Background: Chronic kidney disease (CKD) is common ( approximately 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 3 CKD (>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.