Self-monitoring of Blood Pressure in Patients With Hypertension-Related Multi-morbidity: Systematic Review and Individual Patient Data Meta-analysis

Abstract

Background: Studies have shown that self-monitoring of blood pressure (BP) is effective when combined with co-interventions, but its efficacy varies in the presence of some co-morbidities. This study examined whether self-monitoring can reduce clinic BP in patients with hypertension-related co-morbidity.

Methods: A systematic review was conducted of articles published in Medline, Embase, and the Cochrane Library up to January 2018. Randomized controlled trials of self-monitoring of BP were selected and individual patient data (IPD) were requested. Contributing studies were prospectively categorized by whether they examined a low/high-intensity co-intervention. Change in BP and likelihood of uncontrolled BP at 12 months were examined according to number and type of hypertension-related co-morbidity in a one-stage IPD meta-analysis.

Results: A total of 22 trials were eligible, 16 of which were able to provide IPD for the primary outcome, including 6,522 (89%) participants with follow-up data. Self-monitoring was associated with reduced clinic systolic BP compared to usual care at 12-month follow-up, regardless of the number of hypertension-related co-morbidities (-3.12 mm Hg, [95% confidence intervals -4.78, -1.46 mm Hg]; P value for interaction with number of morbidities = 0.260). Intense interventions were more effective than low-intensity interventions in patients with obesity (P < 0.001 for all outcomes), and possibly stroke (P < 0.004 for BP control outcome only), but this effect was not observed in patients with coronary heart disease, diabetes, or chronic kidney disease.

Conclusions: Self-monitoring lowers BP regardless of the number of hypertension-related co-morbidities, but may only be effective in conditions such obesity or stroke when combined with high-intensity co-interventions.

Keywords: blood pressure; coronary heart disease; diabetes; hypertension; obesity; randomized controlled trial; stroke.

Figure 1.

Effect of self-monitoring on clinic blood pressure at 12-month follow-up by number of hypertension-related co-morbidities (16 studies). Blood pressure difference given in mm Hg. Analyses adjusted for age, sex, baseline blood pressure, and level of intervention, with study-level random effects for intervention and usual care. Abbreviations: SBP, systolic blood pressure; DBP, diastolic blood pressure; CI, confidence intervals; OR, odds ratio. Uncontrolled blood pressure defined by thresholds specified in each contributing study (see Supplementary Table S2 for details).

Figure 2.

Effect of self-monitoring on clinic systolic blood pressure at 12-month follow-up by intervention intensity within specific morbidities. *Two studies only provided one patient each to the model. Blood pressure difference given in mm Hg. Analyses adjusted for age, sex, and baseline blood pressure with study-level random effects for intervention and usual care. Abbreviations: sBP, systolic blood pressure; CI, confidence intervals; CHD, coronary heart disease; CKD, chronic kidney disease.

Figure 3.

Effect of self-monitoring on likelihood of uncontrolled clinic blood pressure at 12-month follow-up by intervention intensity within specific morbidities. *Two studies only provided one patient each to the model. Analyses adjusted for age, sex and baseline blood pressure with study-level random effects for intervention and usual care. Abbreviations: OR, odds ratio; CI, confidence intervals; CHD, coronary heart disease; CKD, chronic kidney disease. Uncontrolled blood pressure defined by thresholds specified in each contributing study (see Supplementary Table S2 for details).