Effect of Intensive Blood Pressure Control on Gait Speed and Mobility Limitation in Adults 75 Years or Older: A Randomized Clinical Trial

Abstract

Importance: Intensive blood pressure (BP) control confers a benefit on cardiovascular morbidity and mortality; whether it affects physical function outcomes is unknown.

Objective: To examine the effect of intensive BP control on changes in gait speed and mobility status.

Design, setting, and participants: This randomized, clinical trial included 2636 individuals 75 years or older with hypertension and no history of type 2 diabetes or stroke who participated in the Systolic Blood Pressure Intervention Trial (SPRINT). Data were collected from November 8, 2010, to December 1, 2015. Analysis was based on intention to treat.

Interventions: Participants were randomized to intensive treatment with a systolic BP target of less than 120 mm Hg (n = 1317) vs standard treatment with a BP target of less than 140 mm Hg (n = 1319).

Main outcomes and measures: Gait speed was measured using a 4-m walk test. Self-reported information concerning mobility was obtained from items on the Veterans RAND 12-Item Health Survey and the EQ-5D. Mobility limitation was defined as a gait speed less than 0.6 meters per second (m/s) or self-reported limitations in walking and climbing stairs.

Results: Among the 2629 participants in whom mobility status could be defined (996 women [37.9%]; 1633 men [62.1%]; mean [SD] age, 79.9 [4.0] years), median (interquartile range) follow-up was 3 (2-3) years. No difference in mean gait speed decline was noted between the intensive- and standard-treatment groups (mean difference, 0.0004 m/s per year; 95% CI, -0.005 to 0.005; P = .88). No evidence of any treatment group differences in subgroups defined by age, sex, race or ethnicity, baseline systolic BP, chronic kidney disease, or a history of cardiovascular disease were found. A modest interaction was found for the Veterans RAND 12-Item Health Survey Physical Component Summary score, although the effect did not reach statistical significance in either subgroup, with mean differences of 0.004 (95% CI, -0.002 to 0.010) m/s per year among those with scores of at least 40 and -0.008 (95% CI, -0.016 to 0.001) m/s per year among those with scores less than 40 (P = .03 for interaction). Multistate models allowing for the competing risk of death demonstrated no effect of intensive treatment on transitions to mobility limitation (hazard ratio, 1.06; 95% CI, 0.92-1.22).

Conclusions and relevance: Among adults 75 years or older in SPRINT, treating to a systolic BP target of less than 120 mm Hg compared with a target of less than 140 mm Hg had no effect on changes in gait speed and was not associated with changes in mobility limitation.

Trial registration: clinicaltrials.gov Identifier: NCT01206062.

Conflict of interest statement

Conflicts of Interest: Dr. Peralta is a Consultant for Cricket Health, Inc. and Vital Labs, Inc. All remaining authors have no conflicts of interest to disclose.

Figures

Figure 1. Diagram of multi-state model for mobility limitation

Boxes denote states for multi-state model, arrows depict possible transitions.

Figure 2. Least square means for gait speed by treatment group over the course of follow-up

Circles denote estimated least square mean for gait speed based on linear mixed model, treating time discretely (0, 12, 24, 36, and 48 months). Error bars represent 95% confidence intervals.