Statistical Analysis Data are presented as urinary DHA excretion (mg/day) for timed collections and urinary DHA-to-creatinine ratio in first morning urine samples. Data for the whole group are presented as a median (range). Differences in the median urinary DHA excretion and the urinary DHA-to-creatinine ratio, off pharmacotherapy and on the two study drugs, febuxostat and allopurinol, were compared with a paired t-test.