commonly used. Hypertension was the most common comorbidity. The demographic data in this study were consistent with those of a national multicenter study, which reported a mean age of the geriatric patients as 67.1±6.2 years, mostly ideal BMI, and ASA II classification.22) ASA II represents a patient with a mild-to-moderate medical condition that may not be completely controlled but does not severely limit their daily activities.23)
To determine the effect of patient characteristics (age, sex, BMI, ASA physical status, and type of anesthesia used) on the cognitive function and QOL of geriatric patients, a multivariate logistic regression test was performed. This study demonstrated that 5.2% of the variations in cognitive function were influenced by patient characteristics. Based on the regression test, age, BMI, and ASA physical status were found to affect cognitive function in geriatric patients. Older patients had higher odds of cognitive dysfunction compared with younger patients. This study is in line with previous studies. A previous study of 578 healthy older people, whose ages varied between 64 and 81 years, found that age is related to cognitive function.24-26) Therefore, this study provides evidence that preoperative age in geriatrics is correlated with postoperative cognitive function.
A higher BMI was also associated with greater odds of having greater postoperative cognitive function, compared with a lower BMI. However, the relationship between BMI and cognitive function in older adults remains controversial. Several studies have reported conflicting results regarding the correlation between BMI and cognitive function. A lower BMI in older people is associated with cognitive impairment and dementia.27) A higher BMI in older people is associated with poorer cognitive outcomes and an increased risk of dementia.28) Underweight older people have a high risk of cognitive impairment and dementia, whereas being overweight is associated with a 21% and 25% reduction in risk.27) However, another study reported that a higher BMI in older people is associated with poorer cognitive outcomes and an increased risk of dementia.28) The results of previous studies can partly be explained by the presence of confounding factors. Some studies controlled for sociodemographic factors (e.g., sex and education) and psychosocial and mental health factors (e.g., anxiety and depression), whereas others controlled for physical comorbidities associated with being overweight and obese (e.g., diabetes and cardiovascular disease).
A higher ASA physical status is associated with increased odds of experiencing a decline in postoperative cognitive function, compared with a lower ASA physical status. Gan et al.29) reported higher ASA physical status in a cognitively impaired group versus a cognitively normal group. Several moderate-to-severe diseases, such as diabetes or uncontrolled hypertension, a history of transient ischemic attack, or coronary artery disease in patients with higher ASA physical status are associated with functional limitations. In the present study, the significant relationship between age, BMI, ASA classification, and changes in cognitive function could be of particular concern regarding factors influencing postoperative cognitive impairment in geriatric patients.
Our investigation of patient QOL revealed that 6.2% of the variation in the postoperative QOL was influenced by the characteristics of the geriatric patients. BMI, presence or absence of comorbidities, regional anesthesia, and cognitive function affect the QOL of geriatric patients. Patients with a higher BMI had higher odds of having a lower QOL, compared with patients with a lower BMI. Compared with those with normal weight (18.5 < BMI < 25 kg/m2), individuals who were overweight or obese had a lower QOL. Some of the long-term effects of being overweight that can affect QOL include diabetes, heart disease, stroke, cancer, osteoarthritis, breathing problems, and high blood pressure. Moreover, diabetes, heart disease, osteoarthritis, and high blood pressure may mediate the association between being overweight and the QOL.30)
The presence of comorbidities has greater odds of decreasing the QOL of geriatric patients, compared with a lack of comorbidities. The chronic impact of comorbidities is associated with a loss in health-related QOL.31) We also observed that regional anesthesia had greater odds of providing a good QOL, compared with general anesthesia. These results complement those of previous studies and underscore the positive outcomes in improving postoperative QOL with a lower risk of failed intubation and providing effective pain control, mobility, and daily activities, which can improve QOL.32)
Normal cognitive function is also associated with changes in the postoperative QOL. Patients with normal cognitive function tended to have a better QOL than did those with impaired cognitive function. In older people, changes in cognitive function tend to be significantly associated with increased depression and decreased QOL.6) Aging causes changes in the brain, leading to decreased cognitive reserve, susceptibility to the stress of surgery and anesthesia, and an increased risk of neurological injury, such as postoperative cognitive dysfunction (POCD). POCD is associated with a decreased QOL, loss of function, and increased mortality.33)
Based on the overall geriatric characteristics in the present study, BMI was correlated with postoperative cognitive function and QOL. We observed a significant positive correlation between BMI and postoperative cognitive function in geriatric patients. Specifically, the results of the regression analysis indicated that a higher BMI was associated with better postoperative cognitive function, as evidenced by a positive regression coefficient (B=0.129) and OR (1.138). For each unit increase in BMI, the odds of better postoperative cognitive outcomes increased by approximately 13.8%. A higher BMI may indicate better nutritional status and metabolic reserves, which can be crucial for recovery and cognitive function after surgery.34) Adequate nutrition can support brain function and resilience to surgical stress. Although a higher BMI is often associated with obesity-related health issues, in the context of geriatric patients, a moderately higher BMI might reflect better overall health, compared with underweight or malnourished conditions, which can adversely affect cognitive function.35)
Conversely, our study results revealed an inverse relationship between BMI and postoperative QOL. The regression coefficient was negative (B=-0.218), and the OR (1.244) suggested that a higher BMI was associated with decreased postoperative QOL, with the odds of experiencing a decline in QOL increasing by approximately 24.4% for each unit increase in BMI. Higher BMI can lead to decreased postoperative mobility and physical function. Obesity is often linked to comorbid conditions, such as osteoarthritis, which can exacerbate postsurgical recovery challenges and reduce QOL.36) Obesity can also increase the risk of surgical complications, including infections, delayed wound healing, and cardiovascular events, all of which can negatively impact postoperative recovery and QOL. Our finding that BMI significantly influenced postoperative cognitive function and QOL is crucial, especially considering the projected growth of the geriatric population. As the global population ages, the number of individuals aged ≥60 years is expected to rise significantly, underscoring the need for improved geriatric management strategies to support the unique needs of older adults. Further research is essential to validate and expand upon these findings, identify the mechanisms by which BMI influences cognitive function and QOL, and evaluate perioperative strategies, such as nutritional support, physical rehabilitation, and tailored anesthesia plans.
The early identification of patients at risk of poor postoperative cognitive function and decreased QOL can lead to more effective perioperative planning through comprehensive preoperative assessments and multidisciplinary care plans. Educating patients and their families about the potential risks and the importance of optimizing health before surgery is also crucial. Integrating these findings into clinical practice will allow clinicians to provide the most beneficial treatment for geriatric patients, potentially choosing between general and regional anesthesia based on BMI and overall health status and offering preoperative and postoperative nutritional support and physical rehabilitation.
The short duration of this study, influenced by the coronavirus disease pandemic, highlights the need for longer follow-up periods in future studies to provide comprehensive data on long-term outcomes. Extended studies involving larger and more diverse populations and considering the potential disruptions caused by public health emergencies are necessary. Despite the limitations of this study, its insights are pivotal for enhancing the management of geriatric patients undergoing surgery and aiding further research to ultimately improve postoperative outcomes and QOL in geriatric patients. One limitation of this study was that we did not record the type of surgery, which could affect the postoperative condition. Instead, we considered the physical status based on the ASA classification to describe the severity of the preoperative conditions. Future studies should include the type of surgery as a variable to better understand its impact on postoperative outcomes.
In conclusion, We observed an association between geriatric characteristics, including age, BMI, ASA physical status, and postoperative cognitive function in geriatric patients. In addition, BMI, presence or absence of comorbidities, regional anesthesia, and cognitive function also affected the postoperative QOL of these patients. These preoperative factors can be used to predict postoperative cognitive function and QOL to achieve adequate postoperative management.
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