title: Validation of a questionnaire for assessing fecal impaction in the elderly: impact of cognitive impairment, and using a proxy.
abstract: BACKGROUND
  Studies on the epidemiology of fecal impaction are limited by the absence of a valid and reliable instrument to identify the condition in the elderly. Our aim is to validate a questionnaire for identifying fecal impaction in the elderly and to assess the impact of cognitive impairment and the aid of a proxy on its reliability.
  
  
  METHODS
  We developed a 5 questions' questionnaire. The questionnaire was presented to twenty doctors to test its face validity. Feasibility was pre-tested with ten non institutionalized subjects who completed the questionnaire twice, once alone or with the help of a proxy, and another along with the researcher.For the validation of the questionnaire all residents in a single nursing-home were invited to participate, allowing the self-decision of using a proxy. Medical records of all subjects were abstracted without knowledge of subjects' answers and agreement between fecal impaction according to self-reported and medical records analyzed. Physical impairment was measured with the Barthel's test and cognitive impairment with the mini-mental test.
  
  
  RESULTS
  In the face validity only minor changes in wording were suggested. In the feasibility pre-test all subjects were able to understand and complete the questionnaire and all questions were considered appropriate and easily understandable.One-hundred and ninety-nine of the 244 residents participated in the study (mean age 86,1 ± 6,6). One hundred and forty two subjects understood all questions; not understanding them was inversely associated with cognitive impairment score (aOR: 0.86; 95% CI: 0.82-0.91). One hundred and sixty decided to use a proxy; the use of a proxy was inversely associated with educative level (0.13 (0.02-0.72), minimental's score (0.85; 0.76-0.95) and Barthel's score (0.96; 0.94-0.99). Agreement between medical records and self-completed questionnaire was 85.9% (kappa 0.72 (0,62- 0,82). Disagreement was unrelated to education and cognitive impairment.
  
  
  CONCLUSIONS
  Our simple questionnaire is reliable for identifying fecal impaction in the elderly by self-report. Limitation imposed by cognitive impairment is minimized with the aid of a proxy.
authors.affiliation: Functional GI DiseasesUnit, Division of DigestiveDiseases, Hospital Clínico San Carlos, Departament of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain. Marta.barcelo@yahoo.es
authors.forename: Marta
authors.initials: M
authors.lastname: Barcelo
authors.forename: Maria Jose
authors.initials: MJ
authors.lastname: Jimenez-Cebrian
authors.forename: Manuel
authors.initials: M
authors.lastname: Diaz-Rubio
authors.forename: Alberto Lopez
authors.initials: AL
authors.lastname: Rocha
authors.forename: Enrique
authors.initials: E
authors.lastname: Rey
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D005244:Fecal Impaction / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009735:Nursing Homes / Q000592:standards; D019727:Proxy / Q000523:psychology; D057566:Self Report / Q000592:standards*; D011795:Surveys and Questionnaires / Q000592:standards*