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Abstract
Objective This research aimed to assess the levels of cognitive function and its contributing factors among individuals experiencing cancer pain (CP) in mainland China.
Design A descriptive, cross-sectional study.
Setting The investigation was undertaken within three tertiary oncology hospitals.
Participants We included 220 hospitalised individuals who reported experiencing cancer-related pain and consented to complete the research questionnaires.
Outcome measures The collected data encompassed sociodemographic and clinical variables, augmented by results from validated questionnaires. Cognitive impairment (CI) was evaluated using the Functional Assessment of Cancer Therapy-Cognitive (FACT-Cog) scale, with scores ranging from 0 to 148. Sleep quality, depression and anxiety were assessed through the Pittsburgh Sleep Quality Index, the Patient Health Questionnaire-9 and the Generalised Anxiety Disorder-7, respectively. A binary logistic regression model was used to identify factors associated with CI in individuals with CP.
Results Of the 225 individuals approached, 220 (97.8%) participated in the study. The mean FACT-Cog score for those with CP was 101.29 (SD=25.24; range=25–148). The prevalence of CI among these individuals was 35.90%. Sleep quality was rated below medium in 45% of participants with CP. More than moderate pain was reported by 28.2%, with 64.6% experiencing depression and 38.6% experiencing anxiety. Increased odds of developing CI were observed in those with CP (OR 1.422, 95% CI 1.129 to 1.841), depression (OR 1.119, 95% CI 1.029 to 1.2117), anxiety (OR 1.107, 95% CI 1.005 to 1.220), advancing age (OR 1.042, 95% CI 1.013 to 1.073), poor sleep quality (OR 1.126, 95% CI 1.013 to 1.252) and a history of smoking (OR 3.811, 95% CI 1.668 to 8.707).
Conclusions CI associated with CP is notably prevalent in China. Those older, with a smoking history, inadequate sleep, more severe pain, depression and anxiety, have a heightened risk of CI. Consequently, interventions need to be personalised, addressing these key determinants.
- Cancer pain
- PAIN MANAGEMENT
- Delirium & cognitive disorders
- Pain management
Data availability statement
Data are available upon reasonable request. The data generated in the current study are available on reasonable request, considering the sensitivity and confidentiality of the data. Due to the nature of the data, which contains personally identifiable information and sensitive information, it cannot be openly shared in a public repository.Data can be obtained from the corresponding author upon reasonable request.
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
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STRENGTHS AND LIMITATIONS OF THIS STUDY:
This study addresses a significant gap by focusing on Chinese patients with cancer pain, acknowledging the unique cultural, economic and healthcare contexts in China.
The research contributes new insights into the current state and factors influencing cognitive impairment (CI) among mainland Chinese individuals with cancer pain, areas previously underreported.
Findings from this study are poised to offer evidence that can inform clinical strategies to enhance cognitive function in patients with cancer experiencing pain.
The study does not account for whether participants with anxiety and depression were receiving medication, nor does it examine the potential effects of such treatments on cognitive function.
The absence of longitudinal follow-up means that changes in the cognitive function of patients with cancer pain over the course of treatment are not captured, limiting the understanding of cognitive trajectories.
Introduction
Cancer remains the foremost cause of mortality worldwide, with its incidence rising annually.1 Among the enduring effects of cancer treatments, an estimated 70% of survivors experience persistent cognitive deficits—including memory lapses, diminished attention, slower information processing and impaired mental health functioning—collectively termed ‘cancer-related cognitive impairment’ (CRCI).2 CRCI is a frequently noted adverse consequence of cancer and its various treatments, such as chemotherapy, surgery, radiation and hormone therapy.3 It is recognised as a significant detractor from the quality of life among those with cancer, with the associated cognitive decline profoundly impacting social engagement, employment and overall life satisfaction.4 The Functional Assessment of Cancer Therapy-Cognitive (FACT-Cog),5 with its four subcomponents, has emerged as a reliable and valid instrument for gauging cognitive impairment (CI) in this population.6
Pain is one of the most common and distressing symptoms of cancer, affecting over half of patients across all stages of the disease.7 Patients may endure pain from the cancer itself—such as bone metastasis, tissue infiltration or nerve compression—or from treatment-related effects, including surgery, chemotherapy and radiation.8 For many, this pain persists long after treatment, becoming a chronic condition.
Notably, pain has been shown to exacerbate CI. Studies by Legrain and others report that chronic pain may diminish cognitive function, particularly memory and attention.9 The prevalence of reported cognitive decline in chronic pain sufferers is significant; findings by The Jorge, for instance, indicate that 73%–81% of these individuals perceive a decrease in memory and a brief recall of events.10 This specific decline in cognitive function among non-central nervous system patients with cancer with pain is termed CP-related CI (CPRCI),11 which can severely curtail social interactions and work productivity.
Despite the prevalence of CI in patients with cancer, research in China has largely centred on elderly populations or those with depression, with scant focus on patients with CP.12–14 Given the growing population of CP sufferers in China, it is crucial to deepen the understanding of CPRCI and its contributing factors to inform intervention strategies.
Furthermore, mental health concerns are prevalent among patients with cancer globally, with estimates indicating that 23%–53% battle conditions such as depression and anxiety—issues that often go unaddressed.15 Longitudinal studies in patients with breast cancer have found that higher levels of anxiety and depression correlate with more significant CI.16 Additionally, poor sleep quality and advanced age have been identified as risk factors for diminished cognitive function in this demographic.17
However, there is a lack of research investigating the status and influencing factors of CI in patients with CP, a gap this study aims to fill on an international scale.
Therefore, this study delves into the cognitive functions of patients with CP to elucidate their level of cognition and the factors influencing it. It seeks to identify the personal attributes most closely associated with perceived cognitive deficits and to uncover strategies to ameliorate cognitive function in patients with CP.
Methods
Study design
A multicentre cross-sectional study was undertaken in select hospitals across China from June 2020 to December 2021. Participants were enlisted from three tertiary cancer hospitals located in Fujian, Wuhan and Shanghai. The centralised ethics committee of Fujian Cancer Hospital (KT2018-001-01) granted approval for this research.
Study participants and inclusion criteria
The study targeted patients meeting the following inclusion criteria: (1) a histopathologically or cytologically confirmed malignant tumour, (2) undergoing hospital treatment, (3) experiencing pain with a Numeric Rating Scale (NRS) score of 1 or higher, (4) a clinical diagnosis of tumour-induced pain, (5) an Eastern Cooperative Oncology Group performance status of 0–2, (6) age 18 years or older, (7) literacy in Chinese sufficient for understanding numeracy and completing questionnaires and (8) provision of written informed consent for participation. Exclusion criteria encompassed those not meeting the above prerequisites, plus individuals with a psychiatric diagnosis, brain tumours, communicative impairments or cerebral metastases.
Sample size determination
The required sample size was calculated using the formula for cross-sectional surveys assessing related factors.18 Citing previous literature where the SD for FACT-Cog was 21.05 and setting an acceptable margin of error at 3 with a confidence level of 95% (α<0.05), a minimum of 178 subjects was deemed necessary to enable an adequate analysis of FACT-Cog status and related factor exploration.19
Measure
Participant characteristics
The study collated participant data spanning sociodemographic details (gender, age, educational attainment, religious affiliation, smoking and alcohol consumption habits, employment status and marital status) and clinical attributes (cancer stage, duration since diagnosis, tumour location, chemotherapy, hormone treatment, analgesic use, pain score and relief, sleep quality and mental health variables, including depression and anxiety).
Cognitive impairment
The FACT-Cog V.3, in its Chinese adaptation, was employed to gauge cognitive function in patients with cancer. It consists of 37 items, divided into four subscales: (1) perceived cognitive impairment (PCI) with 20 items; (2) observations by others on cognitive function, comprising four items; (3) perceived cognitive abilities, including nine items and (4) impact of PCIs on quality of life, encompassing four items. The scoring, based on a five-point Likert scale for individual items, yields a total that can range from 0 to 148, with higher scores reflecting superior cognitive function.20 Per the International Cognition and Cancer Task Force and corroborated by research within the Chinese context, a FACT-Cog total score below 75 is indicative of CI.21 The FACT-Cog V.3 has been extensively validated and used across various clinical settings, demonstrating strong internal consistency with a Cronbach’s alpha ranging from 0.76 to 0.94, with a 0.86 coefficient in the current study.20
Sleep quality
The Pittsburgh Sleep Quality Index (PSQI) is a widely recognised, self-rated questionnaire developed by Buysse et al, assessing sleep quality and disturbances retrospectively over a 1-month period.22 It contains 19 items, which coalesce into seven component scores, each ranging from 0 to 3. These components are aggregated to generate a global PSQI score, varying from 0 to 21, with lower scores indicating better sleep quality. The PSQI interprets scores as follows: 0–5 for good sleep quality, 6–10 for moderate quality, 11–15 for poor and 16 or higher for very poor sleepers. The PSQI’s original form has demonstrated an internal consistency with a Cronbach’s alpha of 0.83.
NRS score
The NRS is an 11-point scale used for the self-assessment of pain intensity by individuals experiencing cancer-related pain, standing as the most commonly applied measure in this domain.23 Patients rate their pain intensity on a scale from 0, representing ‘no pain’, to 10, denoting ‘the worst possible pain’. The NRS categorises pain levels as follows: 0 for no pain, 1–3 for mild pain, 4–6 for moderate pain and 7–10 for severe pain.
Depression assessment
In this study, the Patient Health Questionnaire-9 (PHQ-9) was employed to evaluate depression levels among participants. This instrument is aligned with the depression criteria outlined in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders. Respondents could select from four options to indicate the frequency of their depressive symptoms over a 2-week period: 0 for ‘not at all’, 1 for ‘several days’, 2 for ‘more than half the days’, and 3 for ‘nearly every day’. Scores range from 0 to 27, with higher scores reflecting increased severity of self-reported depression. Interpretation of scores is as follows: 0–4 signifies no depression, 5–9 mild depression, 10–14 moderate depression, 15–19 severe depression and 20–27 very severe depression. The PHQ-9 demonstrates a sensitivity of 80% and specificity of 92%.24 Within the context of this research, the PHQ-9 exhibited a Cronbach’s alpha coefficient of 0.86, confirming its reliability. The PHQ-9’s psychometric robustness has been validated within Chinese populations and is recognised as an effective tool for screening major depressive disorder in individuals with cancer.25
Anxiety evaluation
To assess the severity of anxiety symptoms, the Generalised Anxiety Disorder-7 (GAD-7) scale was used. This self-reporting measure offers four response options, reflecting symptom frequency over the past 2 weeks: 0 for ‘not at all’, 1 for ‘several days’, 2 for ‘more than half the days’ and 3 for ‘nearly every day’. The total score, which can range from 0 to 21, indicates the extent of self-reported anxiety, with higher scores denoting greater anxiety. Score classifications are 0–4 for no anxiety, 5–9 for mild anxiety, 10–14 for moderate anxiety and 15–21 for severe anxiety. The GAD-7 is noted for its high sensitivity (89%) and specificity (82%).26 In the current study, the GAD-7 had a Cronbach’s alpha coefficient of 0.92. It has been effectively employed as a screening instrument for generalised anxiety disorder among patients with cancer and those experiencing CP.27
Data collection procedures
Data were gathered through structured interviews using a questionnaire. Participants' treatment details were collated from medical records, including body mass index (BMI), clinical stage, tumour site, type of chemotherapy, hormone therapy and analgesic use. Prior to data collection, uniform training was provided across all centres to ensure standardised assessment practices. Investigators clearly communicated the study’s objectives, provided guidance for questionnaire completion and reassured participants that their involvement would not influence their future care. Participants were required to sign informed consent forms. Data from completed questionnaires were entered into a centralised management system by the primary centre’s research team and subsequently verified by an independent data manager.
Data entry and statistical analysis protocol
Prior to data entry, a meticulous review was conducted to ensure data quality, completeness, consistency and clarity. Data management was executed using Epidata software V.3.1. For statistical analysis, SPSS software (V.23.0) was employed. Descriptive statistics, including frequency and percentage, were used to delineate all sociodemographic characteristics, with continuous data stratified into respective categories. Mean and SD were calculated to characterise the scores obtained from the FACT-Cog, NRS, PSQI, PHQ-9 and GAD-7 instruments. To compare sociodemographic and clinical variables between groups with and without CI, independent sample t-tests and χ2tests were applied. Furthermore, a binary logistic regression analysis was conducted to investigate the determinants influencing CI in patients with cancer. A p-value of less than 0.05 was indicative of statistical significance. All analyses were executed using IBM SPSS Statistics V.23 for Windows (IBM, Armonk, NY, USA).
Patient and public involvement
There was no patient or public involvement in the planning, execution, reporting, or dissemination strategies of this study.
Results
Sociodemographic characteristics of participants
Of the 225 individuals approached, 220 participated in the study, yielding a response rate of 97.8%. Declines included two eligible patients, while three were excluded due to incomplete questionnaire data. The sample comprised a balanced proportion of male (56.8%) and female (43.2%) participants, with an average age of 56.01 (SD=13.61) years. Notably, 27.3% had a history of smoking and 27.4% reported alcohol consumption. These sociodemographic details are presented in table 1.
Comparison of two groups of sociodemographic with different characteristics (n=220)
Clinical characteristics of participants
With regard to analgesic consumption, 59.5% of participants used opioid analgesics such as morphine and fentanyl, while 32.3% resorted to non-opioid pain relievers like aspirin and paracetamol; 8.2% did not use any analgesics. We standardised the analgesic dosages to oral morphine equivalents according to the NCCN Guidelines for adult CP.28 A majority (74.5%) had cumulative oral morphine doses within the 0–100 mg range. More than a quarter (28.2%) experienced pain above a moderate level. Concerning sleep quality, a significant majority (93.6%) rated theirs as poor (PSQI scores above 5). Very severe depression was reported by 5.9% of participants, and 6.8% experienced severe anxiety. The mean and SD of the scores are detailed in table 2.
Comparison of two groups of clinical with different characteristics (n=220)
Comparative analysis of groups
The average FACT-Cog score was 101.29 (SD=25.24). CI was identified in 35.90% of participants, as indicated by FACT-Cog scores under 75. Participants were categorised into non-CI (FACT-Cog score above 75) and CI groups (FACT-Cog score below 75). An independent-sample t-test revealed a statistically significant difference in FACT-Cog scores between these groups (p<0.001), as shown in table 3. Additionally, there were notable differences in gender, age, marital status, religion, smoking and alcohol use, employment status, BMI, sleep quality, pain intensity, depression and anxiety levels between the two groups, with a significance level set at p<0.25 (refer to tables 1,2).
Comparison of FACT-Cog dimensions between groups
Logistic regression analysis
A binary logistic regression was performed with the occurrence of CI (as indicated by FACT-Cog scores) as the dependent variable. Independent variables included gender, age, mental status, marital status, smoking history, risky alcohol consumption, employment status, BMI, use of analgesics, intensity of pain, sleep quality, depression and anxiety. The analysis revealed that the odds of CI increase by 4.2% with each additional year of age (OR 1.042, 95% CI 1.013 to 1.073). Individuals with a history of smoking were more likely to exhibit CI than non-smokers (OR 3.811, 95% CI 1.668 to 8.707). Furthermore, a one-unit increase in scores on the NRS, PSQI, PHQ-9 and GAD-7 was associated with a 44.2% (OR 1.442, 95% CI 1.129 to 1.841), 12.6% (OR 1.126, 95% CI 1.013 to 1.252), 11.9% (OR 1.119, 95% CI 1.029 to 1.217) and 10.7% (OR 1.107, 95% CI 1.005 to 1.220) increased risk of CI, respectively, as detailed in table 4.
Univariate and multivariate logistic regression analysies for cognitive impairment
Receiver operating characteristic curves were constructed to evaluate the diagnostic accuracy of the CI prediction model (figure 1). The area under the curve was 0.890 (95% CI 0.846 to 0.934), indicating high efficacy in distinguishing between participants with and without CI. The model demonstrated a sensitivity of 0.747 and a specificity of 0.901, with the maximum Youden’s index reaching 0.648.
The receiver operating characteristic analysis for the probability of cognitive impairment.
Discussion
This study investigated the prevalence and determinants of CI among patients with CP in China. It is widely recognised that patients with cancer exhibit higher levels of CI compared with the general population, with deficits often present before treatment initiation.29 These deficits can span various cognitive domains such as verbal memory, language abilities, visuospatial skills, executive function and psychomotor speed, primarily due to the inherent neurotoxicity of the cancer itself, which impairs attention, working memory and executive functioning.30 Additionally, studies have suggested that both cancer-related pain and the side effects of treatments like chemotherapy and radiotherapy contribute to inflammation and oxidative stress, potentially resulting in hippocampal damage and, consequently, cognitive dysfunction.31 In our cohort, the average CI score among Chinese patients with CP was 101.29 (±25.24), with 35.90% of participants exhibiting FACT-Cog scores below 75, indicating a significant presence of cognitive dysfunction. This prevalence rate is notably high, though lower than some US studies. For instance, a 2018 cross-sectional study reported nearly universal CI occurrence among patients with cancer, with varying degrees of severity of pain.32 Another report by Meyers et al identified CI in up to 90% of patients with cancer pretreatment, exceeding the rates observed in our study.33 This discrepancy could be attributed to the inclusion of patients with brain tumours in the previous studies, whose condition directly affects brain function and could exacerbate cognitive deficits.
CI prevalence among patients with CP is also found to be higher than that in the general elderly population.34 This may be due to the increasing recognition of mild cognitive impairment (MCI) as a clinical condition within medical and geriatric care settings. Identifying predictors of cognitive decline is pivotal in geriatrics to devise appropriate interventions.35 Early detection and intervention for cognitive decline in the elderly might be more beneficial for preserving cognitive health.35
However, current research on interventions to mitigate CI in patients with CP is scarce, leading to a rising prevalence of CI in this demographic. Cancer treatments and the complex clinical manifestations of CP can overshadow cognitive issues, making them more challenging to address than physical symptoms like pain. Therefore, healthcare providers should be vigilant in recognising and managing cognitive dysfunction in patients with CP to improve their overall quality of life.
Our analysis indicates that age, smoking history, sleep quality, pain intensity, depression and anxiety are all linked to CI. Notably, the incidence of CI increases with age. For instance, in Shenzhen, southern China, the CI prevalence among those aged 60 and over was 21.46%, while in Guangzhou, 14.2% of the elderly population suffers from MCI.34 It is often the case that older individuals with cancer experience significant pain but do not report it, a situation that may worsen CI. Considering the heightened risk of cognitive decline in this demographic, CIs associated with cancer-related pain may intensify symptoms that are indicative of early-stage dementia.36 Consequently, cognitive screening for this population is critical.
The relationship between smoking and cognitive function remains debated. Certain studies posit that nicotine may have neuroprotective effects on CI, potentially ameliorating negative symptoms and side effects, as well as enhancing aspects of CI by increasing neurotransmission in the prefrontal cortex.37 Contrarily, the link between smoking and cognitive functions in schizophrenia has been inconsistent across research.38 While acute smoking might offer temporary relief from negative symptoms in patients with schizophrenia,39 in general populations, smoking is often a risk factor for CI,40 with strong associations to dementia, impairments in executive functions, cognitive agility, general intellect, learning, memory processing speed and working memory.41 The underlying causes might include cognitive disruptions due to nicotine withdrawal, compromised white matter integrity and reduced grey matter volume in the hippocampus and striatum.42 43 Numerous studies have identified cigarette smoking as a risk factor for Alzheimer’s disease and other neurocognitive disorders.44 Furthermore, smoking is known to deplete cognitive reserves.45 Prolonged nicotine use detrimentally affects cognitive function, reducing the capacity for attention and slowing processing times in both young and older adults.39 Our study corroborated smoking as a significant factor influencing CI, suggesting that cessation advice during cancer treatment could potentially shield against CI. However, as the majority of our study’s participants were non-smokers, further research with a larger cohort of smokers is warranted.
Our study revealed that diminished sleep quality significantly increases the likelihood of CI in patients. Sleep disturbances are known to trigger sympathetic nervous system activation, insulin resistance, hypertension and metabolic dysregulation.46 Adequate sleep is essential for the restoration of compromised neural functions. Conversely, individuals with insomnia may experience a failure to synthesise brain proteins due to a lack of slow-wave sleep, preventing the formation of new neural connections and consequently altering cortical cognitive capabilities. This can lead to deficits in alertness, executive functions, memory, language abilities, visuospatial skills, abstract thinking, calculation and orientation.
Wild’s research indicates that individuals sleeping fewer than 4 hours exhibit rapid cognitive declines.47 Optimal cognitive function appears to be associated with 7–8 hours of sleep across all age demographics, although excessive sleep can result in postsleep inertia. Our findings underscore the importance of recognising early signs of abnormal sleep patterns as potential indicators of cognitive deterioration, thus highlighting sleep quality as a critical component in the prevention of CI.
In assessing the impact of pain on cognitive function, our research identified pain intensity as a significant determinant. Severe pain correlates with decreased cognitive function and an elevated risk of CI. One study on patients with advanced-stage cancer demonstrated a widespread impact of pain symptoms on cognitive processes.48 On comparing a cohort of patients with lung cancer experiencing pain with matched controls based on age, occupation and education, it was observed that the patients exhibited deficits in logical memory, visual reproduction and the ability to recall numbers and logic in reverse order. The most pronounced impairments were found in memory and attention.49
The mechanism by which pain influences cognitive function is thought to involve the transmission of noxious stimuli to the brain, initiating complex physiological and biochemical pathways that interfere with cognitive processing and the integration of information. This results in a decline in the patient’s perceptual responsiveness and information-processing capabilities.50 Another study revealed that pain could lead to inadequate perfusion of the cerebral cortex, reducing blood flow to the frontal and parietal lobes and thus impairing brain function.51 In conclusion, our research suggests that effectively managing pain is imperative for the improvement of cognitive function in patients with cancer.
Furthermore, our study examines the relationship between psychoemotional factors and CI. It has been observed that heightened levels of anxiety and depression are likely to be associated with an increased risk of CI. Research indicates that diminished cognitive function adversely affects the patient’s emotional well-being and overall quality of life, posing a significant challenge to their reintegration into normal social activities.52 Neuropsychological studies have demonstrated that depression, anxiety and emotional states can influence cognitive function. Positive emotions tend to enhance concentration, improve the perception of information and facilitate cognitive enhancement.53 Conversely, negative emotions can increase cognitive load and detrimentally affect attention and logical reasoning abilities.
Among individuals with chronic pain, the likelihood of depression and anxiety is significantly elevated—6.9 times and 4.21 times greater, respectively, suggesting that those suffering from cancer-related pain experience more profound negative emotions than those without such pain.54 Symptoms associated with anxiety and depression can lead to compromised glucocorticoid receptor function and elevated cortisol levels, both of which may contribute to neuronal death and damage to the central nervous system, resulting in a decline in cognitive abilities.55
It is also necessary to consider the cognitive effects of antianxiety and antidepressant medications. A large cohort study found no link between the use of benzodiazepines or similar medications and dementia. Moreover, the dosage and cumulative use of these drugs were not correlated with a decline in cognitive function and might even enhance cognitive capabilities.56 However, this study did not account for specific dosages of anxiolytic and antidepressant drugs, which will be taken into consideration in future research.
Thus, by ameliorating anxiety and depressive symptoms, caregivers may reduce the risk of CI in patients, thereby potentially improving the long-term quality of life for individuals with CP. However, it must be acknowledged that cancer treatments, particularly chemotherapy or endocrine therapy, may induce CI. This study cannot entirely exclude the impact of such treatments and worsened performance-based functioning on cognitive decline. Previous research has established a correlation between cognitive function and psychological symptoms, pain intensity, sleep quality and participants’ deteriorated functioning.12 In the advanced stages of cancer, pain often intensifies due to metastasis or treatment factors, and emotional disorders such as anxiety and depression become prevalent, leading to significant CI.
Additionally, our research indicates that analgesic use did not significantly impact CI. The National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology for adult CP recommend selecting analgesic drugs according to pain intensity. For mild pain (intensity rating of 1–3), non-opioid analgesics are suggested. Moderate pain (intensity rating of 4–6) may be treated with non-opioid analgesics and adjuvant therapies, supplemented with short-acting opioids as needed. Severe pain (intensity rating of 7–10) warrants the use of strong opioids.28 Converting the cumulative dose of opioids to equivalent doses of oral morphine, we determined that neither the analgesic type nor the cumulative dose significantly influenced CI.
Opioids are the cornerstone for managing acute and cancer-related pain, and while they are effective analgesics, the long-term effects on cognitive function remain unclear. Research on this topic is limited and inconsistent. Some studies indicate opioids can cause CI, affecting information processing, learning, memory consolidation and retrieval.57 However, the challenge lies in isolating the cognitive effects of opioids from complications due to cancer, concurrent psychotropic drug use, age and pain itself, among other variables.58
A systematic review comparing cognitive performance between patients with cancer treated with opioids and those not receiving opioids found little difference.58 Pain intensity itself can disrupt cognitive function, but opioids may actually enhance cognition by alleviating pain, suggesting their safe use in managing CP without cognitive hindrance.
We endorse the current three-tiered analgesic protocol for patients with CP, positing that it is cognitively safe and underscores the importance of prompt pain management. However, future studies should aim to differentiate the cognitive effects of opioids from those of pain by comparing groups receiving opioid and non-opioid analgesics, as well as those without pain. Cognitive assessments should be conducted prior to opioid initiation to monitor the progression of pain and other potentially cognitive-impairing factors such as disease advancement, the emergence of brain metastases and the deterioration of physical conditions, including anaemia and dehydration. It is crucial to distinguish the effects of opioids from the effects of pain on cognitive function.
This study is significant as it explores a multitude of factors influencing CI in individuals with CP, incorporating sociodemographic and clinical variables. Furthermore, it elucidates the relationship between age, smoking history, pain severity, sleep quality, depression, anxiety and CI. This enhances our comprehension of cognitive functioning in patients with CP and offers foundational data to devise strategic interventions aimed at mitigating CI in this patient population.
Conclusion
Our study revealed that 35.90% of patients with CP experienced CI, indicating a higher incidence compared with the general population. Age, smoking history, sleep quality, intensity of pain, depression and anxiety were identified as influential factors contributing to CI in patients with CP. The implications of these results are particularly pertinent for the medical community in China, suggesting that older individuals, those with a history of smoking, poor sleep, severe CP and symptoms of anxiety and depression, warrant increased vigilance. Consequently, our findings advocate for a comprehensive approach to crafting interventions aimed at enhancing cognitive function in patients with CP. Effective management of these identified factors is crucial to safeguard the cognitive health of patients with CP.
Data availability statement
Data are available upon reasonable request. The data generated in the current study are available on reasonable request, considering the sensitivity and confidentiality of the data. Due to the nature of the data, which contains personally identifiable information and sensitive information, it cannot be openly shared in a public repository.Data can be obtained from the corresponding author upon reasonable request.
Ethics statements
Patient consent for publication
Ethics approval
This study involves human participants and was approved by the Hospital Ethics Committee of Fujian Cancer Hospital, China (KT2018-001-01). Participants gave informed consent to participate in the study before taking part.
Footnotes
Contributors HZ, RL and HL contributed equally to this study. RL and HL were both corresponding authors of this study, involved in drafting the manuscript or revising it critically for important intellectual content. HZ designed the experiments, acquired data and wrote the manuscript. JW, SR, TH, YL and XK are responsible for data collection. HZ, JW, RL and HL checked the data on the subjects and reviewed the manuscript. RL has made equal contributions to HL throughout the article. All authors contributed to data analysis, drafting and revising the article and gave final approval of the version to be published. The guarantor responsible for the overall content of this article is HL.
Funding This research was supported by the Nursing Sciences Foundation of Fujian Cancer Hospital (No. 2023YN24) and the National Natural Science of Fujian Province. (No.2023J011241).
Competing interests None declared.
Patient and public involvement Patients and/or the public were involved in the design, or conduct, or reporting, or dissemination plans of this research. Refer to the Methods section for further details.
Provenance and peer review Not commissioned; externally peer reviewed.