title: Persistence to antihypertensive drug treatment in Swedish primary healthcare.
abstract: OBJECTIVE
  To determine factors associated with low persistence in patients initiated on drug treatment for hypertension.
  
  
  METHODS
  Cohort study using medical records for patients with hypertension in 48 Swedish primary healthcare centres. Data were linked to national registers on dispensed drugs, hospitalizations, outpatient hospital consultations, deaths, migration, and socioeconomy. We identified 5225 patients (55 % women, mean age 61 years) initiated on antihypertensive drug treatment during 2006-2007. Persistence was measured for two years by the dispensed drugs. Patients with a gap of >30 days between end of dispensed supply and the next dispensed prescription were classified as non-persistent. This was calculated by Kaplan-Meier analysis. Cox proportional hazard regression was used to estimate hazard ratios for discontinuation. Potential predictors included age, gender, blood pressure before initiation of therapy, cardiovascular comorbidity, educational level, country of birth, and income.
  
  
  RESULTS
  Among patients with a dispensed first prescription, 26 % discontinued treatment during the first year, and a further 9 % discontinued during the second year. Discontinuation (all adjusted) was more common in men (P = 0.002) and in younger patients (30-49 years, P < 0.001). Systolic (P < 0.001) but not diastolic blood pressure was positively associated with persistence. Native-born Swedish citizens and patients born in the other Nordic countries had lower discontinuation rates than those born outside the Nordic countries (P < 0.001).
  
  
  CONCLUSIONS
  Major determinants of discontinuation of antihypertensive drug treatment are male sex, young age, mild-to-moderate systolic blood pressure elevation, and birth outside of Sweden.
authors.affiliation: Department of Medicine, Solna, Karolinska Institutet, Centre for Pharmacoepidemiology, T2, Karolinska University Hospital, SE-171 76, Stockholm, Sweden, miriam.qvarnstrom@ki.se.
authors.forename: Miriam
authors.initials: M
authors.lastname: Qvarnström
authors.forename: Thomas
authors.initials: T
authors.lastname: Kahan
authors.forename: Helle
authors.initials: H
authors.lastname: Kieler
authors.forename: Lena
authors.initials: L
authors.lastname: Brandt
authors.forename: Jan
authors.initials: J
authors.lastname: Hasselström
authors.forename: Kristina
authors.initials: K
authors.lastname: Bengtsson Boström
authors.forename: Karin
authors.initials: K
authors.lastname: Manhem
authors.forename: Per
authors.initials: P
authors.lastname: Hjerpe
authors.forename: Björn
authors.initials: B
authors.lastname: Wettermark
mesh_terms: D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001794:Blood Pressure; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care / Q000706:statistics & numerical data*; D013548:Sweden; D016903:Drug Monitoring
chemical_list: D000959:Antihypertensive Agents