Abstract

Background: A successful of home treatment is strongly influenced by patient adherence to treatment. Non-adherence represents not only an important issue for the patient, affecting both the clinical efficacy and safety of the medication regimen, but also has economical and social implication for the community. Objective: The aim of this study is to evaluate medication adherence, persistence to treatment and daily cost of therapy in patients with prostate cancer treated with gonadotropin-releasing hormone agonists, comparing Leuprorelin 3.75mg-11.25mg and Triptorelin 3.75mg-11.25mg.

Materials and Methods: The study was carried out from 2007 to 2012 in an Italian Hospital in Pescara. This is a General Hospital with 800 beds. Medication adherence was measured as the ratio between the Received Daily Dose (RDD) and the Prescribed Daily Dose (PDD), using software developed ad hoc by the hospital pharmacists. The RDD was calculated dividing the dose of drug dispensed in a pharmacy refill by the sum of days between two consecutive drug refills. PDD was determined in basis of the treatment regimen as prescribed by physician. The non-persistence was calculated like the effective days of treatment, that is the sum of days elapsing between the first and the last pharmacy refill, plus the days of treatment supplied with the last refill, minus the days of non-persistence, and it was graphically represented by the Kaplan Meier curves. The daily cost of treatment was calculated on the basis of the RDD.

Results: The patients included in this study were 239 for Leuprorelin and 199 for Triptorelin. The adherence values for all drugs ranged between from 0.92 to 1.00, showing good quality management of treatment at home. The analysis of non-persistence conducted in four years (with patients included until 31 December 2007) showed a decrease by a 21% for Leuprorelin and 38% for Triptorelin, using the Log Rank Test the persistence for two drugs are not significantly different. The cost per RDD was of € 2.24 for Leuprorelin and € 2.84 for Triptorelin.

Conclusion: Often health personnel have not a precise idea on behavior of patient in home therapy for chronic disease; calculation of adherence is very important to know what the real pharmacoutilization of drugs is, and our results showed a good profile of medication adherence for both drugs studied. Economic results give a difference of 60 cent per day, one year of therapy with Triptorelin is approximately € 219 more expensive than Leuprorelin per patient; we think that this kind of comparisons would be encouraged, that could be really useful for decisors of National Regulatory Agencies to negotiate the pricing of drugs on the basis of the real utilization in clinical practice, and for clinicians to make a good cost-effectiveness choice.