Background The estimated prevalence of alcohol use disorders in patients with advanced cancer is reported as 4%–38%. There are limited data regarding alcohol and drug use disorders in caregivers of patients with cancer and the effects on other issues.
Aim To establish the prevalence of alcohol and drug use disorders in a large cohort of patients with advanced cancer and their caregivers.
To evaluate the relationship between alcohol and drug use disorders and patient symptoms and caregiver burden.
Design The patient with cancer and caregiver completed the Alcohol Use Disorders Identification Tool, CAGE questionnaire and Drug Abuse Screening Test. The patient completed the Memorial Symptom Assessment Scale–Short Form, and the caregiver completed the Zarit Burden Questionnaire.
Statistical analysis compared cases and non-cases of alcohol and drug use disorders with symptom and burden score.
Setting/participants Patients with cancer, and their caregivers, were recruited from 11 UK sites, 6 hospices and 5 hospitals.
Results Five hundred and seven patients and their caregivers were recruited. Twenty-seven patients (5%) and 44 caregivers (9%) screened positively for alcohol use disorders on the Alcohol Use Disorders Identification Tool. Thirty patients (6%), and 16 caregivers (3%), screened positively for drug abuse problems on the Drug Abuse Screening Test.
There was a significantly higher carer burden score in caregivers screening positively for alcohol and drug abuse problems.
Conclusions The prevalence of alcohol use disorders in patients with cancer and caregivers was lower than reported in previous studies. Caregiver burden scores were significantly higher in carers screening positively for alcohol and drug use disorders.
Trial registration number Trial registered National Institute for Health Research Clinical Research Network Portfolio (CPMS ID 30723) IRAS ID 198753.
- clinical assessment
- drug administration
- chronic conditions
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More than 300 000 people are diagnosed with cancer annually in the UK. Half of those diagnosed will not survive the disease and are living with advanced cancer for a period of time.1 It is estimated that 8% of cancer deaths in men, and 3% in women, are attributable to excessive alcohol consumption.2 3 However, it is less well known whether excess alcohol consumption continues to be, or starts to be, a problem during the course of the illness. Living with cancer, having burdensome treatments and facing the end of life have a significant emotional impact. It is well documented that rates of psychological illness are higher in people with cancer than the general population.4 5 However, it is unclear whether alcohol and drug use disorders coexist with these problems.
There have been a number of retrospective studies assessing the prevalence of alcohol use disorders in patients with advanced cancer in North America and Europe.6–11 This is reported as being 4%–38% using the CAGE questionnaire. One prospective study used the Alcohol Use Disorders Identification Tool (AUDIT) and reported a prevalence of 18%.12 This study showed no association between alcohol use disorders and physical or psychological symptoms in patients with cancer.
Many people with advanced cancer are appropriately prescribed strong painkillers for their problems. However, there are limited published UK data assessing whether drug misuse exists in this population, either from prescribed opioids or other drugs. It is an important distinction to make in such patients to enable safe prescribing and enhancing quality of life. In the USA, prevalence rates of drug misuse in patients with cancer range from 3% to 19%; however, population-level issues are considerably higher in the USA making it difficult to extrapolate.13–15
Caregivers of patients with advanced cancer suffer higher levels of distress and lower levels of well-being as compared with age-matched non-caregivers.16 17 Caregivers of patients with other chronic problems (head injury, dementia) have high levels of alcohol use disorders, and these are related to worse health outcomes and coping.18 19 A prospective study from Europe assessed cancer caregivers using the CAGE questionnaire; 11% screened positively for alcohol dependence.20 They did not specifically assess the relationship between alcohol dependence and other psychiatric problems or caregiver burden and there was no assessment of drug abuse problems.
There are few published studies that primarily assess the prevalence of alcohol and drug use disorders in both patients with cancer and their caregivers. There are limited datasets evaluating the relationship between alcohol and drug abuse and carer burden, as well as the impact of the behaviours of patients with cancer and symptoms on carer burden.
The aim of this study, supported by Alcohol Change UK and National Institute of Health Research, was to establish the prevalence of alcohol and drug use disorders in a large cohort of patients with advanced cancer and their caregivers. Secondary aims were to evaluate the relationship between these problems and symptoms and carer burden. An overarching purpose of the study is to establish a large accurate dataset to determine if screening would be required for certain cohorts.
This study recruited patients with cancer across 11 UK sites from May 2016 until September 2018. Five centres were National Health Service Hospitals and six sites were independent hospices. Patients were recruited from hospital inpatient and outpatient departments, and hospice inpatient units and community services. Both patient and caregiver consented to be included in the study.
Patients aged >18 years with a diagnosis of advanced cancer and their primary caregiver, as identified by the patient, were approached. Patients without a caregiver were excluded.
Patient and caregiver demographic data were collected at interview. Details about prescribed painkillers and diagnosis were gathered by interview and also chart review. Smoking status was obtained for both patients and their caregivers.
The patient completed the following measures:
AUDIT. A validated questionnaire to screen for the presence of alcohol misuse in the last 12 months. A cut-off score of ≥8 was used to categorise alcohol misuse.21
CAGE questionnaire.22 Four questions about lifetime alcohol consumption. A cut-off score of 2 or more positive answers was used to determine alcohol dependence.
Memorial Symptom Assessment Scale-Short Form (MSAS-SF). A 32-item validated questionnaire assessing physical and psychological symptoms.23 The data will be presented using the three subscales, global distress index (GDI), physical subscale (PHYS) and psychological subscale (PSYCH). PSYCH has been validated to detect anxiety and depressive disorders24
Drug abuse screening test (DAST-10). A validated 10-item questionnaire to assess for drugs abuse over the previous 12 months.25 A cut-off score of ≥2 was used to determine drug abuse.
The caregiver completed the following:
Zarit Burden Inventory (ZBI). A validated 29-item scale designed to measure feelings of burden experienced by caregivers of medically ill persons. A cut-off score of ≥21 was used to determine significant carer burden.26
A sample size of 500 patients was calculated to estimate the prevalence of alcohol use disorders according to the AUDIT with a two-sided 95% CI; according to expected proportion (18%±3.3%).
Patient and caregivers were categorised into cases and non-cases of alcohol use disorders (AUDIT scale), alcohol dependence (CAGE) and drug abuse (DAST-10) to determine the prevalence of each. These different groups were compared with continuous variable data to establish the relationship between alcohol and drug misuse and the patient’s physical and psychological symptoms (MSAS-SF) and carer burden (Zarit). A comparison was also made between the patient’s symptom scales and carer burden. Comparisons between categorical and continuous variables was made using the t-test. Data were analysed using SPSS software.
Patient and caregiver characteristics
A total of 507 patients and their caregivers were recruited over 11 UK sites (744 approached, 237 declined to enter—43% fatigued, 26% caregiver declined, 23% no reason documented, 8% too symptomatic). Forty-eight per cent were recruited from hospital sites and 52% from hospices.
The median age of patients was 68 and their caregivers was 66. Fifty-four per cent of patients were male. The majority of caregivers were spouses or partners. Two hundred and sixteen carers (43%) experienced significant carer burden as defined by the ZBI.
Further details are presented in table 1.
Patient and caregiver prevalence rates of alcohol and drug misuse
Twenty-seven patients (5%) and 44 caregivers (9%) screened positively for alcohol use disorders on the AUDIT. In eight cases, both the patient and caregiver screened positively (table 2).
Fifty-seven patients (11%) and 48 caregivers (9%) screened positively for lifetime alcohol dependence using the CAGE questionnaire.
Eighty-five per cent of patients, and 27% of carers, were taking regular painkillers. The majority of painkillers were prescribed opioids. Thirty patients (6%), and 16 caregivers (3%), screened positively for drug abuse problems on the DAST-10 (table 2).
Factors associated with a high carer burden
There was a significantly higher caregiver burden score in caregivers screening positively for alcohol dependence on the CAGE (table 3). Carer burden was higher in caregivers screening positively on the AUDIT and DAST-10 with a trend towards significance.
A higher burden was also experienced by caregivers if patients had worse physical and psychological symptoms (table 4).
Caregiver burden was not affected by the patient’s drug or alcohol abuse issues.
Relationship between alcohol and drug abuse and patient’s symptoms
Patients with AUDIT-defined alcohol problems had lower global distress index (MSAS-GDI) and physical symptom scores (MSAS-PHYS) than those without (table 5). There was no difference in psychological symptoms (MSAS-PSYCH) between groups.
There was no difference in physical or psychological symptoms between patients screening positively and negatively with the CAGE or DAST-10.
Five per cent of patients and 8% of caregivers screened positively for alcohol use disorders on the AUDIT. Six per cent of patients and 3% of caregivers screened positively for drug abuse on the DAST-10. There was a significantly higher carer burden in caregivers screening positively for drug and alcohol problems.
What this study adds
The prevalence of alcohol use disorders and dependence among patients with cancer was lower than reported in previous studies. Only 5% of patients had harmful levels of alcohol use disorders in the previous year (AUDIT positive) with a higher number having a positive CAGE (11%). The CAGE questionnaire assessed lifetime dependence rather than current issues suggesting a proportion of patients had previously had problems but were not currently using alcohol harmfully.22
The level of current alcohol use disorders in patients and caregivers is lower than the general population for this age range taking into account sex differences.27 However, lifetime alcohol dependence rates (CAGE) are higher than equivalent general population for both patients and caregivers.27 This suggests that individuals with previous issues do not necessarily have current patterns of misuse but must be evaluated carefully and non-judgementally.
Eighty-five per cent of patients were taking prescribed painkillers and 6% screened positively for drug abuse. This is the first estimated prevalence rate of drug abuse in patients with cancer in the UK and is slightly higher than general population levels accounting for age (aged 55+ drug abuse rates are less than 1%).27 This indicates that while drug abuse rates are low, it is an issue that should be assessed when prescribing painkillers for all patients with cancer.
Twenty-seven per cent of caregivers were taking prescribed painkillers. This indicates that caregivers have significant healthcare needs and morbidity of their own.28 While this study did not look in detail at this issue, it supports published data about the physical and psychological health problems prevalent in caregivers.28 Three per cent of caregivers screened positively for drug abuse problems which suggests this problem is uncommon in this population.27 There are no published analogous data for the caregivers of patients with cancer and it establishes a prevalence rate for this group. Concurrent alcohol and drug abuse problems coexisted in only three patients and three caregivers.
There was a significantly higher carer burden score associated with caregiver alcohol and drug use disorders and lifetime alcohol dependence. It is not known whether this is cause or effect. A previous European study did not identify a positive CAGE questionnaire as a risk factor for carer burden.20
A higher carer burden was also associated with patient’s physical and psychological symptom burden. The causes of caregiver burden are complicated, but the literature reports a stronger association between burden and patient’s physical care needs, social networks and information needs than symptoms.29 30 There has been no previous reported association between Zarit burden score and symptoms reported on the MSAS-SF. This is an important finding that warrants further investigation.
The association of alcohol and drug use disorders with carer burden indicates the importance of screening and supporting caregivers of patients with cancer. An individualised needs assessment is recommended to identify issues and implement support strategies. The support strategies would need to be individualised depending on cause and effect of problems but could include referral to carer support groups, alcohol misuse services, enhanced social package, respite services or counselling. All patients started on strong painkillers should be monitored for drug misuse especially as many are now living with cancer, and taking painkillers, for longer time periods.
There were limitations to this study. First, the methods used to define alcohol and drug use disorders and lifetime alcohol dependence were screening tools. They are indicative of problems, but a structured clinical interview would be used in practice to diagnose these issues. Second, the prevalence rates were low, and the study was not powered to detect differences between groups. Despite this, the fact that differences were seen reveals a powerful link between data described above.
There were a considerable number of people who declined to take part in the study. This was predominantly due to fatigue and caregiver not being present during working hours. However, it is possible that people with alcohol and drug use disorders were more reluctant to take part thus underestimating the prevalence. Lastly, the study took place in the UK and despite using multiple sites, conclusions may not be able to be extrapolated to other countries with different healthcare systems. As such, this study represents a preliminary study assessing these issues and further studies are required to develop intervention for patients and caregivers.
Contributors Each author made a considerable contribution to the study and meet the full requirements for authorship. KW was guarantor responsible for overall content and was study Chief Investigator. She takes responsibility for planning, conduct and reporting of work. AND was involved in planning of work, data analysis and reporting. CL and AB were involved in conduct of work and reporting of data.
Funding This study was funded by Alcohol Change UK and supported by the National Institute of Health Research.
Competing interests None declared.
Patient consent for publication Obtained.
Ethics approval This study received approval from the South East Coast–Surrey Research Ethics Committee on 5 April 2016 (IRAS 198753/REC 16/LO/0631).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request. The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.