[Cost measurement based on a cost diary in patients with inflammatory bowel disease]

Cost diaries administered by patients have been used as a method to measure costs for different diseases. Our aim was to test the application of a patient cost diary in patients with inflammatory bowel disease (IBD) and to measure disease specific resource utilization and costs.

A specific patient cost diary for IBD was developed and tested in a prospective pilot study. 105 outpatients with IBD of a University Hospital agreed to participate over a 4 week follow-up period. They were asked to report weekly their use of medical care and costs related to their illness. Visits to health care providers, hospitalizations, drug use, costs due to absence from paid and unpaid work, travel costs as well as out-of-pocket expenses were considered.

The response rate was 90 %. Almost 70 % of the patients estimated the diary as easy to fill in. Compared with other data sources, the cost measurement using the cost diary showed good agreement regarding costs of drug therapy and outpatient hospital treatment. Mean costs due to illness were estimated to be 1,500 Euro per 4 weeks. This corresponds to total costs of about 20,000 Euro per year of care. 69 % of total costs were indirect costs due to illness-related absence from work, days of inactivity at home, and early retirement. Direct health care and direct non health care costs (e. g. travel costs) were responsible for 27 % and 4 % of costs, respectively.

The presented instrument offers a suitable and practical method of assessing IBD-related resource utilization. The prospectively obtained data for direct medical and non medical, as well as indirect costs allow a cost measurement from the societal perspective. The presented cost diary can be used for measuring costs for economic evaluations of medical interventions.