title: Medication adherence and persistence in severe obstructive sleep apnea.
abstract: OBJECTIVE
  The aim of this study was to compare 2 groups of patients with severe obstructive sleep apnea (OSA) who were taking medication for cardiovascular disease: those who were compliant with nasal continuous positive airway pressure (CPAP) treatment and those who refused treatment or were noncompliant with CPAP treament.
  
  
  METHODS
  In a cohort of 2158 patients with severe OSA (apnea-hypopnea index >30) a 2-year prospective longitudinal assessment of adherence and persistence with 3 medication categories (antihypertensives, statins, and antiplatelets) was carried out using the administrative database of the National Health Service. Medication adherence was evaluated by calculating the medication possession ratio (%MPR = days supplylactual days to refill x 100) for each drug. Medication persistency was defined as the proportion of subjects having filled a prescription in the last 30 days of the 2-year period. CPAP use was assessed at every follow-up visit after the treatment was prescribed. Medication adherence was compared between patients who had adequate CPAP adherence (> 4 h/day) and those who declined CPAP therapy or had discontinued CPAP due to an average use of less than 4 hours per day.
  
  
  RESULTS
  The average 2-year MPR for antihypertensives, statins, and antiplatelets was not different among patients who used CPAP (88%, 81%, 95%) or did not use CPAP (86%, 77%, 93%). Female sex and increased number of comorbidities were predictors of good medication adherence (MPR > 80%). The rates of persistence for the 3 studied medications after the 2-year observation period were not different between the 2 groups (patients with or without CPAP).
  
  
  CONCLUSIONS
  Medication adherence and persistence during a 2-year period for 3 well-known protective cardiovascular medications were not different in patients with severe OSA, whether or not they were treated with CPAP.
authors.affiliation: Pharmacy Services, Hospital Universitario Miguel Servet, Zaragoza, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Villar
authors.forename: Monica
authors.initials: M
authors.lastname: Izuel
authors.forename: Santiago
authors.initials: S
authors.lastname: Carrizo
authors.forename: Eugenio
authors.initials: E
authors.lastname: Vicente
authors.forename: Jose M
authors.initials: JM
authors.lastname: Marin
mesh_terms: D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000008:administration & dosage; D002318:Cardiovascular Diseases / Q000188:drug therapy* / Q000453:epidemiology*; D015331:Cohort Studies; D015897:Comorbidity; D045422:Continuous Positive Airway Pressure / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000008:administration & dosage; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage; D011446:Prospective Studies; D012737:Sex Factors; D020181:Sleep Apnea, Obstructive / Q000453:epidemiology*; D013030:Spain; D016903:Drug Monitoring
chemical_list: D000959:Antihypertensive Agents; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D010975:Platelet Aggregation Inhibitors