A multilevel analysis of factors affecting the difference in dental patients' and caregivers' evaluation of oral quality of life

In a previous study, we observed that the concordance between patients' and caregivers' evaluation of oral health-related quality of life (OHRQoL) was low. The aim of this study was to use multilevel analysis to investigate the possible determinants of the low concordance, taking into account different patients' demographic and clinical variables, the financial system used by patients to pay for dental treatment, and the role of the different caregivers and clinics. The OHRQoL of patients was assessed both by the patients and by their caregivers, using the Oral Health Impact Profile (OHIP)-14. Data were collected in four clinics, and patients were evaluated by one of 27 caregivers. We tested eight multilevel models, using the difference (caregivers OHIP - patients OHIP) as the dependent variable. Data were complete for 432 patients. The mean difference was 4.4 (standard deviation = 8.2; higher scores indicated a higher impact on OHRQoL). The variance due to patients was partly explained by their age, gender, and number of teeth, with a greater OHIP difference for older vs. younger patients, for women than for men, and in patients with fewer teeth. Almost 30% of the variance was due to caregivers, while the effect of clinics was not significant. It is important to study the possible causes of the different judgments concerning patients' OHRQoL by patients and caregivers, in order to improve the patients' satisfaction with care.