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
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Abstract |
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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 47024 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 7074 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
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Introduction |
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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.
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Patients and methods |
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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 1995December 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 120027 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 (Cohens kappa = 0.81 across all three interviews).
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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 19951996. 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.
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Results |
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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 94058 250).
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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 06430).
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 0227). 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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Discussion |
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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 7579 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 privatepublic 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.
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The NTDS Group |
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Acknowledgments |
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Conflict of interest statement. None declared.
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References |
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