World's first privacy-preserving ePRO system developed for inflammatory bowel disease patients

While patients often find it difficult to tell their doctors about certain symptoms or life events, many of these unspoken details contain critical information. To enhance the quality of medical care while protecting patient privacy, a joint research team, including Assistant Professor Yuki Ohta, Lecturer Sadahisa Ogasawara, and Associate Professor Jun Kato from the Department of Gastroenterology at Chiba University Hospital, Specially Appointed Professor Kensuke Yoshimura from the hospital's Center for Next Generation of Community Health, and NTT DOCOMO Business, has developed the world's first privacy-preserving ePRO system and demonstrated its utility. The study targeted patients with inflammatory bowel disease (IBD), such as ulcerative colitis and Crohn's disease, which are difficult to cure completely and require continuous treatment. The findings were published in npj Digital Medicine.

Traditionally, the quality of medical care has centered on objective indicators such as physical examinations, disease observation, and laboratory tests by physicians. In recent years, new patient-centered evaluation metrics, such as the severity of symptoms, the extent of side effects, quality of life (QOL), and the impact on work and daily life, have gained prominence. These Patient-Reported Outcomes (PROs) are now heavily emphasized by the FDA in drug development and approval reviews. Utilizing PROs is particularly vital in chronic diseases to improve both the quality of care and patient QOL.

However, traditional PROs face challenges such as the patients' anxiety that doctors see their raw answers, time lag due to data input, input errors, and complex paper-based management. To address these issues, electronic Patient-Reported Outcomes (ePROs) have become more widespread.

On the other hand, if transparency and privacy are not fully guaranteed, patients still find it difficult to reveal their true conditions. For instance, when healthcare professionals or researchers can access individual responses, it creates a psychological burden ("my answers might be watched") or raises concerns that "the answers might affect my treatment." Especially in medical fields involving highly private symptoms, patients may give socially desirable answers instead of expressing their true reality.

The joint research group developed "ASAHI," a system based on NTT's secure computation service "Sekihi." ASAHI encrypts both PRO and clinical data separately before matching and analyzing them. The smartphone-based survey was conducted among 322 IBD patients who consented to participate within Far East 1000, a multicenter prospective long observational study examining disease activity, treatment reality, and complications across 15 facilities in Chiba Prefecture. Out of 277 patients who responded to the initial survey, the team analyzed the responses of 173 patients (53.7%) who completed the follow-up survey.

The results revealed a significant communication gap: 28.9% of the patients did not correctly understand their medication information, and 68% of their attending doctors were unaware of this misunderstanding.

In IBD treatment, bowel urgency (a severe urge to defecate so sudden that it could cause fecal incontinence if one does not rush to a restroom immediately) stands out as a major challenge. While 92.7% of the patients recognized it as a "symptom that should be reported," only 65.1% actually reported it to their doctors. Furthermore, among those who did report it, only 68.5% had their doctors successfully note or capture the fact that they were experiencing bowel urgency.

"Although we cannot see which specific patient or doctor is involved, shedding light on the fact that these gaps occur allows us to provide more attentive and meticulous medical care," Ogasawara stated.

The survey also looked into the patients' living conditions. It revealed that patients who developed the disease at a younger age tended to have lower annual incomes, and their incomes tended to remain low over time. This is also the kind of question patients can answer only because they know "nobody will find out who said it."

Ohta remarked: "As an IBD specialist, I have always felt that we aren't fully picking up on the struggles our patients face. The beauty of this system is that it captures these voices and channels them back to benefit the patients. Furthermore, if doctors don't consciously recognize what patients are struggling with, they cannot address it. Bowel urgency is a symptom that has finally gained public recognition over the last year or two. Before that, no one even noticed it. We hope to expand this system to other chronic diseases to better connect patients with medical care and society."

Journal Information
Publication: npj Digital Medicine
Title: Privacy preserving digital platform for patient reported outcomes in inflammatory bowel disease
DOI: 10.1038/s41746-026-02814-z