title: Post-marketing surveillance using pharmacy-based cohorts: results of a pilot study.
abstract: OBJECTIVE
  To assess the feasibility of recruiting subjects for follow-up studies of drug exposures using pharmacy records but without involving dispensing pharmacists.
  
  
  METHODS
  Working with Eckerd Corporation, a large chain pharmacy, we attempted to enroll subjects taking either hyoscyamine (Levsin and others) or dicyclomine (Bentyl and others). Adults who filled prescriptions during the recruitment period were randomly assigned to one of four enrollment approaches that used a script and materials we provided: (1) an introductory phone call from an Eckerd pharmacy technician with an offer of a $5 payment; (2) an introductory phone call with no payment; (3) a questionnaire mailed from Eckerd with introductory letters enclosed and an offer of a $5 payment and (4) the same mailed packet but with no payment offered. Willing subjects responded directly to us; they received a follow-up questionnaire approximately 6 weeks following enrollment. This method also provided limited information about subjects who chose not to enroll, permitting us to assess the representativeness of the study population.
  
  
  RESULTS
  The enrollment rates for the four groups were 35, 22, 21 and 17% respectively. Rates of completion of the follow-up questionnaire were 86, 83, 83 and 79% respectively. Participants appeared to be representative of the target population. The differential cost per enrolled subject in each group was $39.25, $50.45, $41.95 and $48.26 respectively.
  
  
  CONCLUSIONS
  This method provides an efficient way to create cohorts of users of specific prescription medications, with enrollment and retention rates that compare favorably with other approaches, allows a limited evaluation of representativeness, and is logistically feasible.
authors.affiliation: Slone Epidemiology Center, Boston University, Boston, Massachusetts 02215, USA. clouik@slone.bu.edu
authors.forename: Carol
authors.initials: C
authors.lastname: Louik
authors.forename: Allen A
authors.initials: AA
authors.lastname: Mitchell
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001285:Atropine / Q000009:adverse effects; D015331:Cohort Studies; D003157:Community Pharmacy Services; D004025:Dicyclomine / Q000009:adverse effects; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D016347:Medical Records Systems, Computerized; D008875:Middle Aged; D010276:Parasympatholytics / Q000009:adverse effects; D018579:Patient Selection; D010865:Pilot Projects; D011358:Product Surveillance, Postmarketing / Q000191:economics / Q000379:methods*; D011795:Surveys and Questionnaires
chemical_list: D010276:Parasympatholytics; D004025:Dicyclomine; D001285:Atropine