title: Initial medication non-adherence: prevalence and predictive factors in a cohort of 1.6 million primary care patients.
abstract: Adherence to medicines is vital in treating diseases. Initial medication non-adherence (IMNA) - defined as not obtaining a medication the first time it is prescribed - has been poorly explored. Previous studies show IMNA rates between 6 and 28% in primary care (PC). The aims of this study were to determine prevalence and predictive factors of IMNA in the most prescribed and expensive pharmacotherapeutic groups in the Catalan health system.
  
  
  
  This is a retrospective, register-based cohort study which linked the Catalan PC System (Spain) prescription and invoicing databases. Medication was considered non-initiated when it was not collected from the pharmacy by the end of the month following the one in which it was prescribed. IMNA prevalence was calculated using July 2013-June 2014 prescription data. Predictive factors related to patients, general practitioners and PC centres were identified through multilevel logistic regression analyses. Missing data were attributed using simple imputation.
  
  
  
  Some 1.6 million patients with 2.9 million prescriptions were included in the study sample. Total IMNA prevalence was 17.6% of prescriptions. The highest IMNA rate was observed in anilides (22.6%) and the lowest in angiotensin-converting-enzyme (ACE) inhibitors (7.4%). Predictors of IMNA are younger age, American nationality, having a pain-related or mental disorder and being treated by a substitute/resident general practitioner in a resident-training centre.
  
  
  
  The rate of IMNA is high when all medications are taken into account. Attempts to strengthen trust in resident general practitioners and improve motivation to initiate a needed medication in the general young and older immigrant population should be addressed in Catalan PC.
authors.affiliation: Teaching, Research & Innovation Unit, Fundació Sant Joan de Déu, Esplugues de Llobregat, Spain.|Primary Care Prevention and Health Promotion Research Network (redIAPP), Barcelona, Spain.|School of Pharmacy, University of Barcelona, Barcelona, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Aznar-Lou
authors.affiliation: Mental Health Policy Unit, The Brain and Mind Research Institute; and Centre for Disability Research and Policy, Faculty of Health Sciences, University of Sydney, Sydney, Australia.
authors.forename: Ana
authors.initials: A
authors.lastname: Fernández
authors.affiliation: Teaching, Research & Innovation Unit, Fundació Sant Joan de Déu, Esplugues de Llobregat, Spain.
authors.forename: Montserrat
authors.initials: M
authors.lastname: Gil-Girbau
authors.affiliation: Faculty of Health and Sport Sciences, University of Zaragoza, Huesca, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Fajó-Pascual
authors.affiliation: Primary Care Prevention and Health Promotion Research Network (redIAPP), Barcelona, Spain.|Unidad de Investigación del Distrito Sanitario de Atención Primaria Málaga-Guadalhorce, Málaga, Spain; Instituto de Investigación Biomédica de Málaga (IBIMA), Málaga, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Moreno-Peral
authors.affiliation: Insitut Catalá de la Salut (ICS), Catalonia, Spain.
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Peñarrubia-María
authors.affiliation: Primary Care Prevention and Health Promotion Research Network (redIAPP), Barcelona, Spain.|Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Spain.
authors.forename: Antoni
authors.initials: A
authors.lastname: Serrano-Blanco
authors.affiliation: Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Spain.|CIBER en Epidemiología y Salud Pública, CIBERESP, Spain.
authors.forename: Albert
authors.initials: A
authors.lastname: Sánchez-Niubó
authors.affiliation: School of Pharmacy, University of Barcelona, Barcelona, Spain.
authors.forename: María Antonia
authors.initials: MA
authors.lastname: March-Pujol
authors.affiliation: Insitut Catalá de la Salut (ICS), Catalonia, Spain.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Jové
authors.affiliation: Teaching, Research & Innovation Unit, Fundació Sant Joan de Déu, Esplugues de Llobregat, Spain.|Primary Care Prevention and Health Promotion Research Network (redIAPP), Barcelona, Spain.|School of Pharmacy, University of Barcelona, Barcelona, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Rubio-Valera
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D011307:Drug Prescriptions; D005260:Female; D005544:Forecasting; D058005:General Practitioners; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000150:complications / Q000453:epidemiology; D008875:Middle Aged; D010146:Pain / Q000150:complications / Q000453:epidemiology; D015995:Prevalence; D011320:Primary Health Care / Q000706:statistics & numerical data*; D012042:Registries; D012189:Retrospective Studies; D012959:Socioeconomic Factors; D013030:Spain / Q000453:epidemiology; D016896:Treatment Outcome; D016903:Drug Monitoring
keywords: adherence; big data; clinical pharmacology; pharmacoepidemiology; primary care