Validation of a French Version of the DHEQ - Oral Health-related Quality of Life and Dentin Hypersensitivity
Phase: NA
Conditions: Dentin Hypersensitivity, Quality of Life
Sponsor: University Hospital, Clermont-Ferrand

Validation of a French version of the DHEQ - Quality of Life Questionnaire 
in Relation to Oral Health and Dentin Hypersensitivity 
 
11/06/2024 
 
 

1. Study protocol 
 
1.1. Expected duration of participation of individuals  
All participants (n=216) will be invited to a 45-minute visit (test). A second visit will be organized 
for the 60 patients randomly selected for a 15-day retest. 
The maximum duration of participation is therefore 15 days. 
 
 
1.2. Description of the acts performed on the persons (description of each visit) 
 
Visit 1 (Test): Patients will be seen by the local investigator/examiner who will assess the eligibility 
of patients according to the inclusion and non-inclusion criteria described above. 
 
HD group 
- Clinical examination performed to confirm the diagnosis of HD (Schiff score on the air jet test ≥1); 
- Air jet test: determination of the Schiff score (score ≥1) and the EVA score; 
- Self-administration of DHEQ-fr, GOHAI and OHIP questionnaires. 
Control group 
- Clinical examination performed to confirm the absence of HD; 
- Self-administration of DHEQ-fr, GOHAI and OHIP questionnaires. 
 
Visit 2 (Retest) 
HD Group and Control 
- Self-administration of DHEQ-fr questionnaires. 
 
1.3. Description of the general logistical organization of the trial 
Patient recruitment will be done in three centers (Odontology Department of Clermont-Ferrand, 
Bordeaux and Lyon), after informing all practitioners and practicing students about the present 
study and the need to refer patients with HD symptoms to the local investigator. 
A local co-investigator/examiner will conduct visits to all patients at the investigator center in 
which they practice; His senior will ensure methodological and administrative supervision of the 
Investigator Center in which he works. 
The principal investigator and the biostatistician will take charge of the data analysis. 
 
1.4. Study samples and biological analyses 
No samples will be taken during this study. No biological analysis will be performed during this 
study. 
 
2. Statistical analysis plan 
 
2.1. Data Analysis Method 
 

2.1.1. General 
The statistical analysis will be carried out with the Stata software (version 15, StataCorp, 
College Station), considering a first-kind bilateral risk of error of 5%.  
The sample will be described by associated numbers and percentages for categorical variables 
and by mean and standard deviation or median and interquartile range for quantitative 
variables, with respect to their statistical distribution. Normality will be studied by the 
Shapiro-Wilk test and/or histogram. Graphical representations will be associated with the 
analyses as much as possible.  
Patients will be described and compared between groups at baseline according to the 
following variables: compliance with eligibility criteria, epidemiological characteristics and 
clinical characteristics.  
A description of the deviations from the protocol, the patients distributed according to these 
deviations and the causes of abandonment will also be carried out.  
The initial comparability of the two arms will be assessed on the main characteristics of the 
participants and potential factors associated with the primary outcome. Any difference 
between the two groups on one of these characteristics will be determined according to 
clinical considerations and not just statistical ones. Comparisons between groups will be made 
systematically (1) without adjustment and (2) by adjusting for factors whose distribution could 
be unbalanced between groups despite the matching.  
 
2.1.2. Statistical analyses  
The validation of the DHEQ-fr will consider the study of psychometric properties according to the 
following plan: 
 
The measure of acceptability will be based on the calculation of missing data at the item level and 
for the overall score; the scale will be considered applicable if the conditions of use show that the 
cost of implementation is modest, that the acceptability by patients and the medical community 
is high, and that the time to pass is low. 
The fidelity of the instrument will be assessed according to two criteria: 
o Internal consistency will be assessed by calculating the Cronbach alpha coefficient (Kuder-
Richardson αk) and will be studied against the usual recommendations described as follows: 
αk≥0.9 excellent; 0.9> αk ≥ 0.8 correct; 0.8> αk ≥0.7 acceptable; 0.7> αk ≥0.6 moderate; 0.6> 
αk ≥0.5 low; and 0.5< αk not acceptable. 
o Test-retest reproducibility, the ability to produce comparable responses when the measure is 
repeated while the individual's condition remains stable, will be assessed by calculating the 
intensity of agreement (for items of a quantitative nature: Lin's coefficient of agreement and 
for items of a categorical nature: agreement rate: for each item, percentage of identical 
responses during the test and retest and the Kappa coefficient of agreement (denoted k) 
compared to the following recommendations:  no agreement (k<0.2), low agreement (k 0.2 to 
0.4), moderate agreement (k 0.4 to 0.6), substantial agreement (k 0.6 to 0.8), or excellent 
agreement (k> 0.8). The overall score will be compared in a test-retest situation by the paired 

Student's test in addition to the correlation coefficient (Pearson or Spearman with regard to 
the statistical distribution) and the Lin concordance coefficient. A graphical representation of 
Bland and Altman will complete these analyses. 
 
Internal structure validity explores the coherence of the internal layout of the questionnaire. This 
validity will be evaluated by studying the following parameters: for items of a categorical nature: 
proportion of patients for each of the modalities of each item ('difficulty', denoted p), variance of 
each item (denoted p(1-p)), 'item-score' correlations (so-called biserial point correlation 
coefficient, i.e. correlation between a dichotomous variable and a quantitative variable) and multi-
trait matrix of correlation coefficients (inter-item and item-dimension) for the items of a 
quantitative nature. 
A factor analysis will allow us to study the relationships between the modalities of each of the 
items. 
These analyses will be complemented by an item response theory approach; specifically, a 
Rasch model analysis will be implemented to study the internal structure of the AHS, taking 
into account inter and intra item variability. The following indicators will be calculated, among 
others: one-dimensionality, item difficult, DIF (Differential Item Functioning), reliability alpha 
(PSI: person separation index), fit (overall, outfit, infit). 
 
 
The DHEQ-fr scores of patients in the HD group will be compared to those of the "control" group 
by Student's t-test or Mann-Whitney test if the conditions for the application of the t-test are not 
met. Homoscedasticity will be studied by Fisher-Snedecor test. Results will be expressed in terms 
of effect sizes and 95% confidence intervals. 
 
The study of the relationships between variables of a quantitative nature (DHEQ-fr, GOHAI, OHIP-
49 and 14) will be analyzed by estimation of correlation coefficients (Pearson or Spearman, with 
regard to the statistical distribution). 
 
 
2.1.3. Method of accounting for missing, unused or invalid data 
A sensitivity analysis will be conducted to measure the impact of missing data and determine the 
most appropriate imputation method. Complete and missing samples will be compared for key 
socio-demographic and clinical characteristics, as will test and retest samples. 
Additional analyses will then be carried out according to the statistical nature of the missing data 
(missing at random or not). 
 
2.1.4. Interim analyses 
An intermediate analysis will be carried out as part of a Master II thesis. Inclusions will be 
continued during this period as there is no risk to participants.