Projected Health and Economic Burden of Comorbid Gout and Chronic Kidney Disease in a Virtual US Population: A Microsimulation Study.

INTRODUCTION: Gout, a common comorbidity of chronic kidney disease (CKD), is associated with high morbidity and healthcare utilization. However, a large proportion of gout remains undermanaged or untreated which may lead to worse patient outcomes and greater healthcare costs. This study estimates the present and future health and economic burden of controlled and uncontrolled gout in a virtual United States (US) CKD population. METHODS: A validated microsimulation model was used to project the burden of gout in patients with CKD in the USA through 2035. Databases were utilized to build a virtual CKD population of "individuals" with controlled or uncontrolled gout. Modelling assumptions were made on the basis of the literature, which was sparse in some cases. Health and economic outcomes with the current care (baseline) scenario were evaluated, along with potential benefits of urate-lowering intervention scenarios. RESULTS: The prevalence of comorbid gout and CKD in the USA was projected to increase by 29%, from 7.9 million in 2023 to 9.6 million in 2035 in the baseline scenario. Gout flares, tophi, and comorbidity development were also projected to increase markedly through 2035, with the economic burden of gout in the CKD population subsequently increasing from $38.9 billion in 2023 to $47.3 billion in 2035. An increased use of oral urate-lowering therapies in undermanaged patients, and pegloticase use in patients refractory to oral urate-lowering therapies were also project to result in 744,000 and 353,000 fewer uncontrolled gout cases, respectively, by 2035. Marked reductions in complications and costs ensued. CONCLUSIONS: This study projected a substantial increase in comorbid gout and CKD. However, improved use of urate-lowering interventions could mitigate this growth and reduce the health and economic burdens of gout.

Intensive urate-lowering with pegloticase plus methotrexate co-therapy in uncontrolled gout patients with and without chronic kidney disease: A retrospective case series.

Chronic kidney disease (CKD) and gout commonly co-occur. Pegloticase lowers serum urate (SU) in uncontrolled gout patients but antidrug antibodies limit urate-lowering response and increase infusion reaction (IR) risk. Methotrexate (MTX) co-administration increases pegloticase response rate and mitigates IR risk but CKD limits MTX use. This pooled case series examined pegloticase + MTX co-therapy in uncontrolled gout patients with and without CKD. Cases of pegloticase + MTX co-therapy in existing datasets were retrospectively examined. Baseline eGFR classified patients as CKD (eGFR < 60 mL/min/1.73 m2) or non-CKD (eGFR ≥ 60 mL/min/1.73 m2). Patient characteristics, treatment parameters, laboratory values, urate-lowering response rate (≥12 pegloticase infusions received and SU < 6 mg/dL just before infusion 12), and AEs were examined. Fifteen CKD (eGFR: 43.2 ±â€…11.3 mL/min/1.73 m2; SU: 8.6 ±â€…2.2 mg/dL), 27 non-CKD (eGFR: 82.9 ±â€…19.0 mL/min/1.73 m2; SU: 9.5 ±â€…1.7 mg/dL) patients were included. Comorbidity profiles were similar, but CKD patients were older (72.0 ±â€…9.9 vs 52.3 ±â€…14.3 years) and more often female (33.3% vs 7.4%). Treatment parameters were similar with 4-week MTX Run-in followed by mean of 14.7 ±â€…8.1 [CKD] vs 14.1 ±â€…7.1 [non-CKD] pegloticase infusions. However, CKD patients had lower MTX dose (14.8 ±â€…5.8 vs 19.3 ±â€…4.9 mg/week). Urate-lowering response was similar (92% vs 86%). eGFR increased during treatment in 60% of CKD (+11.5 ±â€…20.9 mL/min/1.73 m2, 87% stable/improved CKD-stage) and 44% of non-CKD (+4.2 ±â€…15.0 mL/min/1.73 m2) patients. AEs were similar (≥1 AE CKD: 53%, non-CKD: 67%; gout flare most-reported). One case each of pancytopenia and IR (mild) occurred in non-CKD patients. These real-world data show similar pegloticase + MTX efficacy in CKD and non-CKD patients. No new safety signals were identified, with most CKD patients showing renal function stability or improvement during therapy.

Comparative Levels of Urinary Biomarkers of Renal Injury and Inflammation Among Patients With Diabetic Nephropathy With or Without Hyperuricemia.

BACKGROUND: The association between hyperuricemia and development of progressive chronic kidney disease has received increasing attention in recent years. Recent preclinical studies have shown that non-crystalline uric acid can induce renal-specific arteriolopathy, leading to renal injury and tubulointerstitial inflammation. METHODS: We conducted a open-label cross-sectional study of 25 patients with chronic kidney disease stage III (estimated glomerular filtration rate [eGFR], 7.0 mg/dL) levels of serum uric acid. To determine the correlation between hyperuricemia on urinary protein levels and renal disease progression, we retrospectively compared urine protein and eGFR data between the 2 groups. RESULTS: Eleven patients with normal uric acid levels and 14 with hyperuricemia were enrolled. Urinary levels of both kidney injury molecule-1 (KIM-1) and monocyte chemoattractant protein-1 (MCP-1) were significantly higher in patients with hyperuricemia. Among the normouricemic White and African American (AA) subgroups, there was no difference in KIM-1 or MCP-1 levels, whereas KIM-1 levels were significantly higher among hyperuricemic AA patients with hyperuricemia. Urinary protein was significantly higher between Whites and AA patients with serum uric acid level >7.0 mg/dL as well as patients with urinary KIM-1 levels >1000 pg/mg Cr. A trend toward a more rapid decline in eGFR was noted among hyperuricemic AAs; however, this trend was not statistically significant. CONCLUSIONS: Patients with type 2 diabetic nephropathy and persistently elevated serum uric acid levels express higher levels of both KIM-1 and MCP-1 reflective of on-going renal injury and inflammation.

Pegloticase efficacy and safety in kidney transplant recipients; results of the phase IV, open-label PROTECT clinical trial.

INTRODUCTION: Kidney transplant (KT) recipients have a high prevalence and severity of gout. Pegloticase (pegylated recombinant uricase) rapidly metabolizes serum uric acid (sUA), and its efficacy is not impacted by kidney function. METHODS: This open-label, Phase 4 trial (PROTECT NCT04087720) examined safety and efficacy of pegloticase in 20 participants with KT > 1 year prior to enrollment and with uncontrolled gout (sUA ≥7 mg/dL, intolerance/inefficacy to urate lowering therapy, and ≥1 of the following: tophi, chronic gouty arthritis, ≥2 flares in past year) and functioning KT (estimated glomerular filtration rate [eGFR] ≥15 mL/min/1.73 m2 ) on stable immunosuppression therapy. RESULTS: The primary endpoint was sUA response during month 6 (sUA < 6 mg/dL for ≥80% of time). The study enrolled 20 participants (mean ± SD); age: 53.9 ± 10.9 years, time since KT: 14.7 ± 6.9 years, sUA: 9.4 ± 1.5 mg/dL, gout duration: 8.4 ± 11.6 years; all on ≥2 stable doses of immunosuppression agents. Pegloticase (8 mg intravenous every 2 weeks) in KT recipients with uncontrolled gout showed a high response rate of 89% (16/18 responders). Two participants discontinued treatment solely due to COVID-19 concerns prior to month 6 were not included in the primary analysis. Pegloticase exposures were higher than those historically observed with pegloticase monotherapy, and no anaphylaxis or infusion reaction events occurred during the study. CONCLUSIONS: This improved response rate to pegloticase in the KT population reflects observations from other trials and reports on immunomodulation with pegloticase. As the KT population has a high prevalence of gout and limitations with oral urate lowering medication options, these findings suggest a potential option for uncontrolled gout therapy in KT participants.

Gout Prevalence, Practice Patterns, and Associations with Outcomes in North American Dialysis Patients.

INTRODUCTION: Gout occurs frequently in patients with kidney disease and can lead to a significant burden on quality of life. Gout prevalence, and its association with outcomes in hemodialysis (HD) and peritoneal dialysis (PD) populations located in North America, is unknown. METHODS: We used data from North America cohorts of 70,297 HD patients (DOPPS, 2012-2020) and 5117 PD patients (PDOPPS, 2014-2020). We used three definitions of gout for this analysis: (1) having an active prescription for colchicine or febuxostat; (2) having an active prescription for colchicine, febuxostat, or allopurinol; or (3) having an active prescription for colchicine, febuxostat, or allopurinol, or prior diagnosis of gout. Propensity score matching was used to compare outcomes among patients with versus without gout. Outcomes included erythropoietin resistance index (ERI=erythropoiesis stimulating agent dose per week/(hemoglobin×weight)), all-cause mortality, hospitalization, and patient-reported outcomes (PROs). RESULTS: The gout prevalence was 13% in HD and 21% in PD; it was highest among incident dialysis patients. Description of previous history of gout was rare, and identification of gout defined by colchicine (2%-3%) or febuxostat (1%) prescription was less frequent than by allopurinol (9%-12%). Both HD and PD patients with gout (versus no gout) were older, were more likely male, had higher body mass index, and had higher prevalence of cardiovascular comorbidities. About half of patients with a gout history were prescribed urate-lowering therapy. After propensity score matching, mean ERI was 3%-6% higher for gout versus non-gout patients while there was minimal evidence of association with clinical outcomes or PROs. CONCLUSION: In a large cohort of PD and HD patients in North America, we found that gout occurs frequently and is likely under-reported. Gout was not associated with adverse clinical or PROs.

DUET: A Phase 2 Study Evaluating the Efficacy and Safety of Sparsentan in Patients with FSGS.

BACKGROUND: We evaluated and compared the effects of sparsentan, a dual endothelin type A (ETA) and angiotensin II type 1 receptor antagonist, with those of the angiotensin II type 1 receptor antagonist irbesartan in patients with primary FSGS. METHODS: In this phase 2, randomized, double-blind, active-control Efficacy and Safety of Sparsentan (RE-021), a Dual Endothelin Receptor and Angiotensin Receptor Blocker, in Patients with Focal Segmental Glomerulosclerosis (FSGS): A Randomized, Double-blind, Active-Control, Dose-Escalation Study (DUET), patients aged 8-75 years with biopsy-proven FSGS, eGFR>30 ml/min per 1.73 m2, and urinary protein-to-creatinine ratio (UP/C) ≥1.0 g/g received sparsentan (200, 400, or 800 mg/d) or irbesartan (300 mg/d) for 8 weeks, followed by open-label sparsentan only. End points at week 8 were reduction from baseline in UP/C (primary) and proportion of patients achieving FSGS partial remission end point (FPRE) (UP/C: ≤1.5 g/g and >40% reduction [secondary]). RESULTS: Of 109 patients randomized, 96 received study drugs and had baseline and week 8 UP/C measurements. Sparsentan-treated patients had greater reductions in UP/C than irbesartan-treated patients did when all doses (45% versus 19%; P=0.006) or the 400 and 800 mg doses (47% versus 19%; P=0.01) were pooled for analysis. The FSGS partial remission end point was achieved in 28% of sparsentan-treated and 9% of irbesartan-treated patients (P=0.04). After 8 weeks of treatment, BP was reduced with sparsentan but not irbesartan, and eGFR was stable with both treatments. Overall, the incidence of adverse events was similar between groups. Hypotension and edema were more common among sparsentan-treated patients but did not result in study withdrawals. CONCLUSIONS: Patients with FSGS achieved significantly greater reductions in proteinuria after 8 weeks of sparsentan versus irbesartan. Sparsentan was safe and well tolerated.

Open-Label, Randomized Study of Transition From Tacrolimus to Sirolimus Immunosuppression in Renal Allograft Recipients.

UNLABELLED: Calcineurin inhibitor-associated nephrotoxicity and other adverse events have prompted efforts to minimize/eliminate calcineurin inhibitor use in kidney transplant recipients. METHODS: This open-label, randomized, multinational study evaluated the effect of planned transition from tacrolimus to sirolimus on kidney function in renal allograft recipients. Patients received tacrolimus-based immunosuppression and then were randomized 3 to 5 months posttransplantation to transition to sirolimus or continue tacrolimus. The primary end point was percentage of patients with 5 mL/min per 1.73 m(2) or greater improvement in estimated glomerular filtration rate from randomization to month 24. RESULTS: The on-therapy population included 195 patients (sirolimus, 86; tacrolimus, 109). No between-group difference was noted in percentage of patients with 5 mL/min per 1.73 m(2) or greater estimated glomerular filtration rate improvement (sirolimus, 34%; tacrolimus, 42%; P = 0.239) at month 24. Sirolimus patients had higher rates of biopsy-confirmed acute rejection (8% vs 2%; P = 0.02), treatment discontinuation attributed to adverse events (21% vs 3%; P < 0.001), and lower rates of squamous cell carcinoma of the skin (0% vs 5%; P = 0.012). CONCLUSIONS: Our findings suggest that renal function improvement at 24 months is similar for patients with early conversion to sirolimus after kidney transplantation versus those remaining on tacrolimus.

Naturally acquired West Nile virus encephalomyelitis in transplant recipients: clinical, laboratory, diagnostic, and neuropathological features.

BACKGROUND: In the 2003 West Nile virus (WNV) epidemic, Colorado reported more WNV cases than any other state, including an unprecedented number in organ transplant recipients. METHODS: Physicians caring for transplant recipients hospitalized with naturally acquired WNV encephalitis provided data to characterize the clinical symptoms, results of diagnostic studies, and outcomes. RESULTS: Eleven transplant recipients were identified (4 kidney, 2 stem cell, 2 liver, 1 lung, and 2 kidney/pancreas). Seven were directly admitted to 1 of the 2 hospitals in the study, and 4 were referred to 1 of these centers from regional hospitals. All but 1 patient had a prodrome typical of WNV encephalitis in nonimmunosuppressed patients. Ten patients developed meningoencephalitis, which in 3 cases was associated with acute flaccid paralysis. One patient developed acute flaccid paralysis without encephalitis. Six patients had significant movement disorders including tremor, myoclonus, or parkinsonism. All patients had cerebrospinal fluid pleocytosis and WNV-specific IgM in the cerebrospinal fluid and/or serum. Cerebrospinal fluid cytologic studies (n = 5) showed atypical lymphocytes, some resembling plasma cells; however, flow cytometry (n = 3) showed that cells were almost exclusively of T-cell (not B-cell or plasma cell) lineage. Magnetic resonance images of the brain were abnormal in 7 of 8 tested patients, and electroencephalograms were abnormal in 7 of 7, with 2 showing periodic lateralized epileptiform discharges. Nine of 11 patients survived infection, but 3 had significant residual deficits. One patient died 17 days after admission, and autopsy findings revealed severe panencephalitic changes with multifocal areas of necrosis in the cerebral deep gray nuclei, brainstem, and spinal cord as well as diffuse macrophage influx in the periventricular white matter. A second patient died of complications of WNV encephalitis 6 months after hospital admission. CONCLUSIONS: Naturally acquired WNV encephalitis in transplant recipients shows diagnostic, clinical, and laboratory features similar to those reported in nonimmunocompromised individuals, but neuroimaging, electroencephalography, and autopsy results verify that these patients develop neurological damage at the severe end of the spectrum.

The impact of costimulatory molecule gene polymorphisms on clinical outcomes in liver transplantation.

CTLA-4 and CD28 deliver opposing signals for T-cell proliferation. We examined single nucleotide polymorphisms (SNPs) CTLA-4 -318C/T and CD28 IVS3 +17T/C for associations with acute rejection in liver transplant recipients. These and two other polymorphisms in CTLA-4 [microsatellite polymorphism +642(AT)n and SNP +49 A/G] were also analyzed for influence on graft survival. Two hundred and eleven liver transplant recipient genotypes were determined by direct sequencing or restriction fragment length polymorphism analysis of PCR-amplified genomic DNA. Mean graft survival for patients with the GG genotype of CTLA-4 +49 A/G was 58.5 +/- 6.0 months compared with 70.3 +/- 4.0 months and 73.8 +/- 2.8 months for the AA and AG genotypes, respectively (p = 0.0055). This is in support of previous studies suggesting decreased CTLA-4 function and increased incidence of autoimmune disease for this genotype. The 92-, 94-, and 100-bp alleles of CTLA-4 +642(AT)n occurred more often in African-American transplant recipients and were associated with decreased graft survival (p = 0.0001 and 0.007, respectively) but the independence of these variables could not be established. No associations with acute rejection or graft survival were found for CTLA-4 -318C/T or CD28 IVS3 +17T/C. The described associations between CTLA-4 gene polymorphisms and transplant outcomes provide the foundation for further investigations leading to genetic risk stratification for transplant recipients.

Genetic variability and transplantation.

PURPOSE OF REVIEW: The purpose of this review is to summarize recent advances within the area of genetic polymorphisms with a specific emphasis on renal transplantation, and to discuss the potential clinical applications. RECENT FINDINGS: Due to recent advances in molecular techniques, there has been an abundance of publications describing genetic variability in molecules relevant to transplant outcome. Many studies are now demonstrating associations between polymorphisms in these candidate genes and outcomes in organ transplantation. SUMMARY: These studies emphasize the potential role of genetic variability in transplantation, and provide the rationale for large prospective studies to clearly define the potential benefits of genotyping in the risk stratification of transplant recipients.

Analysis of gene polymorphisms in the regulatory region of MCP-1, RANTES, and CCR5 in liver transplant recipients.

Chemokines and their receptors play a major role in the inflammatory and immune responses that mediate allograft outcome. The production of some chemokines varies among individuals and these variations may be determined by genetic polymorphisms, most commonly within the regulatory region of the gene. We investigated whether the functional polymorphisms of the chemokines RANTES, MCP-1 and chemokine receptor CCR5 are associated with the incidence of acute rejection and long-term liver graft survival. Two hundred nine liver transplant recipients were genotyped using polymerase chain reaction sequence-specific primers for the following polymorphisms: RANTES-28, MCP-1 -2518, and CCR5-59029. There was no association with any of the three genotypes and the incidence of acute rejection episodes. In addition, no association of RANTES-28, MCP-1 -2518, or CCR5 -59029 variants with long-term liver graft survival was found. In conclusion, variants of RANTES-28, MCP-1 -2518, and CCR5-59029 neither influenced the incidence of acute rejection nor affected long-term allograft survival upon liver transplantation in the context of this analysis.

A Monocyte chemoattractant protein-1 (MCP-1) polymorphism and outcome after renal transplantation.

Among the factors modulating transplant rejection and cardiovascular disease, chemokines and their respective receptors deserve special attention. In this respect, increased expression of MCP-1 and the corresponding receptor CCR2 have been demonstrated in renal transplant rejection and coronary artery disease. The impact of the MCP-1-2518G and CCR2-64I genotypes on renal allograft function was investigated in 232 patients who underwent transplantation over an 11-yr period. Genomic DNA was genotyped using PCR with sequence-specific primers followed by restriction fragment length polymorphism analysis. Eighteen (7.8%) patients were homozygous for the MCP-1-2518G mutation. The G/G allele of MCP-1 -2518 behaved as a determinant for long-term allograft survival and resulted in reduction of the mean graft survival, as compared with the heterozygous (A/G) or wild-type (A/A) allele (67 +/- 14 versus 95 +/- 4 mo; Log rank P = 0.0052). The 64I mutation of CCR2 had no effect on kidney graft failure (93 +/- 6 and 91 +/- 5 mo, respectively; P = 0.81). None of the investigated polymorphisms showed a significant shift in gene frequency in acute rejection and rejection-free groups. In conjunction with these findings, peripheral blood mononuclear cells from kidney transplant recipients carrying the G-allele were characterized by a 2.5-fold higher MCP-1 secretion (P < 0.05). In conclusion, recipients of renal transplants homozygous for the -2518 G mutation of the MCP-1 gene are at risk for premature kidney graft failure. This variant of MCP-1 may be a future predictor for long-term kidney graft failure.