Parental reports of the oral health-related quality of life of children with cerebral palsy

For this cross-sectional study, a convenience sample was selected. It comprised children with CP who attended the Center of Attendance for Special Needs Patients - CAPE of the Dental School, University of São Paulo. The CAPE performs preventive and restorative treatment for individuals with different types of disabilities.

The sampling was conducted in two stages: initially, all children from 6 to 14 years of age, of both genders in the database system at the center were identified, resulting in a total of 75 children. The patients’ parents were contacted by phone and informed about the study. From a total of 75 children, 5 could not be contacted because they have moved, 2 children have died, 3 were hospitalized and from 5 of them, the parents did not want to participate in the study. Therefore, the final sample size comprised of 60 children with CP and their respective parents. Parents who were fluent in Brazilian Portuguese and who were willing to participate in the study (all of them) signed an informed consent.

On the day of the dental visit, one of the parents (always the same) was invited to answer two questionnaires: one on the children’s OHRQoL and another on socioeconomic conditions. These questionnaires were collected in face-to-face interviews by one interviewer blind to the oral examinations and impairments characteristics of the child. The interviews were completed before the oral clinical examination of the patient and all parents agree to answers the questions. Concerning the OHRQoL questionnaire, the interviewer was trained in the reading and intonation of each question and option of responses.

Data were collected by one examiner with experience in children with cerebral palsy. The type of CP was evaluated according to the topographic distribution[9]: hemiplegia, diplegia and quadriplegia. Communication ability was evaluated according to the study of Dickinson et al.[5]: normal; mild disability (some difficulty identified, but uses speech); moderate disability (communication mainly uses non-speech forms) and severe disability (no formal communication is identified). The Gross Motor Functioning Classification System (GMFCS) was evaluated according to Palisano et al.[10]. The parents were also asked if the children have seizures.

The OHRQoL instrument used in this study was a 47-item questionnaire which combines two questions on global ratings, the Brazilian version of the Parental-Caregivers Perceptions Questionnaire (P-CPQ)[11] and the Family Impact Scale (FIS)[12] components of the Child Oral Health Quality of Life Questionnaire (COHQOL^©)[13]. The P-CPQ and FIS were validated in the original language[14, 15] and recently transculturally adapted and completely validated in the Brazilian Portuguese language. The interviews for this study were done in February 2009 at the University of São Paulo. This instrument evaluates the perception of parents on OHRQoL of children aged 6 to 14 years. The proxy-report was chosen due to the difficulties to assess self-report in most of these children. The questions were asked in reference to the frequency of events in the previous three months. The items were scored using a five-point Likert scale (response options: never = 0, once or twice = 1, sometimes = 2, often = 3, every day or almost every day = 4). A “Don’t know” response option prevents the loss of valuable information, which would occur if complete data from participants with nonresponse to some items were deleted[14]. Then, the number of “Don’t know” responses was counted individually. Due to the fact that this could affect the data analyses, the “Don’t know” responses were considered as missing in Table1. Therefore, the mean response in each domain was calculated by adding the total score for the domain and dividing by the number of questions with responses. Some other ways to handle “don’t know” responses are described in Marshman et al. (2007)[16].

The following subscale scores were created by summing the responses to conceptually based, discrete subsets of items: oral symptoms domain - 6 items; functional limitations domain - 8 items; emotional well-being domain – 7 items; and social well-being domain – 10 items. In addition, scores from 14 items on the impacts of the child’s oral condition on parents and other family members were summed to generate the family impact scale (FIS). Two questions on global ratings were also answered by parents in the instrument. One of them on the child’s oral health “How would you rate the health of your child’s teeth, lips, jaws and mouth?” and other on the impact of the oral/orofacial condition on his or her overall well-being “How much is your child’s overall well-being affected by the condition of his/her teeth, lips, jaws or mouth?”. They had a five-point response format from ”excellent” to ”poor” for the child’s oral health and from ”not at all” to ”very much” for the overall well-being.

The total instrument score, and scores for individual subscales (domains), were generated by summing the numerical response options according to the five-point Likert scale. The range score of the instrument range from a minimum of 0 to a maximum of 188, including global ratings. Higher scores mean poorer OHRQoL or vice-versa. Therefore, global and the domains’ scores were presented in the tables, but were independently analyzed and discussed.

The parent was also invited to answer a questionnaire on their socioeconomic conditions. It included data on household crowding (inhabitant per room), number of siblings, mother’s and father’s education and family income (as measured in terms of the Brazilian minimum wage - BMW, a standard for this type of assessment, which corresponds to approximately US$ 220.00 per month).

The patients’ clinical oral examination was realized for the prevalence of dental caries in an individual. DMFT and dmft are indexes to numerically express the caries prevalence and are obtained by calculating the number of decayed, missing, filled teeth in the primary dentition (dmft) and decayed, missing, filled teeth in the permanent dentition (DMFT). These indexes were described by the World Health Organization[17]. For children with mixed dentition, the caries index was obtained by the sum of the dmft and DMFT scores. The overall measure of dmft and DMFT of the children examined was evaluated separately and together by the sum of the components d + m + f/D + M + F. The dmft/DMFT was categorized according to the severity of dental caries, based on the previously proposed scores[17]: dmft/DMFT 0 = caries free; dmft/DMFT 1-2 = low severity; dmft/DMFT 3-4 = moderate severity or dmft/DMFT ≥ 5 high severity.

The child’s oral examination for dental caries was carried out by one calibrated examiner. This examiner was a specialist in pediatric dentistry previously trained with pictures of clinical cases for the disorders and diseases by a benchmark examiner (A.L.C). The intra-examiner reliability was established by re-examination of 10 (16.67% of sample) patients and the Kappa value for agreement was 0.95. The clinical examinations were performed, after prophylaxis, in a dental unit using an operating light, a 3-in-1 syringe for drying the teeth, plane mouth mirrors and periodontal probes.

After a descriptive analysis, the total mean scores of the OHRQoL instrument (outcome) and those for the individual domains were analyzed for differences between impairment characteristics and oral health conditions, and socioeconomic factors. For this initial exploratory analysis, parametric and non-parametric tests were used.

Univariate Poisson Regression analysis correlated the total mean score of the OHRQoL instrument to each impairment and oral health conditions and socioeconomic factors. In this analysis, the outcome was employed as a count outcome, represented by the addition of the scores in the instrument, as performed previously[19, 20] and rate ratios (RR) and 95% confidence intervals (95% CI) were calculated. Later, a multivariate model was built with several covariates (communication ability, dental caries, household crowding, father’s education and family income), selected by a forward stepwise procedure with p < 0.20 as the cut-off point. A multivariate Poisson regression analysis correlated the outcome to several impairments and oral health covariates adjusted by socioeconomic factors. The covariates were kept in the final model if p <0.05. Statistical analyses used Stata 8.0, 2003 (Stata Corp, College Station, TX).