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Association Between Small Decrease in Serum Sodium Concentration within the Normal Range and All‐Cause and Cardiovascular Mortality in Elderly Adults over 5 Years
Author(s) -
Ahn Shin Y.,
Park Yoon S.,
Lee Seong W.,
Baek Seon H.,
Kim Sejoong,
Na Ki Y.,
Kim Ki W.,
Chae DongWan,
Chin Ho J.
Publication year - 2016
Publication title -
journal of the american geriatrics society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.992
H-Index - 232
eISSN - 1532-5415
pISSN - 0002-8614
DOI - 10.1111/jgs.13937
Subject(s) - medicine , sodium , confidence interval , proportional hazards model , prospective cohort study , cohort , cohort study , dietary sodium , population , gastroenterology , blood pressure , chemistry , environmental health , organic chemistry
Objectives To determine the importance of a decrease in serum sodium concentration within the normal range in elderly adults. Design Prospective cohort. Setting The Korean Longitudinal Study on Health and Aging. Participants Randomly selected, community‐based elderly population with a corrected serum sodium level between 135.0 and 145.0 mEq/L (N = 949). Measurements Survival status was determined during 63.3 ± 16.6 months of follow‐up. Results Participants were divided into corrected sodium groups as follows: 73 (7.7%) in Group 1 (sodium 135.0–138.0 mEq/L), 635 (66.9%) in Group 2 (sodium 138.1–142.0 mEq/L), and 241 (25.4%) in Group 3 (sodium 142.1.0–145.0 mEq/L). There were 34 (46.6%) deaths in Group 1, 124 (19.5%) in Group 2, and 52 (21.6%) in Group 3 ( P < .001). In a Cox proportional hazards analysis, a 2‐mEq/L higher sodium level reduced the risk of death by 14.9% (95% confidence interval (CI) = 0.1–27.4%, P = .048). Group 1 had risk of mortality that was 2.7 times as high as that of Group 2 (95% CI = 1.76–4.11, P < .001). Participants with a measured sodium level of 138.0 mEq/L or less and a corrected sodium level greater than 138.0 mEq/L had a better survival rate than those with a measured sodium level of 138.0 mEq/L or less and a corrected sodium level of 138.0 mEq/L or less. Conclusion A slightly lower serum sodium concentration within the normal range was a major risk factor for mortality in elderly adults. Sodium level corrected according to serum glucose concentration was a more meaningful risk factor than measured sodium level.