Quality of life and adherence to treatment in early-treated Brazilian phenylketonuria pediatric patients

Early dietary treatment of phenylketonuria (PKU), an inborn error of phenylalanine (Phe) metabolism, results in normal cognitive development. Although health-related quality of life (HRQoL) of PKU patients has been reported as unaffected in high-income countries, there are scarce data concerning HRQoL and adherence to treatment of PKU children and adolescents from Brazil. The present study compared HRQoL scores in core dimensions of Brazilian early-treated PKU pediatric patients with those of a reference population, and explored possible relationships between adherence to treatment and HRQoL. Early-treated PKU pediatric patient HRQoL was evaluated by self- and parent-proxy reports of the Pediatric Quality of Life Inventory (PedsQL) core scales. Adherence to treatment was evaluated by median Phe levels and percentage of results within the therapeutic target range in two periods. Means for total and core scales scores of PedsQL self- and parent proxy-reports of PKU patients were significantly lower than their respective means for controls. Adequacy of median Phe concentrations and the mean percentage of values in the target range fell substantially from the first year of life to the last year of this study. There was no significant difference in mean total and core scale scores for self- and parent proxy-reports between patients with adequate and those with inadequate median Phe concentrations. The harmful consequences for intellectual capacity caused by poor adherence to dietary treatment could explain the observed decrease in all HRQoL scales, especially in school functioning. Healthcare system and financial difficulties may also have influenced negatively all HRQoL dimensions.

苯丙酮尿症（phenylketonuria, PKU）是一种苯丙氨酸（phenylalanine, Phe）代谢先天缺陷性疾病，早期饮食干预可使其患者获得正常的认知发育。尽管高收入国家的相关报道显示苯丙酮尿症患者的健康相关生活质量（health-related quality of life, HRQoL）未受显著影响，但目前针对巴西苯丙酮尿症儿童及青少年的健康相关生活质量与治疗依从性的研究数据仍较为匮乏。本研究对比了接受早期干预的巴西苯丙酮尿症儿科患者与参照人群的核心维度健康相关生活质量评分，并探讨了治疗依从性与健康相关生活质量之间的潜在关联。本研究采用儿童生活质量量表（Pediatric Quality of Life Inventory, PedsQL）核心量表的患者自评与家长代评方式，评估早期干预苯丙酮尿症儿科患者的健康相关生活质量；治疗依从性则通过两个时段的中位苯丙氨酸水平及治疗靶范围内检测结果的占比进行评估。苯丙酮尿症患者的儿童生活质量量表自评与家长代评的总分及各核心量表得分均值，均显著低于对照人群的对应均值。中位苯丙氨酸浓度达标率及靶范围内数值占比均值，从患者出生第一年至本研究纳入的最后一年呈显著下降趋势。中位苯丙氨酸浓度达标与未达标患者的儿童生活质量量表自评及代评的总分与核心量表得分均值，均无显著差异。饮食治疗依从性不佳对智力造成的不良影响，或可解释本次研究中观察到的所有健康相关生活质量维度评分下降的现象，尤其是在学校功能维度方面。医疗体系与经济负担问题可能也对所有健康相关生活质量维度产生了负面影响。