Costs of dialysis for elderly people in the UK

Reinhold P. Grün1, Niculae Constantinovici2, Charles Normand1 and Donna L. Lamping1 for the North Thames Dialysis Study (NTDS) Group

1London School of Hygiene and Tropical Medicine and 2Department of Primary Care and Population Sciences, Royal Free and University College Medical School, London, UK

Correspondence and offprint requests to: Dr R. P. Grün, Kaiserstrasse 12, D-14109 Berlin, Germany. Email: rp.gruen{at}t-online.de



   Abstract
 Top
 Abstract
 Introduction
 Patients and methods
 Results
 Discussion
 The NTDS Group
 References
 
Background. Growing acceptance rates of elderly patients for dialysis requires a careful planning of renal services expansion. As little is known about the actual resource use in patients 70 years and over, we evaluated the entire range of costs related to treatment, hospitalization, medication and other health and social service use, and assessed the impact of socio-demographic and clinical factors on costs.

Methods. Service use and costs were assessed in a 12-month prospective cohort study of 171 dialysis patients, 70 years of age and over, from four hospital-based renal units in London, UK.

Results. Total costs ranged between £14 940 and £58 250 per annum. The average annual cost was £22 740 [95% confidence interval (CI), £21 470–24 020]. The majority of costs were allocated to dialysis treatment and transport (70%), hospitalizations (12%) and medication (12%). Other health and social services accounted for only 6% of total costs. Dialysis and hospitalization costs were £68.4 per day on average. Univariate subgroup analyses showed no significant difference between patients on peritoneal dialysis (£64.5) and haemodialysis (£71.5, P = 0.13). Age 80 years and over and presence of peripheral vascular disease (PVD) were associated with higher daily costs of £73.3 compared with £63.2 in the 70–74 age group (P = 0.033) and £76.9 vs £63.8 in patients without PVD (P = 0.022), respectively. Proximity to death was associated with a nearly £40 increase in daily costs (£96.8 vs £59.7; P < 0.001). Multiple linear regression analyses confirmed these findings and showed that age 80 years and over and presence of peripheral and cerebrovascular disease were significant predictors of costs. There was a large but marginally significant difference in costs in patients with cancer. We found no evidence that diabetes was associated with higher dialysis and hospitalization costs.

Conclusions. The costs of providing dialysis for patients 70 years and over are largely shaped by the treatment costs rather than by use of community health and social services. Though age above 80 and co-morbidity are associated with increased resource use, average treatment costs are not higher than estimates for dialysis patients in general. This suggests that there is no case for providing treatment to younger patients and denying it to elderly patients on grounds of cost.

Keywords: economic costs; elderly patients; haemodialysis; health and social service use; peritoneal dialysis



   Introduction
 Top
 Abstract
 Introduction
 Patients and methods
 Results
 Discussion
 The NTDS Group
 References
 
Older people form the most rapidly expanding group of dialysis patients in Europe. Between 1983 and 1993, the proportion of patients over 70 years of age starting dialysis increased from 10 to 25% [1]. Given the high costs of renal replacement therapy (RRT), funding agencies are concerned about the resource implications of these changes.

In 2000, 10% (n = 1465) of dialysis patients in England were 75 years of age or over, and 28% (n = 4103) were over 65 [2]. Though the number of elderly patients has increased in recent years, the acceptance rate to RRT is still lower than in other European countries [3]. Lack of resources, distance to renal units, regional imbalances in service provision and implicit rationing are factors that restrict access to RRT [4]. Findings from a strategic review of renal services in the UK estimate that 1% of total health expenditure is currently being spent on RRT and that double this amount will be required to provide RRT to all patients who could benefit from treatment [5].

Planning of service expansion and commissioning RRT requires reliable information on resource use and costs. Although previous studies have provided useful data that included elderly patients [46], little is known about actual patterns of resource use in this age group. The purpose of this study is to inform the decision-making process about consequences for costs of service expansion.

The specific objectives of this study are: (i) to identify the entire range of costs related to treatment, hospitalization, medication and other health and social service use incurred by elderly people on dialysis; and (ii) to examine the impact of socio-demographic and clinical factors on costs.



   Patients and methods
 Top
 Abstract
 Introduction
 Patients and methods
 Results
 Discussion
 The NTDS Group
 References
 
Approach taken
The cost evaluation was conducted as part of the North Thames Dialysis Study (NTDS), a prospective cohort study to evaluate clinical outcomes, quality of life (QOL) and costs in dialysis patients aged 70 years or over [7]. The evaluation took a societal viewpoint, which included the costs of medical and social services as well as privately borne costs. Individual profiles of service use were constructed for each patient to assess actual resource use and to perform analysis of cost variation between subgroups.

Patients and setting
Patients 70 years or over who were on chronic dialysis, defined according to the 90-day rule [8], were followed-up over 12 months. Two cohorts of patients who were 70 years or older at their first dialysis were studied: ‘new’ patients who started dialysis during the study period (May 1995–December 1996) and ‘stock’ patients who were already on dialysis during the recruitment period.

Patients were recruited from four renal units in the former Northwest Thames Region. Three of the units are attached to teaching hospitals and one to a general district hospital. All units have an open access policy for accepting patients onto dialysis, with no upper age limit. All units use bicarbonate haemodialysis; three units use low-flux dialysis with cellulose membranes and one uses high-flux with polysulfone membranes. The majority of haemodialysis (HD) patients receive three dialysis sessions per week. Most patients receiving peritoneal dialysis (PD) are treated on a continuous ambulatory basis (CAPD). Six patients changed modality during the course of treatment. Patients on erythropoietin (EPO) received weekly doses of 6500 IU on average (range 1200–27 000 IU/week). Co-morbid conditions were assessed at baseline, including diabetes, ischaemic heart disease, peripheral vascular disease, cerebrovascular disease and cancer.

Identification of cost generating events
The costing model with primary and summary cost variables is described in Table 1. Data about service use were obtained from medical records and interviews with patients at study entry and at 6- and 12-month follow-up. Data from medical records were used to assess the costs of treatment, hospitalizations and medication. Use of other health and social services was assessed by patient questionnaires at baseline and at 6 and 12 months follow-up. Questions about the use of in-patient, out-patient, accident and emergency facilities and frequency of GP consultations were derived from the 1994 General Household Survey [9]. Questions about the use of other health and social services were based on the 1991 GHS supplement for people over 65 years of age [10]. Reported frequencies of service use were extrapolated to a 12-month period to produce an individual matrix of service use for each patient. We evaluated the reliability of the patients’ self-reports of hospitalization by comparing recalled and recorded hospitalizations (Cohen’s kappa = 0.81 across all three interviews).


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Table 1. Primary and summary cost variables by data source

 
Assessment of costs
Cost data for the financial year 1995–1996 were available from three hospitals. Weighted averages for dialysis-related treatment costs were attached to patients from the unit for which cost information was not available. A cost appraisal, based on bottom-up costs from one hospital, was used as a template to establish costs of the other units [11]. Costs of chronic dialysis were separated from costs of transplantation, ward costs and costs of acute dialysis, and allocated to the different modalities of treatment. Staff costs were apportioned on the basis of staff time estimates, overhead costs by activity or staff expenditure, where appropriate. Costs of other hospital departments were obtained from the Chartered Institute of Public Finance and Accountancy database [12] for the North Thames region. Medication costs were assessed individually on the basis of recorded doses using cost information provided by one of the hospital pharmacies.

Unit costs of GP consultations, district nurse visits and personal social services were obtained from different sources [7]. Reported frequencies of service use were multiplied by unit prices to obtain individual profiles of annual costs. All prices were calculated for the financial year 1995–1996. The actual time spent on PD or HD was taken into account in the six patients who changed treatment modality.

Analytical methods
The costs of treatment, hospitalizations and medication were calculated as both average annual cost and average cost per day to account for varying lengths of follow-up. Confidence intervals (CIs) for the average total costs per annum and for the daily costs of dialysis and hospitalization were checked using a non-parametric bootstrap technique. All estimates were based on 1000 bootstrap replications. Bootstrapped confidence limits proved to be similar to those calculated through parametric methods assuming a normal distribution. Despite the skewness in cost data, we present results of cost comparisons between subgroups and CIs provided by unpaired t-tests and linear regression models, for ease of interpretation [13].

The independent impact of socio-demographic variables (sex and age) and clinical variables (treatment modality and co-morbidity) on costs was evaluated using standard multiple regression models adjusted for study cohort and length of time since treatment initiation. Statistical tests were two-sided and used the 0.05 level of significance. CIs were calculated with 95% probability. Statistical analyses were performed in SPSS 10.0 for Windows.



   Results
 Top
 Abstract
 Introduction
 Patients and methods
 Results
 Discussion
 The NTDS Group
 References
 
Socio-demographic and clinical data
Of the 174 patients who agreed to take part in the study, cost data were available for 171 (76 new, 95 stock) patients. The mean age was 77.0 years (range 70–93), 67% were men and 56% were on HD. The majority (60%) of patients were married, while 30% lived alone and three lived in residential care. Over half (55%) were classified as non-manual occupational class. Co-morbid conditions included diabetes (20%), ischaemic heart disease (49%), peripheral vascular disease (35%), cerebrovascular disease (16%) and cancer (7%). Forty patients died during the 12-month follow-up period, with similar frequency in new and stock patients (23%). The overall hospitalization rate was 2.0 admissions/person-year. A third of patients had no hospitalizations during the study period. Those who were admitted as in-patients had an average length of stay of 23.3 days over the 12-month period (range 1–142).

Distribution of total costs
An estimate of the total cost of treatment in elderly patients, including dialysis treatment, transport, hospitalizations, medication, and other health and social services, was available for 102 (47 new, 55 stock) patients who completed all three interviews (Table 2). The average total annual cost was £22 740 (range: £14 940–58 250).


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Table 2. Average costs (£) during 12-month follow-up (n = 102)

 
Costs of dialysis treatment, hospitalizations and medications were assessed in all 171 patients, including those who died (n = 40) and those who refused follow-up visits or could not be interviewed at 6 or 12 months (n = 29). Due to differences in case mix, the average daily use of resources in the whole group of patients is higher than in the 102 who completed all three interviews (£68.4 vs £58.6/day). In the former group, patients were sicker, as indicated by more co-morbidity and longer and more frequent hospitalizations (data not shown). Therefore, the average total cost of £22 740 is a conservative estimate.

Seventy percent of annual costs were allocated to dialysis treatment and transport (£15 930), 12% to hospitalizations (£2760) and almost 12% to medication (£2700). Expenditure on EPO represented >91% of medication costs (mean £2470, range 0–6430).

Costs for other health and social services accounted for only 6% of total costs. The average annual cost of other hospital services, including day case, out-patient and accident and emergency attendances, was £634. Use of GP services was relatively low: one in six patients reported having seen their GPs during the 2 weeks prior to the baseline interview at study entry. District nurse services were used by 21% of all patients, mainly for injections of EPO at home and help with CAPD (mean £45, range 0–227). About two-thirds of CAPD patients were able to administer the treatment without help from other people, whereas 37% of patients required help with bags and dressings from friends or relatives.

Use of social services accounts for 2.3% of the total annual costs. The major component of these costs is related to residential care, home care and domestic help. Other cost categories such as meals-on-wheels, social workers and day centres are relatively small cost items. A total of 19 patients received home care, 23 had private domestic help and three patients lived in a nursing home, which explains the highly skewed distribution of costs for social services. The majority of patients (94%) reported receiving some kind of informal care.

Unadjusted cost differences between subgroups
Univariate subgroup comparisons indicated that age 80 years and over and peripheral vascular disease were associated with higher daily costs (Table 3). There were weak but non-significant cost differences associated with ischaemic heart disease, cerebrovascular disease and cancer, but no evidence of higher costs in patients with diabetes mellitus. There were no significant differences in costs between new and stock patients or between HD and PD patients. Proximity to death was strongly associated with costs, which were significantly higher in patients who died during follow-up than in survivors (£96.8 vs £59.7/day, P < 0.001).


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Table 3. Costsa per day (£) by subgroup (n = 171)

 
Predictors of costs
Multiple regression models largely confirmed the results of univariate analyses. Adjusted cost differences and 95% CIs are shown in Table 3. Significant independent predictors of costs were age 80 years and over and presence of peripheral and cerebrovascular disease. Cost differences associated with age 75–79 years and presence of cancer just failed to reach the significance level, while ischaemic heart disease did not show an independent predictive effect. We found no evidence that diabetes was associated in any way with higher costs of dialysis and hospitalization.



   Discussion
 Top
 Abstract
 Introduction
 Patients and methods
 Results
 Discussion
 The NTDS Group
 References
 
Much of the current debate about funding renal services in the UK focuses on the resource implications of providing RRT to a growing elderly population. We therefore evaluated the entire range of costs of dialysis treatment and other health and social services for elderly people on dialysis, and analysed cost variation between subgroups of patients. This approach provides more accurate information on patterns of cost and service use than studies that assess average costs across all age groups.

One important finding from this study is that the costs of community health and social services do not add substantially to the cost of treatment. However, it is important to consider that many patients received a substantial amount of care from relatives or friends. Use of GP and other health services is only a marginal cost factor, as one would expect from patients who receive comprehensive specialist care. Total costs are thus largely dominated by requirements for providing dialysis treatment, rather than by the use of community health and social services.

A possible limitation of this finding is participation bias, as patients who completed the questionnaire on use of community services showed lower levels of co-morbidity and therefore were probably healthier than the non-participants [14]. This could underestimate the cost of community services in both the non-participants and in the wider population of elderly patients on dialysis. However, the high hospitalization rates of severely ill participants who died during follow-up suggest that elderly dialysis patients are more likely to receive specialist in-patient care rather than community care.

Although age and diabetes are known to be associated with higher costs, the cost increase in patients over 65 years is relatively small, as indicated by USRDS data [15]. This is consistent with our findings of higher costs in those aged over 80 but not significantly higher in the 75–79 year age groups. Interestingly, diabetes mellitus was not associated with increased costs, but the presence of other co-morbidities was an important predictor of costs. These findings confirm results from a previous study showing that other co-morbid conditions have a greater impact on survival than diabetes [4].

However, the effect of co-morbidity on costs needs to be interpreted with caution. A limitation of this study is the small number of patients that did not permit detailed analyses of the level of severity of diabetes and other co-morbidities and their effect on costs. As health care costs in elderly people have been shown to vary according to the severity of co-morbidity, it is important that future studies on larger numbers of patients use a more detailed approach that assesses the level of severity of disease, such as the Cumulative Illness Rating Scale or other appropriate measures. It would also be important in future research to examine the effect of cognitive and physical performance on costs, as these factors have been shown to have an independent influence on costs of health care for the elderly [16].

Proximity to death was found to be strongly associated with higher costs, a phenomenon that has been described in a number of health care settings [17]. This effect is clearly visible in this population. Although unadjusted analyses showed to some extent lower costs in PD compared with HD (mean difference £7/day), this was not supported in multivariate analysis. Cost differences between HD and PD appear to change in relation to proximity to death, where the number of hospitalizations increases in PD patients (data not shown). This means that PD costs are lower on a day to day basis but, when the whole patient experience is considered, the costs are similar for HD and PD.

One limitation of the study is that cost data were derived from renal centres in the London area, which may not be generalizable to other renal units of the country and to the private sector. It is known from US data that regional cost differences are due to a number of factors including ethnicity, cost of living, type of provider and patterns of service use [15]. An important area for further research is identifying the extent of cost variations across different regions of the UK, and between private and public sector facilities. Further research should also address the costs of dialysis services provided under a private–public partnership.

A possible limitation of collecting cost information alongside an observational cohort study is selection bias. Though the age and gender distribution of the study population are similar to patients of the renal units in England, the proportion of patients on HD is higher in the study population, which may overestimate total average cost [7]. However, the individual cost profiles we used allow a separate assessment of costs by modality and other clinical factors that affect service use. Unlike cost estimates from aggregate expenditure data, this approach provides more robust cost estimates, which can be used for planning and budgeting of renal services and reflect the actual resource use of elderly patients.

There is still an ongoing debate on criteria for RRT in elderly patients [18,19]. It is important to note that average treatment costs for elderly people on dialysis are not higher than estimates for dialysis patients in general [4,5,20]. Elderly patients, however, show a different pattern of service use insofar as they are less likely to receive transplantation, home dialysis or automated PD and are more dependent on social services. Costs are largely shaped by the requirements of dialysis treatment, which in most patients accounts for the major part of costs. Frequency of hospitalization and use of EPO explain much of the cost variation, but these costs account for less than a quarter of total costs on average.

Co-morbidity is associated with above average costs, though the incremental amounts are relatively small in relation to total RRT programme costs. It would not be justified to consider these differences as a criterion for decision making, as the presence of co-morbidity is more a rule than an exception in elderly patients on RRT. We have also shown that mental health-related QOL in elderly people on dialysis is similar to that of elderly patients in the general population [7], indicating one of the benefits of dialysis to elderly people. Overall, there is no case on the grounds of costs for providing treatment to younger patients but denying it to elderly patients.



   The NTDS Group
 Top
 Abstract
 Introduction
 Patients and methods
 Results
 Discussion
 The NTDS Group
 References
 
The NTDS Group includes Donna Lamping, Charles Normand and Reinhold Grün, London School of Hygiene and Tropical Medicine; Niculae Constantinovici, Royal Free and University College Medical School; Paul Roderick, Southampton University; Lynne Henderson, Kensington and Chelsea and Westminster Health Authority; Susan Harris and Edwina Brown, Charing Cross Hospital; and Christina Victor, St George’s Hospital Medical School, London, UK.



   Acknowledgments
 
We thank the dialysis patients that participated in the study, D. Keir Charing Cross Hospital, B. Saunders Lister Hospital, and R. Proudfoot, S. Cano, J. Litaker and A. Steriu for research assistance. This study was funded by the North Thames Regional Health Authority Research and Development Responsive Funding Programme, London UK. The Department of Public Health Kensington and Chelsea and Westminster Health Authority, London, UK provided additional funding for interpreters.

Conflict of interest statement. None declared.



   References
 Top
 Abstract
 Introduction
 Patients and methods
 Results
 Discussion
 The NTDS Group
 References
 

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  15. US Renal Data System. Annual Data Report: Atlas of End-stage Renal Disease in the United States. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA; 2002
  16. Taylor DH, Schenkman M, Zhou J, Sloan FA. The relative effect of Alzheimer’s disease and related dementias, disability, and comorbidities on cost of care for elderly persons. J Gerontol B Psychol Sci Soc Sci 2001; 56: 285–293
  17. McGrail K, Green B, Barer M, Evans R, Hertzman C, Normand C. Age, cost of acute and long term care and proximity to death: evidence for 1987–88 and 1994–95 in British Columbia. Age Ageing 2000; 29: 249–253[Abstract]
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Received for publication: 2. 1.03
Accepted in revised form: 14. 5.03





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