Doctor of Philosophy

dissertationThe objective of this body of research was to (1) survey current self-management skills and treatment knowledge in patients with phenylketonuria (PKU) and (2) evaluate self-efficacy, patient activation, dietary adherence, and blood phenylalanine (Phe) levels in individuals with PKU before and after a 6-month motivational interviewing (MI) intervention. Patients with PKU aged 7-30 years (n=43) completed one of three age-specific self-management questionnaires during standard metabolic clinic appointments and were invited to participate. Separately, patients with PKU aged 7-35 years (n=31) participated in a 6-month intervention including phone-based MI, goal setting, and a monthly summary. Participants completed stage of change (SOC), self-efficacy, patient activation, and food frequency questionnaires online and obtained monthly blood Phe samples. Demographic data were collected from the electronic medical record. We considered p0.01 for all) with only approximately half of adults meeting clinical recommendations. Higher self-management skills and treatment knowledge were not associated with lower blood Phe levels (R2=0.249, p=0.025), which may reflect the small sample size. Most participants were in the action/maintenance SOC for PKU treatment behaviors during the 6-month MI intervention. Self-efficacy significantly increased from baseline (7.4±1.9) to month 6 (8.6±1.3) among adolescent and adult participants (p=0.002). There was no increase in patient activation (p=0.10) or dietary adherence, though most (n=28/31) reported adherence to medical formula at baseline. Pre-intervention blood Phe slope for all participants (β=0.71) was not significantly different from the intervention slope (β=0.26, p=0.13). Higher baseline SOC (β=-61.6, p=0.005) and increasing self-efficacy (β=-64.5, p<0.001) were associated with a decreased blood Phe slope. Self-management skills were lower than clinically recommended and did not consistently increase with age. We demonstrated a significant increase in self-efficacy with MI and, in turn, higher self-efficacy was associated with a reduction in blood Phe levels. Our results suggest strategies to support self-management and increase motivation for behavior change are necessary. Phone-based MI is feasible with a PKU population has potential to increase confidence to engage in self-management behaviors

Correlation of Age-Specific Phenylalanine Levels on Intellectual Outcome in Patients with Phenylketonuria

It is widely appreciated by the medical community that subtle deficits in intellect, academic skills and executive functioning exist in early treated phenylketonuria (PKU). In this study, we described the relationship between intellectual outcome and concentration/variation in blood phenylalanine (Phe) during specific developmental periods (0-5 years, 6-10 years, \u3e10 years). We also examined the association between mean number of blood Phe samples and maintenance of Phe within treatment range (120-360 ìmol/L) and within one standard deviation (SD) of index of dietary control, defined as the mean of 12-month median Phe. Retrospective data was collected from 55 patients receiving treatment at the University of Utah Metabolic Clinic. Index of dietary control (IDC) and SD blood Phe steadily increased and mean number of samples decreased during each developmental period. The correlation between IDC during 6-10 years of life and perceptual reasoning was -.370 (p = 0.006). Using multivariate linear regression, IDC during 0-5 years and 6-10 years were associated with a 0.5-point decrease and 0.3-point decrease in perceptual reasoning scores for every 100 ìmol/L increase in blood Phe, though associations were nonsignificant (p = 0.067; 0.082). SD of Phe was not associated with any measure of intelligence. The likelihood of IDC \u3e360 ìmol/L in those 6-10 years was 32.3% lower for each additional blood Phe sample per year (p = 0.001). The present study suggests frequent blood Phe monitoring during ages 6-10 years may reduce blood Phe and prevent deficits in perceptual reasoning later in life

Phone-based motivational interviewing to increase self-efficacy in individuals with phenylketonuria

Objective: To measure change in patient activation and self-efficacy in individuals with phenylketonuria (PKU) before and after a 6-month phone-based motivational interviewing (MI) intervention and determine the feasibility of implementing dietary counseling for PKU using an MI approach. Methods: Participants (n = 31) included preadolescents (7–12 years), adolescents (13–17 years), and adults (18–35 years) with early-treated PKU. Participants completed online questionnaires assessing self-reported stage of change (SOC), patient activation, and self-efficacy for PKU self-management behaviors. The intervention included monthly phone-based dietary counseling using MI during which participants set monthly goals. Results: Patient activation and self-efficacy were significantly different by age group (both p < 0.01) with higher scores in older participants. Self-efficacy significantly increased from baseline to month 6 among adolescents and adults (7.4 ± 1.9 and 8.6 ± 1.3, respectively, p = 0.002). Preadolescents did not have a significant change in self-efficacy (p = 0.79). There was no increase in patient activation for preadolescents or adolescents/adults (p = 0.19 and p = 0.24, respectively). Indicators of learning problems were not significantly associated with self-efficacy (p = 0.33) or patient activation (p = 0.83). Conclusion: These results demonstrate the feasibility of implementing phone-based dietary counseling for PKU using MI. This study also supports further investigation of MI as an intervention approach to improving self-efficacy and self-management behaviors in adolescents and adults with PKU