title: Phenomenon of declining blood pressure in elderly--high systolic levels are undervalued with Korotkoff method.
abstract: BACKGROUND
  Systolic blood pressure (SBP) decline has been reported in octogenarians. The aim was to study if it could be observed while measuring SBP with two methods: Korotkoff (K-BP) and Strain-Gauge-Finger-Plethysmography (SG-BP), and which of them were more reliable in expressing vascular burden.
  
  
  METHODS
  A cohort of 703 men from a population of Malmö, Sweden, were included in "Men born in 1914-study" and followed-up at ages: 68 and 81 years. 176 survivors were examined with K-BP and SG-BP at both ages, and 104 of them with Ambulatory Blood Pressure at age 81/82. Ankle Brachial Index (ABI) was measured on both occasions, and Carotid Ultrasound at age 81.
  
  
  RESULTS
  From age 68 to 81, mean K-BP decreased in the cohort with mean 8.3 mmHg, while SG-BP increased with 13.4 mmHg. K-BP decreased in 55% and SG-BP in 31% of the subjects. At age 81, K-BP was lower than SG-BP in 72% of subjects, and correlated to high K-BP at age 68 (r = --.22; p < .05). SG-BP at age 81 was correlated with mean ambulatory 24-h SBP (r = .480; p < .0001), daytime SBP (r = .416; p < .0001), nighttime SBP (r = .395; p < .0001), and daytime and nighttime Pulse Pressure (r = .452; p < .0001 and r = .386; p < .0001). KB-BP correlated moderately only with nighttime SBP (r = .198; p = .044), and daytime and nightime pulse pressure (r = .225; p = .021 and r = .264; p = .007). Increasing SG-BP from age 68 to 81, but not K-BP, correlated with: 24-h, daytime and nighttime SBP, and mean daytime and nighttime Pulse Pressure. Increasing SG-BP was also predicted by high B-glucose and low ABI at age 68, and correlated with carotid stenosis and low ABI age 81, and the grade of ABI decrease over 13 years.
  
  
  CONCLUSIONS
  In contrast to K-BP, values of SG-BP in octogenarians strongly correlated with Ambulatory Blood Pressure. The SG-BP decline in the last decade was rare, and increasing SG-BP better than K-BP reflected advanced atherosclerosis. It should be aware, that K-BP underdetected 46% of subjects with SG-BP equal/higher than 140 mmHg at age 81, which may lead to biased associations with risk factors due to differential misclassification by age.
authors.affiliation: Division of Geriatric Medicine, Skane University Hospital in Malmö, Lund University, SWEDEN. Arkadiusz.Siennicki-Lantz@med.lu.se
authors.forename: Arkadiusz
authors.initials: A
authors.lastname: Siennicki-Lantz
authors.forename: Sölve
authors.initials: S
authors.lastname: Elmståhl
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000379:methods / Q000592:standards; D018660:Blood Pressure Monitoring, Ambulatory / Q000379:methods / Q000592:standards*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000175:diagnosis* / Q000503:physiopathology*; D008297:Male; D011446:Prospective Studies; D013599:Systole / Q000502:physiology*