Introduction: Low adherence and persistence values, which indicate real-life efficiency, have been widely reported in patients suffering from COPD (Chronic Obstructive Pulmonary Disease). Poor adherence may be related to treatment dosage, thus, simplifying the dosing regimen might improve adherence. The objective of the present study was either to evaluate adherence and persistence in primary drugs used in COPD treatment after 3 years in real life and assess whether the different dosing regimen affects adherence levels to therapy.
Materials and methods: A pharmacological, observational, non-interventional, retrospective study was carried out by taking into consideration the drugs dispensed between 1 January 2011 and 31 December 2018 at the hospital pharmacy of Pescara. Adherence was reckoned as the ratio between Received Daily Dose (RDD) and Prescribed Daily Dose (PDD). Treatment persistence was reckoned as the time from the start of treatment until its discontinuation. The evaluation of the two drug used indices was carried out by using three different dose regimens: Defined Daily Dose (DDD), minimum daily dose, maximum daily dose.
Results: During the study period, 52,374 patients met the inclusion criteria, and after applying the exclusion criteria, 3432, 3608, and 3594 were eligible for analysis by maximum daily, dose, DDD, and minimum daily dose, respectively. For the majority of active ingredients, adherence data was less than 0.8, that is the cut-off universally accepted as ideal value for adherence. In terms of adherence, a statistically significant difference has been highlighted in active ingredients requiring a single daily inhalation, with respect to active ingredients requiring multiple inhalations. Persistence curves have shown no statistically significant difference.
Conclusions: It would be appropriate to promote the use of drugs which require a single daily dose in order to improve adherence in these patients.
Keywords: COPD; adherence; dosing regimen; inhaled drug; persistence; real life.