title: Prevalence, trends and functional impairment associated with reduced estimated glomerular filtration rate and albuminuria among the oldest-old U.S. adults.
abstract: BACKGROUND
  The prevalence of reduced estimated glomerular filtration rate (eGFR) among U.S. adults aged 80 years and older increased between 1988 to 1994 and 2005 to 2010. Trends in the prevalence of albuminuria over this time period have not been reported in this population.
  
  
  METHODS
  We conducted a cross-sectional analysis of U.S. adults aged 80 years and older in the National Health and Nutrition Examination Survey 1988 to 1994 (n = 1020), 1999 to 2004 (n = 995) and 2005 to 2010 (n = 971) to calculate the prevalence of albuminuria (albumin-to-creatinine ratio [ACR] ≥30 mg/g) by calendar period. The number of U.S. adults aged 80 years and older with elevated ACR and separately reduced eGFR was calculated by calendar period.
  
  
  RESULTS
  Among participants aged 80 years and older, the prevalence of albuminuria was 30.9%, 33.0% and 30.6% in 1988 to 1994, 1999 to 2004 and 2005 to 2010 (P = 0.9). The proportion of U.S. adults aged 80 years and older with both eGFR <45 ml/min/1.73 m and ACR ≥30 mg/g increased from 6.8% in 1988 to 1994 to 8.4% and 9.5% in 1999 to 2004 and 2005 to 2010, respectively (P = 0.008). In 1988 to 1994, 1999 to 2004 and 2005 to 2010, there were 1.78 (95% confidence interval [CI], 1.29-2.27), 2.35 (95% CI, 1.93-2.78) and 2.74 (95% CI, 2.32-3.16) million U.S. adults aged 80 years older with albuminuria and 2.34 (95% CI, 1.79-2.89), 3.55 (95% CI, 2.96-4.14) and 4.58 (95% CI, 3.87-5.28) million, respectively, with eGFR <60 ml/min/1.73 m.
  
  
  CONCLUSIONS
  The proportion of U.S. adults aged 80 years and older with an elevated ACR remained relatively stable between 1988 to 1994 and 2005 to 2010. However, due to the growth of the oldest-old, the absolute number with albuminuria increased substantially over the past 2 decades.
authors.affiliation: Department of Veterans Affairs Medical Center (CBB), Birmingham/Atlanta Geriatric Research, Education, and Clinical Center, Atlanta, Georgia; Division of General Medicine and Geriatrics, Department of Medicine (CBB), Emory University, Atlanta, Georgia; and Department of Epidemiology (PM, PS), School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: C Barrett
authors.initials: CB
authors.lastname: Bowling
authors.forename: Pradeep
authors.initials: P
authors.lastname: Sharma
authors.forename: Paul
authors.initials: P
authors.lastname: Muntner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000419:Albuminuria / Q000453:epidemiology / Q000503:physiopathology*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D009749:Nutrition Surveys; D015995:Prevalence; D014481:United States