title: Does the mode of administration of the Oral Health Impact Profile-49 affect the outcome score?
abstract: OBJECTIVE
  To determine if there are differences in outcome scores if the Oral Health Impact Profile-49 (OHIP-49) is delivered by two different modes of administration (manual-self complete versus telephone interview).
  
  
  METHODS
  Patients with chronic periodontitis (n=83, 54% females and 46% males, mean age 49.1±9.5 years) completed the OHIP-49 using two modes of administration (manual self-complete and telephone interview) in a randomly assigned order, with a minimum washout period of 2 weeks between modes, both episodes occurring prior to any periodontal treatment being provided. To assess convergent validity, after each mode of administration, the patients were additionally asked a global question about their oral health-related quality of life (OHRQoL).
  
  
  RESULTS
  Median OHIP-49 scores recorded by manual self-complete (median 36 [IQR=20-70]) were significantly higher than those recorded by telephone interview (median 27 [IQR=11-61]) (p<0.01). The global question was well correlated to the OHIP domains, but did not reveal any evidence of an order effect such as was seen with OHIP-49 itself (which showed a higher impact on OHRQoL during the first administration in either mode).
  
  
  CONCLUSIONS
  The mode of administration (manual-self complete versus telephone interview) did substantially influence the OHIP-49 scores in patients with chronic periodontitis. The OHRQoL differed between the two modes of administration, with significantly higher scores (indicating poorer OHRQoL) when the questionnaire was manually self-completed.
  
  
  CONCLUSIONS
  The mode of administration of quality of life questionnaires such as OHIP-49 could potentially affect the outcome scores derived. This study investigated whether there is a difference in outcome scores if OHIP-49 is delivered via manual self-complete or by telephone interview in patients with chronic periodontitis. We found that there was a significant difference between the two modes: manual self-completion by the patients yielded significantly higher scores than completion by telephone interview. It is therefore important to be consistent in the mode of completion of OHIP-49, as mixing modes could introduce additional error into clinical studies that utilise this instrument.
authors.affiliation: School of Dental Sciences, Centre for Oral Health Research, Newcastle University, Newcastle upon Tyne, UK. Electronic address: r.s.desai@newcastle.ac.uk.
authors.forename: Radhika
authors.initials: R
authors.lastname: Desai
authors.affiliation: School of Dental Sciences, Centre for Oral Health Research, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Justin
authors.initials: J
authors.lastname: Durham
authors.affiliation: School of Dental Sciences, Centre for Oral Health Research, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Wassell
authors.affiliation: School of Dental Sciences and Institute of Cellular Medicine, Centre for Oral Health Research, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Preshaw
mesh_terms: D000203:Activities of Daily Living; D000293:Adolescent; D000328:Adult; D000368:Aged; D001294:Attitude to Health; D055113:Chronic Periodontitis / Q000523:psychology*; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D009909:Oral Health; D010146:Pain / Q000523:psychology; D011788:Quality of Life; D012649:Self Concept; D057566:Self Report; D013315:Stress, Psychological / Q000523:psychology; D055815:Young Adult
keywords: OHIP-49; Oral Health Impact Profile; Periodontitis; Quality of life