title: Explaining the variation between practices in the duration of new antidepressant treatment: a database cohort study in primary care.
abstract: BACKGROUND
  Practices vary in the duration of newly initiated antidepressant treatment, even after adjusting for patient characteristics. It was hypothesised that this may be because of differences between practices in demographic (practice deprivation and antidepressant prescribing rates), organisational (practice size and proportion of female GPs), and clinical factors (proportion of new episodes of depression coded).
  
  
  OBJECTIVE
  To examine the effect of practice characteristics on the duration of new selective serotonin reuptake inhibitor antidepressant treatment in primary care.
  
  
  METHODS
  Database cohort study of 28 027 patients from 237 GP practices in Scotland.
  
  
  METHODS
  Prescription data were used to estimate duration of treatment for individual patients beyond three time points: 30, 90, and 180 days. Data at patient and practice level were analysed by multilevel logistic regression to quantify the variation between practices.
  
  
  RESULTS
  The mean rate of diagnostic coding for depression in patients beginning a course of treatment was 29% (range 0-80%). Practice-level deprivation and rate of new antidepressant prescribing were not associated with duration of treatment. The practice level factor most strongly associated with duration of treatment at practice level was the proportion of patients coded as having depression: odds ratio for continuing beyond 30 days was 1.54 (95% confidence interval [CI] = 1.22 to 1.94); beyond 90 days, 1.37 (95% CI = 1.09 to 1.71); and beyond 180 days 1.41 (95% CI = 1.10 to 1.82).
  
  
  CONCLUSIONS
  Encouraging coding and structured follow-up at the onset of treatment of depression is likely to reduce early discontinuation of antidepressant treatment and improve outcomes.
authors.affiliation: Division of Applied Medicine, University of Aberdeen, Aberdeen.
authors.forename: Christopher
authors.initials: C
authors.lastname: Burton
authors.affiliation: Division of Applied Medicine, University of Aberdeen, Aberdeen.
authors.forename: Isobel
authors.initials: I
authors.lastname: Cameron
authors.affiliation: Centre for Population Health Sciences, University of Edinburgh, Edinburgh.
authors.forename: Niall
authors.initials: N
authors.lastname: Anderson
mesh_terms: D000928:Antidepressive Agents / Q000627:therapeutic use*; D003866:Depressive Disorder / Q000188:drug therapy* / Q000453:epidemiology; D004334:Drug Administration Schedule; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D055553:Prescription Drugs / Q000627:therapeutic use; D011320:Primary Health Care / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012606:Scotland / Q000453:epidemiology; D013997:Time Factors
chemical_list: D000928:Antidepressive Agents; D055553:Prescription Drugs
keywords: antidepressant treatment; clinical practice variation; depressive disorder; prescribing; primary health care