Abstract 15954: A Randomized Trial of the Effect of Antihypertensive Therapy at Low, Intermediate, and High Altitude: The INTERVENCION Study
Background: Altitude above sea level has a major influence on cardiovascular function, but no data exist regarding the chronic effect of altitude on the response to antihypertensive therapy. Similarly, randomized trials assessing different pharmacologic agents for the treatment of hypertension among populations living at moderate or high altitude are lacking.
Methods: We performed a prospective, randomized, multicenter clinical trial (clinicaltrials.gov NCT02373163) in which 146 subjects with untreated hypertension were enrolled at low altitude (LA, <2000 m), intermediate altitude (IA, 2000-3500 m) and high altitude (HA, >3500 m), in a 1:2:2 ratio. At each altitude level, subjects were randomized in a 1:1:1 ratio to hydrochlorothiazide (25 mg/d), amlodipine (10 mg/d) or telmisartan (80 mg/d) for 28 days. At each altitude level, randomization was stratified by age group and gender to achieve an equal distribution across altitude levels The primary endpoint of the trial was the change in 24-hour systolic blood pressure.
Results: 24-hour SBP was significantly reduced by all 3 drugs: -5.94 mmHg (95%CI=-8.41 to -3.47) by HCTZ, -7.53 mmHg (95%CI=-10.25 to -4.82) by amlodipine, and - 8.44 mmHg (95%CI=-10.88 to -6 mmHg) by telmisartan.There were no significant differences in the 24-hour SBP reduction between the arms. Altitude level was found to be a significant modifier of the response to antihypertensive therapy (P for interaction=0.023), with greater responses at HA compared to LA (P=0.035). The effect of altitude on the response increased with greater 24-SBP at baseline (P for interaction=0.013).
Conclusions: Altitude is a significant modifier of the response to antihypertensive therapy, with a greater response occurring at HA.
Author Disclosures: J. Medina-Lezama: None. O. Narvaez Guerra: None. K. Herrera Enriquez: None. M. Zapata Ponze De Leon: None. A. Janeth Rondon Rodríguez: None. S. Perez Moscoso: None. J.A. Chirinos: Research Grant; Significant; NIH, American College of Radiology Network, Fukuda Denshi, Bristol Myers Squibb, Microsoft and CVRx Inc. Other Research Support; Modest; Fukuda Denshi, Withings, Atcor Medical. Consultant/Advisory Board; Modest; Fukuda Denshi, Microsoft Research, Merck and Vital Labs. Consultant/Advisory Board; Significant; Bristol Myers Squibb, OPKO Healthcare.
- © 2016 by American Heart Association, Inc.