Home blood pressure telemonitoring for improving blood pressure control in middle‐aged and elderly patients with hypertension

Abstract The blood pressure (BP) control rate among treated hypertensives in China remains low at 37.5%. The relationship between home blood pressure telemonitoring (HBPT) and BP control is controversial. The authors aimed to investigate the relationship between HBPT and BP control in middle‐aged and elderly hypertensives. In total, 252 hypertension patients aged between 60 and 79 years were enrolled. The patients were given either HBPT through interactive platforms between physicians and patients (telemonitoring group, n = 126) or conventional management (routine management group, n = 126). All patients were followed‐up for 15 months. BP control was defined as home systolic blood pressure < 135 mm Hg and home diastolic blood pressure < 85 mm Hg. At baseline, there were no significant differences in the baseline BP control rate (p = .083). However, after 15 months, the BP control rate improved in both groups, and the telemonitoring group (71.3%) had a significantly higher BP control than the routine management group (49.8%) (p < .001). The change of BP control rate from baseline in the routine management group increased by 26.1%, and that of the telemonitoring group increased by 35.4%. The results of the fully adjusted binary logistic regression showed that HBPT was positively associated with BP control after adjusting for confounders (OR = 4.15, 95% CI 2.05–8.39). Similar results were observed after 3, 9, and 12 months. The association of HBPT with BP control was similar in subgroups. In conclusions, HBPT is recommended for BP control in middle‐aged and elderly hypertensives in the community setting.


INTRODUCTION
Hypertension is a primary risk factor for cardiovascular diseases, 1,2 and blood pressure (BP) control accordingly reduces the risk of cardiovascular disease and mortality. [3][4][5] The standardized management rate of hypertension patients receiving treatment in China has reached 70.3%, but the control rate of hypertension is only 15.3%, and the treatment control rate is 37.6%. 6 China has become an aging society, the data from 2015 Report on Nutrition and Chronic Diseases in China showed that hypertension was prevalent in 58.9% of the Chinese population aged older than 60 years in 2012. 7 This highlights the urgent need for efficient management to improve the control rate of hypertension, especially in middle-aged patients with hypertension.
Several studies have shown that home blood pressure telemonitoring (HBPT) is effective in lowering BP [8][9][10][11][12] and reducing treatment costs. [13][14][15] Accordingly, HBPT is recommended by an increasing number of experts. 16,17 However, the findings from previous studies regarding the relationship between HBPT and BP control are still controversial. In some randomized clinical trials, telemonitoring did not have a significant effect on improving BP control or lowering BP. [18][19][20] In view of the differences in research design, target population, management method, and data analysis of these studies, additional studies are important. The effectiveness of HBPT in elderly patients has not been confirmed owing to the limitation of network operation technology in this population. 21 Therefore, we aimed to investigate whether HBPT is independently related to BP control in middle-aged and elderly patients with hypertension.

Study design
This was a nonrandomized controlled trial. The patients were assigned to different management groups at baseline. Patients in the telemonitoring group were given HBPT through interactive platforms between physicians and patients on the basis of routine management of hypertension. Meanwhile, the patients in the routine management group were given routine management of hypertension for a total of 15 months.
The target independent variable was the different methods of BP
They were recruited from seven communities in Baotou, China, between January 31, 2017 and July 31, 2017. Patients who were willing to participate in the program and who provided informed consent were included consecutively. Patients were grouped per their preferences; those who were willing to buy a Bluetooth sphygmomanometer and who consented to telemonitoring of home blood pressure were included in the telemonitoring group. Otherwise they were included in the routine management group. The inclusion criteria were as follows: (1)

Treatment protocol
Study physicians were assigned to each group to provide the assigned intervention. The patients in the two groups were managed by titration of antihypertensive treatment based on home BP measurements.
The protocol for measuring home blood pressure for the two groups of patients was the same: BP was measured every morning and evening, with an emptied bladder, and measured after rest. The BP in every morning was measured within 1 h of waking up, prior to intake of antihypertensive drugs, and prior to eating breakfast. The BP at night was measured after dinner and before going to bed. Physicians prescribed individualized, guidance-based medications for achieving normotension among the patients. Patients in the routine management group were followed-up every 3 months. They were asked to self-monitor In addition, patients in telemonitoring group were followed-up every 3 months. The physician also titrated the antihypertensive medicine in the outpatient follow-up.

Follow-up procedure
The

Variables
HBPT was defined as a categorical variable. The final outcome variable (dichotomous variable) was BP control. Outcomes related to BP were based only on home blood pressure monitoring. Mean home blood pressure for the two groups of patients was calculated similarly. Home blood pressure was measured continuously for 7 days before each follow-up, and the average of BP for the following 6 days was taken; the sum of all BP data was divided by the number of observations. BP con-

Statistical analysis
Continuous variables were expressed as the mean ± standard deviation, and categorical variables were expressed as frequencies or percentages. We used χ 2 (categorical variables), Student's t test Statistical significance was defined as a two-sided p value < .05.

Baseline patient characteristics
In total, 116 and 136 patients were male and female, respectively.
The mean age was 65.7 years (SD: 4.5, range: 60-79 years), and the mean BMI was 26.3 kg/m 2 (SD: 3.0). The baseline patient characteristics stratified by group are presented in Table 1. The telemonitoring group was younger, had less physical activity, and had lower TG, but it also had a higher percentage of patients with a family history of hypertension. At baseline, the number of antihypertensive medications in the routine management group and the telemanagement group were 2 (1, 2) and 2 (1, 2), respectively (p = .294). In total, 125 patients in each group completed the 15-month follow-up (one patient in the telemonitoring group died of lung cancer, and one patient in the routine manager group withdrew due to an emerging tumor).

BP and BP control rate
At baseline, there was no significant difference in SBP (p = .167) (

Univariate analysis
Blood pressure control was correlated with the management methods.
The results of the univariate analyses are listed in Table S1. HBPT, sex, age, duration of hypertension, physical activity, BMI, and Cr were found to be associated with achieving BP control.

Results of unadjusted and adjusted binary logistic regression
We constructed three models to analyze the independent effects of HBPT on BP control at 15 months (multivariate binary logistic regression). The effect sizes (odds ratio [OR]) and 95%CIs are listed in Table 4.
After adjustment in multivariable analyses, HBPT were significantly associated with BP control. Compared with routine management, the addition of telemonitoring and timely intervention by a physician resulted in a higher BP control rate, with an OR of 4.15 (95% CI 2.05-8.39).
We also constructed three models to analyze the independent effects of HBPT on BP control at 3, 6, 9, and 12 months (multivariate  (Table   S2).

Subgroup analysis
Stratified analyses of the associations between HBPT and BP control are presented in Figure 1.

DISCUSSION
This study showed that the use of telemonitoring enabled timely intervention for the management of hypertension in middle-aged and F I G U R E 1 Forest plot for the subgroup analyses conducted to determine the size of the effect of using different types of BP management at 15 months following the interventions. Adjusted for age, sex, body mass index, duration of hypertension, family history of hypertension, smoking status, physical activity, creatinine, triglyceride, high density lipoprotein cholesterol, baseline systolic blood pressure, and baseline diastolic blood pressure. Abbreviations: n.total, total number of patients in the telemonitoring group; n.control%, the number of patients in the telemonitoring group whose blood pressure had been controlled elderly patients and ultimately resulted in higher BP control rate. showed that the improvement in BP control rates were significantly higher in the m-health system group than that in the matched control group (from 42% to 67% vs. from 59% to 67%, p < .01). Margolis and coworkers 9,10 suggested that HBPT combined with pharmacist management reduced BP in diabetes patients with uncontrolled systolic hypertension and improved hypertension control. This management method had sustained effects for up to 24 months (12 months after the intervention ended). 9 Chandler and coworkers 26 also found that HBPT combined with electronic medication trays can also significantly reduce SBP among Hispanic adults with uncontrolled hypertension.
Similar findings have also been reported in meta-analyses. [27][28][29] In 2017, a systematic review and meta-analysis of 46 randomized controlled trials on home BP telemonitoring was published. 29  The clinical value of our study is as follows: (1) smartphone apps can provide patients with accurate medical information and provide tools to promote self-monitoring and self-management, (2) Our management methods are HBPT combined with educational support, danger reminders, doctor-patient interaction, and real-time intervention through smartphone apps. These methods may help optimize antihypertensive treatment, reduce the frequency of face-to-face consultations, and have the potential to facilitate patient self-management, (3) Furthermore, it might be expected to offer particular advantages to patients in remote areas where telemonitoring might enable access to a physician, and (4) When patients' BP exceeded the safe range, doctors provided patients with timely intervention, which greatly reduced the occurrence of hypertensive crisis. Therefore, we believe that telemonitoring and management can improve the long-term prognosis of patients. Although there is still a lack of data in this regard, we will continue to observe for long-term prognosis.
Meanwhile, the study limitations include potential selection bias due to a non-randomized controlled design. However, we adjusted for confounders by incorporating covariates into the association analysis. The stability of the results was verified by subgroup analysis. In addition, our research participants were middle-aged elderly patients with hypertension, but we excluded those who met the exclusion criteria, such as SBP ≥190 mm Hg or DBP < 60 mm Hg. These limitations limit the generalizability of our findings. Future studies should include patients aged younger than 60 years. We did not analyze patient adherence and could not exclude bias. However, we considered that adherence of the telemonitoring group may be better, and that the management mode of telemonitoring should also promote adherence. In future research, we will consider the impact of adherence.
In conclusions, HBPT helps improve BP control and lowers BP in middle-aged and elderly patients with hypertension. HBPT is positively associated with BP control. HBPT provides remarkable support decision tools for physicians. Thus, HBPT can be recommended for the management of BP in the community setting in middle-aged and elderly patients with hypertension.