Glomerular and tubular function in renal transplant patients treated with and without ciclosporin A

Gout Severity in Recipients of Kidney Transplant

PURPOSE

This retrospective analysis of medical chart data was performed to compare severity and treatment of gout in patients with or without a history of kidney transplantation (KT).

METHODS

Via an online survey, a panel of board-certified US nephrologists (N = 104) provided the following deidentified chart data for their 3 most recent patients with gout: age, sex, serum uric acid, numbers of swollen or tender joints, visible tophi, gout flare events (prior 12 months), gout drug treatment history, and KT history. The presence of "severe, uncontrolled gout" was defined as: serum uric acid ≥ 7.0 mg/dL, ≥1 tophi and ≥2 flares in the last 12 months, and history of xanthine oxidase inhibitor treatment.

RESULTS

Twenty-five out of 312 (8.0%) gout patients had a history of KT. Univariate analysis found that patients with gout and history of kidney transplants had: greater prevalence of severe uncontrolled gout (27% vs 8%, P = .007) and tophi (36% vs 17%, P = .030), and higher rates of failure or physician perceived contraindication to allopurinol (44% vs 23%, P = .028).

CONCLUSION

This study provides preliminary evidence that gout in patients with history of KT is more severe and poses greater challenges to pharmacologic management. Although gout has been linked to worse outcomes among kidney recipients in the literature, there are presently no publications on gout severity among patients with KT in comparison to other patients with gout. Further investigation of disease severity and appropriate, effective treatment options in recipients of kidney transplant with a diagnosis of gout, especially prior to the transplant, is warranted.

Drug-induced hyperuricaemia and gout

Hyperuricaemia is a common clinical condition that can be defined as a serum uric acid level >6.8 mg/dl (404 µmol/l). Gout, a recognized complication of hyperuricaemia, is the most common inflammatory arthritis in adults. Drug-induced hyperuricaemia and gout present an emergent and increasingly prevalent problem in clinical practice. Diuretics are one of the most important causes of secondary hyperuricaemia. Drugs raise serum uric acid level by an increase of uric acid reabsorption and/or decrease in uric acid secretion. Several drugs may also increase uric acid production. In this review, drugs leading to hyperuricaemia are summarized with regard to their mechanism of action and clinical significance. Increased awareness of drugs that can induce hyperuricaemia and gout, and monitoring and prevention are key elements for reducing the morbidity related to drug-induced hyperuricaemia and gout.

Hyperuricemia after orthotopic liver transplantation: divergent associations with progression of renal disease, incident end-stage renal disease, and mortality

Background

Although hyperuricemia is common after orthotopic liver transplantation (OLT), its relationship to mortality, progressive kidney disease, or the development of end stage renal disease (ESRD) is not well-described.

Methods

Data from 304 patients undergoing OLT between 1996 and 2010 were used to assess the association of mean serum uric acid (UA) level in the 3-months post-OLT with mortality, doubling of creatinine, and ESRD incidence. Post-OLT survival to event outcomes according to UA level and eGFR was assessed using the Kaplan Meier method and multivariate Cox proportional hazards models.

Results

Mean UA level among the 204 patients with an eGFR level ≥60 ml/min/1.73 m² was 6.4 mg/dl compared to 7.9 mg/dl among the 100 patients with eGFR <60 (p < 0.0001). During a median of 4.6 years of follow-up, mortality rate, doubling of creatinine, and ESRD incidence were 48.9, 278.2, and 20.7 per 1000 person-years, respectively. In the first 5 years of follow-up, elevated UA was associated with mortality (Hazard Ratio, HR = 1.7; p = 0.045). However, among those with eGFR ≥ 60, UA level did not predict mortality (HR = 1.0; p = 0.95), and among those with eGFR < 60, elevated UA was a strong predictor of mortality (HR = 3.7[1.1, 12.0]; p = 0.03). UA was not associated with ESRD, but was associated with doubling of creatinine among diabetics (HR = 2.2[1.1, 4.3]; p = 0.025).

Conclusion

In this post-OLT cohort, hyperuricemia independently predicted mortality, particularly among patients with eGFR < 60, and predicted doubling of creatinine among diabetics.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-017-0518-5) contains supplementary material, which is available to authorized users.

Uric acid and transplantation

Hyperuricemia is a common complication in organ transplant recipients, with a higher incidence in kidney and heart recipients. Risk factors for post-transplant hyperuricemia include reduced glomerular filtration rate, diuretic use, cyclosporine therapy, increasing age at transplant, obesity, and metabolic syndrome, as well as the presence of pretransplant hyperuricemia. The impact of hyperuricemia in patient and graft survival is unclear because uric acid only recently has been considered a risk factor for cardiovascular disease and graft survival. The effect of uric acid on graft function remains controversial, with studies suggesting that uric acid is an independent risk factor for chronic allograft dysfunction, contrasting with other studies suggesting that hyperuricemia is only a marker of reduced glomerular filtration rate. Strategies to reduce uric acid levels include reduction or avoidance of cyclosporine treatment, adequacy of antihypertension treatment, avoidance of diuretics, nutritional management, and use of uric acid-lowering agents. In this article, we review the incidence and risk factors for the development of post-transplant hyperuricemia, the effect of different immunosuppressive regimens in uric acid handling, and recent results from studies comparing uric acid levels and renal function in organ transplant recipients that try to identify which comes first: hyperuricemia or chronic allograft dysfunction?

Three-year follow-up of human transplanted kidneys by diffusion-weighted MRI and blood oxygenation level-dependent imaging

PURPOSE

To prospectively determine the 3-year stability and potential changes of functional parameters in renal allograft recipients obtained from diffusion-weighted imaging (DWI) and blood oxygenation level-dependent (BOLD) MRI.

MATERIALS AND METHODS

Nine renal allograft recipients underwent DWI and BOLD-MRI twice, once 7 ± 3 months after transplantation, and again 32 ± 2 months after the first MRI. DWI yielded an apparent diffusion coefficient (ADC) and the perfusion contribution (F(P) ). BOLD imaging yielded R2, providing an estimation of renal oxygenation. Coefficients of variation between (CV(b) ) and within subjects (CV(w) ) were calculated.

RESULTS

The parameters were stable after 32 months in eight of the nine patients, who had well-functioning allografts. Mean diffusion values were very similar in the first and second scan. CV(w) and CV(b) for ADC values were less than 3.5% and 5.9%, respectively, in cortex and medulla, but were higher for F(P) (15%-18%). CV(w) and CV(b) of R2 were also low (medulla: CV(w) = 10.8%, CV(b) = 11.4%; cortex: CV(w) and CV(b) = 7.2%). R2 increased significantly (P = 0.035) in cortex but not in medulla, suggesting reduced cortical oxygen content. One subject with decreased glomerular filtration rate demonstrated strongly altered parameters.

CONCLUSION

In the absence of graft dysfunction, DWI and BOLD imaging yield consistent results over 3 years in stable human renal allograft recipients.

Combined sirolimus-calcineurin inhibitor immunosuppressive therapy in simultaneous heart and kidney transplantation: a retrospective analysis of a single hospital's experience

Simultaneous heart and kidney transplantation (SHKT) has become an accepted therapeutic option for patients with end-stage heart failure associated with end-stage renal disease. The immunosuppressive therapy is usually based upon a heart transplantation protocol using a calcineurin inhibitor (CNI). Sirolimus (SRL) is a potent nonnephrotoxic immunosuppressant with antiproliferative activity in nonimmune cells. Its use has recently been reported to show less nephrotoxicity among both heart and kidney transplants. However, the data for the SHKT are limited. We retrospectively examined the causes of 5 patients who received combined SRL-CNI immunosuppressive therapy with reduced CNI doses from 2003 to 2009. There was no mortality during follow-up. Two of the 3 patients who received a conversion regimen recovered renal function. One who suffered severe proteinuria after transplantation proceeded to hemodialysis at 3 years after conversion. Both of the patients who received the combined regimen de novo remained stable regarding their renal function. Cardiac function was stable in these patients; there was neither allograft rejection nor allograft coronary vasculopathy. We observed that patients without dyslipidemia or hyperuricemia before SHKT were less likely to develop these disorders under the combined regimen. Early medical intervention after close follow-up of lipid and uric acid values by dose adjustments resulted in a stable status of our patients.

Replacement of Calcineurin-Inhibitors With Sirolimus as Primary Immunosuppression in Stable Cardiac Transplant Recipients

BACKGROUND

Calcineurin-inhibitor (CNI) nephrotoxicity is a major cause of morbidity and mortality after cardiac transplantation. The aim of this study was to assess over 2 years the safety and effect on renal function of withdrawal of CNI immunosuppression and replacement with sirolimus (SRL) in stable cardiac transplant recipients.

METHODS

CNI was substituted with SRL in 78 cardiac transplant recipients (SRL group) of whom 58 (group A) had CNI-induced renal impairment (glomerular filtration rate [GFR] <50 mL/min) and 20 (group B) had preserved renal function (GFR >50 mL/min). Fifty-one patients (CNI group) with renal impairment (GFR < or =50 mL/min) maintained on CNI served as controls. Secondary immunosuppressants were unchanged.

RESULTS

In the SRL group, GFR increased from 47.0+/-18.0 to 61.2+/-22.2 ml/min (P=0.0001) 24 months after SRL initiation. In Group A, GFR increased from 40.5+/-12.7 to 53.9+/-19.8 mL/min (P<0.0001). In Group B, GFR increased marginally from 67.2+/-15.8 to 83.5+/-27.8 mL/min (P=0.10). In the CNI group, GFR declined from 40.5+/-14.0 mL/min to 36.4+/-12.5 mL/min (P=0.23) after 24 months of follow up. There was no significant difference in cardiac rejection or cardiac allograft function. In SRL group, proteinuria increased from 299+/-622 mg/day to 517+/-795 mg/day (P=0.0002) 12 months after SRL initiation and then stabilized; it did not differ from CNI group at 24 months (637+/-806 vs. 514+/-744 mg/day, P=0.39). Uric acid decreased from 7.6+/-2.4 to 6.2+/-1.9 mg/dL (P=0.0007) in the SRL group.

CONCLUSIONS

Graduated substitution of CNI with SRL in cardiac transplant recipients is safe and improves renal function, without cardiac compromise.

Hyperuricemia and gout following pediatric renal transplantation

Hyperuricemia and gout are common complications in adult renal transplant recipients. In pediatric recipients, however, hyperuricemia seems to be rare, but data are scarce. Thirty-two children (21 males, 11 females) were investigated for a median time of 4.8 years (range: 0.4-11.2 years) following renal transplantation. The median age of this pediatric study group was 13.9 years (range: 5.7-20.3 years), and the calculated glomerular filtration rate (GFR) was 61 ml/min per 1.73 m(2) (range:12-88 ml/min per 1.73 m(2)). All patients were given calcineurin inhibitors, with 22 and ten children receiving cyclosporine A (CSA) and tacrolimus (TAC), respectively. The median plasma uric acid was 385 micromol/l (range: 62-929 micromol/l); 15 children (47%) were above the age-related normal range. Only one patient experienced gouty arthritis. There was a significant correlation between plasma uric acid concentration and both time span after transplantation and plasma creatinine, and an inverse correlation to GFR (p<0.05). No significant correlation was found between plasma uric acid and body mass index (BMI). Plasma uric acid concentrations were neither different among CSA- and TAC-treated children, nor did they correlate with drug exposure or blood trough levels of CSA or TAC. Plasma uric acid concentration was not different when compared to children with chronic renal failure (CRF) of a similar degree in native kidneys. We conclude that hyperuricemia is common among pediatric renal transplant recipients and rather a consequence of chronic renal transplant dysfunction than the use of calcineurin inhibitors. Gout, however, is rare.

Gout in renal transplant recipients

AIMS

The aims of the present audit were to determine the prevalence of gout in renal transplant recipients in Canterbury, New Zealand, to identify risk factors for gout, and to assess the range of treatments used, their efficacy and complications. In addition, the authors wished to assess the impact of post-renal transplant gout on the patient.

METHODS

Patients with post-transplantation gout were identified from the Christchurch Hospital Nephrology database. For each patient with gout a post-renal transplantation recipient without gout post transplant was found matched for age, sex and date of transplant. Case notes were audited and patients interviewed.

RESULTS

In total, 47/202 (23%) living renal transplant recipients had gout post transplant. Those patients with gout were more likely to be taking a loop diuretic (68%vs 34%, P < 0.001), to have a higher serum urate and impaired renal function and to have had gout prior to the transplant. Of those patients who developed gout post transplant 70% had an attack at least every 3 months. Of those who returned to work post transplant 48% required time off work because of gout.

CONCLUSION

out is an important problem in the post-transplant population causing significant morbidity and time off work. Diuretics, impaired renal function, gout prior to transplantation and hyperuricaemia are important risk factors. The need for diuretic therapy should be kept under review in these patients. Hypouricaemic therapy should be considered early in those who develop gout post renal transplantation. Further studies are required to determine whether treatment for asymptomatic hyperuricaemia is justified.

Epidemiology of crystal arthropathy

Gout is an inflammatory arthritis mediated by the crystallization of uric acid within the joints and often is associated with hyperuricemia. Data suggest that the overall disease burden of gout remains substantial and may be increasing. Identifying and characterizing modifiable risk factors for gout is a major step in preventing and managing this painful condition. As more scientific data on the risk factors and comorbidities of gout become available, their integration into gout prevention and care strategies may become essential. This article reviews the relevant epidemiologic data, with a focus on recent progress and data on other crystal arthropathies.

Gout in solid organ transplantation: a challenging clinical problem

Hyperuricaemia occurs in 5-84% and gout in 1.7-28% of recipients of solid organ transplants. Gout may be severe and crippling, and may hinder the improved quality of life gained through organ transplantation. Risk factors for gout in the general population include hyperuricaemia, obesity, weight gain, hypertension and diuretic use. In transplant recipients, therapy with ciclosporin (cyclosporin) is an additional risk factor. Hyperuricaemia is recognised as an independent risk factor for cardiovascular disease; however, whether anti-hyperuricaemic therapy reduces cardiovascular events remains to be determined. Dietary advice is important in the management of gout and patients should be educated to partake in a low-calorie diet with moderate carbohydrate restriction and increased proportional intake of protein and unsaturated fat. While gout is curable, its pharmacological management in transplant recipients is complicated by the risk of adverse effects and potentially severe interactions between immunosuppressive and hypouricaemic drugs. NSAIDs, colchicine and corticosteroids may be used to treat acute gouty attacks. NSAIDs have effects on renal haemodynamics, and must be used with caution and with close monitoring of renal function. Colchicine myotoxicty is of particular concern in transplant recipients with renal impairment or when used in combination with ciclosporin. Long-term urate-lowering therapy is required to promote dissolution of uric acid crystals, thereby preventing recurrent attacks of gout. Allopurinol should be used with caution because of its interaction with azathioprine, which results in bone marrow suppression. Substitution of mycophenylate mofetil for azathioprine avoids this interaction. Uricosuric agents, such as probenecid, are ineffective in patients with renal impairment. The exception is benzbromarone, which is effective in those with a creatinine clearance >25 mL/min. Benzbromarone is indicated in allopurinol-intolerant patients with renal failure, solid organ transplant or tophaceous/polyarticular gout. Monitoring for hepatotoxicty is essential for patients taking benzbromarone. Physicians should carefully consider therapeutic options for the management of hypertension and hyperlipidaemia, which are common in transplant recipients. While loop and thiazide diuretics increase serum urate, amlodipine and losartan have the same antihypertensive effect with the additional benefit of lowering serum urate. Atorvastatin, but not simvastatin, may lower uric acid, and while fenofibrate may reduce serum urate it has been associated with a decline in renal function. Gout in solid organ transplantation is an increasing and challenging clinical problem; it impacts adversely on patients' quality of life. Recognition and, if possible, alleviation of risk factors, prompt treatment of acute attacks and early introduction of hypouricaemic therapy with careful monitoring are the keys to successful management.

Pathophysiology, Clinical Presentation and Treatment of Gout

Gout is a common form of inflammatory arthritis that has been managed primarily in general medical practices for centuries. It appears that there has been an increasing prevalence of gout over the past decades, implying a growing public health burden. Accurate diagnosis and recognition of the various stages and manifestations of gout enable realistic goal setting for management. Recent evidence suggests new risk factors and potentially refutes others. Management of gout requires characterising and modifying risk factors and associated disorders, and commonly initiating drug therapy. Pharmacotherapy of gout includes the management of acute flares with anti-inflammatory agents such as NSAIDs and glucocorticoids and long-term treatment with urate-lowering drugs. Although pharmacotherapy is generally safe and effective, there are caveats and limitations to all gout therapies. Patient non-adherence and errors with the use of drugs for gout treatment are important factors leading to medical failures. With early intervention, careful monitoring and patient education, gout is a condition that can be managed very effectively. The advent of new drugs (such as febuxostat and urate oxidase [uricase]) and enhanced understanding of the pathogenesis of gout continue to improve our therapeutic options, particularly in a subset of patients with refractory disease and those who are intolerant to currently available medications.

Physiologic Impact of Low-Dose Dopamine on Renal Function in the Early Post Renal Transplant Period

BACKGROUND

Low-dose dopamine (LDD) (< or =5.0 microg/kg/min) is often used in the early postrenal transplant period for its perceived improvements in renal function parameters. However, there is little published evidence to support its use. The aim of this study was to evaluate the effects of LDD on the physiologic parameters of the transplanted kidney.

METHODS

With local ethics approval, 20 consecutive adult patients (age range, 27-74 years), who underwent cadaveric renal transplantation with cyclosporine immunosuppression, were randomized into two study groups, each with 10 patients. The study period was over 9 hrs on the first postoperative day. This 9-hr block was divided into three 3-hr periods. Patient group 1 received a dopamine infusion over the second 3-hr period only, and patient group 2 received a dopamine infusion over both the first and third 3-hr periods. During these periods, urine flow rate (UFR), effective renal plasma flow (ERPF), creatinine clearance (CC), and total urinary sodium excretion rate (tUNa) were measured.

RESULTS

In both groups, there were significant (P<0.05, Wilcoxon rank sum test) increases in ERPF, UFR, CC, and tUNa during LDD infusion periods compared with periods of no LDD infusion. No changes in heart rate or mean arterial blood pressure were seen with LDD administration.

CONCLUSIONS

LDD significantly increases ERPF, UFR, CC, and tUNa in the transplanted allograft kidney treated with cyclosporine immunosuppression in the early posttransplant period.

Uric acid and transplantation

Hyperuricemia is a common complication in organ transplant recipients, and frequently is associated with chronic cyclosporine immunosuppressive therapy. Kidney and heart transplant recipients are prone to develop posttransplant hyperuricemia. Risk factors for hyperuricemia include decreased glomerular filtration rate (GFR), diuretic use, and preexistent history of hyperuricemia. The influence of hyperuricemia in patient and graft survival is unclear because uric acid is not usually considered a common risk factor for cardiovascular disease that affects graft and patient survival. However, there have been small studies that have suggested that control of uric acid levels contributes to recovery of renal function (in heart and liver transplant recipients) and in an improvement in GFR in renal transplant recipients. Despite controversies in the need for hyperuricemia treatment in transplant patients, strategies to decrease uric acid levels includes a decrease or avoidance of cyclosporine treatment, adequacy of antihypertension treatment, avoidance of diuretics, nutritional management, and use of uric acid-decreasing agents. In this article we review the incidence and risk factors for the development of posttransplant hyperuricemia, discuss the influence of different immunosuppressive agents on uric acid metabolism, and suggest some alternative treatments for posttransplant hyperuricemia. We also consider that uric acid should be considered as a potential risk factor for renal allograft nephropathy or for renal dysfunction in nonrenal transplant recipients, as well as a comorbid factor for a decrease in patient and graft survival.

Hyperuricemia and gout in renal transplant recipients

Hyperuricemia, unlike clinical gout, is extremely common in renal transplant patients. The high prevalence of hyperuricemia is related to prolonged exposure to cyclosporine rather than to its dose or serum concentration. Serum creatinine levels do not show significant correlation with hyperuricemia, behaving more like a surrogate marker for cyclosporine dose and trough level. The low incidence of gout in renal transplant patients, despite the hyperuricemia, may be related to the prolonged immunosuppression effect.

Recommendations for the outpatient surveillance of renal transplant recipients. American Society of Transplantation

Many complications after renal transplantation can be prevented if they are detected early. Guidelines have been developed for the prevention of diseases in the general population, but there are no comprehensive guidelines for the prevention of diseases and complications after renal transplantation. Therefore, the Clinical Practice Guidelines Committee of the American Society of Transplantation developed these guidelines to help physicians and other health care workers provide optimal care for renal transplant recipients. The guidelines are also intended to indirectly help patients receive the access to care that they need to ensure long-term allograft survival, by attempting to systematically define what that care encompasses. The guidelines are applicable to all adult and pediatric renal transplant recipients, and they cover the outpatient screening for and prevention of diseases and complications that commonly occur after renal transplantation. They do not cover the diagnosis and treatment of diseases and complications after they become manifest, and they do not cover the pretransplant evaluation of renal transplant candidates. The guidelines are comprehensive, but they do not pretend to cover every aspect of care. As much as possible, the guidelines are evidence-based, and each recommendation has been given a subjective grade to indicate the strength of evidence that supports the recommendation. It is hoped that these guidelines will provide a framework for additional discussion and research that will improve the care of renal transplant recipients.

Sulfinpyrazone reduces cyclosporine levels: a new drug interaction in heart transplant recipients

BACKGROUND

Management of cyclosporine (CsA)-associated hyperuricemia in heart transplantation (HT) is difficult. Because of the myelotoxicity of combined allopurinol and azathioprine, we tested sulfinpyrazone.

METHODS

We studied 120 HT recipients (109 men; mean age at HT, 52+/-10 years). All had received allopurinol for at least 6 months, which was stopped for 1 month before initiation of sulfinpyrazone. Mean follow-up from HT to onset of sulfinpyrazone (200 mg/day) was 59+/-41 months. We stopped the drug after 6+/-2 months. We compared CsA level and daily dose, serum creatinine, blood urea, and uric acid at onset and before interruption of sulfinpyrazone and, as control, in the last 6 months of allopurinol.

RESULTS

Mean uricemia decreased with allopurinol (0.58+/-0.12 vs. 0.41+/-0.07 mmol/liter, p = 0.0001) as well as with sulfinpyrazone (0.51+/-0.13 vs. 0.40+/-0.12 mmol/liter, p = 0.0001). Mean creatinine increased (171+/-42 and 164+/-35 micromol/liter, p = 0.01) with allopurinol, whereas it tended to decrease with sulfinpyrazone (160+/-35 and 154+/-48 micromol/liter, p = NS). Mean urea did not change with allopurinol (14+/-5 vs. 15+/-7 mmol/liter, p = NS), but fell with sulfinpyrazone (14.01+/-5 vs. 12.60 +/-5 mmol/liter, p = 0.0004). Mean CsA levels were constant with allopurinol (193+/-73 vs. 188+/-65 ng/ml, p = NS), although CsA dose was slightly reduced (2.7+/-0.8 vs. 2.6+/-0.8 mg/kg/day, p = 0.007). Conversely, CsA levels dropped with sulfinpyrazone (183+/-89 vs. 121 +/-63 ng/ml, p = 0.0001) despite an increase in CsA daily dose (2.6 +/-0.9 vs. 2.8+/-0.9 mg/kg/day, p = 0.0001). Two subjects were treated for acute rejection. We observed no other side effects. In HT recipients sulfinpyrazone, as an alternative to allopurinol, is effective in achieving metabolic control of hyperuricemia. However, this drug reduced CsA levels, thus the risk of rejection is present.