To integrate items from two widely used oral health-related quality of life (OHRQoL) questionnaires, the General Oral Health Assessment Index (GOHAI) and the Oral Impacts on Daily Performances (OIDP), as well as culturally-specific items of the Oral Health Impact Profile (OHIP) into a four-dimensional OHRQoL model consisting of Oral Function , Orofacial Pain , Orofacial Appearance , and Psychosocial Impact .
Subjects came from an ancillary study of the Dimensions of Oral Health-Related Quality of Life Project (N = 267 patients, mean age ± SD: 54.0 ± 17.2 years, 58% women.) Patients filled in the original 49 items of OHIP and 22 additional OHRQoL items in a cross-sectional study. These additional items consisted of 7 culturally specific OHIP items and 15 GOHAI or OIDP items with unique content not covered in OHIP-49. Before data collection, three experts hypothesized to which of the four OHRQoL dimensions these items belong. Hypotheses were tested in correlation analyses between the 22 items and the four dimension scores that were derived from OHIP-49.
Five of the 22 items did not provide sufficient information to which dimension they belong. In 16 of the remaining 17 items, the pattern of correlation coefficients fitted experts’ a priori hypotheses. Acceptance of 16 of the 17 hypotheses was interpreted as evidence that additional (not in OHIP-49 contained) OHRQoL items can be assigned to Oral Function , Orofacial Pain , Orofacial Appearance , and Psychosocial Impact .
Items of three OHRQoL instruments can be integrated into a dimensional OHRQoL model consisting of Oral Function , Orofacial Pain , Orofacial Appearance , and Psychosocial Impact .
Oral Function , Orofacial Pain , Orofacial Appearance , and Psychosocial Impact can serve as a simple and clinically appealing set of oral health-related quality of life (OHRQoL) dimensions and therefore provide an opportunity for simpler, but psychometrically improved OHRQoL measurement in the future.
Oral health-related quality of life (OHRQoL) is a popular concept to assess the impact of oral conditions and the effects of dental interventions. Many instruments exist to measure OHRQoL. This situation attests to the dental community’s interest in OHRQoL, but it also challenges comparability and communication of results. Therefore, from a conceptual point of view, reduction of the number of instruments seems necessary to improve standardization for using OHRQoL assessment globally. In addition, to be confident in the instrument scores, psychometric properties such as reliability, validity, responsiveness, and interpretability need to be known. From a practical point of view, this can only be achieved for a limited number of questionnaires.
However, instead of abandoning some OHRQoL instruments, combining them with other instruments – a synthesis of questionnaires – seems a promising strategy that can achieve better quality instruments while reducing their quantity. Some studies have already utilized several OHRQoL instruments together and other studies have even submitted them as a combined measure of OHRQoL in analyses . However, a more formal assessment whether instruments can be combined has not been performed yet. The prerequisite for a synthesis would be that instruments measure the same underlying latent attribute. Substantial correlations among OHRQoL questionnaire scores attest to this proposition empirically . However, these results apply to the OHRQoL global measure, the instrument summary score, but instrument combination needs to be done on the dimension level because these are the attributes that are actually measured and OHRQoL is just the global umbrella term. Conceptually, the hypothesized constructs that are measured by the General Oral Health Assessment Index (GOHAI) and the Oral Impacts on Daily Performances (OIDP) − two frequently used OHRQoL questionnaires − are similar to the four dimensions of OHRQoL ( Oral Function , Orofacial Pain , Orofacial Appearance , and Psychosocial Impact ) measured by OHIP , the most widely used OHRQoL instrument. Therefore, OHIP’s dimensions may serve as the framework to integrate the other OHRQoL instruments’ items. If this proposition would hold, GOHAI and OIDP items as well as the existing culture-specific OHIP items , i.e., additional indicators of the OHRQoL construct measured with OHIP, should fall into the four OHIP-based dimensions. A relevant target population where such a new grouping of OHRQoL items could be studied would be prosthodontic patients. They could be considered typical dental patients because their number is large, they usually suffer from tooth loss resulting from the two major oral diseases, caries and periodontitis, and several other dental treatments are often performed in conjunction with prosthodontic therapy .
Our study aimed to integrate items from two widely used OHRQoL questionnaires, the General Oral Health Assessment Index (GOHAI) and the Oral Impacts on Daily Performances (OIDP), as well as culturally specific items of the Oral Health Impact Profile (OHIP) into a four-dimensional OHRQoL model consisting of Oral Function , Orofacial Pain , Orofacial Appearance , and Psychosocial Impact .