Observational Study Evaluating the Economic Impact of Breakthrough Pain in Cancer Patients in Clinical Practice in Spain: The IMDI Study

INTRODUCTION: Breakthrough pain (BTP) has great repercussions on the quality of life, and on the use of health resources. The scope of BTP costs in cancer patients is unknown. The purpose of this study was to evaluate the economic cost of BTP in patients with cancer and the relationship with their quality of life. METHODS: A 1-month observational prospective cost-of-illness study was designed. The patients recorded the consumption of health resources and drugs related to BTP in a diary. The current symptoms in Edmonton Symptoms Assessment Scale (ESAS) and their quality of life (EORTC QLQ-C30, version 3) were assessed. The direct medical and non-medical costs fixed and variable and the indirect costs of the patient and the caregivers were evaluated. Factors related to cost and quality of life were identified using linear generalized models (LGM) type gamma and logistic link. Participants were oncologic patients with BTP, older than 18 years, with controlled basal pain. RESULTS: Eight Spanish pain units, eight palliative care units, and one oncology department included 152 patients. One hundred patients (65.8%) were male and the mean age was 66.8 years (95% CI 64.8–68.8). The total cost per patient was 2941.60 euros per month: 88% direct medical costs, 5% non-medical direct costs, and 7% indirect costs due to lost productivity. A better score in EORTC QLQ-30 quality of life was associated with a reduction in overall costs. CONCLUSIONS: The study showed the results of the first real-life prospective study evaluating the cost of illness of BTP in cancer patients demonstrating that the presence of breakthrough pain in a cancer patient causes a very significant increase in healthcare costs. FUNDING: Kyowa Kirin Farmacéutica, S.L.U.