title: The impact of weight loss and low BMI on mortality of nursing home residents - Results from the nutritionDay in nursing homes.
abstract: Weight loss and low body-mass-index (BMI) are well-known risk factors for mortality among older persons. Both items represent a reduced nutritional state but their nature is different. It is, however, unclear which of these factors is more important for prognosis and if there is interference or interaction between them.
  
  
  
  To measure the prevalence of low BMI and weight loss in nursing home residents and to analyze their impact on mortality.
  
  
  
  The nutritionDay in nursing homes is an international annual one-day cross sectional survey evaluating malnutrition and 6-months mortality. The data collected from 2007 to 2012 were analyzed. The mortality risk due to a BMI <20 kg/m(2) and weight loss >5 kg was calculated by logistic regression analysis with adjustment for confounding factors.
  
  
  
  In total, 10,298 residents with a mean age of 85 years (78% female) from 191 nursing homes in 13 countries were included in the analysis. Eighteen percent (17.7%) had a low BMI < 20 kg/m(2), and 11.3% lost > 5 kg of body weight in the previous year. Low BMI <20 kg/m(2) and weight loss >5 kg were both independent and significant risk factors for 6-months mortality (OR 1.7 and 1.5; p < 0.001 in the adjusted model). In comparison to the effect size of low BMI and weight loss alone, the interaction of both factors was substantial (OR = 1.4; p = 0.056). The average 6-months mortality was 13.8%. Subjects with BMI ≥20 kg/m(2) without weight loss >5 kg presented the lowest mortality of 11.2%. In subjects with one of the two features, weight loss >5 kg or low BMI <20 kg/m(2), mortality was significantly increased to 17.4% and 19.8%, respectively. However, if both features were present simultaneously the mortality increased disproportionally to 35.7% (OR 3.5; p < 0.001). In addition, this study presents an overlap and a strong dose-effect relationship of both items with regard to the 6-month mortality.
  
  
  
  A BMI <20 kg/m(2) and weight loss >5 kg in one year are both independent and equally relevant risk factors for the 6-months mortality of nursing home residents aged 65 years or older. For this reason weight loss should be avoided and residents with a low BMI and weight loss should receive particular attention and nutritional care.
authors.affiliation: Department of Internal Medicine and Geriatrics, St. Marien-Hospital Borken, Borken, Germany; Friedrich-Alexander-Universität Erlangen-Nürnberg, Chair of Geriatric Medicine, Institute for Biomedicine of Aging, Nürnberg, Germany. Electronic address: rainer.wirth@hospital-borken.de.
authors.forename: Rainer
authors.initials: R
authors.lastname: Wirth
authors.affiliation: Friedrich-Alexander-Universität Erlangen-Nürnberg, Chair of Geriatric Medicine, Institute for Biomedicine of Aging, Nürnberg, Germany.
authors.forename: Melanie
authors.initials: M
authors.lastname: Streicher
authors.affiliation: Department of Internal Medicine and Geriatrics, St. Marien-Hospital Borken, Borken, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Smoliner
authors.affiliation: Friedrich-Alexander-Universität Erlangen-Nürnberg, Chair of Geriatric Medicine, Institute for Biomedicine of Aging, Nürnberg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Kolb
authors.affiliation: Medical University Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Hiesmayr
authors.affiliation: Department of Geriatrics, Marienhospital Herne, University of Bochum, Germany; Department of Biometrics and Epidemiology, University of Bochum, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Thiem
authors.affiliation: Friedrich-Alexander-Universität Erlangen-Nürnberg, Chair of Geriatric Medicine, Institute for Biomedicine of Aging, Nürnberg, Germany.
authors.forename: Cornel Christian
authors.initials: CC
authors.lastname: Sieber
authors.affiliation: Friedrich-Alexander-Universität Erlangen-Nürnberg, Chair of Geriatric Medicine, Institute for Biomedicine of Aging, Nürnberg, Germany.
authors.forename: Dorothee
authors.initials: D
authors.lastname: Volkert
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D001835:Body Weight; D003430:Cross-Sectional Studies; D005260:Female; D015577:Geriatric Assessment; D006707:Homes for the Aged; D006801:Humans; D016015:Logistic Models; D008297:Male; D009026:Mortality; D009735:Nursing Homes; D015596:Nutrition Assessment; D009752:Nutritional Status; D012307:Risk Factors; D011795:Surveys and Questionnaires; D015431:Weight Loss
keywords: BMI; Geriatric; Mortality; Nursing home; Nutrition; Weight loss