title: Loss to follow-up in a longitudinal study on urogenital tract symptoms in Dutch older men.
abstract: OBJECTIVE
  To describe loss to follow-up (LTFU) in a longitudinal community-based study on urogenital tract dysfunction in older men.
  
  
  METHODS
  A cohort study of men recruited from a Dutch municipality was performed. A baseline study and two follow-up rounds--all with questionnaires and additional measurements--were performed with, on average, 2.1-year intervals. Baseline characteristics were compared between participants and non-participants in the first and in the second follow-up study.
  
  
  RESULTS
  The response rates in the first and in the second follow-up were 78.0 and 80.0%, respectively. Various characteristics were found to be related to LTFU (i.e., more than 5% difference in response rate). Lower urinary tract symptoms were related to LTFU in the first and second follow-up. Sexual dysfunction was related to LTFU only in the second follow-up. Adjustment for confounders yielded odds ratios for the primary outcome variables (lower urinary tract symptoms, sexual dysfunction, and health status) that approximated the value of 1. LTFU according to these variables was different in men with and without other chronic illnesses.
  
  
  CONCLUSIONS
  LTFU seems not to be related to the primary outcome variables in this study. Describing response patterns in longitudinal studies is important, especially in studies involving older participants, as often is the case in urological research.
authors.affiliation: Department of General Practice, Erasmus MC, Rotterdam, The Netherlands. blanker1106@zonnet.nl
authors.forename: Marco H
authors.initials: MH
authors.lastname: Blanker
authors.forename: Jennie
authors.initials: J
authors.lastname: Prins
authors.forename: J L H Ruud
authors.initials: JL
authors.lastname: Bosch
authors.forename: Boris W V
authors.initials: BW
authors.lastname: Schouten
authors.forename: Roos M D
authors.initials: RM
authors.lastname: Bernsen
authors.forename: Frans P M J
authors.initials: FP
authors.lastname: Groeneveld
authors.forename: Arthur M
authors.initials: AM
authors.lastname: Bohnen
mesh_terms: D000367:Age Factors; D000368:Aged; D015897:Comorbidity; D015986:Confounding Factors, Epidemiologic; D005500:Follow-Up Studies; D006304:Health Status; D006801:Humans; D008297:Male; D052801:Male Urogenital Diseases / Q000453:epidemiology*; D008875:Middle Aged; D015999:Multivariate Analysis; D009426:Netherlands / Q000453:epidemiology; D012044:Regression Analysis; D011795:Surveys and Questionnaires; D013997:Time Factors