Characterizing Frailty Status in the Systolic Blood Pressure Intervention Trial

J Gerontol A Biol Sci Med Sci. 2016 May;71(5):649-55. doi: 10.1093/gerona/glv228. Epub 2016 Jan 11.

Abstract

Background: The Systolic Blood Pressure Intervention Trial (SPRINT) is testing whether a lower systolic blood pressure (BP) target of 120 mm Hg leads to a reduction in cardiovascular morbidity and mortality among hypertensive, nondiabetic adults. Because there may be detrimental effects of intensive BP control, particularly in older, frail adults, we sought to characterize frailty within SPRINT to address ongoing questions about the ability of large-scale trials to enroll representative samples of noninstitutionalized, community-dwelling, older adults.

Methods: We constructed a 36-item frailty index (FI) in 9,306 SPRINT participants, classifying participants as fit (FI ≤ 0.10), less fit (0.10 < FI ≤ 0.21), or frail (FI > 0.21). Recurrent event models were used to evaluate the association of the FI with the incidence of self-reported falls, injurious falls, and all-cause hospitalizations.

Results: The distribution of the FI was comparable with what has been observed in population studies, with 2,570 (27.6%) participants classified as frail. The median FI was 0.18 (interquartile range = 0.14 to 0.24) in participants aged 80 years and older (N = 1,159), similar to the median FI of 0.17 reported for participants in the Hypertension in the Very Elderly Trial. In multivariable analyses, a 1% increase in the FI was associated with increased risk for self-reported falls (hazard ratio [HR] = 1.030), injurious falls (HR = 1.035), and all-cause hospitalizations (HR = 1.038) (all p values < .0001).

Conclusions: Large clinical trials assessing treatments to reduce cardiovascular disease risk, such as SPRINT, can enroll heterogeneous populations of older adults, including the frail elderly, comparable with general population cohorts.

Keywords: Falls; Frailty; Multimorbidities.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Age Factors
  • Aged
  • Aged, 80 and over
  • Antihypertensive Agents / therapeutic use*
  • Cohort Studies
  • Female
  • Frail Elderly
  • Geriatric Assessment
  • Health Status Indicators
  • Health Status*
  • Humans
  • Hypertension / complications*
  • Hypertension / drug therapy*
  • Male
  • Middle Aged
  • Regression Analysis
  • Risk Factors

Substances

  • Antihypertensive Agents

Grant support