Background: Hypertension often requires lifelong treatment. Self-measured blood pressure (SMBP) monitoring, the regular measurement of blood pressure (BP) by the patient at home, has been proposed as a means of improving treatment adherence and BP control.
Purpose: To systematically review the trial evidence on the comparative effectiveness of hypertension management with versus without SMBP monitoring, and of different additional support interventions with SMBP. To determine predictors of adherence with SMBP monitoring.
Data Sources: MEDLINE®, Cochrane Central Register of Controlled Trials, existing systematic and narrative reviews, recent conference proceedings, and the Food and Drug Administration.
Study Selection: To address comparative effectiveness, we included prospective comparative studies of SMBP with or without additional support versus usual care or an alternative SMBP intervention. We included studies that used arm (not wrist) monitors for at least 8 weeks and excluded studies of pregnant women or people on hemodialysis. We also included longitudinal cohort studies in addressing adherence predictors.
Data Extraction: Details on design, patients, interventions, outcomes, and quality were extracted into standard forms. We standardized extraction by training on multiple articles, after which each study was extracted by one methodologist and the extraction reviewed by at least one other.
Data Synthesis: In total, 49 studies met eligibility criteria. There were 24 comparisons of SMBP alone versus usual care, 24 of SMBP plus additional support versus usual care, 12 of SMBP plus additional support versus SMBP without additional support or with less intense additional support, and 1 study evaluating predictors of adherence to SMBP. No studies of SMBP monitoring in children were identified. For SMBP alone versus usual care, the strength of evidence is moderate and supports a lower BP with SMBP (SBP/DBP -3.1/-2.0 mmHg at 6 months). For SMBP plus additional support versus usual care, the strength of evidence is high and supports a lower BP with SMBP use (SBP/DBP -3.4 to -8.9/-1.9 to -4.4 mmHg) up to 12 months. For SMBP plus additional support versus SMBP alone or with less intense additional support, the strength of evidence is low, failing to support a difference in BP. For all comparisons, evidence for clinical outcomes was insufficient; for all other outcomes (surrogate and intermediate outcomes, and health care encounters) strength of evidence was low, thus failing to support a difference. No trials compared different SMBP devices or provided evidence on the relationship between BP control and clinical or surrogate outcomes. There is insufficient evidence concerning predictors of SMBP adherence.
Limitations: Very few trials evaluated objective clinical outcomes. The trials were greatly heterogeneous, varying in population, intervention, and outcome measures and definitions. Many studies were of moderate to poor quality and had short followup periods. No studies evaluated children.
Conclusions: SMBP with or without additional support may confer a small benefit in BP control compared with usual care, but the BP effect beyond 12 months and the attendant long-term clinical consequences remain unclear. Given clinical heterogeneity and limited head to head comparisons, the evidence limits our ability to draw definitive conclusions about the incremental effect of any specific additional support. Future research should standardize patient inclusion criteria, BP treatment targets for home BP, and SMBP and additional support protocols to maximize the interpretability and applicability of SMBP trials.