Abstract
BACKGROUND: Orphan drugs have a high economic impact with a small number of patients. In recent years their prescription has significantly increased. PURPOSE: To describe and to analyse the evolution of expenditure on orphan drugs according to the diagnosis. MATERIAL AND METHODS: Retrospective study that includes all the patients for whom orphan drugs have been dispensed from January 2014 to December 2016. The parameters specified were: number of patients per drug, per diagnosis and per economic expenditure(€), and percentage of total expenditure and annual expenditure. The data were obtained from the optimised computerised order entry ATHOS(®) software and collected in an Excel(®) database designed for this purpose. RESULTS: TWENTY-SEVEN ACTIVE SUBSTANCES WERE IDENTIFIED: The number of patients was 252, 279 and 295 in the years 2014, 2015 and 2016 respectively, with a total expenditure of €16.219,960 that was distributed in 29%, 33% and 38% respectively. The diagnoses that supposed a greater expense (% of annual expense) were: metabolic disease 33%, 34%, 37%; multiple myeloma 20%, 22%, 23%; oncologic disease 16%, 18%, 22%; pulmonary hypertension 20%, 15%, 5%; and paroxysmal nocturnal haemoglobinuria 7%, 6%, 6%. The percentage of patients in relation to the diagnosis was constant during the three years, being that oncology and multiple myeloma presented the highest number of patients (38%), followed by pulmonary hypertension (6.3%) and metabolic disease (1.9%). With regard to the total expenditure of three years, metabolic diseases accounted for 35%, multiple myeloma 22%, oncology diseases 19%, pulmonary hypertension 13% and paroxysmal nocturnal haemoglobinuria 6%. Regarding drugs, lenalidomide accounted for 21% of total expenditure, followed by agalsidase alfa with 12%, alglucosidase alfa 7%, eculizumab 6%, nilotinib 5% and brentuximab 2%. Regarding the average expenditure per patient/year, paroxysmal nocturnal haemoglobinuria entailed a cost per patient of €317.808, followed by metabolic disease with €118.326, multiple myeloma €20.119 and oncology disease €4.075. Spending on orphan drugs was approximately 15% of the total hospital pharmacy consumption. CONCLUSION: In the last three years, the number of patients with prescribed orphan drugs has increased, with a rise of €1.3 million. Metabolic diseases are one of the biggest expenses every year, with a very small number of patients and a high cost per patient/year. No conflict of interest