The role of potassium in postural hypotension: electrolytes and neurohumoral factors in elderly hypertensive patients using diuretics

J Intern Med. 1995 Apr;237(4):375-80. doi: 10.1111/j.1365-2796.1995.tb01189.x.

Abstract

Objective: To study the association between postural hypotension and (i) electrolyte levels and (ii) neurohumoral factors in elderly hypertensive patients using diuretics.

Design: Cross-sectional study of patients and controls.

Setting: The subjects were gathered from senior citizen clubs or they were referred to the study by general practitioners. The subjects were examined on a geriatric ward in Turku City Hospital.

Subjects: Seven subjects with postural hypotension and 13 controls.

Measurements: Plasma electrolyte levels and neurohumoral response to head-up tilt.

Results: There were significantly more hypokalaemic subjects in the postural hypotension group (5/7) than in the control group (1/13) (P < 0.01). The plasma potassium level was negatively correlated to plasma aldosterone (r = -0.57; P < 0.01) and renin activity (r = -0.69; P < 0.001). Subjects with postural hypotension had higher levels of noradrenaline, both supine (P < 0.05) and during tilt (P < 0.05). There were no significant differences in supine or tilt levels of plasma adrenaline, vasopressin, atrial natriuretic peptide, aldosterone and renin activity between the groups.

Conclusion: The results suggest that potassium depletion is associated with postural hypotension in elderly hypertensive patients using diuretics. However, it is unclear whether there is a causative link between potassium depletion and postural hypotension or whether they are both caused by some other factor, e.g. volume contraction.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Aldosterone / blood
  • Atrial Natriuretic Factor / blood
  • Case-Control Studies
  • Cross-Sectional Studies
  • Diuretics / adverse effects*
  • Diuretics / therapeutic use
  • Electrolytes / blood*
  • Epinephrine / blood
  • Female
  • Humans
  • Hypertension / blood*
  • Hypertension / complications
  • Hypertension / drug therapy
  • Hypotension, Orthostatic / blood*
  • Hypotension, Orthostatic / chemically induced
  • Male
  • Neurotransmitter Agents / blood*
  • Potassium / blood*
  • Renin / blood
  • Tilt-Table Test
  • Vasopressins / blood

Substances

  • Diuretics
  • Electrolytes
  • Neurotransmitter Agents
  • Vasopressins
  • Aldosterone
  • Atrial Natriuretic Factor
  • Renin
  • Potassium
  • Epinephrine