Prevalence and complications of chronic kidney disease in a representative elderly population in Iceland

Chronic kidney disease (CKD) is common in the elderly, but data are limited on the distribution of glomerular filtration rate (GFR) and albuminuria and the prevalence of CKD and related complications in this population. A cross-sectional study of 3173 older Icelandic adults [42% men; mean (standard deviation, SD) age of 80 (5) years] was performed to examine the distribution of estimated glomerular filtration rate (eGFR) from creatinine and cystatin C, the albumin-to-creatinine ratio (ACR), and CKD-related metabolic complications (hyperparathyroidism, anemia, hypoalbuminemia, increased anion gap, acidosis, hyperphosphatemia and hyperkalemia). There was substantial variability in eGFR [mean (SD) 64 (18) mL/min/1.73 m(2)] and ACR [median (interquartile range) 8 (5, 17) mg/g]. The prevalence (95% confidence interval) of reduced eGFR (< 60 mL/min/1.73 m(2)), albuminuria (ACR > 30 mg/g) and CKD (either reduced eGFR or albuminuria) was 40% (38-41), 14% (12-15) and 45% (43-47), respectively. The prevalence of complications was higher among those with versus without CKD: hyperparathyroidism (38 versus 15%), anemia (26 versus 14%), hypoalbuminemia (19 versus 13%), increased anion gap (9 versus 5%), acidosis (5 versus 1%); (P a parts per thousand currency sign 0.02 for all), except hyperphosphatemia (1 versus 1%) and hyperkalemia (0% overall). The burden of CKD and CKD-related complications is high among community dwelling elderly Icelandic adults. The wide range of eGFR and ACR suggests heterogeneity in processes leading to CKD and that factors beyond aging contribute to the development of CKD in the elderly.