PDB74 COMPARISON OF HEALTHCARE RESOURCE USE AND COSTS BETWEEN PATIENTS WITH DIAGNOSED HOMOCYSTINURIA AND PHENYLKETONURIA IN THE UNITED STATES

Abstract

Homocystinuria (HCU) and phenylketonuria (PKU) are inborn errors of metabolism identified through newborn screening (NBS) requiring life-long dietary and medical therapy to prevent sequelae. NBS for HCU is inadequate, resulting in a diagnosis later in life, often after disease-defining comorbid conditions have developed. We hypothesized that the delay in HCU diagnosis is associated with higher life-time medical costs and compared healthcare resource use and costs between HCU and PKU patients. In the IBM MarketScan® claims database, resource use and costs for patients diagnosed with HCU or PKU (1/1/2010- 12/31/2016) were calculated over patients’ period of continuous database enrollment after the first diagnosis during the study period using per patient per month (PPPM) standardization. T-tests were used to compare the results. Patients with HCU (N=6,613) had significantly more inpatient (IP) admissions, compared to PKU patients (N=5,120) (mean ±SD: 0.04 ±0.49 vs. 0.01 ±0.08, p=0.001), as well as more ER visits (0.05 ±0.29 vs. 0.04 ±0.27, p=0.049), lab tests (2.4 ±5.5 vs. 1.2 ±3.6, p<0.001), and outpatient (OP) prescriptions (2.5 ±3.1 vs. 1.0 ±2.4, p<0.001). PPPM IP admission costs among HCU patients were nearly 3x those of PKU patients ($1,191 ±$26,270 vs. $407 ±$4,564, p=0.035), monthly ER costs were twice as high ($85 ±$514 vs. $39 ±$178, p<0.001), and monthly lab costs were 80% higher ($84 ±$333 vs. $47 ±$176, p<0.001). Total monthly medical costs were twice as high among HCU patients, compared to PKU ($2,224 ±$26,689 vs. $1,060 ±$6,777, p=0.002). Similar numbers of patients with HCU and PKU were identified in the database. HCU patients incurred higher monthly medical costs than PKU patients. More than half of the medical costs for HCU patients were attributable to IP admissions. Improved screening, diagnosis, and treatment for HCU are necessary to reduce the medical costs associated with the condition.