Introduction
Hypertension is a major modifiable risk factor for cardiovascular disease and remains a substantial public health burden [1, 2, 3]. Because elevated blood pressure (BP) is usually asymptomatic, many adults are first recognized as having elevated BP during routine health examinations. Reassessment after an elevated BP value at a workplace health checkup may help distinguish persistent BP elevation from transient or context‐dependent elevation and may provide an opportunity for earlier preventive management.
In Japan, annual workplace health checkups are conducted under the Industrial Safety and Health Act and include BP and cardiometabolic risk assessment [4]. Health guidance after workplace health checkups is widely used as a preventive strategy, but engagement with risk reduction and medical follow‐up remains variable [5, 6]. A single BP measurement obtained at a workplace health checkup may not represent usual BP because of short‐term variability and the white‐coat effect [7, 8, 9].
Contemporary recommendations therefore emphasize accurate BP measurement and out‐of‐office confirmation when appropriate [10].
Home BP monitoring provides repeated measurements under usual living conditions and has demonstrated value for hypertension diagnosis and management [11, 12, 13]. Smartphone‐connected BP monitors additionally allow automatic recording and visualization of repeated measurements. Randomized trials and meta‐analyses have shown that self‐monitoring, telemonitoring, and mobile health approaches can improve BP control, particularly in patients with established hypertension receiving clinical care [14, 15, 16, 17, 18].
However, evidence is more limited for adults identified with elevated BP at routine workplace health checkups, including those without a formal hypertension diagnosis, and for interventions that use home BP reassessment to guide early lifestyle management.
We therefore conducted a randomized pilot trial among municipal employees with elevated BP identified at annual workplace health checkups. We evaluated whether smartphone‐connected home BP monitoring combined with physician‐led lifestyle guidance based on home BP values improved BP and metabolic risk profiles compared with the same scheduled guideline‐based lifestyle counseling without study‐provided home BP feedback.
Methods
Study Design and Participants
This open‐label, randomized, parallel‐group pilot trial was conducted among municipal employees of a single local government in Iwate Prefecture, Japan. Of 515 employees who underwent the annual workplace health checkup in January 2023, 129 had systolic BP (SBP) ≥ 140 mmHg and/or diastolic BP (DBP) ≥ 90 mmHg. All 129 employees received a written overview of the study and an invitation to participate.
Fifty‐eight employees applied to participate, and all 58 provided written informed consent and met the eligibility criteria for study participation. Inclusion criteria were age < 75 years as of April 1, 2023, no routine home BP monitoring, and no physician‐imposed restriction on BP lowering. Individuals receiving medical treatment, including antihypertensive therapy, were not excluded.
No consent was withdrawn either before or after study initiation, and no applicant or participant was excluded for failure to meet the eligibility criteria. All 58 participants proceeded to randomization. Participant flow is shown in Figure 1.
Randomization and Allocation Concealment
Participants were randomly allocated to the intervention or control group using stratified randomization according to sex (male or female), age (< 50 or ≥ 50 years), and SBP (< 150 or ≥ 150 mmHg). The age and SBP cutoffs were prespecified on the basis of age and BP distributions among potentially eligible employees in the 2022 workplace health checkup data to improve balance in age and baseline BP severity. A computer‐generated random number table was used to prepare the allocation sequence.
Allocation was concealed using sequentially numbered envelopes that were opened after enrollment.
Counseling Schedule and Components Common to Both Groups
After randomization, participants in both groups were scheduled for two physician‐led lifestyle counseling sessions: an initial session and a second session approximately 3 months later. The same physician delivered both sessions in both groups using the Japanese Society of Hypertension Guidelines for the Management of Hypertension 2019 [19]. The counseling domains were the same in both groups and included salt reduction, alcohol reduction, weight control, smoking cessation, exercise, and discussion of relevant workplace health checkup findings.
Thus, the scheduled number and timing of counseling sessions and the lifestyle topics addressed did not differ between groups. The principal between‐group difference was the BP information available for reassessment and feedback: The intervention group used repeated home BP measurements, whereas the control group used workplace health checkup BP at the initial session and BP measured at the 3‐month counseling visit for reassessment. Neither group received any additional scheduled counseling sessions beyond these two visits.
The study schedule is shown in Figure 2.
Definition of High Cardiovascular Risk
Cardiovascular risk in this study was classified according to the Japanese Society of Hypertension Guidelines for the Management of Hypertension 2019 [19]. Participants were classified as being at high cardiovascular risk if they met any of the following criteria: (1) a history of cardiovascular or cerebrovascular disease, nonvalvular atrial fibrillation, diabetes mellitus, or chronic kidney disease with proteinuria, or the presence of at least three of the following risk factors: Age ≥ 65 years, male sex, dyslipidemia, and current smoking; (2) at least one of these four risk factors plus either workplace health checkup or counseling‐visit BP ≥ 160/100 mmHg or mean home BP ≥ 155/95 mmHg; or (3) workplace health checkup or counseling‐visit BP ≥ 180/110 mmHg, or mean home BP ≥ 175/105 mmHg. Participants who did not meet any of these criteria were classified as being at low‐to‐moderate cardiovascular risk.
Intervention Group: Home BP Monitoring Before the Initial Counseling Session
Participants allocated to the intervention group were provided with an upper‐arm smartphone‐connected sphygmomanometer (HEM‐7281T, Omron Healthcare Co., Ltd., Japan). The compatible smartphone application (OMRON connect, Omron Healthcare Co., Ltd., Japan) was installed on each participant's smartphone and connected to the device by Bluetooth. Before the initial counseling session, participants were instructed to obtain two consecutive home BP measurements at each of two daily occasions for at least 7 days: in the morning after waking and urination and before breakfast, and in the evening after urination and before bedtime.
Measurements were automatically recorded in the application. The application calculated and displayed the mean of all morning and evening BP measurements obtained during the most recent 7 days of the monitoring period. This 7‐day mean home BP was used as the BP measure for the initial reassessment and counseling.
Initial Counseling and Referral Criteria
At the initial counseling session, the same guideline‐based lifestyle domains described above were addressed. In the intervention group, the emphasis of counseling was individualized using the 7‐day mean home BP together with workplace health checkup parameters, including estimated salt intake, body mass index (BMI), body weight, waist circumference, glycated hemoglobin (HbA1c), high‐density lipoprotein cholesterol (HDL‐C), low‐density lipoprotein cholesterol (LDL‐C), triglycerides, medication use, smoking, and alcohol consumption. Participants classified as being at high cardiovascular risk according to the Japanese Society of Hypertension Guidelines were advised to seek medical care irrespective of the home BP level.
Participants classified as being at low‐to‐moderate cardiovascular risk received lifestyle counseling without an automatic referral at the initial session. The BP reassessment and referral rules for both groups are summarized in Figure 3.
Three‐Month Home BP Reassessment and Second Counseling Session
Approximately 3 months after the initial counseling session, participants in the intervention group repeated the same home BP monitoring schedule before the second counseling session: two consecutive measurements at each of two daily occasions for at least 7 days, with the most recent 7‐day mean used for reassessment. At the second counseling session, a mean home BP ≥ 135 mmHg systolic and/or ≥ 85 mmHg diastolic was considered persistently elevated and prompted a recommendation for medical consultation in addition to continued lifestyle counseling. If mean home BP was < 135/85 mmHg, lifestyle counseling was continued without a new BP‐based referral.
For participants who had already been advised to seek care because of high cardiovascular risk but had not yet attended a medical facility, the recommendation was reinforced regardless of the follow‐up home BP value. Continuation of home BP monitoring outside the two designated monitoring periods was not mandatory and was left to participants' discretion.
Control Group
Participants in the control group did not receive a study‐provided home BP monitor or smartphone application. They received the same two‐session counseling schedule and the same guideline‐based lifestyle counseling domains as the intervention group. At the initial counseling session, BP‐related assessment and feedback were based on the January 2023 workplace health checkup BP together with the same workplace health checkup parameters used in the intervention group.
Participants classified as being at high cardiovascular risk were advised to seek medical care irrespective of BP reassessment. Approximately 3 months later, BP was measured at the second counseling visit and used for reassessment. A visit SBP ≥ 140 mmHg and/or DBP ≥ 90 mmHg prompted a recommendation for medical consultation; if BP was < 140/90 mmHg, lifestyle counseling was continued without a new BP‐based referral.
For participants previously advised to seek care because of high cardiovascular risk but who had not yet attended a medical facility, the recommendation was reinforced regardless of the 3‐month visit BP. Participants were not prohibited from initiating home BP monitoring independently.
Outcome Assessment
Both groups underwent the subsequent annual workplace health checkup in January 2024. With participants' consent, the researchers obtained results from the January 2023 and January 2024 workplace health checkups from workplace records. The primary outcome was change in SBP measured at the annual workplace health checkup from January 2023 to January 2024.
Secondary outcomes included changes in DBP, estimated salt intake, body weight, waist circumference, BMI, HbA1c, LDL‐C, HDL‐C, triglycerides, smoking status, daily alcohol consumption, and use of antihypertensive, antidiabetic, and lipid‐lowering medications. The January 2024 workplace health checkup was used for outcome assessment only and was not used to make within‐study referral or treatment‐escalation decisions. Neither group received study‐provided lifestyle counseling beyond the two scheduled sessions.
Sample Size
The sample size calculation was based on the primary outcome. Using data from previous routine workplace health checkups, the standard deviation of SBP was assumed to be 13 mmHg. An anticipated between‐group difference of 10 mmHg in SBP change, a two‐sided α level of 0.05, and 80% power yielded a required sample size of 27 participants per group (54 total).
Allowing for an anticipated dropout rate of 25%, the target sample size was set at 72 participants.
Statistical Analysis
Continuous baseline variables were compared between groups using unpaired t tests and categorical baseline variables using Fisher exact tests. Within‐group pre‐post changes in paired categorical variables, including smoking status, daily alcohol consumption, and use of antihypertensive, antidiabetic, and lipid‐lowering medications, were assessed using McNemar tests. Pre‐post changes in continuous variables within each group were assessed using paired t tests.
Between‐group differences in changes in continuous variables from baseline to follow‐up were assessed using unpaired t tests. Analyses followed the intention‐to‐treat principle, with participants analyzed in their randomized groups regardless of adherence or initiation of antihypertensive medication during follow‐up. A sensitivity analysis excluded participants who initiated antihypertensive medication.
Statistical analyses were performed using SPSS Statistics version 29.0 (IBM Corp., Armonk, NY, USA). All tests were two‐tailed, and p < 0.05 was considered statistically significant.
Ethics and Trial Registration
The study was approved by the Ethics Committee of Iwate Medical University and conducted with authorization from the President of Iwate Medical University (Approval No. MH2022‐107). Written informed consent was obtained from all participants.
The study was conducted in accordance with the Declaration of Helsinki, and personal data were anonymized. The study protocol was finalized and ethics approval was obtained on December 9, 2022, before participant enrollment. The trial was retrospectively registered with the University Hospital Medical Information Network Clinical Trials Registry (UMIN‐CTR; UMIN000060224) on December 28, 2025, after completion of participant follow‐up [20].
At study initiation, the investigators were not aware that prospective registration was required for subsequent publication of a randomized intervention study, which resulted in delayed registration. The delayed registration was not intended to permit selective publication or reporting, including withholding negative findings. Eligibility criteria, randomization, allocation concealment, intervention procedures, and outcome assessment were determined and conducted according to the study protocol before study outcomes were known; therefore, delayed registration did not influence allocation or study conduct.
The findings were not intentionally reported selectively.
Results
Of 515 employees who underwent the January 2023 workplace health checkup, 129 had workplace health checkup SBP ≥140 mmHg and/or DBP ≥90 mmHg. All 129 received a study overview and invitation to participate; 58 applied to participate, and all 58 provided written informed consent and met the eligibility criteria. No consent was withdrawn before or after study initiation, and no participant was excluded for failure to meet the eligibility criteria.
All 58 participants were randomized. No participants were lost to follow‐up after randomization, and outcome data at the subsequent annual health checkup were available for all 58 randomized participants (Figure 1). Baseline characteristics are presented in Table 1.
No significant between‐group differences were observed in baseline characteristics.
At baseline, 10 participants (32%) in the intervention group and 9 (33%) in the control group were classified as being at high cardiovascular risk, with no between‐group difference (Fisher exact test, p = 1.000; Table 1). In accordance with the study protocol, these participants were advised to seek medical care at the initial or follow‐up guidance session as appropriate. Three participants in the intervention group initiated antihypertensive medication, whereas none did so in the control group; no participant discontinued antihypertensive medication.
Within‐person changes in medication use, smoking status, and daily alcohol consumption are summarized in Table 2. McNemar tests showed no significant changes in these paired categorical outcomes in either group.
Changes in continuous variables from baseline to the subsequent annual health checkup are shown in Table 3. In the intervention group, SBP, DBP, body weight, and HbA1c decreased significantly and HDL‐C increased significantly. No significant changes were observed in estimated salt intake, BMI, waist circumference, LDL‐C, or triglycerides.
In the control group, none of the continuous variables changed significantly.
Between‐group differences in changes from baseline are presented in Table 4. Compared with the control group, the intervention group showed a greater reduction in SBP (between‐group difference, −9.9 mmHg; 95% CI, −17.0 to −2.8; p = 0.007) and HbA1c (−0.1 percentage points; 95% CI, −0.2 to −0.04; p = 0.008). In the sensitivity analysis excluding the three participants who initiated antihypertensive medication, the intervention group continued to show greater reductions in SBP (−7.7 mmHg; 95% CI, −14.6 to −0.8; p = 0.029), body weight (−1.4 kg; 95% CI, −2.8 to −0.03; p = 0.046), and HbA1c (−0.2 percentage points; 95% CI, −0.3 to −0.1; p = 0.006) than the control group.
Discussion
In this randomized pilot trial, smartphone‐connected home BP monitoring combined with home BP‐guided, physician‐led lifestyle counseling improved the primary outcome of annual workplace health checkup SBP among adults with elevated BP identified at a workplace health checkup. The randomized between‐group comparison showed a 9.9 mmHg greater reduction in SBP in the intervention group, together with a small but statistically significant reduction in HbA1c. In sensitivity analyses excluding the three participants who initiated antihypertensive medication, the between‐group SBP difference remained significant.
These findings support further evaluation of home BP‐guided management as an early intervention strategy after elevated BP is detected at routine workplace health checkups.
Self‐measured BP monitoring is recommended as a complement to office measurement because repeated out‐of‐office values improve assessment of usual BP and can support hypertension management [10, 11, 12, 13, 21]. Randomized studies have shown that self‐monitoring, telemonitoring, and smartphone‐supported interventions can improve BP control, particularly when measurement is combined with clinical or behavioral support [14, 15, 16, 17, 18, 22, 23]. The present study extends this evidence to adults identified with elevated BP at workplace health checkups rather than solely to patients recruited from treated hypertension populations, and it included individuals without a formal hypertension diagnosis.
Repeated home BP measurements were used to reassess BP status and tailor subsequent feedback and referral recommendations.
Clinically, this strategy addresses a common management gap after an elevated workplace health checkup BP is identified. A workplace health checkup BP can appropriately trigger counseling or referral, but treatment decisions based on a single measurement may be influenced by transient BP elevation. In the intervention group, short‐term home monitoring provided repeated measurements under usual living conditions, and the most recent 7‐day mean was used at each counseling session to individualize BP‐related feedback and referral.
In contrast, the control group received the same scheduled counseling sessions and lifestyle topics, but BP reassessment was based on the workplace health checkup BP initially and on BP measured at the 3‐month counseling visit. Therefore, the intervention did not increase the number of scheduled counseling contacts; it changed the BP information used to guide those contacts. The subsequent annual workplace health checkup BP was an outcome measure only and did not override earlier referral decisions based on home BP or the 3‐month control‐group visit BP.
This approach is consistent with the broader role of out‐of‐office BP in confirming persistent BP elevation and supporting management decisions [10, 13, 24].
The home BP procedure in this trial was designed to provide repeated information for short‐term reassessment. Participants obtained two consecutive measurements in the morning and evening for at least 7 days before each of the two counseling sessions, and the smartphone application automatically displayed the mean of all morning and evening measurements from the most recent 7 days. This approach may have increased participants' awareness of their BP status and provided the physician with information more representative of usual BP than a single workplace health checkup measurement [18].
However, the trial cannot determine whether smartphone connectivity itself was necessary for the observed effect; the tested strategy combined repeated home BP measurement, automatic recording and visualization, and home BP‐guided feedback within an otherwise matched two‐session counseling schedule.
The intervention was also associated with changes beyond BP. Body weight and HbA1c decreased significantly within the intervention group, and the between‐group reduction in HbA1c was significant. These findings should not be interpreted as evidence for a direct metabolic effect of home BP monitoring.
Rather, repeated measurement and individualized counseling may have increased awareness of overall cardiovascular risk and encouraged multiple lifestyle changes. This interpretation is consistent with prior work showing that health guidance and risk awareness can influence preventive behaviors [5, 6].
Three participants initiated antihypertensive medication during follow‐up, all in the intervention group. Home BP monitoring may have contributed to recognition of persistent BP elevation and subsequent medical evaluation. However, the within‐group change in antihypertensive medication use was not statistically significant, and baseline high cardiovascular risk was similar between groups.
Importantly, sensitivity analyses excluding these participants showed that the intervention group retained greater reductions in SBP and HbA1c, and also had a greater reduction in body weight. Pharmacological treatment alone is therefore unlikely to explain the principal findings.
This study has several limitations. First, it was an open‐label pilot trial conducted in a single municipal workforce with a small sample size, which limits precision and generalizability. Second, although the number and scheduled timing of counseling sessions and the lifestyle domains addressed were matched between groups, the intervention was multicomponent and included home BP measurement, smartphone‐based recording and visualization, and use of home BP values for individualized feedback and referral; the independent contribution of each component cannot be distinguished.
Third, information was not collected on home BP monitoring outside the two designated monitoring periods in the intervention group or on whether participants in the control group independently initiated home BP monitoring during follow‐up. Fourth, sufficiently detailed information on changes in physical activity was not available, so its contribution to the observed changes could not be assessed. Fifth, regression to the mean may have contributed to BP reductions because elevated workplace health checkup BP was both an eligibility criterion and the baseline measurement.
Randomization and identical eligibility criteria in both groups reduce, but do not eliminate, this concern for the between‐group comparison. Finally, implementation feasibility, cost, acceptability, and scalability were not formally evaluated.
In conclusion, among adults with elevated BP identified at workplace health checkups, smartphone‐connected home BP monitoring combined with home BP‐guided lifestyle counseling produced greater reductions in annual workplace health checkup SBP and HbA1c than the same scheduled guideline‐based lifestyle counseling without study‐provided home BP feedback. Larger multicenter trials are needed to confirm the effectiveness, durability, and implementation value of this approach for early hypertension management.
Author Contributions
Shinichi Omama: Conceptualization, Investigation, Data Curation, Formal Analysis, Writing – Original Draft. Tomohiro Takahashi: Methodology, Formal Analysis, Writing – Review & Editing. Tetsuya Yamada: Methodology, Writing – Review & Editing.
Shinya Maita: Methodology, Writing – Review & Editing. Osamu Shimooki: Funding Acquisition, Project Administration, Writing – Review & Editing. All authors reviewed and approved the final manuscript.
Funding
This work was supported by Iwate Prefecture through a Grant‐in‐Aid for Regional Medical Research of Iwate. The funder had no role in the study design; data collection, analysis, or interpretation; preparation of the manuscript; or the decision to submit the manuscript.
Ethics Statement
The study was approved by the Ethics Committee of Iwate Medical University (Approval No. MH2022‐107) on December 9, 2022, before participant enrollment.
Consent
Written informed consent for participation was obtained from all participants.
Conflicts of Interest
The authors declare no conflicts of interest.
Permission to Reproduce Material
Not applicable. All tables and figures are original to the authors.
Clinical Trial Registration
University Hospital Medical Information Network Clinical Trials Registry (UMIN‐CTR), UMIN000060224; retrospectively registered December 28, 2025. Registration was delayed because the investigators were not aware at study initiation that prospective registration was required for subsequent publication of a randomized intervention study. The study protocol and ethics approval were finalized before enrollment, and delayed registration did not influence randomization, allocation, intervention delivery, outcome assessment, or selective reporting.