Perspectives of end stage renal failure therapy in Singapore

Haemodialysis in Singapore started in 1961 when a patient with kidney failure was dialysed using the twin coil artificial kidney. Over the years, we have seen various new techniques like rapid high efficiency dialysis, haemodiafiltration (HDF) and rapid high flux HDF introduced. Dialysers with newer membranes have improved solute transport, biocompatibility and water removal. Mini heparinisation and heparin-free dialysis have circumvented problems of bleeding in high risk patients. Technological advances in haemodialysis will continue with more new modalities introduced. Newer forms of vascular access through the subclavian and internal jugular veins have phased out the use of chronic arterio-venous (AV) shunts. Continuous ambulatory peritoneal dialysis (CAPD) was introduced in 1980. This has been a boon for cardiac and diabetic patients. The initial problems with peritonitis are now manageable with our current rate of 24.1 patient months compared to 13.2 patient months in 1983. This has been achieved through the use of ultraviolet (UV) germicidal exchange device and transfer tube changes by trained nursing personnel as well as better patient training and education. New techniques have included the "O" disconnect set, the use of 2.5 litre dialysate, low calcium dialysate and the introduction of continuous cycling peritoneal dialysis (CCPD). Future focus will be on the problems of nutrition and protein loss. Renal transplantation remains the ideal renal replacement therapy. Cadaveric renal transplantation was initiated in 1970 and living related donor transplant in 1976. From 1970-1985, immunotherapy was azathioprine-based and from 1985, cyclosporin A (CyA) was introduced. CyA has abrogated many immunological risk factors. Preformed cytotoxic antibodies are still important.(ABSTRACT TRUNCATED AT 400 WORDS)

The Singapore Renal Registry: an overview

The Singapore Renal Registry (SRR) is created to collect and analyse information on incidence, prevalence, morbidity and mortality of End Stage Renal Disease (ESRD) in Singapore. Its objectives include the implementation of a consolidated renal disease data system, report on incidence and trends over time of renal disease, analyse aggregate data on effect of various modalities of therapy, identify problems and opportunities for special studies and research. The framework of the Registry encompasses the following areas: incidence, demographics and causes of ESRD, utilization of treatment modalities, institutions providing treatment, morbidity and survival rates of various treatment modalities, the paediatric sector, the private sector, international comparisons and research areas. This overview will present whatever existing data and renal statistics that are currently available on a regional or national basis. The collection of nationwide statistics will provide a database to formulate national averages of individual renal statistics. Statistics can also be collected to provide valuable data for planning and projection for future needs.

Cytomegalovirus infection in renal transplant patients with hepatitis B--case report

Cytomegalovirus (CMV) infection in Hepatitis B carrier renal transplant patients who are immunosuppressed can be easily overlooked especially in those presenting with jaundice and liver failure. Recognising hepatitis due to CMV in renal transplant patients who are also hepatitis B carriers is important therapeutically as measures for the treatment and prevention of CMV infection are already available. This is especially so as Hepatitis B has a moderately high prevalence in this part of the world. We describe our clinical experience of cytomegalovirus infection in two renal transplant patients who are also asymptomatic hepatitis B carriers.

Infection in continuous ambulatory peritoneal dialysis (CAPD): aetiology, complications and risk factors

Continuous ambulatory peritoneal dialysis (CAPD) was started in the Singapore General Hospital in 1980. Peritonitis and exit site infections have been the major cause of morbidity and catheter loss in CAPD. In 1990, 130 patients were on CAPD and the peritonitis rate was one episode in 20.4 patient months. Gram positive organisms accounted for 54% of the infections of which Staphylococcus epidermidis was the commonest (24%). Catheter removal was required in 14% of the cases and 9% of the patients discontinued CAPD as a result of peritonitis. The exit site infection rate was one episode in 27.5 patient months and the commonest organism was Staphylococcus aureus (54%). Twenty-three (47%) of the cases of exit site infection required catheter removal and 83% of the cases were the result of S. aureus infections. Patients with preexisting exit site infections experienced more episodes of peritonitis. Patients above the age of 50 years experienced more episodes of peritonitis and exit site infection. Sex, diabetes and the duration on CAPD did not influence the frequency of infections. Patients using the UV Germicidal Exchange Device had fewer episodes of peritonitis than those using the conventional spike system.

Can therapeutic interventions prevent chronic renal failure?

One way to prevent chronic renal failure (CRF) is to institute preventive measures against renal diseases in the general population. Patients with hereditary kidney diseases should have genetic counselling. Certain infections affecting or causing kidney diseases can be eradicated. People should be cautious in the use of analgesics and non-steroidal anti-inflammatory agents. Exposure to hydrocarbons, heavy metals and toxic gases should be avoided. Proper management of diabetes mellitus, gout, renal stones and hypertension can prevent renal damage. In patients with established renal disease, the following factors if treated or modified can prevent or ameliorate renal injury: glomerular hypertension, cell mediated proliferation, lipid induced proliferation, coagulation and thrombosis. Pregnancy in patients with renal disease should be well managed and termination advised if necessary. Reversible causes of renal failure as well as acute reversible elements can be removed or treated. Acute renal failure due to toxins can be avoided, although prevention requires awareness of association with renal failure. Prevention too depends on early detection of nephrotoxic injury like: greater awareness of hazards of environmental toxins, careful monitoring of dosage of nephrotoxic drugs and when possible, total avoidance of nephrotoxins should be the rule. Finally, in patients with glomerular disease, prevention or amelioration of glomerular damage with pharmacological agents have been achieved in some instances.

Social and cultural aspects of organ donation in Asia

In Asian countries, it is more difficult to obtain cadaver kidneys for renal transplantation because of certain socio-cultural beliefs and customs. The issues affecting living related kidney donation are more social than cultural. This is due to the web of family pressures and personal conflicts for both donor and recipient surrounding the donation. Important misconceptions and fears are: fear of death, the belief that removal of organ violates sanctity of decreased, concern about being cut up after death, desire to be buried whole, dislike of idea of kidneys inside another person, wrong concept of brain death, and the idea of donation being against religious conviction. In Singapore, with the introduction of the Human Organ Transplant Act (HOTA) in 1988, the number of cadaveric transplants have increased, including those from the Medical Therapy Act (MTA). HOTA and education have played pivotal roles in bringing about an increased yield of cadaveric kidneys. With the availability of living unrelated donor (LUD) transplants in India, our living related donor (LRD) transplant programme has suffered, because patients would rather buy a kidney from overseas than get a relative to donate one. Patients are also going to China for overseas cadaveric transplants where the kidneys come from executed convicts. People in countries like Hong Kong, Japan and the Philippines share the same Asian tradition of not parting with their organs after death. Muslim countries like Malaysia require the deceased to have earlier pledged his kidneys for donation prior to death before they can be harvested for transplantation at death.

The impact of HLA match transfusions and presensitization on renal transplantation in the cyclosporine era

The successful engraftment of a renal transplant is dependent on multiple factors, immunological factors being of major importance. Specifically, histocompatibility, lymphocytotoxic antibodies and pretransplant blood transfusions have been shown to play a major role in determining graft outcome in renal transplant recipients receiving Azathioprine-Prednisolone immunosuppression. The impact of the immunosuppressive drug, Cyclosporine on graft outcome in relation to established risk factors were examined among 116 cadaveric and 34 living related renal allograft recipients from our center. Histoincompatibility and pretransplant blood transfusions did not significantly affect graft survival among cadaveric transplant recipients. Similarly, graft survival was not significantly different between two haplotype-matched and less well-matched living-related graft recipients (75% versus 96.5% respectively). On the other hand, lymphocytotoxic antibodies remained a major risk factor for immunologically mediated graft loss among cadaveric graft recipients (48.0% versus 92.2% four year graft survival among those with and without antibodies respectively). These results suggest that Cyclosporine has abrogated some immunological risk factors in renal transplantation.

Seroprevalence of antibodies to the hepatitis C virus in Singapore

The prevalence of antibodies to the hepatitis C virus (anti-HCV) in Singapore was assessed using a recombinant-based enzyme linked immunoassay system. 1004 serum samples were obtained from normal subjects (463), hemodialysis patients (112), hepatitis B virus (HBV) carriers (188), patients with hepatocellular carcinoma (HCC) (58) and patients with non-hepatitis B virus related liver diseases (183). Anti-HCV was found to be positive in 1.7% of healthy subjects, and in 20% of patients on regular hemodialysis. Three percent of HBV carriers were positive for anti-HCV. Twelve percent of patients with acute hepatitis with no known causes and 20% patients with chronic hepatitis with no known causes were positive for anti-HCV. Among patients with cirrhosis for which no known causes were found 33% were positive for anti-HCV. Thirty six percent of patients with HCC not associated with the presence of HBsAg were positive of anti-HCV. None of the patients with known causes of liver disease were positive for anti-HCV.

Effects of triple therapy in IgA nephritis: a follow-up study 5 years later

This study is a 5-year post trial assessment of patients with IgA nephritis who entered a 3-year prospective controlled trial of cyclophosphamide, dipyridamole (D) and low-dose warfarin (W). Patients entered the trial from 1979 to 1981 and the trial ended in 1984 with those in the treatment group having more stable renal function and less proteinuria compared to the control group. Present reassessment of the patients in 1989 showed no difference in the renal function between those in the treatment group (n = 27) and the control group (n = 21). 6 patients in the treatment group and 7 in the control group were in ESRF. At the conclusion of the trial in 1984, among the 27 patients in the original treatment group, 13 patients elected to continue with D + W while the other 14 patients chose to cease therapy and therefore served as the new control group. 5 years later, renal function in the new treatment group (n = 13) was significantly stable compared to the new control group (n = 14), (serum creatinine 1.4 +/- 0.7 versus 4.4 +/- 3.2 mg/dl, p less than 0.01). Furthermore, all the 6 patients with ESRF in the original treatment group of 27 patients were from the new control group (n = 14) where treatment with D + W had been ceased. None of the patients still on D + W are in ESRF.

Pharmacokinetics and nephrotoxicity of cyclosporine

Cyclosporine (CsA) is a potent immunosuppressive agent which has dramatically improved graft and patient survivals in clinical solid organ transplantation. However, CsA nephrotoxicity (NTX) is the most frequent and serious side effect of CsA therapy and occurs in a significant proportion of patients. The clinical presentation of NTX is that of reduced creatinine clearance, elevation of serum creatinine and a disproportionate rise in blood urea. The clinical picture occurs as three syndromes, namely acute, subacute and chronic CsA NTX. Regardless of the clinical syndrome, the pathoaetiology of NTX is related to decline in renal blood flow and increase in renal vascular resistance probably due to CsA induced changes in renal haemodynamics. Unfortunately, the dose that yields an optimal therapeutic index, namely maximal efficacy with minimal toxicity has yet to be defined. Optimal dosing is confounded by not only inter and intraindividual variabilities in drug absorption, distribution and metabolism, but also by the lack of a clear relationship between drug efficacy and trough CsA level monitoring. This paper describes the pharmacokinetics and nephrotoxicity of CsA and evaluates various strategies to overcome this toxicity.

Pattern of proteinuria in IgA nephritis by SDS-PAGE: clinical significance

Of sixty patients with IgA nephritis, none had CRF at first examination, 13 developed CRF with creatinine above 1.6 mg/dl within 6 years. Among these patients who had analysis of proteinuria by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), 31 patients had middle molecular weight (MMW) proteinuria alone (pattern 1), 10 had MMW and Low MW (LMW) or tubular proteinuria (pattern 2), 10 had high MW (HMW) and MMW proteinuria (Pattern 3) and 9 had HMW, MMW and LMW proteinuria (Pattern 4). At the end of a follow up period of 6 years (1983-1989) patients with mixed proteinuria had a higher incidence of chronic renal failure (CRF), 11/29 (38%) compared to those with pattern 1 proteinuria, 2/31 (6%) (chi 2 = 8.7, p less than 0.005). Based on the glomerular selectivity index (GSI), 19 patients had nonselective proteinuria but they did not have a higher incidence of CRF. By the selectivity index (SI), 18 patients had nonselective proteinuria and they showed a significantly higher incidence of CRF. Compared to the 41 patients who did not have LMW proteinuria, 19 patients with LMW proteinuria had more severe proteinuria. After a follow-up period of 6 years, patients with LMW proteinuria had a higher incidence of CRF (10% versus 47%, p less than 0.001). The presence of LMW proteinuria indicates a less favourable outcome and the pattern of proteinuria as assessed by the SDS-PAGE appears to be a better prognostic index in IgA nephritis than the SI and the GSI.

Maintenance haemodialysis in Singapore

The chronic haemodialysis programme of the Singapore General Hospital started in 1968 as a hospital-based fully nurse-assisted programme. This has since expanded to include Self Dialysis and Home Dialysis programmes. Data of 425 patients who entered the dialysis programmes was analysed retrospectively. The major cause of end stage renal failure was chronic glomerulonephritis (52%). Almost half of the patients in the haemodialysis programme were patients on self-dialysis (49%). There were 157 withdrawals and 116 deaths. Survival has improved tremendously with the use of treated water for dialysis from 1981. The 5 year survival in an earlier group of patients dialysed with untreated water was 48% compared with 81% in a late group dialysed with treated water (p less than 0.001). The pattern of complications has also changed with a lower incidence of dialysis osteomalacia, hypertension, hepatitis and eradication of dialysis dementia.

Acute renal failure prognostic indices in hospital inpatients referred for haemodialysis

Forty-eight patients with acute renal failure (ARF) who were referred to the Department of Renal Medicine, Singapore General Hospital for acute dialysis between August 1985 and August 1989 were studied retrospectively to identify risk factors associated with ARF that serve as prognostic indicators. There was no difference in the mean age of survivors and non-survivors (49.5 +/- 17.5 years vs 53.5 +/- 18 years, p greater than 0.05). The overall mortality rate was 52%. ARF as a result of surgical complication had a higher mortality rate in comparison to ARF from medical complications (66% vs 50%, p greater than 0.05). Septicaemia was the most common cause of ARF requiring dialysis. Hepatobiliary sepsis was the most frequent cause of septicaemia. Pre-dialysis serum urea and creatinine levels, and the number of dialysis treatments did not affect the outcome. Poor prognostic indicators included oliguria or anuria, fluid overload and coma. Patients tended to have a worse outcome if they had more than three risk factors taken from the following list:-decreased renal perfusion, assisted ventilation, coma, gastrointestinal dysfunction, recent surgery, sepsis, congestive heart failure, hepatobiliary dysfunction, malignancy, diabetes mellitus, chronic renal insufficiency and poor nutritional status. Early referral of patients with septicaemia due in particular to hepatobiliary infection may improve the prognosis.

Acute cyclosporin A induced nephrotoxicity in renal allografts

Immunosuppression with Cyclosporin A has resulted in dramatic improvements in the results of cadaveric kidney transplantation in Singapore. However, its major limitation is its nephrotoxicity which can appear in various forms after transplantation including a delay in graft function and chronic renal dysfunction. The clinical course of two patients with initial function but delayed onset of acute functional Cyclosporine nephrotoxicity are described. Recovery was documented in both cases with reduction of Cyclosporine dosage. A decline in renal blood flow and increase in renal vascular resistance is likely to have played a role in the pathogenesis of the acute functional nephrotoxicity. Cyclosporine induced imbalance in Prostaglandin synthesis within the kidney has been implicated.

Cell-mediated immunity in patients on hemodialysis: relationship with hepatitis B carrier status

We compared cell-mediated immune responses in two groups of patients on hemodialysis. One group of patients were chronic carriers of hepatitis B virus (HBV), and the patients of the other group were HBV antigen negative. Our results show that despite the presence of normal numbers of T cells and an increased CD4/CD8 ratio in both groups of patients compared to healthy controls (p less than 0.0001), only the group of patients who were chronic HBV carriers showed depressed lymphoproliferative responses to phytohemagglutinin (p less than 0.001) and concanavalin A (p less than 0.0001). In contrast, a control group of healthy adult HBV carriers showed normal T cell subsets and lymphoproliferative responses to mitogens, indicating that HBV infection per se did not result in depressed lymphoproliferative responses. These results further substantiate the notion that depressed cell-mediated immunity in chronic renal failure is an important factor in predisposing patients to HBV infection with subsequent development of the chronic carrier state.