Prevalence of comorbid conditions among adult patients diagnosed with phenylketonuria

• Published in: Molecular genetics and metabolism 2018-11, Vol.125 (3), p.228-234
• Main Authors: Burton, Barbara K., Jones, Kyle Bradford, Cederbaum, Stephen, Rohr, Fran, Waisbren, Susan, Irwin, Debra E., Kim, Gilwan, Lilienstein, Joshua, Alvarez, Ignacio, Jurecki, Elaina, Levy, Harvey
• Format: Article
• Language: English
• Subjects: Amino-acid metabolism; Comorbidities; Dietary management; Insurance Claim-based data; Phenylalanine hydroxylase; Phenylketonuria
• ISSN: 1096-7192; 1096-7206
• DOI: 10.1016/j.ymgme.2018.09.006

Phenylalanine hydroxylase (PAH) deficiency, otherwise known as phenylketonuria (PKU), is an inborn error of metabolism that requires treatment to be initiated in the newborn period and continued throughout life. Due to the challenges of treatment adherence and the resulting cumulative effects of high and labile blood phenylalanine, PKU exerts a significant burden of disease. Retrospective studies using large databases allow for unique perspectives on comorbidities associated with rare diseases. An evaluation of comorbidities across various organ systems is warranted to understand the disease burden in adult patients. The aim of this insurance claim-based observational study was to assess the prevalence of comorbid conditions across various organ systems (e.g. dermatological, renal, respiratory, gastrointestinal, hematological, and others) among adult PKU patients compared with matched controls from the general population. This retrospective, case-controlled study selected patients from United States insurance claims databases from 1998 to 2014 using International Classification of Diseases, Ninth Revision (ICD-9) codes for diagnosis of PKU. The date of first diagnosis during the study period was index date and this was not necessarily the first time the patient was diagnosed with PKU. Cases were matched with a 1:5 ratio with general population (non-PKU controls) on age, sex, race, geographic location, duration of time in the database and insurance type. Prevalence and prevalence ratio (PR) calculations for comorbidities across various organ systems among adults (≥20 years old) with PKU were compared with the general population (non-PKU controls). The conditions were selected based on complications associated with PKU and feedback from clinicians treating PKU patients. A total of 3691 PKU patients and 18,455 matched, non-PKU controls were selected, with an average age of 35 years. The mean healthcare costs incurred by the PKU patients during baseline, were approximately 4 times that of the controls ($4141 vs $1283; p