Cost of illness of inflammatory bowel disease in the UK: a single centre retrospective study

Abstract

Background and aims: The potentially high costs of care associated with inflammatory bowel disease (IBD) are recognised but we have little knowledge of the scale, profile, or determinants of these costs in the UK. This study aimed to describe costs of illness for a group of IBD patients and determine factors associated with increased healthcare costs.

Setting: A university hospital serving a target population of approximately 330 000.

Patients and methods: A six month cohort of IBD patients receiving any form of secondary care was identified, comprising 307 cases of ulcerative (or indeterminate) colitis and 172 cases of Crohn's disease. Demographic and clinical data were abstracted from clinical records and individual resource use was itemised for all attributable costs (including extraintestinal manifestations). Item costs were derived from national and local sources. Cost data were expressed as mean six month costs per patient (with 95% confidence interval (CI)) obtained using non-parametric bootstrapping. Determinants of cost were analysed using generalised linear regression modelling. A postal survey of patients was undertaken to examine indirect costs, out of pocket expenses, and primary care visits.

Results: Inpatient services (medical and/or surgical) were required by 67 patients (14%) but accounted for 49% of total secondary care costs. Drug costs accounted for less than a quarter of total costs. Individual patient costs ranged from 73 to 33,254 UK pounds per six months. Mean (95% CI) six month costs per patient were 1256 UK pounds ( 988 pounds, 1721 pounds) for colitis and 1652 UK pounds (1221 pounds, 2239 pounds) for Crohn's disease. Hospitalisation, disease severity grade, and disease extent correlated positively with cost of illness but costs were independent of age or sex. Compared with quiescent cases of IBD, disease relapse was associated with a 2-3-fold increase in costs for non-hospitalised cases and a 20-fold increase in costs for hospitalised cases. Survey data suggested average six month costs were < 30 UK pounds per patient for primary care visits (both diseases) and median loss of earnings were 239 UK pounds for colitis and 299 UK pounds for Crohn's disease.

Conclusions: This study represents the first detailed characterisation of the scale and determinants of costs of illness for IBD in a British hospital. Hospitalisation affected a minority of sufferers but accounted for half of the total direct costs falling on the healthcare system.

Figure 1

Contribution of different items and services to six month direct costs of care for inflammatory bowel disease patients (as per cent of totals). ASA, aminosalicylic acids; OP, outpatient; IP, inpatient.

Figure 2

Frequency distribution of individual patient direct costs (per six months) in Crohn’s disease (A) and ulcerative colitis (B). *Two outlying costs (£29 167 and £33 254) are not displayed.

Figure 3

Mean (95% confidence interval) six month costs versus disease severity in Crohn’s disease (A) and ulcerative colitis (B). Rem, remission; Mild, mild disease; S-Resp, severe disease, drug responsive; S-Dep, severe disease, drug dependent; S-Ref, severe disease, drug refractory; Surg, surgery; PS, rem; post surgical remission.

Figure 4

Mean (95% confidence interval) six month costs versus disease extent.