Assessing the minimally important difference in the oral impact on daily performances index in patients treated for periodontitis.
OBJECTIVE
To assess changes over time and determine the minimally important difference (MID) in the Oral Impact on Daily Performances (OIDP) index for patients with severe generalized periodontitis receiving periodontal treatment.


METHODS
This study was nested in a larger randomized controlled trial and consisted of 45 consecutive subjects of the larger trial (17 receiving intensive and 28 receiving conservative periodontal care). The OIDP index assessed impacts on quality of life (QoL) at baseline and 1 month after treatment. Repeated-measures ANOVA was used for comparison over time and between treatment groups. To estimate the MID, two subjective global transition scales, related to periodontal and oral health, respectively, were used as anchors, whereas the effect size (ES), standardized response mean and standard error of measurement were also calculated.


RESULTS
The mean OIDP score after treatment was significantly lower than at baseline, indicating improvement in QoL, but there were no differences between treatment groups. Based on an agreement between different methods, the MID of the OIDP index was around five scale points and corresponded to a moderate ES.


CONCLUSIONS
The MID for the OIDP index among patients treated for severe generalized periodontitis provides meaning to change scores and facilitates interpretation of findings.
Department of Epidemiology and Public Health Periodontology Unit, Eastman Dental Institute, University College London, London, UK. g.tsakos@ucl.ac.uk
Georgios
G
Tsakos
Eduardo
E
Bernabé
Francesco
F
D'Aiuto
Hynek
H
Pikhart
Maurizio
M
Tonetti
Aubrey
A
Sheiham
Nikolaos
N
Donos
D000203:Activities of Daily Living; D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D016009:Chi-Square Distribution; D012534:Dental Scaling; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008911:Minocycline / Q000627:therapeutic use; D017063:Outcome Assessment, Health Care / Q000379:methods* / Q000706:statistics & numerical data; D057747:Periodontal Debridement; D010518:Periodontitis / Q000523:psychology* / Q000628:therapy*; D011788:Quality of Life; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data; D018434:Sickness Impact Profile; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires
D000900:Anti-Bacterial Agents; D008911:Minocycline