The Economic Impact of Irritable Bowel Syndrome

J. M. Inadomi, M. B. Fennerty, D. Bjorkman


Aliment Pharmacol Ther. 2003;18(7) 

In This Article


The search strategy yielded 95 published manuscripts from the MEDLINE database. Seventy-four additional references were obtained from the EMBASE database and five additional studies through PreMEDLINE. No additional published studies were noted in the databases of Current Contents or the Cochrane Library. When duplicate entries had been accounted for, there were 174 published manuscripts identified. The review of each manuscript identified 11 articles that met all the inclusion criteria ( Table 1 and Table 2 ). There were six studies using data derived from the USA, three from the UK and one each from Canada and Italy. Nine studies reported mean or median per patient direct costs, one reported total direct costs for the entire US population, and one stated both per patient and total (UK) costs. Productivity costs were stated per patient in three studies, total for the US population in one study, and were not reported in the remaining seven studies.

The studies presented in this review used several methods of cost calculation. The most common method was to abstract mean patient resource utilization, such as the number of clinic visits, hospitalizations and procedures, through chart reviews or insurance databases, and to combine these data with the mean unit costs of each resource, derived from local or national accounting databases. An alternative method was to follow a cohort of subjects via a cost-accounting system to capture the charges or costs incurred over time to manage irritable bowel syndrome-related symptoms. Two studies looked only at the cost of evaluation to obtain a diagnosis of irritable bowel syndrome, modelling the resource use of hypothetical cohorts of patients and national cost data. It should be emphasized that, whilst some studies evaluated the resource utilization directly related to irritable bowel syndrome care, other studies reported resource consumption for all health care of irritable bowel syndrome patients, thereby including costs incurred for the management of non-irritable bowel syndrome diagnoses.

Direct Costs of Irritable Bowel Syndrome. Combined data on direct health care resource utilization are presented in Table 3 . Talley et al. performed a population-based study using postal surveys to identify subjects who had irritable bowel syndrome by the Manning criteria.[24] This was the only study included in this review that examined subjects even if they had not consulted a physician for symptoms of irritable bowel syndrome. Two previously validated surveys (Bowel Disease Questionnaire and Elderly Bowel Symptoms Questionnaire) were administered to the population of Caucasians living in Olmstead County, MN, USA. The economic impact was based on charge data (not costs) from the Mayo Clinic and Olmstead Medical Group, and included out-patient, emergency room, in-patient and procedural services (facility and physician) and laboratory and radiology charges, but excluded out-patient medication. The authors reported charges accumulated for all health care, thereby potentially including charges for the management of non-irritable bowel syndrome diagnoses. Median direct health care charges were estimated at US$742 per irritable bowel syndrome patient annually (25-75% quartiles, US$177-1654).

Coremans et al. estimated the initial cost of diagnostic tests to the Italian National Health Service in the evaluation of patients with irritable bowel syndrome.[25] Providing a complete blood count with differential, erythrocyte sedimentation rate, faecal occult blood test, flexible sigmoidoscopy and lactose tolerance test would translate to US$55, equating to 0.093% of the Italian National Health Service budget. The costs of management for irritable bowel syndrome beyond the initial diagnosis were not considered in this study.

The cost of caring for irritable bowel syndrome patients in the UK was reported in a study by Wells et al.[26] The mean unit costs of medication and of out-patient or in-patient services provided by general practitioners and gastroenterologists were combined with national irritable bowel syndrome prevalence and resource utilization data to estimate the total direct health care costs. National records were also used to calculate the annual number of visits to general practitioners per irritable bowel syndrome patient, and the average cost per visit. A market research study of general practitioners estimated the number of medications prescribed per year, and these data were combined with the average cost per prescription to determine the pharmaceutical expenditure for irritable bowel syndrome. Additional surveys were conducted to determine the number of irritable bowel syndrome patients seen yearly by gastroenterologists and the proportion admitted to hospital. National data were used to determine the number of gastroenterology consultants in the UK and the average cost per consultant visit and hospital admission to determine in-patient and out-patient costs. Through the compilation of these cost data, it was estimated that £45.6 million was spent annually in the UK for irritable bowel syndrome care, translating into approximately £90 annually in costs per patient.

The annual mean direct costs of caring for irritable bowel syndrome patients in Canada were estimated at Canadian$259.[27] In this study by Bentkover et al., the investigators reviewed the medical records of 120 irritable bowel syndrome patients to estimate resource utilization for medical services, including physician fees, procedures and drugs. They calculated the unit costs of providing these services from provincial reimbursement registers and private insurance plan reimbursement, and combined these data with the prevalence of irritable bowel syndrome to calculate the total direct costs expended in Canada. This study limited costs to those directly related to irritable bowel syndrome care.

Levy et al. reported the total direct costs of providing all health care in 373 patients identified in medical records as having been diagnosed with irritable bowel syndrome (criteria for diagnosis not stated).[28] The costs were from the perspective of the health maintenance organization in the state of Washington, and included out-patient, in-patient and prescription drug costs. Total mean costs per patient were estimated to be US$9497 over the 3-year period of analysis, and included not only irritable bowel syndrome care costs but also costs of unrelated medical diagnoses. The authors found that the total costs of health care delivery in irritable bowel syndrome patients were significantly greater than those expended for non-irritable bowel syndrome patients. In a related study, the authors examined direct costs limited to the management of irritable bowel syndrome-related diagnoses.[29] Using the same health maintenance organization database, 3153 patients with an irritable bowel syndrome diagnosis [identified by International Classification of Diseases, Ninth Revision (ICD-9) codes] were tracked via a cost accounting system to calculate the expenditure 1 year prior to (to capture evaluation costs) to 2 years after the first health care encounter for irritable bowel syndrome. They estimated the mean direct cost of irritable bowel syndrome care to be US$619 per patient annually. It should be noted that the total cost of all health care for irritable bowel syndrome patients remained significantly greater than that of health maintenance organization enrolees without an irritable bowel syndrome diagnosis, but only 33% of the difference in the total cost of care was due to lower gastrointestinal-related services.

Creed et al. examined patients in the UK with severe disease, defined as irritable bowel syndrome patients (Rome criteria) with persistent symptoms despite medical therapy including education, dietary advice, anti-spasmodic agents, laxatives or anti-diarrhoeals.[30] The records of 257 patients in a prospective trial of medical vs. psychotherapy were abstracted to determine the resource use related to in-patient, out-patient and non-hospital health care encounters, prescription medication and alternative medical therapy (such as reflexology). Unit costs were assigned to these services, as well as to direct non-health care costs such as travel, non-prescription drugs, childcare and housework or personal care. The mean per patient cost over a 12-month period was estimated to be US$1743. This figure represented the total health care costs that were incurred annually and was not limited to irritable bowel syndrome management.

The costs of providing a diagnosis of irritable bowel syndrome in patients were also estimated through computer modelling by Suleiman and Sonnenberg.[31] The costs of diagnosis from the perspective of a third-party insurer ranged from US$320 for providing a history and physical examination, basic laboratory tests and a breath test for bacterial overgrowth, to US$1212 for adding colonoscopy with biopsy and radiological small bowel study. No further management costs were considered in this modelling analysis.

A managed care perspective of irritable bowel syndromecosts was studied by Patel et al.[32] Health care utilization of irritable bowel syndrome patients was captured during the year before and the year after the first clinical encounter in which an ICD-9 code (564.1) was documented. The investigators tracked emergency department, in-patient, out-patient, medication, procedural and laboratory charges (not costs) through a claims database. The reported values represented the total health care expenditure and were not limited to irritable bowel syndrome management. Median charges per patient were US$2237 during the year preceding and US$2504 during the year following the index encounter.

Akehurst et al. reviewed the medical records of irritable bowel syndrome patients (Rome I criteria) in six practices in the UK to determine resource use, including medication, in-patient, out-patient, emergency department or home visits.[33] Unit costs for these resources were derived from nationally published estimates and local provider unit financial returns. Costs were not limited to irritable bowel syndrome-related health care encounters, and thus total health care consumption was reported in this study. The mean direct cost per patient per year was calculated to be £316 (median cost, £160).

Most recently, Sandler et al. provided an estimate of the total cost of irritable bowel syndrome to the US healthcare system.[10] In this study, four databases (National Hospital Discharge Survey, National Ambulatory Medical Care Survey, National Hospital Medical Care Survey and the Group Health Cooperative of Puget Sound claims database) were used to estimate resource use and unit costs for each resource. The costs included hospital facility costs, out-patient and in-patient physician costs, out-patient hospital costs for procedures and pharmaceutical therapy costs that were derived from charge data using cost-to-charge ratios. In addition, costs were weighted on the basis of whether irritable bowel syndrome was the primary or secondary diagnosis for each health care encounter. The total direct cost for irritable bowel syndrome care in the US was estimated to be over $1.3 billion annually.

The proportions of direct health care resources expended through in-patient and out-patient services and for medication are shown in Figure 1. Only studies reporting these sub-categories were included. The estimates vary widely, with in-patient services accounting for 7-80% of the total direct health care costs, out-patient services responsible for 16-68% of the costs and medication use responsible for 2-27% of the costs. It should be noted that the studies varied geographically, by the perspective of the analysis, in reporting costs vs. charges and by the source of their cost estimates, thus affecting not only the absolute value but also the relative proportion spent in each cost category.

Proportion of direct health care resources allocated to in-patient or out-patient services or medication.

Productivity (Indirect) Costs of Irritable Bowel Syndrome. Four studies reported the productivity costs associated with irritable bowel syndrome ( Table 4 ). The study by Akehurst et al. reported that 46/102 (45%) irritable bowel syndrome patients had taken time off work related to symptoms of their disease, and that 15% had taken more than 1 week off work in the previous 3 months prior to entry into the study.[33] This study did not translate the productivity losses into monetary units.

The analysis by Bentkover et al. estimated productivity costs of Canadian $748 annually.[27] This estimate was based on lost time at work valued at the mean Canadian wage rate. Creed et al. likewise limited productivity costs to work productivity losses, estimated to be US$335 annually.[30] Finally, Sandler et al. calculated productivity costs by combining the time away from work due to health care encounters for clinic visits, hospitalizations and procedures with National Statistical Abstract 2000 data on age- and gender-specific wage estimates.[10] The total productivity cost for the US was estimated to be US$205 million annually. It should be noted that none of the studies identified in this review were able to report data concerning decreases in work productivity due to disease morbidity, nor intangible costs incurred as a result of pain or decrement in the quality of life.

Total Costs of Irritable Bowel Syndrome. Three studies reported both direct and productivity costs of irritable bowel syndromecare ( Table 5 ). The annual mean costs related to irritable bowel syndrome management were estimated to be Canadian$1007 per patient.[27] The total health care costs for 'severe irritable bowel syndrome patients' in the UK were equivalent to US$2078.[30] The total (direct and productivity) cost related to irritable bowel syndrome management in the USA was estimated to be US$1.56 billion annually (1998 dollars).[10] It is reiterated that these cost data may be underestimates due to the lack of inclusion of additional productivity costs, such as those due to impaired ability to work or to enjoy leisure activities.

Several studies reported the difference in health care expenditure between individuals with irritable bowel syndrome or irritable bowel syndrome symptoms and control populations without irritable bowel syndrome symptoms. The study of subjects with irritable bowel syndrome in Olmstead County, MN, USA showed that the odds of incurring some direct medical cost were significantly greater in subjects with irritable bowel syndrome symptoms than in those without symptoms.[24] In this study, median annual charges amongst subjects identified with irritable bowel syndrome were US$742, compared with US$429 spent on controls without irritable bowel syndrome. In the two studies performed by Levy et al., direct health care costs were significantly higher in irritable bowel syndrome patients than in population controls.[28,29] Annual per person costs related to lower gastrointestinal diagnoses were higher amongst irritable bowel syndrome patients than in controls (US$619 vs. US$102, respectively; P< 0.05), as were costs for all health care provided (US$4044 vs. US$2719; P< 0.05). Similar results based on charges were obtained by Patel et al.; patients with irritable bowel syndrome had significantly higher out-patient, drug and total charges compared with controls without irritable bowel syndrome.[32] Lastly, National Health Service costs in the UK were found to be significantly higher in irritable bowel syndrome patients (£316.20; s.d., £474.66) than in non-irritable bowel syndrome control patients (£192.87; s.d., £373.29).[33]

Two studies compared the costs of irritable bowel syndrome with the costs required to manage other gastrointestinal diseases.[10,29] Compared with the estimated US$1.56 billion (1998 dollars) for direct and indirect irritable bowel syndrome costs, Sandler et al. estimated gastro-oesophageal reflux disease to be associated with total costs reaching US$9.8 billion. Other notable diseases with high costs included gall-bladder disease (US$6 billion), colorectal cancer (US$5 billion) and peptic ulcer disease (US$3.3 billion).[10] Levy et al. reported that the annual mean direct health care costs for patients with irritable bowel syndrome [US$4376; 95% confidence interval (CI), US$4039-4713] were substantially less than those of patients with inflammatory bowel disease (US$7237; 95% CI, US$6539-7935), but similar to those of patients with gastro-oesophageal reflux disease (US$5144; 95% CI, US$4877-5411).[29] It should be noted that the latter study did not include indirect costs, and that the Sandler et al. study reported national expenditure that takes into account the prevalence of irritable bowel syndrome. These differences may account for the discrepancy in the estimates of the costs between the studies.

Several studies examined demographic variables associated with resource use in irritable bowel syndrome. Increasing age,[24] higher education[24] and female gender[29,30] were associated with higher costs, although one study reported that gender was not a significant predictor of costs.[24] Mean costs between irritable bowel syndrome sub-groups did not differ significantly in one study, although pain-predominant subjects experienced a trend towards higher costs than constipation- or diarrhoea-predominant subjects.[30]


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