Analysis of the Medication Persistence Rate for and Adherence to Oral 5-Aminosalicylic Acid Preparations in Japanese...

5-aminosalicylic acid (5-ASA) is the first-line drug for the treatment of mild-to-moderate ulcerative colitis (UC). Three oral sustained-release formulations are often used. However, no unified view of their actual use in routine medical practice has been presented to date.

Using a health insurance claims database, we extracted patients with an initial diagnosis of mild-to-moderate UC during the period from December 1, 2017, to March 31, 2022. For the three types of oral 5-ASA formulation, we calculated and compared descriptive statistics of medication persistence rates (MPR), proportions of days covered (PDC), and adherence proportion (PDC ≥80%) in the extracted population.

An oral 5-ASA formulation was used in combination with a topical preparation (cohort 1) in 899 patients, and oral 5-ASA was used alone (cohort 2) in 1,829 patients. In cohort 1, MPR at days 151-180 with concomitant use of topical formulation was significantly higher for the Multi Matrix System™ (MMX) formulation (65.2%) compared with that for pH-dependent formulation (51.7%, p < 0.025), while MPR tended to be higher for MMX than for the time-dependent formulation (56.4%, not significant). During days 151-180 after starting the oral formulation, MPR for MMX (66.7% and 65.8%) was higher than for pH-dependent (55.9% and 55.3%) and time-dependent (57.6% and 55.9%) formulations in cohorts 1 + 2 and 2, respectively. In cohort 1, there was a significant difference between MMX (68.3%) and pH-dependent (57.1%) formulations, but no significant difference was seen with time-dependent formulations (61.8%). In terms of the proportion of adherence until day 180, MMX was significantly better than the other formulations.

The analyses of the three oral 5-ASA formulations suggested that both MPR and medication adherence were better for the MMX formulation than for time-dependent or pH-dependent formulations.