UMIN-ICDS Clinical Trial

Public title

An AB-design pilot study evaluating the effectiveness of a personalized smartphone intervention (JITAI) combined with a wearable device to optimize sedentary time in outpatients with heart disease

Acronym

Sit-Time Optimization App Study with heart disease

Scientific Title

Optimization of sedentary time using a personalized digital-nudge JITAI app combined with a wearable device: a pilot AB-design single-case series in stable cardiovascular disease patients.

Scientific Title:Acronym

Pilot study of Behavioral Engagement with Adaptive Tools for SITting Time with heart disease patients

Region

Japan

Condition

cardiovascular disease

Classification by specialty

Cardiology

Cardiovascular surgery

Classification by malignancy

Others

Genomic information

NO

Narrative objectives1

The primary objective of this study is to evaluate the feasibility and preliminary efficacy of an intervention combining a digital nudge-based JITAI app and wearable devices tailored to individual characteristics (TIPI-J) using a single-subject AB design targeting community-dwelling patients with stable cardiovascular disease, and to estimate the effect size to inform future RCT designs. The primary outcomes will be reductions in total daily sitting time and the cumulative duration of continuous sitting sessions lasting 30 minutes or longer. Secondary outcomes will include the number of times the participant stands up, step count, implementation and acceptability indicators (number of app launches, wear rate), patient-reported outcomes (KCCQ-12, fatigue VAS), and physiological indicators (resting heart rate). Safety will be assessed descriptively by monitoring the frequency of adverse events.

Basic objectives2

Safety,Efficacy

Basic objectives -Others

Trial characteristics_1

Trial characteristics_2

Developmental phase

Primary outcomes

Change in mean daily sedentary time (min/day)
Timing: compare the last week of Phase A (pre-intervention, Week 2) with the last week of Phase B (after 4 weeks of intervention, Week 6); data source: Fitbit API, synced daily.

Key secondary outcomes

Sum of >= 30-minute prolonged sitting (min/day): change in weekly means between end of Phase A (Week 2) and end of Phase B (Week 6).

Sum of prolonged sitting >= 30 minutes (min/day): change in weekly means between end of Phase A (Week 2) and end of Phase B (Week 6).

Sit-to-stand counts (counts/day): same timing.

Steps (steps/day): same timing.

Resting heart rate (bpm): change from end of Phase A to end of Phase B, plus maintenance at 2 weeks after Phase B (Week 8; notification-off follow-up).

Implementation / acceptability: app launches (per day; averaged across 4 weeks of Phase B) and wear adherence (%; proportion of prescribed wear time from 09:00 to 21:00).

Patient-reported outcomes (PROs): KCCQ-12 (total and domain scores) and fatigue VAS at registration, weekly, and 2 weeks after Phase B (Week 8).

User experience: SUS score and a semi-structured interview at the end of Phase B (Week 6).

Safety: frequency and severity of adverse events (exercise-related, cardiovascular, device-related, skin irritation). Cumulative from start of Phase A through end of follow-up (Week 8); Phase B breakdown as needed.

Study type

Interventional

Basic design

Single arm

Randomization

Non-randomized

Randomization unit

Blinding

Open -no one is blinded

Control

Self control

Stratification

Dynamic allocation

Institution consideration

Blocking

Concealment

No. of arms

1

Purpose of intervention

Educational,Counseling,Training

Type of intervention

Behavior,custom

Other

Interventions/Control_1

Name: Personalized JITAI smartphone intervention plus wrist-worn wearable
Category: Behavioral (digital health), device use
Exposure window: 4 weeks during Phase B (Phase A is 2-week observation without notifications; notifications are turned off for 2-week post-B follow-up)
Components:

A JITAI smartphone app delivers 0 to 3 prompts per day, tailored by real-time activity and baseline personality assessment (TIPI-J)

Prompts are triggered when prolonged sitting reaches 30 minutes or when overall activity is low, encouraging brief sit-to-stand and short walks

A wrist-worn wearable continuously captures daytime activity and syncs to the app
Use instructions: Wear and run the app primarily from 09:00 to 21:00. Study staff provide onboarding and safety checks; no scheduled human coaching during the intervention
Comparator: Within-subject self-control. Weekly means during Phase A (observation, no notifications) are compared with Phase B (intervention)

Interventions/Control_2

Interventions/Control_3

Interventions/Control_4

Interventions/Control_5

Interventions/Control_6

Interventions/Control_7

Interventions/Control_8

Interventions/Control_9

Interventions/Control_10

Age-lower limit

18

years-old

<=

Age-upper limit

100

years-old

>=

Gender

Male and Female

Key inclusion criteria

Recruiting patients with stable cardiovascular disease who live in the local area (and have not been hospitalized for at least 12 months)

Inclusion Criteria
1. Smartphone user who routinely uses the communication app LINE
2. Independent in activities of daily living
3. Agrees to wear a wearable device

Key exclusion criteria

1. Patients with dementia
2. Patients with atrial fibrillation (as Fitbit pulse measurements may be inaccurate)

Target sample size

10

Name of lead principal investigator

1st name	Koichi
Middle name
Last name	Naito

Organization

Nagoya Aoi University

Division name

Department of Physical Therapy, Faculty of Medical Science

Zip code

4678610

Address

3-40 Shioji-cho, Mizuho-ku, Nagoya, Aichi, Japan

TEL

0528385026

Email

naito@nagoya-aoi.ac.jp

Name of contact person

1st name	Koichi
Middle name
Last name	Naito

Organization

Nagoya Aoi University

Division name

Department of Physical Therapy, Faculty of Medical Science

Zip code

4678610

Address

3-40 Shioji-cho, Mizuho-ku, Nagoya, Aichi, Japan

TEL

0528385026

Homepage URL

Email

naito@nagoya-aoi.ac.jp

Institute

Nagoya Aoi University

Institute

Department

Personal name

Koichi Naito

Organization

Ministry of Education, Culture, Sports, Science and Technology

Organization

Division

Category of Funding Organization

Japanese Governmental office

Nationality of Funding Organization

Co-sponsor

Nagoya City University

Name of secondary funder(s)

Organization

Nagoya Aoi University Institutional Review Board for Human Researc

Address

3-40 Shioji-cho, Mizuho-ku, Nagoya, Aichi, Japan

Tel

05288521111

Email

somu@nagoya-aoi.ac.jp

Secondary IDs

NO

Study ID_1

Org. issuing International ID_1

Study ID_2

Org. issuing International ID_2

IND to MHLW

愛知県

Institutions

Date of disclosure of the study information

2026

Year

06

Month

24

Day

URL releasing protocol

Publication of results

Unpublished

URL related to results and publications

Number of participants that the trial has enrolled

8

Results

Results date posted

Results Delayed

Results Delay Reason

Date of the first journal publication of results

Baseline Characteristics

Participant flow

Adverse events

Outcome measures

Plan to share IPD

IPD sharing Plan description

Recruitment status

No longer recruiting

Date of protocol fixation

2025

Year

10

Month

01

Day

Date of IRB

2025

Year

10

Month

01

Day

Anticipated trial start date

2026

Year

02

Month

01

Day

Last follow-up date

2027

Year

12

Month

31

Day

Date of closure to data entry

Date trial data considered complete

Date analysis concluded

Other related information

Registered date

2026

Year

06

Month

24

Day

Last modified on

2026

Year

06

Month

24

Day

Link to view the page

Value
https://center6.umin.ac.jp/cgi-open-bin/icdr_e/ctr_view.cgi?recptno=R000067543