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| Journal of the New Zealand Medical Association,
11-November-2005, Vol 118 No 1225
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Older patients in the nephrology clinic—should they be
referred?
Sarah Lynn, Richard Sainsbury, Martin Searle
In industrialised countries there has been an exponential
rise in the number of elderly patients with identified renal disease. This is
not unexpected given the ageing population, increased life expectancy, decline
in renal function with age,1 and the elderly’s increased access to care.
Advances in dialysis technology mean that life-sustaining treatment for the
elderly is now feasible and an increasing number of elderly patients are being
accepted onto dialysis programs worldwide.2,3
In Australia, 45% of patients starting dialysis in 2003 were
aged 65 years or older compared to 36% in 1997. The American Society of
Nephrology has recognised this growth and coined the term ‘gerontologizing
nephrology.’4 In this era of limited resources and growing outpatient
clinic waiting lists, consideration needs to be given to which elderly patients
should be referred for specialist review.
National Referral Guidelines for Renal Medicine exist but
are not directed specifically at the elderly.5 There is also a degree of
uncertainty amongst general practitioners and specialists about which elderly
patients to refer and the timing of referral. It is felt by some that an
elevated creatinine in an asymptomatic older patient does not immediately
warrant a specialist referral but opposing this is the evidence of under
referral of such patients to nephrologists.6,7
It also needs to be recognised that a number of elderly
patients with observed renal impairment do not progress. Patients who require
long-term dialysis have improved outcomes if they are referred early to allow
time for education and planning.8
A retrospective case note audit was performed to assess the
pattern of referral of elderly patients and their management in the clinic and
to develop referral guidelines for these patients.
MethodsNew patients aged 65 years or older attending the
Nephrology Clinic at Christchurch Hospital between January 2000 and December
2001 were included in this study. The Clinic services a population of 350,000
and reviews 170 new patients each year. Patients seen following inpatient review
were excluded. New patients were identified by using the Nephrology Department
clinical database PROTON (Clinical Computing Plc, London, United Kingdom) and
the Hospital’s Patient Management System.
The clinical record for each patient was then reviewed
and data collected on the reason for referral, investigations performed,
treatment given, diagnosis made, and management offered. Estimated creatinine
clearance (CrCl) was calculated using the Cockcroft and Gault formula.9 The
first outcome assessed was whether a definite diagnosis was made. This was
considered to be an aetiologic diagnosis if made following a renal biopsy,
immunological testing, or renal imaging (including angiography). All other cases
were considered to be clinical diagnoses.
We next assessed what treatment was offered and whether
this resulted in a change in clinical management. Treatment offered included
immunosuppressive therapy, dialysis education, or advice to the general
practitioner on medication or clinical monitoring. Information related to
service delivery was also collected including time to clinic appointment
following referral and the rate of enrolment into follow-up. Data was collected
to December 2001 and numbers commencing dialysis were collected to December
2004.
ResultsThere were 68 elderly new patients referred in the study
time period. This represented 18% of the clinic workload and 0.12% of the
elderly population in Christchurch. Seven case notes were not available for
review. The mean age of the patients was 74 years (range 65-88 years) with 57%
males. Referrals from general practitioners made up 74% with most referring only
a single patient. The remaining referrals came from a wide range of specialists.
The mean waiting time for clinic review was 31.7 days with no difference between
the two referral groups.
Table 1. Reasons for referral
Referrals—There
were several reasons for referral (Table 1) with some patients presenting with
more than one problem. The commonest presentation was an elevated plasma
creatinine (69%), with a mean serum creatinine of 0.20 mmol/L and a mean
estimated CrCl of 32 ml/min. Seven patients had a 30% improvement in the serum
creatinine between the time of referral and clinic assessment.
Hypertension was mentioned in the referral in 10%, however
87% of all patients referred had a blood pressure >130/80 mmHg (mean 162/80,
range 112/67–240/100). Proteinuria was the reason for referral in 13% of
the patients (range 0.37–7g/24hr) with an additional 5% referred for
investigation of nephrotic syndrome.
Investigations—Only
54% of the patients had their urine examined for blood or protein prior to
referral. Following clinic review, urinalysis was performed in 97% with no other
patients found to have significant proteinuria (i.e. >1g/24hr) or haematuria.
In Christchurch, the general practitioners have limited access to renal
ultrasound for patients without private health insurance: only 43% of patients
referred had this test performed in the community while 36% had an ultrasound
following clinic review. Serum protein electrophoresis was performed in 31%. Two
patients had renal artery imaging performed prior to referral. Another patient
was offered this investigation but declined.
Table 2. Renal biopsy findings
FSGS=Focal and segmental
glomerulosclerosis.
All patients presenting with nephrotic syndrome or
proteinuria >3g/24hr were offered a renal biopsy, aside from one patient
presumed to have familial focal and segmental glomerulosclerosis on the basis of
a strong family history. Four patients had a renal biopsy performed and a
further two patients declined this procedure (Table
2). The remaining five patients with
proteinuria either had known diabetes mellitus or hypertension with no
significant renal impairment and so did not have a renal biopsy.
Diagnosis—A
range of diagnoses were made (Table 3) and included hypertensive renal disease
(30%), chronic renal failure—cause unknown (18%), and diabetic nephropathy
(8%). In the majority of cases the diagnosis was clinical with only 12 (20%)
patients having a diagnosis made by investigation.
Management—In
the majority of cases (80%), assessment resulted in advice to the referrer which
changed management in 36% of cases. This included advice on clinical monitoring,
antihypertensive treatment, stopping specific nephrotoxins, and optimising
glycaemic control. Four patients were treated with oral prednisone to treat a
variety of conditions: renal sarcoidosis, renal vasculitis, multiple myeloma,
and focal and segmental glomerulosclerosis.
Five patients were offered dialysis education, with three
commencing peritoneal dialysis and the remaining two declining to proceed with
treatment. Over the next 3 years, four more patients received dialysis
education. Review in the Nephrology Clinic was organised for 30% of the patients
and 11% were referred on to another specialty.
Table 3. Diagnoses of renal disease
APKD=Adult polycystic
kidney disease.
DiscussionThis paper is a review of our practice and is the only
published data in New Zealand on referral patterns of elderly patients to a
nephrology service. Most of the elderly patients in our study had chronic renal
disease that was asymptomatic and did not warrant intensive investigation. These
patients were commonly managed by providing advice to the general practitioner
and it has to be questioned whether a clinic visit is the only means of
conveying this information.
The value patients place on being seen by a specialist was
not determined due to the retrospective nature of the study. A proportion (25%)
of patients did require further investigation and specific treatment and it is
this group in particular that should continue to be referred for specialist
review. We were unable to determine if the clinic visit resulted in improved
outcomes long term as the follow-up was short, and we did not attempt to make
any comparisons with the younger patients referred to the service
This study highlights the low referral rates of older people
with renal disease, which may also reflect the low recognition of renal disease
in the community. The AusDiab study10 provides important and useful prevalence
data that can be extrapolated to our population. It clearly showed that age is
the strongest predictor of renal impairment with GFR <60 ml/min found in
54.8% of people
≥65 and GFR
<30 ml/min in 1.7% of elderly.
This equates to 31,300 people in Canterbury with moderate
renal impairment and 970 with severe renal impairment. These numbers would
overwhelm the renal service if all were referred for specialist review.
Resources for specialist assessment are limited and the gap between demand and
availability is likely to expand as morbidity increases in the ageing community
and quality of care improves.
Proposed referral guidelines for patients aged 75 years or
older are included (Appendix 1) that would facilitate identification of those
patients who require specialist review. These guidelines promote selection of
patients in whom investigation is likely to yield a result (e.g. renal
vasculitis); where aggressive management is important to slow the progression of
disease (ie. significant proteinuria, difficult to control hypertension); and
when dialysis should be considered. These are in keeping with other national
guidelines11.
Patients who do proceed to dialysis need to be referred
promptly. Indeed, several studies have shown that late referral for patients who
require dialysis is associated with poorer outcomes.8,12 In our clinic, waiting
time is not a barrier to review with the mean waiting time for a non-urgent
review in this study being 1 month. Urgent referrals are seen on a same day
basis where required.
Hypertensive and vascular renal disease were the most common
renal diagnoses. Vascular comorbidities (such as ischaemic heart disease) which
would have been useful to help determine the aetiology of the renal impairment
were not routinely recorded. The high rates of hypertension suggest that the
national hypertension guidelines of aiming for blood pressure (BP) <130/80
mmHg are not being adhered to and/or are difficult to achieve.13 There were
relatively low rates of diabetic nephropathy.
Other studies have also shown this pattern of a higher
incidence of vascular renal disease and lower rates of diabetic disease in the
elderly compared with younger patients 2,14. This is worth bearing in mind as
the majority of studies showing slowing of progression of renal disease have
been in those with diabetic nephropathy.
Urinalysis should be performed in all patients with new or
worsening renal impairment, and the low use of this test in our referral group
is disappointing. This issue is not confined to older patients—as a
similar rate was seen in a recent department audit of all referrals (unpublished
data). Urinalysis is a simple, inexpensive test that provides important
information regarding glomerular and other renal diseases, and it may identify
those patients in whom a renal biopsy should be considered.
The presence of proteinuria indicates a significant risk of
progressive kidney damage;15,16 proteinuria >1g/24hr was identified in 1% of
people aged
≥65 in the
AusDiab study.10 It has been shown in younger subjects that the rate of
progression of chronic renal disease can be reduced by management of
hypertension17 and the use of angiotensin-converting enzyme inhibitors
(ACEI),18,19 with the greatest benefit seen in those patients with > 1g/day
of proteinuria. For some patients, the use of ACEI will result in a rise in
creatinine and potassium. This is allowable if it does not rise more than 30%
above baseline and stabilises within the first 2 months of treatment, as these
patients seem to receive the greatest benefit in renoprotection.20
Most older patients with renal impairment need to be managed
in primary care. Renal function needs to be assessed by calculating the
estimated creatinine clearance—as elderly patients (particularly
overweight females) can have a serum creatinine within the normal range but
significantly impaired function.
To increase awareness of renal failure in the elderly,21
general practitioners are being encouraged to use the Cockcroft and Gault
equation. Local laboratories are now using an equation used in the MDRD study15
to calculate creatinine clearance (as weight and age are not required). In
addition, renal ultrasound is useful to detect obstructive uropathy and to
confirm the chronicity of the renal impairment by measuring renal size.
Asymmetry of kidney size may indicate renovascular disease.
It is unfortunate that timely access to imaging can be difficult to organise
from the community and wider access to these investigations is required. Thus it
is essential that preventive strategies to delay the progression of early renal
disease are promoted to general practitioners alongside the proposed
guidelines.22
Renal disease in the elderly is common and further thought
needs to be given to how our health service will manage this epidemic. There
will be a growing need to balance the technical possibilities of treatments such
as dialysis against the available resources. In 2003, there were 1699 patients
receiving dialysis in New Zealand with annual treatment costs of $50,000 per
patient.23 This number is increasing at a rate of 9% per annum and one-third of
these patients are aged over 65 years (elderly).
The benefits of dialysis are questionable for some of these
patients. Ultimately, the decision to investigate and treat needs to be
individualised depending on the presence of comorbidities, social circumstances,
and patient choice.
Appendix 1Referral Guidelines:
Author information:
Sarah Lynn, Consultant Physician, The Princess Margaret Hospital; Richard
Sainsbury, Professor of Geriatric Medicine, The Princess Margaret Hospital;
Martin Searle, Nephrologist, Nephrology Department, Christchurch Hospital;
Christchurch
Correspondence: Dr
Sarah Lynn, The Princess Margaret Hospital, PO Box 800, Christchurch. Fax: (03)
337 7803; email: sarah.lynn@cdhb.govt.nz
References:
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