Chronic kidney disease prevalence in a UK residential care home population

Background. Chronic kidney disease (CKD) is common (similar to 30%) in non-institutionalized older people but little is known about the prevalence of CKD amongst older people living in residential care. Methods. An observational study of older subjects [ n = 250, median age 86 ( range 67-100) years, 79% female, 100% Caucasian, 16% diabetic, 48% hypertensive, 5% known renal disease, mean number of medications 7] who were recruited over a 9-month period from 155 residential care homes in east Kent ( total population 3811) using a randomization process. The estimated glomerular filtration rate (eGFR, ml/min/1.73 m(2)) was calculated using the Cockcroft and Gault equation corrected for the body surface area and the simplified Modification of Diet in Renal Disease (MDRD) Study equation. Serum cystatin C concentration was also measured. Results. Using the MDRD equation 18% had eGFR = 60, 39% stage 3A CKD ( eGFR 45-59), 34% stage 3B CKD ( eGFR 30-44) and 10% stage 4 CKD ( eGFR 15-29). By the Cockcroft-Gault equation the equivalent figures were 3%, 18%, 48% and 31%, respectively. Agreement between the equations for staging of CKD was poor (kappa = 0.07). However, > 80% of residents were categorized as having stage 3CKD(> 40% stage 3B) or worse whichever equation was used. Serum cystatin C concentration was increased in 92% of the population. Increasing age and higher body mass index were predictive of decreased renal function. Conclusion. Significant CKD is prevalent and unrecognized in this population. This may have important management implications particularly for treatment with renally excreted drugs, fracture prevention or managing cardiovascular risk.