SINGLE-CENTER EXPERIENCE AND CURRENT INDICATIONS OF RENAL BIOPSY IN ELDERLY PATIENTS
Francesca Calero MD, J. Ballarín MD
E-mail: 16814fcg@comb.es
Fundació Puigvert
Barcelona, Spain
| DISCUSSION BOARD |
INTRODUCTION
It is probably a general experience, at least in developed countries all over the world, that elderly patients are referred to hospitals for nephrologic evaluation more often every day.
A longer life expectancy, an increasing quality of life despite age, as well as an easier access to health resources may all account for this fact.
Among several diagnostic procedures, renal biopsy is one of the most important tools available for nephrologists, but its indication has always been a matter of debate.
Many clinicians routinely biopsy patients with nephrotic syndrome or a nephritic urinary sediment. Christine K. Abrass says in a recent editorial that "the best determination of potential benefit of an invasive diagnostic procedure comes from the demonstration that knowledge of a specific diagnosis guides the selection of treatments that produce improved outcomes". Nevertheless, indications for kidney biopsy differ considerably among nephrologists.
Different studies have reported series of elderly patients biopsied in an attempt to establish the most prevalent diagnosis in glomerular diseases. .There is great debate as to whether the benefit gained from de knowledge of renal histology outweighs the risk too the patient from the biopsy procedure. An article published in 1994 by Richards demonstrate that knowledge of renal histology is essential in the management of patients with renal disease.
Regarding these experiences and being the indications of renal biopsy always controversial, it is the aim of the present study to evaluate the diagnostic and therapeutic yield of renal biopsies performed at our center in the last twelve years, in the group of patients older than 65 years.
Definitions. We defined diagnostic yield as the percentage of patients with a specific diagnosis, including those entities accepted by the nephrology community, and considered therapeutic yield the percentage of patients treated with immunosuppressive therapy as a consequence of the renal biopsy result.
Patients and methods. In this study we have analyzed 210 out of a total of 828 biopsies performed in our center between 1989 and last year. These biopsies were done in 210 patients older than sixty-five. There were 140 males and seventy females with a mean age of 72 years. The oldest patient was 88 years old with an excellent quality of life and up to 23 patients presented in this study were older than eighty.
We used a 14 o 16 G spring-loaded needle under real –time ultrasound guidance. An additional ultrasound was performed in all patients the day after the biopsy and before discharge.
RESULTS
Renal biopsy indications, diagnostic yield and therapeutic yield are listed in table 1.
|
RB indication |
Cases |
% |
Diagnosis |
% |
IS treatment |
% |
|
Acute Renal Failure |
91 |
41 |
82 |
90 |
40 |
44 |
|
Nephrotic Syndrome |
67 |
31 |
61 |
91 |
16 |
24 |
|
Persistent prot-hematuria |
45 |
21 |
38 |
84 |
5 |
11 |
|
Chronic Renal Failure |
16 |
7 |
12 |
75 |
- |
- |
91 patients were biopsied as part of the work-up for the acute renal failure. It represents almost half of the kidney biopsies performed. 31% of our patients were biopsied because of nephrotic syndrome. The remaining biopsies were done to study persistent Proteinuria-Hematuria syndromes and, finally, 7 % of biopsies were performed as a part of the work-up for chronic renal failure of unknown origin.
Among the 91 cases presenting as Acute Renal Failure, a specific diagnosis was obtained in 90 % of the biopsies. Not surprisingly, Vasculitis and Extracapilar Glomerulonephritis were present in almost 40% of our patients. In a recent publication Mark Haas reported this diagnosis in a 30% approximately of his patients biopsied of Acute Renal Insufficiency.
Other glomerular diseases such Mesangiocapillary Glomerulonephritis, Amyloidosis, IgA nephropathy, diabetes and so on ere present in almost 30% of the patients.
It’s worth noticing that only 9% of the patients in our series suffer from a form of acute tubulointerstitial disease.
When we evaluate the Nephrotic Syndrome group, we find that Membranous Nephropathy is the most common diagnosis in up to 33% of patients, Amyloidosis was diagnosed in 8 patients (12%)We noticed that 8% of our patients displayed Minimal Change Disease and 6% suffered from Mesangial Glomerulonephritis.
In the group of persistent proteinuria-hematuria, Non IgA, and Mesangial IgA Nephropathy are the most common diagnosis. (33%).
The diagnosis found in the patients biopsied for Chronic Renal Failure of unknown etiology as the primary indication for the procedure was benign nephrosclerosis (18%); Membranous Nephropathy (6,3%); IgA nephropathy (6,3%); Glomerulosclerosis (25%).
Notice that we have got a specific diagnosis in almost 90% of the biopsies. (Table 1).
We would like to emphasize that when biopsy was performed for acute renal failure, 44% of the patients received immunosuppressive treatment as a consequence of the results of the histological analysis.
This study points out as well that 24% of the patients presenting nephrotic syndrome received immunosuppressive therapy. Thus, 76% of our patients were spared of such protocols because of the direct result of the biopsy.
Only 1,4% of major complications were observed; two arteriovenous fistulas requiring percutaneous embolization and one surgical nephrectomy. Other patients experienced minor complications: macroscopic hematuria (9); perirrenal hematoma (16), blood transfusion (4).
DISCUSSION AND REFLEXIONS
The causes of renal disease in the young and the elderly vary in their frequency. 2,4. There are many indications for renal biopsy in older patients, with the nephrotic syndrome being the most common, followed by acute renal failure. In our patients acute renal failure has been the most common indication. The increasing diagnosis of vasculitis, due to ANCA determination, may have influenced in this aspect. In these patients renal biopsy offer a very important therapeutic yield and help us not to treat unnecessarily.
In older patients, the prevalence of Nephrotic syndrome is really unknown. In patients biopsied because of this cause, Membranous Glomerulonephritis is the most common diagnosis 2,3,4 , but Minimal Change disease is another important diagnosis. 2 .Some authors have suggested a course a steroids therapy in these patients without a biopsy and the response observed. However, in the elderly, steroids may carry a risk of significant complications and there is reluctance to use them blindly. In our opinion and based in our results, renal biopsy allows to save unnecessary immunosuppressive treatments in nephrotic patients.
Renal biopsy might not be justified for the diagnosis of persistent microhematuria-proteinuria or chronic renal failure. In these patients the knowledge of renal histological characteristics do not change the management. In this group of patients the indication for renal biopsy should remain determined by the personal experience and confidence of the physician wit the procedure, as well as by the clinical conditions of the patient.
The present study was done to analyze the increasing number of patients aged 65 years and older who are being biopsed and how the renal biopsy diagnosis is useful in the management of renal disease.
Despite of complications, in our patients represents 1,4% of major complications, and after careful considerations, we consider the renal biopsy in experienced hands a safe method to have a proper diagnosis and permit formulation of a effective treatment plan.
Indications for renal biopsy in elderly patients include rapid decline in renal function, nephrotic syndrome, acceleration of chronic renal failure without clear cause and atypical manifestations in some diabetic patients.
Nephrologists have traditionally provided "primary care" to their dialysis patients. O
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