Physical Activity In Renal Disease (PAIRED) and the effect on hypertension: study protocol for a randomized controlled trial.

BACKGROUND: The prevalence of hypertension among people with chronic kidney disease is high with over 60% of people not attaining recommended targets despite taking multiple medications. Given the health and economic implications of hypertension, additional strategies are needed. Exercise is an effective strategy for reducing blood pressure in the general population; however, it is not known whether exercise would have a comparable benefit in people with moderate to advanced chronic kidney disease and hypertension.

METHODS: This is a parallel-arm trial of adults with hypertension (systolic blood pressure greater than 130 mmHg) and an estimated glomerular filtration rate of 15-45 ml/min 1.73 m2 . A total of 160 participants will be randomized, with stratification for estimated glomerular filtration rate, to a 24-week, aerobic-based exercise intervention or enhanced usual care. The primary outcome is the difference in 24-h ambulatory systolic blood pressure after 8 weeks of exercise training. Secondary outcomes at 8 and 24 weeks include: other measurements of blood pressure, aortic stiffness (pulse-wave velocity), change in the Defined Daily Dose of anti-hypertensive drugs, medication adherence, markers of cardiovascular risk, physical fitness (cardiopulmonary exercise testing), 7-day accelerometry, quality of life, and adverse events. The effect of exercise on renal function will be evaluated in an exploratory analysis. The intervention is a thrice-weekly, moderate-intensity aerobic exercise supplemented with isometric resistance exercise delivered in two phases. Phase 1: supervised, facility-based, weekly and home-based sessions (8 weeks). Phase 2: home-based sessions (16 weeks).

DISCUSSION: To our knowledge, this study is the first trial designed to provide a precise estimate of the effect of exercise on blood pressure in people with moderate to severe CKD and hypertension. The findings from this study should address a significant knowledge gap in hypertension management in CKD and inform the design of a larger study on the effect of exercise on CKD progression.

TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT03551119 . Registered on 11 June 2018.