European Geriatric Medicine - Supplement 1 - Volume 6

European Geriatric Medicine 6S1 (2015) S157–S176

Available

online

ScienceDirect

www.sciencedirect.com

Symposia

Invited symposium

S-02

The old kidney

–

challenges and possibilities

R. Pettersen

Lovisenberg Diacon Hospital, Oslo, Norway

Chair:

Renate Pettersen, MD PhD, Geriatric Department,

Lovisenberg Diacon Hospital, Oslo, Norway

As a consequence of the increasing lifespan in Europe and other

parts of the world, clinicians will face an increasing prevalence

of renal dysfunction in the older population – due to both

physiological changes and disease. The processes involved are

complex and represent a challenge for the clinician. The increasing

prevalence of end-stage kidney disease in this age group also raises

questions about choice of treatment. In this symposium, important

basic mechanisms and new aspects of the assessment of renal

function will be presented, as well as new data on transplantation

outcomes.

Water and electrolyte physiology in old age

–

clinical and

experimental data

(Professor Elias Lianos, Athens, Greece): The

homeostatic control of water and electrolyte balance by the aging

kidney is impaired, the key reason being that the physiologic limits

for the excretion of water, sodium, potassium, and hydrogen ions are

narrowed. As aging progresses, the risk of hyper- or hypovolemia

increases owing to impaired water handling. Control of potassium

level also becomes impaired resulting in hyperkalemia, particularly

when patients receive certain drugs. Specific changes in water

and electrolyte homeostasis include: decrease in total body

water, urinary concentrating ability, aldosterone secretion/effect,

thirst mechanism and free-water clearance, and an increase

in antidiuretic hormone (ADH). Despite these changes, body

fluid homeostasis is effectively maintained under normal day-to-

day circumstances. Problems are frequently iatrogenic and arise

when older patients are placed under fluid restriction or are

prescribed medications that further derail the already impaired

homeostatic control of water and electrolytes. Awareness of age-

related limitations of fluid and electrolyte homeostasis can help

the physician prevent complications such as hypotonicity and

hypertonicity, hyperkalemia, and volume depletion.

Differences between decreased GFR and renal failure: clinical,

social and economic consequences from the geriatric angle

(Professor Juan F. Macias Nunez, Salamanca, Spain): Chronic renal

insufficiency (CRI) is identified by a decrease in GFR. It is a clinical

daily practice to diagnose CRI based on the critical value of eGFR

60ml/min by means of the MDRD screening formula, not validated

for persons aged

70 years. We should always remember the

difference between screening formulae and diagnosis. Diagnose

of CRI should be confirmed by doctors in persons suspicious of CRI

by screening formulae.

The normal ageing process is characterized by a decrease in

GFR without repercussion in the equilibrium of the internal

milieu. GFR reaches a peak between 120–130ml/min/1.73m

the age of 30, attenuating at a constant rate of 0.8ml/min/year,

although for persons aged 70–110 years, the decline averages

1.05ml/min/year. Establishing an incorrect diagnosis of CRI will

have some undesirable effects. The worst is that may deny aged

individuals appropriate treatment for other diseases (oncological,

haematological or others) and also prevent from being included

in clinical trials because the tendency to equalize CRI to

eGFR

60ml/min. To overcome this error, we found that the

association of haematocrit, urea and gender (HUGE) according to

the following formula:

L = 2.505458 − 0.264418

Hematocrit + 0.118100

Urea [+ 1.383960 if

male],

showed the highest ability to discriminate CRI from non CRI

individuals. The HUGE formula, with data obtained from a

general population, offers a straightforward readily available

and inexpensive tool to differentiate CRI from eGFR

60ml/min

particularly useful in persons

70 years.

Kidney transplantation

–

a treatment option for the failing old

kidney?

(Associate Professor Kristian Heldal, Skien, Norway): The

general population is getting older. The dramatic increase of

patients developing end-stage renal disease (ESRD) has occurred

predominantly in the older adult population. In old patients with

ESRD the nephrologists will need to decide further treatment. The

options are; medical treatment only, life-long dialysis or kidney

transplantation (KTx). There are very few absolute contraindications

(active infection, recent malignancy), but many relative or potential

contraindications in older patients considered for KTx. Worldwide,

organs available for transplantation are limited. Many transplant

centers therefore set an upper age limit for KTx. In Norway there

is no upper age limit. Even octogenarians may be transplanted. It

is vital that patients who are accepted for KTx are those who will

derive most benefit, and correct selection of patients is therefore

of outmost importance.

Currently older patients are evaluated for transplantation using the

same algorithm as used for younger patients. Survival analyses have

revealed that even patients older than 70 years of age will benefit

from transplantation compared with permanent dialysis with the

proviso that the patient is capable of tolerating surgery and the

subsequent medical treatment (i.e. burden of immunosuppression).

Prolonged time on dialysis treatment and presence of acute allograft

rejection, have been identified as modifiable risk factors for poor

survival. To shorten the time on dialysis before transplantation,

it is important to increase the number of available donor organs.

This can be done by use of living donors or older deceased donors

for older patients. By optimizing the immunosuppressive therapy

number of acute rejections can be reduced. The post operative cost

of a successful KTx is approximately 8000 €/year while continued

dialysis costs 7–80,000 €/year. KTx is thus an attractive treatment

option for eligible patients both in terms of survival and economics

Even if transplantation increases survival, information about older

patients’ health related quality of life (HRQOL) after transplantation

is lacking. At present we are conducting a study comprising

approximately 200 kidney transplant candidates with the aim of

describing HRQOL longitudinally from time of wait listing until five