The direct healthcare costs associated with ankylosing spondylitis patients attending a UK secondary care rheumatology unit
1University of Sheffield, Sheffield, 2Staffordshire Rheumatology Centre, Stoke on Trent and 3Royal College of Nursing Institute, Oxford, UK.
Correspondence to: R. M. Ara, Health Economics and Decision Science, ScHARR, University of Sheffield, 30 Regent Court, Sheffield S1 4DA, UK. E-mail: r.m.ara{at}sheffield.ac.uk
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionConclusionAcknowledgementsReferences |
|---|
Objectives. To explore the direct healthcare resources associated with ankylosing spondylitis (AS) in the UK. A secondary objective was to establish if resources, and thus healthcare costs, vary by disease severity.
Methods. Medical records of 147 sequential AS patients attending a UK secondary care rheumatology unit were examined to assess the direct healthcare resources used over the previous 12 months. Starting with a detailed inventory and measurement of resources consumed, unit cost multipliers were applied to the quantity of each type of resource consumed. The mean cost per patient was estimated using the total cost divided by the number of patients included.
Results. The mean (median) annual cost per patient was £1852 (£892). The distribution of cost data was skewed, with 11% of patients incurring 50% of the total costs. The three most relevant cost domains were physiotherapy, hospitalization and medication costs at 32, 21 and 20% of the total costs, respectively. Twenty percent of the patients received physiotherapy, 13% received inpatient care and almost all incurred medication costs. Thirty-four percent of patients were prescribed disease-modifying anti-rheumatic drugs and 85% non-steroidal anti-inflammatory drugs. Over 50% of patients had at least one comorbidity.
Conclusion. Direct costs accelerate steeply with disease activity (Bath Ankylosing Spondylitis Disease Activity Index >6.0) and increasing loss of function (Bath Ankylosing Spondylitis Functional Index >6.0) in patients with AS. The most severely affected patients incur 50% of the total costs, and physiotherapy accounts for 32% of the total healthcare costs in the UK.
KEY WORDS: Cost of illness, Healthcare costs, Economics, Ankylosing spondylitis, Chronic disease
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionAcknowledgementsReferences |
|---|
Ankylosing spondylitis (AS) is a chronic, progressive inflammatory disease [1] characterized by pain and stiffness of the back, peripheral joints and extra-articular sites [2]. Typically presenting in young men, it can impact on physical, social and psychological health [2]. The prognosis for AS is poor, and management centres on controlling pain and improving physical function [3].
Non-steroidal anti-inflammatory drugs (NSAIDs) are the main medication for AS [4]. Disease-modifying anti-rheumatic drugs (DMARDs) such as methotrexate [5] and sulphasalazine [6] control peripheral arthritis but have no proven benefit on axial inflammation. Anti-TNF inhibitors reduce both axial and peripheral inflammation in AS [7, 8] but have larger cost implications. The Assessment in Ankylosing Spondylitis (ASAS) group [9] and the British Society for Rheumatology (BSR) [4] have suggested a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score [10] greater than 4/10 as the cut-off for anti-TNF treatment in AS.
While comprehensive economic evaluations of biological agents inform policy decision makers, no data exist for the secondary care costs of AS in the UK. A review of the costs associated with AS [11, 12] show that healthcare settings, patient characteristics and treatment costs vary widely across differing healthcare systems [1, 11, 13–15]. While disease activity and function are strongly related to overall health use, the major cost in European studies was hospitalization [1, 11] in contrast to high medication costs in the US [15].
The current study examines the direct healthcare resources utilized by AS patients attending a UK secondary care rheumatology unit and explores if healthcare costs vary with disease activity (BASDAI) [10] and function [Bath Ankylosing Spondylitis Functional Index (BASFI)] [16].
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionAcknowledgementsReferences |
|---|
The medical records of 147 sequential AS patients (diagnosed using the modified New York criteria [17]) attending outpatient clinics (December 2003 to June 2004) at the Staffordshire Rheumatology Centre, a UK secondary care rheumatology unit, were examined retrospectively to assess the direct healthcare resources used during the previous 12 months.
Unit cost multipliers were applied to a detailed inventory of the quantity of each resource consumed. Using data collected routinely for local reimbursement purposes, resources include: physiotherapy sessions, outpatient appointments, inpatient days, laboratory-based tests, X-rays, scans and prescribed medications. The distinction between AS-related (orthopaedic, uveitis, pain and rheumatological care) and non-AS-related (cardiovascular, gastrointestinal investigations and care) resources was made by the consulting rheumatologist.
Disease impact was determined by disease-specific instruments measuring disease activity (BASDAI [10]) and function (BASFI [15]). The BASDAI consists of six visual analogue scales dealing with fatigue, spinal pain, joint pain, localized tenderness and quality and quantity of morning stiffness over the past week. The mean of items five and six is calculated, then scores are summed and transformed to a 0–10 scale where higher scores indicate higher disease activity. The BASFI consists of eight visual analogue scales dealing with physical function and two scales reflecting the patient's ability to cope with daily activities. Scores are summed and transformed to a 0–10 scale where higher scores indicate higher functional disability.
To establish if total annual costs are associated with disease severity, patients were subgrouped according to disease severity: moderate (BASDAI <4.0, BASFI <4.0), severe (BASDAI 4.0–6.0, BASFI 4.0–6.0) and very severe (BASDAI 
6.0, BASFI 6.0) [10]. The selected bands were informed by ASAS [10] and BSR [4] guidance.
Statistical analyses
SPSS (version 12) was used for data analysis including descriptive statistics (mean, S.D., median and range), the distribution of costs and associations between variables (Pearson or Spearman correlation coefficients with significance set at P < 0.01).
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionAcknowledgementsReferences |
|---|
Demographic features
A total of 87% of patients were male with a mean age of 51 yrs (S.D. 11.2) and mean disease duration of 18 yrs (S.D. 11.5). The mean BASDAI score was 4.3 (S.D. 2.3; range 0.02–9.2); 56% had a BASDAI score
4.0. The mean BASFI score was 4.4 (S.D. 2.9; range 0.0–9.3). BASDAI and BASFI scores were strongly correlated (r = 0.77; P < 0.001).
Resource utilization
Only direct medical resource use such as clinic visits, inpatient care, technical procedures including radiographic examinations, CT scans, endoscopies, prescribed medications, laboratory tests and physiotherapy were included. Unit costs were obtained from a number of sources [18, 19].
The three most relevant costs were physiotherapy, hospitalization and medication costs at 32, 21 and 20% of the total costs, respectively. Over the course of the year, 30 patients incurred a total of 1127 physiotherapy appointments (mean 38, median 24 for the 30 patients, cohort mean 7.7). The distribution of physiotherapy appointments was skewed, with the majority of patients (22) receiving <45 appointments and six receiving >90 appointments each. The number of physiotherapy appointments significantly correlated with BASDAI and BASFI scores and medication costs (r = 0.50, 0.53 and 0.21; P < 0.01). A further 11 patients attended private physiotherapy (costs not included in this study).
Nineteen patients were hospitalized for a total of 278 inpatient days (mean length of stay 14.6 days). BASDAI and BASFI scores correlated with inpatient days (r = 0.30 and 0.31; P < 0.01). Outpatient appointments correlated with hospital (r = 0.30; P < 0.01) and medication costs (r = 0.42; P < 0.01). Thirty-four percent of the patients received DMARDs and 85% NSAIDs. No patients received anti-TNF agents. Fourteen percent of the patients had treatment to prevent NSAID-related adverse events such as gastric conditions. Over 50% of patients had at least one comorbidity including cardiovascular disease: angina (7%), hypercholesterolaemia (10%) and hypertension (17%) and AS-related disease: iritis (13%) and psoriasis (5%).
Annual direct healthcare costs
The distribution of patients was heavily skewed, with a small number of individuals incurring comparatively high costs. The total annual costs ranged from £101 to £15 973, with an asymmetric distribution. A long distributional tail appears beyond £5000, with just 11 patients having costs concentrated beyond £7000. The mean total annual cost (Table 1) was £1852 (S.D. £2662; median £892).
|
The total annual cost per patient correlated with both disease activity (BASDAI, r = 0.39, P < 0.001) and functional disability (BASFI, r = 0.48, P < 0.001). BASDAI groups <4.0, 4.0–6.0 and >6.0 had mean (median, S.D.) annual costs (Fig. 1) of £1072 (£571, £1947), £1679 (£924, £2263) and £3485 (£2112, £3485), respectively. The corresponding values for patients grouped by BASFI scores <4.0, 4.0–6.0 and >6.0 were £1010 (£571, £1872), £995 (£774, £1199) and £3544 (£1804, £3357). The mean total costs for patients with BASDAI
6.0 and BASFI 6.0 was much greater when compared with patients less severely affected. This increase in cost was partly due to the increase in physiotherapy.
|
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionAcknowledgementsReferences |
|---|
The direct healthcare mean (median) annual costs of patients with AS attending a secondary care rheumatology unit in the UK were £1852 (£892). The distribution of cost data was skewed by a small number of individuals (11/147) incurring high costs and 11% of the individuals incurring 50% of the costs. The median value therefore provides useful information on the typical costs for the majority of less severely affected patients.
The number of high-cost individuals may vary considerably over time and between rheumatology departments. While none of the sample received joint replacements or spinal surgery during the study period, other studies have found that patients with AS do incur these costs. Kobelt et al. [13] reported that 22/1413 patients received joint replacements within a 3-month period (annualized to 6%), and Boonen et al. [1] reported that 7/209 patients received orthopaedic surgery over a 2-yr period (annualized to 7%). Kobelt et al. [14] estimated that 3% of the patients would undergo surgery every year based on 4/545 receiving orthopaedic surgery during a 3-month period. The current study contains a different AS population group, more relevant to most UK rheumatology units, based on secondary rather than tertiary care, in which it is reasonable to expect less severe disease and lower joint replacement rates.
The ratio of direct to indirect costs in patients with AS can be substantial. A US study reported that indirect costs contributed 73% of the total costs [16], and similar ratios have been reported in other studies [13, 20]. When excluding non-medical resources such as informal care, the mean annual direct cost (estimate £1742) derived from a cross-sectional survey of AS patients in Bath is comparable with the mean direct cost (£1852) in the current study. With the exception of patients with severe disease, the changes in mean costs across disease severity in this study are also similar to those in a recent Dutch economic evaluation [20]. Boonen et al. [1] reports direct annual costs of 
1.7k and 4.7k (£1.1k and £3.1k) for BASDAI <4.0 and 4.0, respectively. Our study cohort incurred costs of £1.1k and £2.5k when grouped similarly. Using only the hospitalization and medication data [13], the annual costs incurred by the cohort in Bath were approximately £600, £1.4k and £3.0k for BASDAI and BASFI scores of 2.0, 5.0 and 8.0 while those in the current study were approximately £615, £1.1k and £1.8k, respectively. Further research exploring indirect costs in UK patients should be considered.
Patients with AS incur considerable costs from physiotherapy. While the study cohort had a mean of 7.6 physiotherapy sessions per patient per year, accounting for 32% of the total costs, only 20% received NHS physiotherapy sessions (mean 38, median 24). A further 8% attended privately funded non-NHS group physiotherapy (costs not included in this study). These findings are similar to those observed in other studies. Boonen et al. [1] report that physiotherapy contributes 35% of the direct costs. Kobelt et al. [14] report that 18% of patients received physiotherapy. The provision of physiotherapy differs between countries, settings and providers. Further research into the most efficient provision of physiotherapy, including identifying patients most likely to benefit, would be useful to inform future economic studies in AS.
Prescribed medication accounted for 20% of the total costs in the current study, which is comparable with other findings. Boonen et al. [1] report that pharmaceutical treatments contribute 13, 25 and 30% of total direct costs in AS patients in The Netherlands, Belgium and France, respectively [1].
Several assumptions were used to compute healthcare costs in the current study. Average costs were used to estimate the impact of admission to hospital as there was no access to individual inpatient hospital resource consumption data. Conservative estimates of costs were made, hence underestimation is more likely than overestimation. Only accessible data such as clinical visits, inpatient care, technical procedures, prescribed medications, laboratory-based tests and physiotherapy appointments were included. Future studies would benefit from the inclusion of additional information such as the number of general practitioner visits, over-the-counter medication and formal home care.
This is the first UK study that presents cost data separately according to AS or non-AS-related use. The data show 21% of the total cost was accrued from inpatient costs; however, 75% of this is due to non-AS-related causes. Conversely, while 20% of the total costs were due to medications, only 25% of this was due to non-AS-related causes.
The secondary care centre setting of the study makes it more relevant than those performed in tertiary centres, as patient populations in tertiary centres tend to be skewed to include more severely affected individuals. Patient selection was restricted to patients receiving rheumatologists’ care, who may receive more intense treatment than patients cared for in the community. However, the sample covered the full spectrum of disease activity and functional disability, giving an indication of the direct health care costs across the spectrum of AS patients.
Our results indicate that disease duration does not impact on the direct costs. This might suggest that patients with severe disease and subsequently higher resource requirements reach a plateau of need reasonably early in disease. If these patients could be reliably identified, intervention in this group with effective treatment such as biological therapy early in their disease course could have a large effect on diminishing disease impact, functional deterioration and both direct and indirect costs.
|
Conclusion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionAcknowledgementsReferences |
|---|
Direct healthcare costs associated with AS patients attending a UK secondary care rheumatology unit accelerate steeply with both disease activity and increasing loss of function. The significant cost of biological treatments that are used to control disease activity and maintain patients’ function might be offset by the high cost associated with those patients with the most severe disease.
|
Acknowledgements |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionAcknowledgementsReferences |
|---|
We are grateful to Tracey Young for advice.
Funding: This study was supported with an unrestricted educational research grant from Wyeth Pharmaceuticals. Wyeth had no influence on findings or interpretation. Wyeth had no influence on findings or interpretation.
Disclosure statement: J.C.P. has received an unrestricted educational grant from Wyeth Pharmaceuticals. All other authors have declared no conflicts of interest.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionAcknowledgementsReferences |
|---|
- Boonen A, van der Heijde D, Landewe R, et al. Direct costs of ankylosing spondylitis and its determinants: an analysis among three European countries. Ann Rheum Dis (2003) 62:732–40.
[Abstract/Free Full Text] - Russell A. Ankylosing spondylitis: history (2007) London: Mosby. 1–2.
- Boonen A, de Vet H, van der Heijde D, van der Linden S. Work status and its determinants among patients with ankylosing spondylitis. A systematic review of the literature. J Rheumatol (2001) 28:1056–62.
[Abstract/Free Full Text] - Keat A. BSR guideline for prescribing TNF alpha blockers in adults with ankylosing spondylitis. Rheumatology (2005) 44:939–47.
[Free Full Text] - Creemers M, Franssen M, van der Putte L, Gribnau F, van Riel P. Methotrexate in severe ankylosing spondylitis: an open study. J Rheumatol (1995) 22:1104–7.[Web of Science][Medline]
- Dougados M, van der Linden S, Leirisalo-Repo M, et al. Sulphasalazine in the treatment of spondyloarthropathy: a randomised, multicentre, double-blind placebo controlled study. Arthritis Rheum (1995) 38:618–27.[Web of Science][Medline]
- Davis J, van der Heijde D, Braun J, et al. Recombinant tumor necrosis factor receptor (etanercept) for treating ankylosing spondylitis. Arthritis Rheum (2003) 48:3230–6.[CrossRef][Web of Science][Medline]
- Van der Heijde D, Da Silva J, Dougados M, et al. Once-weekly 50-mg dosing of etanercept is as effective as twice-weekly dosing in patients with ankylosing spondylitis. (2006) Abstract EULAR [SAT0195].
- Braun J, Pham T, Sieper J, et al. International ASAS consensus statement for the use of anti-tumour necrosis factor agents in patients with ankylosing spondylitis. Ann Rheum Dis (2003) 62:817–24.
[Abstract/Free Full Text] - Garrett S, Jenkinson T, Kennedy L, Whitelock H, Gaisford P, Calin A. A new approach to defining disease status in ankylosing spondylitis: the Bath Ankylosing Spondylitis Disease Activity Index. J Rheumatol (1994) 21:2286–91.[Web of Science][Medline]
- Boonen A. A review of work participation, cost of illness and cost-effectiveness studies in ankylosing spondylitis. Nat Clin Pract Rheumatol (2006) 2:546–53.[CrossRef][Web of Science][Medline]
- Boonen A, van der Heijde D. Review of the cost of illness of ankylosing spondylitis and methodological notes. Expert Rev Pharmacoecon Outcome Res (2005) 5:163–81.[CrossRef]
- Kobelt G, Andlin-Sobocki P, Brophy S, Jonsson L. The burden of ankylosing spondylitis and the cost-effectiveness of treatment with infliximab (Remicade(R)). Rheumatology (2004) 43:1158–66.
[Abstract/Free Full Text] - Kobelt G, Andlin-Sobocki P, Maksymowych WP. Costs and quality of life of patients with ankylosing spondylitis in Canada. J Rheumatol (2006) 33:289–95.
[Abstract/Free Full Text] - Ward MM. Functional disability predicts total costs in patients with ankylosing spondylitis. Arthritis Rheum (2002) 46:223–31.[CrossRef][Web of Science][Medline]
- Calin A, Garrett S, Whitelock H, et al. A new approach to defining functional ability in ankylosing spondylitis: the development of the Bath Ankylosing Spondylitis Functional Index. J Rheumatol (1994) 21:2281–5.[Web of Science][Medline]
- van der Linden S, Valkenberg H, Cats A. Evaluation of diagnostic criteria for ankylosing spondylitis – a proposal for modification of the New York criteria. Arthritis Rheum (1984) 27:361–8.[Web of Science][Medline]
- British National Formulary. BNF 2007. (1 December 2005, date last accessed). http://www.bnf.org/bnf/.
- Curtis L, Netten A. Unit costs of health and social care 2005. (1 December 2005, date last accessed). http://www.pssru.ac.uk.
- Boonen A, van der Heijde D, Severens J, Boemdermaker A. Markov model into the cost-utility over five years of etanercept and infliximab compared to usual care in patients with active ankylosing spondylitis. Ann Rheum Dis (2006) 65:201–8.
[Abstract/Free Full Text]
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  J. A. SINGH and V. STRAND Spondyloarthritis Is Associated with Poor Function and Physical Health-Related Quality of Life J Rheumatol, May 1, 2009; 36(5): 1012 - 1020. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||