CHAPTER 12

The population with chronic kidney disease (CKD) is aging. According to the 2013 United States Renal Data System, the prevalence of CKD in persons older than 65 is 224,106, or 38% of all the people with CKD. The number of older adults between the ages of 65 and 74 with CKD was 127,628 and for those over 75 it was 96,478. In 2011, of those newly diagnosed with CKD, 26,566 were between 65 and 74 and 27,926 were over 75. Thirty-seven percent of people receiving renal replacement therapy (RRT) were older than 65 years (1). The mean age of new dialysis clients is 65 years, and 75 and over is the fastest growing age group of new dialysis clients (2). Of the 115,643 total new clients with CKD, 48% (55,460 persons) are older than 65 with chronic kidney disease not yet requiring RRT (1). In addition to dialysis, transplantation is also an option for older dialy- sis clients. In 2011, there were 2,951 clients older than 65 who had a kidney transplant, or 17.9% of all kidney transplants (3). In 2011, $250 billion was spent on CKD care in people over the age of 65 (1).

The leading causes of CKD in the general US pop- ulation and those older than 65 are hypertension and diabetes mellitus (1). The combined effect of frailty and protein-energy wasting (decreased body stores of protein and fat) in the older dialysis person leads to a myriad of problems (Figure 12.1, see page 170), from impaired cognitive function, impaired physical func- tioning, increased cardiovascular risk, and poorer quality of life (4). Preventing development of nutri- tional deficiencies in the older adult with chronic kidney disease requires collaboration between the long- term care facility and the renal care team. Early inter- vention and close monitoring of nutritional status is imperative in meeting the goal of preventing protein energy wasting.

As CKD progresses from stage 1 to stage 5, effec- tive medical nutrition therapy (MNT) to slow the pro- gression of the kidney disease and to treat the metabolic

The Aging Kidney and Renal Disease

abnormalities associated with worsening kidney function becomes a challenge for the registered dietitian nutrition- ist (RDN) and the client. The evaluation and treatment of older adults with CKD requires understanding the stages of CKD, as defined by the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI) and illustrated in Table 12.1 (see page 170 [5]). Creatinine clearance (CrCl) is a rough estimation of glo- merular filtration rate (GFR) and can be calculated from a 24-hour timed urine collection. The two most common methods for estimating GFR are the Modified Diet in Renal Disease (MDRD) and the Cockcroft-Gault formula (6). The calculation using the Cockcroft-Gault formula is as follows:

Men:

(140 – Age) × Weight (kg) Serum Creatinine (mg/dL) × 72

Women: (140 – Age) × Weight (kg) × 0.85 Serum Creatinine (mg/dL) × 72

Most laboratories now calculate the GFR using the MDRD formula and include it anytime a creatinine and blood urea nitrogen (BUN) is obtained. Little research exists to show that either of the formulas more accurately estimates GFR in the older adult (6). As the client’s GFR decreases, medical manage- ment, including MNT, will be needed. Once stage 5 is reached, some form of RRT such as dialysis or trans- plantation may be initiated as a life-sustaining measure. Nutrition recommendations for clients at all stages of kidney disease must be individualized. The guidelines presented in Table 12.2 are a starting point for nutrition care of older adults with kidney disease (see page 175) (7-10).