Development and validation of a quality of life instrument for patients with oral potentially malignant disorders: studies of impact in a population of Telugu speaking adults

Abstract

Oral Potentially Malignant Disorders (OPMDs) are those oral mucosal conditions that have a predilection for becoming malignant (Warnakulasuriya et al. 2007). Similar to oral cancer itself and other oral conditions, OPMDs can cause significant morbidity that affects physical, social and psychological wellbeing, thus affecting the quality of life (QoL) of those so afflicted. The literature on the assessment of QoL in patients with OPMD is very limited, especially from developing countries, which might be due to the unavailability of a disease-specific QoL instrument (Tadakamadla et al. 2015). This thesis developed and validated a disease-specific self-administered QoL questionnaire for OPMD patients. The study was conducted in two phases in the oral medicine clinics of Panineeya Institute of Dental Sciences and Research Centre, Hyderabad, India. The first phase involved qualitative methodology for developing the OPMDQoL questionnaire. Qualitative data were collected through interviews and focus group discussions with 32 Telugu speaking patients with an OPMD who were undergoing treatment. Patients were those diagnosed with Oral Leukoplakia (OL), Oral Submucous Fibrosis (OSF) and Oral Lichen Planus (OLP) which are the most common OPMDs in the Indian subcontinent. Thematic analysis and coding of the qualitative data were conducted using Nvivo by two individuals independently to generate themes and the items for the questionnaire. Moreover, existing oral health-related QoL questionnaires, including those extant for patients with head and neck cancer, were reviewed to generate the items. A final list of 48 items was prepared, after inputs from oral physicians using a modified Delphi technique, from the 60 items that were generated through qualitative analysis and questionnaires. This was followed by the development of final questionnaire by item reduction using a clinical impact method which involved administration of the list of questions to 15 patients who rated the importance of each item. Based on these importance ratings, the final questionnaire (OPMDQoL) was developed: This consisted of 20 items under four domains: ‘difficulties with diagnosis’, ‘physical impairment and functional limitations’, ‘psychological and social wellbeing’ and the ‘effect of treatment on daily life’. Each item is scored using a five-point Likert scale, and the overall OPMDQoL and domain scores are calculated by summing the scores of each item with a higher score representing poorer QoL. In the second phase, the validity and reliability of OPMDQoL was assessed. OPMDQoL, Telugu translations of the Chronic Oral Mucosal Disease Questionnaire (COMDQ) (Ni Riordain et al. 2011b) and Short form 12 item (version 2) of the health survey questionnaire (SF-12v2) (Ware et al. 1996) were administered to 150 OPMD patients (50 each of OL, OSF and OLP) and to controls who were free from any type of OPMD. A thorough clinical examination was conducted and history, including lifestyle habits, was recorded from all patients. OPMDQoL demonstrated good discriminant validity as patients presented poorer scores than the controls. Also, it had good convergent validity evaluated by assessing its correlation with an existing questionnaire (COMDQ) designed for use in patients with any type of oral mucosal disease. An exploratory factor analysis was also conducted, and findings demonstrated a four-factor structure that conforms to the hypothesised four domains. The impact of the clinical diagnosis (OL, OSF or OLP) and of disease severity on disease-specific and generic QoL was then assessed. Patients with OL reported better OPMDQoL than those with OSF and OLP, while no differences were observed between the three OPMDs for the mental health components of the SF-12v2 questionnaire and for the ‘psychological and functional wellbeing’ domain of the OPMDQoL instrument. When domain scores were compared, OLP patients reported significantly higher scores for the domain ‘difficulties with diagnosis’ while OL patients presented lower scores for the dimension, ‘physical impairment and functional limitations’ than did patients with the other OPMD. Disease severity had a significant association with both OPMDQoL and with the mental health component of SF-12v2, QoL diminishing as disease severity increased. In conclusion, the newly developed OPMDQoL exhibited good validity and reliability in a sample of Telugu Speaking OPMD patients. Disease severity was found to be associated with poor QoL assessed using OPMDQoL. Taken together, the results of this work indicate that this questionnaire might be used in studies of disease progression and to evaluate response to therapy, in routine clinical practice. OPMDQoL can be used in different cultures and languages following cross-cultural adaptation and can also be used to compare the effectiveness of treatments.