title: The impact of co-morbidity on GPs' pharmacological treatment decisions for patients with an anxiety disorder.
abstract: BACKGROUND
  Co-morbidity may influence GPs' treatment decisions for patients with anxiety. However, knowledge about differences in the pharmacological treatment of anxiety disorders in patients with and without co-morbidity is lacking.
  
  
  OBJECTIVE
  To compare GPs' pharmacological treatment patterns for anxiety in patients with and without co-morbidity.
  
  
  METHODS
  Data were extracted from computerized medical records of 77 general practices participating in the Dutch National Information Network of General Practice (LINH). We used diagnosis and prescription data of patients, aged 18-65 years, with a newly diagnosed anxiety disorder (n=4604). A mixed model technique was used to determine if there was a difference in the pharmacological treatment of anxiety with and without co-morbidity.
  
  
  RESULTS
  During the year after diagnosing anxiety, anxious patients who also suffered from chronic somatic morbidity or social problems were prescribed more benzodiazepines (effect size [ES]=0.44, 95% confidence interval [CI]=0.16-0.72 and ES=0.67, 95% CI=0.22-1.25, respectively) but no more antidepressants than patients with anxiety only. Compared to patients with a single diagnosis of anxiety, anxious patients who suffered simultaneously from other psychiatric conditions received twice as many antidepressant prescriptions (ES=2.07, 95% CI=1.89-2.56) as well as twice as many benzodiazepine prescriptions (ES=1.98, 95% CI=1.84-2.60) during the year after diagnosing anxiety. For all subgroups, the prescription rate of benzodiazepines remained high throughout the year after diagnosing anxiety.
  
  
  CONCLUSIONS
  Our results indicate that psychiatric co-morbidity in anxious patients leads to higher prescription levels of both antidepressants and benzodiazepines. Chronic somatic co-morbidity and co-morbid social problems also lead to higher prescription levels of benzodiazepines, but does not seem to influence GPs' prescribing of antidepressants. The prescription pattern of benzodiazepines was inconsistent with guideline recommendations.
authors.affiliation: Centre for Quality of Care Research (WOK), Nijmegen, The Netherlands. m.smolders@kwazo.umcn.nl
authors.forename: Mirrian
authors.initials: M
authors.lastname: Smolders
authors.forename: Miranda
authors.initials: M
authors.lastname: Laurant
authors.forename: Eric
authors.initials: E
authors.lastname: van Rijswijk
authors.forename: Jan
authors.initials: J
authors.lastname: Mulder
authors.forename: Jozé
authors.initials: J
authors.lastname: Braspenning
authors.forename: Peter
authors.initials: P
authors.lastname: Verhaak
authors.forename: Michel
authors.initials: M
authors.lastname: Wensing
authors.forename: Richard
authors.initials: R
authors.lastname: Grol
mesh_terms: D000328:Adult; D001008:Anxiety Disorders / Q000188:drug therapy*; D015331:Cohort Studies; D015897:Comorbidity; D003657:Decision Making; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D016347:Medical Records Systems, Computerized; D008875:Middle Aged; D009426:Netherlands; D010821:Physicians, Family; D010818:Practice Patterns, Physicians'