The diagnostic accuracy of multi-frequency bioelectrical impedance analysis in diagnosing dehydration after stroke

Mohannad W Kafri, Phyo Kway Myint, Danielle Doherty, Alexander Hugh Wilson, John F Potter, Lee Hooper

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Background: Non-invasive methods for detecting water-loss dehydration following acute stroke would be clinically useful. We evaluated the diagnostic accuracy of multi-frequency bioelectrical impedance analysis (MF-BIA) against reference standards serum osmolality and osmolarity.
Material and Methods: Patients admitted to an acute stroke unit were recruited. Blood samples for electrolytes and osmolality were taken within 20 minutes of MF-BIA. Total body water (TBW%), intracellular (ICW%) and extracellular water (ECW%), as percentages of total body weight, were calculated by MF-BIA equipment and from impedance measures using published equations for older people. These were compared to hydration status (based on serum osmolality and calculated osmolarity). The most promising Receiver Operating Characteristics curves were plotted.
Results: 27 stroke patients were recruited (mean age 71.3, SD10.7). Only a TBW% cut-off at 46% was consistent with current dehydration (serum osmolality >300 mOsm/kg) and TBW% at 47% impending dehydration (calculated osmolarity ≥295–300 mOsm/L) with sensitivity and specificity both >60%. Even here diagnostic accuracy of MF-BIA was poor, a third of those with dehydration were wrongly classified as hydrated and a third classified as dehydrated were well hydrated. Secondary analyses assessing diagnostic accuracy of TBW% for men and women separately, and using TBW as a percentage of lean body mass showed some promise, but did not provide diagnostically accurate measures across the population.
Conclusions: MF-BIA appears ineffective at diagnosing water-loss dehydration after stroke and cannot be recommended as a test for dehydration, but separating assessment by sex, and using TBW as a percentage of lean body weight may warrant further investigation.
Original languageEnglish
Pages (from-to)548-570
Number of pages23
JournalMedical Science Monitor
Volume19
DOIs
Publication statusPublished - 2013

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Electric Impedance
Dehydration
Osmolar Concentration
Stroke
Body Water
Water
Serum
Body Weight
ROC Curve
Electrolytes
Sensitivity and Specificity
Equipment and Supplies
Population

Keywords

  • Aged
  • Aged, 80 and over
  • Body Fluid Compartments
  • Body Water
  • Dehydration
  • Electric Impedance
  • Female
  • Humans
  • Male
  • Middle Aged
  • Osmolar Concentration
  • ROC Curve
  • Stroke

Cite this

The diagnostic accuracy of multi-frequency bioelectrical impedance analysis in diagnosing dehydration after stroke. / Kafri, Mohannad W; Myint, Phyo Kway; Doherty, Danielle; Wilson, Alexander Hugh; Potter, John F; Hooper, Lee.

In: Medical Science Monitor, Vol. 19, 2013, p. 548-570.

Research output: Contribution to journalArticle

Kafri, Mohannad W ; Myint, Phyo Kway ; Doherty, Danielle ; Wilson, Alexander Hugh ; Potter, John F ; Hooper, Lee. / The diagnostic accuracy of multi-frequency bioelectrical impedance analysis in diagnosing dehydration after stroke. In: Medical Science Monitor. 2013 ; Vol. 19. pp. 548-570.
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abstract = "Background: Non-invasive methods for detecting water-loss dehydration following acute stroke would be clinically useful. We evaluated the diagnostic accuracy of multi-frequency bioelectrical impedance analysis (MF-BIA) against reference standards serum osmolality and osmolarity.Material and Methods: Patients admitted to an acute stroke unit were recruited. Blood samples for electrolytes and osmolality were taken within 20 minutes of MF-BIA. Total body water (TBW{\%}), intracellular (ICW{\%}) and extracellular water (ECW{\%}), as percentages of total body weight, were calculated by MF-BIA equipment and from impedance measures using published equations for older people. These were compared to hydration status (based on serum osmolality and calculated osmolarity). The most promising Receiver Operating Characteristics curves were plotted.Results: 27 stroke patients were recruited (mean age 71.3, SD10.7). Only a TBW{\%} cut-off at 46{\%} was consistent with current dehydration (serum osmolality >300 mOsm/kg) and TBW{\%} at 47{\%} impending dehydration (calculated osmolarity ≥295–300 mOsm/L) with sensitivity and specificity both >60{\%}. Even here diagnostic accuracy of MF-BIA was poor, a third of those with dehydration were wrongly classified as hydrated and a third classified as dehydrated were well hydrated. Secondary analyses assessing diagnostic accuracy of TBW{\%} for men and women separately, and using TBW as a percentage of lean body mass showed some promise, but did not provide diagnostically accurate measures across the population.Conclusions: MF-BIA appears ineffective at diagnosing water-loss dehydration after stroke and cannot be recommended as a test for dehydration, but separating assessment by sex, and using TBW as a percentage of lean body weight may warrant further investigation.",
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T1 - The diagnostic accuracy of multi-frequency bioelectrical impedance analysis in diagnosing dehydration after stroke

AU - Kafri, Mohannad W

AU - Myint, Phyo Kway

AU - Doherty, Danielle

AU - Wilson, Alexander Hugh

AU - Potter, John F

AU - Hooper, Lee

PY - 2013

Y1 - 2013

N2 - Background: Non-invasive methods for detecting water-loss dehydration following acute stroke would be clinically useful. We evaluated the diagnostic accuracy of multi-frequency bioelectrical impedance analysis (MF-BIA) against reference standards serum osmolality and osmolarity.Material and Methods: Patients admitted to an acute stroke unit were recruited. Blood samples for electrolytes and osmolality were taken within 20 minutes of MF-BIA. Total body water (TBW%), intracellular (ICW%) and extracellular water (ECW%), as percentages of total body weight, were calculated by MF-BIA equipment and from impedance measures using published equations for older people. These were compared to hydration status (based on serum osmolality and calculated osmolarity). The most promising Receiver Operating Characteristics curves were plotted.Results: 27 stroke patients were recruited (mean age 71.3, SD10.7). Only a TBW% cut-off at 46% was consistent with current dehydration (serum osmolality >300 mOsm/kg) and TBW% at 47% impending dehydration (calculated osmolarity ≥295–300 mOsm/L) with sensitivity and specificity both >60%. Even here diagnostic accuracy of MF-BIA was poor, a third of those with dehydration were wrongly classified as hydrated and a third classified as dehydrated were well hydrated. Secondary analyses assessing diagnostic accuracy of TBW% for men and women separately, and using TBW as a percentage of lean body mass showed some promise, but did not provide diagnostically accurate measures across the population.Conclusions: MF-BIA appears ineffective at diagnosing water-loss dehydration after stroke and cannot be recommended as a test for dehydration, but separating assessment by sex, and using TBW as a percentage of lean body weight may warrant further investigation.

AB - Background: Non-invasive methods for detecting water-loss dehydration following acute stroke would be clinically useful. We evaluated the diagnostic accuracy of multi-frequency bioelectrical impedance analysis (MF-BIA) against reference standards serum osmolality and osmolarity.Material and Methods: Patients admitted to an acute stroke unit were recruited. Blood samples for electrolytes and osmolality were taken within 20 minutes of MF-BIA. Total body water (TBW%), intracellular (ICW%) and extracellular water (ECW%), as percentages of total body weight, were calculated by MF-BIA equipment and from impedance measures using published equations for older people. These were compared to hydration status (based on serum osmolality and calculated osmolarity). The most promising Receiver Operating Characteristics curves were plotted.Results: 27 stroke patients were recruited (mean age 71.3, SD10.7). Only a TBW% cut-off at 46% was consistent with current dehydration (serum osmolality >300 mOsm/kg) and TBW% at 47% impending dehydration (calculated osmolarity ≥295–300 mOsm/L) with sensitivity and specificity both >60%. Even here diagnostic accuracy of MF-BIA was poor, a third of those with dehydration were wrongly classified as hydrated and a third classified as dehydrated were well hydrated. Secondary analyses assessing diagnostic accuracy of TBW% for men and women separately, and using TBW as a percentage of lean body mass showed some promise, but did not provide diagnostically accurate measures across the population.Conclusions: MF-BIA appears ineffective at diagnosing water-loss dehydration after stroke and cannot be recommended as a test for dehydration, but separating assessment by sex, and using TBW as a percentage of lean body weight may warrant further investigation.

KW - Aged

KW - Aged, 80 and over

KW - Body Fluid Compartments

KW - Body Water

KW - Dehydration

KW - Electric Impedance

KW - Female

KW - Humans

KW - Male

KW - Middle Aged

KW - Osmolar Concentration

KW - ROC Curve

KW - Stroke

U2 - 10.12659/MSM.883972

DO - 10.12659/MSM.883972

M3 - Article

VL - 19

SP - 548

EP - 570

JO - Medical Science Monitor

JF - Medical Science Monitor

SN - 1234-1010

ER -