Urinary retinol binding protein predicts renal outcome in systemic immunoglobulin light-chain (AL) amyloidosis.

Renal risk stratification in systemic immunoglobulin light-chain (AL) amyloidosis is according to estimated glomerular filtration rate (eGFR) and urinary protein creatinine ratio (uPCR), the latter attributed to glomerular dysfunction, with proximal tubular dysfunction (PTD) little studied. Urinary retinol binding protein 4 (uRBP), a low molecular weight tubular protein and highly sensitive marker of PTD, was prospectively measured in 285 newly diagnosed, untreated patients with systemic AL amyloidosis between August 2017 to August 2018. At diagnosis, the uRBP/creatinine ratio (uRBPCR) correlated with serum creatinine (r = 0·618, P < 0·0001), uPCR (r = 0·422, P < 0·0001) as well as both fractional excretion of phosphate and urate (r = 0·563, P < 0·0001). Log uRBPCR at diagnosis was a strong independent predictor of end-stage renal disease {hazard ratio [HR] 2·65, [95% confidence interval (CI) 1·06-6·64]; P = 0·038}, particularly in patients with an eGFR >30 ml/min/1.73 m2 [HR 4·11, (95% CI 1·45-11·65); P = 0·008] and those who failed to achieve a deep haematological response to chemotherapy within 3 months of diagnosis [HR 6·72, (95% CI 1·83-24·74); P = 0·004], and also predicted renal progression [HR 1·91, (95% CI 1·18-3·07); P = 0·008]. Elevated uRBPCR indicates PTD and predicts renal outcomes independently of eGFR, uPCR and clonal response in systemic AL amyloidosis. The role of uRBPCR as a novel prognostic biomarker merits further study, particularly in monoclonal gammopathies of renal significance.

Cardiorenal AL amyloidosis: risk stratification and outcomes based upon cardiac and renal biomarkers.

Systemic AL amyloidosis is a cause of type 5 cardiorenal syndrome. Response to treatment is currently reported according to organ-specific amyloidosis consensus criteria (ACC), which are not validated in cardiorenal AL amyloidosis. Of 1000 patients prospectively enrolled into the UK ALchemy study, 318 (32%) had combined cardiac and renal amyloidotic organ dysfunction at diagnosis, among whom 199 (63%) died; median survival by Kaplan-Meier analysis was 18·5 months. Fifty (16%) patients required renal replacement therapy (RRT). At diagnosis, independent predictors of death and dialysis were N-terminal pro-B-type natriuretic peptide (NT-proBNP) >8500 ng/l (hazard ratio [HR] 3·30, P < 0·001; HR 3·00, P < 0·001), and estimated glomerular filtration rate (eGFR) < 30 ml/min/1·73 m2 (HR 1·89, P = 0·011; HR 6·37, P < 0·001). At 6 months, an increase in NT-proBNP of >30% and a reduction in eGFR of ≥25% were independent predictors of death (HR 2·17, P = 0·009) and dialysis (HR 3·07, P = 0·002), respectively. At 12 months, an increase in NT-proBNP >30% was highly predictive of death (HR 3·67, P < 0·001) and dialysis (HR 2·85, P = 0·010), whereas ACC renal response was predictive of neither. Cardiorenal AL amyloidosis is associated with high early mortality. Outcomes are dictated by NT-proBNP and eGFR at diagnosis rather than proteinuria, and thereafter predominantly by changes in NT-proBNP concentration.

Prolonged renal survival in light chain amyloidosis: speed and magnitude of light chain reduction is the crucial factor.

Renal involvement causing progressive chronic kidney disease (CKD) is present in 70% of patients with systemic Ig light-chain (AL) amyloidosis at diagnosis. Chemotherapy that substantially suppresses free light chain production is associated with improved patient survival, but its benefit in delaying the onset of renal replacement therapy among patients who present with established advanced CKD has not been studied. To evaluate this, we studied 1000 patients enrolled in the prospective UK AL amyloidosis chemotherapy study (ALchemy). Of these, 84 patients had advanced amyloid-related CKD defined by an estimated glomerular filtration rate (eGFR) under 20 ml/min/1.73 m2. We determined outcomes among these 84 patients, who had a median eGFR of 10 ml/min/1.73 m2, in relation to response to chemotherapy evaluated at three, six, and 12 months from baseline. Patients who achieved suppression of 90% or more in their amyloidogenic free light chain (dFLC) within three months of baseline had significantly better overall survival, prolonged time to dialysis, and prolonged time to the composite endpoint of 'death or dialysis' compared to those who achieved lesser degrees of clonal response at the same time point. Even when this target of greater than 90% dFLC response was achieved but was delayed beyond 3 months, it was associated with worse outcomes. Cox regression analyses confirmed that a 90% or better dFLC response within 3 months was the only significant independent predictor of all three of these outcome measures. Thus, renal survival among patients with systemic immunologic light chain amyloidosis who present with advanced CKD is strongly dependent upon the magnitude and speed with which the underlying hematologic disorder is suppressed by chemotherapy.

Increased fracture risk in plasma cell dyscrasias is associated with poorer overall survival.

Pathological fractures are a common complication of plasma cell dyscrasias (PCD) and are associated with significant morbidity. Routine use of bisphosphonates over the past decade has aimed to reduce the risk of fractures in patients with multiple myeloma, but despite this, fractures continue to represent a significant burden of disease. In this study we report the fracture rate of hospital in-patients with PCD in England. Data from the national registry Hospital Episode Statistics between 2001 and 2015 were used to determine fracture rate and its effect on overall survival. Fracture rates were 17·8 times higher than the general population in the first year after admission with PCD, and remained elevated for up to 10 years after first admission. The increased fracture risk preceded the first admission with PCD and, conversely, the incidence of PCD increased after admission with one or more fractures. Overall survival is improving with PCD, however poorer survival is found in patients with a preceding fracture (Hazard ratio 1·20). Despite widespread bisphosphonate use, fractures remain common in PCD, and are associated with poorer outcomes.

Multiple myeloma can be accurately diagnosed in acute kidney injury patients using a rapid serum free light chain test.

BACKGROUND: Acute kidney injury (AKI) is common in patients with multiple myeloma (MM). Whether serum free light chain (sFLC) measurements can distinguish between myeloma and other causes of AKI requires confirmation to guide early treatment. A rapid and portable sFLC test (Seralite®) is newly available and could reduce delays in obtaining sFLC results and accelerate diagnosis in patients with unexplained AKI. This study evaluated the accuracy of Seralite® to identify MM as the cause of AKI. METHOD: sFLCs were retrospectively analysed in patients with AKI stage 3 as per KDIGO criteria (i.e. serum creatinine ≥354 µmol/L or those on dialysis treatment) (n = 99); 45/99 patients had a confirmed MM diagnosis. RESULTS: The Seralite® κ:λ FLC ratio accurately diagnosed all MM patients in the presence of AKI: a range of 0.14-2.02 returned 100% sensitivity and specificity for identifying all non-myeloma related AKI patients. The sFLC difference (dFLC) also demonstrated high sensitivity (91%) and specificity (100%): an optimal cut-off of 399 mg/L distinguished between myeloma and non-myeloma AKI patients. We propose a pathway of patient screening and stratification in unexplained AKI for use of Seralite® in clinical practice, with a κ:λ ratio range of 0.14-2.02 and dFLC 400 mg/L as decision points. CONCLUSIONS: Seralite® accurately differentiates between AKI due to MM and AKI due to other causes in patients considered at risk of myeloma. This rapid test can sensitively screen for MM in patients with AKI and help inform early treatment intervention.

Cyclophosphamide, bortezomib, and dexamethasone therapy in AL amyloidosis is associated with high clonal response rates and prolonged progression-free survival.

Bortezomib has shown great promise in the treatment of amyloid light-chain (AL) amyloidosis. We present our experience of 43 patients with AL amyloidosis who received cyclophosphamide, bortezomib, and dexamethasone (CVD) upfront or at relapse. Of these, 74% had cardiac involvement and 46% were Mayo Cardiac Stage III. The overall hematologic response rate was 81.4%, including complete response (CR) in 41.9% and very good partial response with >90% decrease in difference between involved/uninvolved light chain (VGPR-dFLC) in 51.4%. Patients treated upfront had higher rates of CR (65.0%) and VGPR-dFLC (66.7%). The estimated 2-year progression-free survival was 66.5% for patients treated upfront and 41.4% for relapsed patients. Those attaining a CR or VGPR-dFLC had a significantly better progression-free survival (P=.002 and P=.026, respectively). The estimated 2-year overall survival was 97.7% (94.4% in Mayo Stage III patients). CVD is a highly effective regimen producing durable responses in AL amyloidosis; the deep clonal responses may overcome poor prognosis in advanced-stage disease.

Systemic amyloidosis in England: an epidemiological study.

Epidemiological studies of systemic amyloidosis are scarce and the burden of disease in England has not previously been estimated. In 1999, the National Health Service commissioned the National Amyloidosis Centre (NAC) to provide a national clinical service for all patients with amyloidosis. Data for all individuals referred to the NAC is held on a comprehensive central database, and these were compared with English death certificate data for amyloidosis from 2000 to 2008, obtained from the Office of National Statistics. Amyloidosis was stated on death certificates of 2543 individuals, representing 0·58/1000 recorded deaths. During the same period, 1143 amyloidosis patients followed at the NAC died, 903 (79%) of whom had amyloidosis recorded on their death certificates. The estimated minimum incidence of systemic amyloidosis in the English population in 2008, based on new referrals to the NAC, was 0·4/100 000 population. The incidence peaked at age 60-79 years. Systemic AL amyloidosis was the most common type with an estimated minimum incidence of 0·3/100 000 population. Although there are various limitations to this study, the available data suggest the incidence of systemic amyloidosis in England exceeds 0·8/100 000 of the population.

A prospective study of nutritional status in immunoglobulin light chain amyloidosis.

Weight loss is common in systemic immunoglobulin light chain amyloidosis but there are limited data on the impact of nutritional status on outcome. Using the Patient-Generated Subjective Global Assessment (PG-SGA) score, we prospectively examined nutritional status in 110 consecutive newly-diagnosed, treatment-naïve patients with immunoglobulin light chain amyloidosis attending the UK National Amyloidosis Centre. At study entry, 72 of 110 (66%) patients had a PG-SGA score of 4 or over, indicating malnutrition requiring specialist nutritional intervention. Number of amyloidotic organs, elevated alkaline phosphatase, presence of autonomic neuropathy and advanced Mayo disease stage were independently associated with poor nutritional status (P<0.05). Quality of life was substantially poorer among those with higher PG-SGA scores (P<0.001). Furthermore, PG-SGA score was a powerful independent predictor of patient survival (P=0.02). Malnutrition is prevalent and is associated with poor quality of life and reduced survival among patients with systemic immunoglobulin light chain amyloidosis. The PG-SGA score would be an appropriate tool to evaluate whether nutritional intervention could improve patient outcomes.

Inflammatory bowel disease and systemic AA amyloidosis.

BACKGROUND: Systemic AA amyloidosis is a recognised complication of inflammatory bowel disease. AA amyloidosis is a potential cause of end-stage renal failure and mortality but little is known of the natural history of this condition in inflammatory bowel disease. METHODS: We evaluated the clinical phenotype, disease progression and outcome amongst 26 patients with inflammatory bowel disease and AA amyloidosis followed prospectively at a single center between 1989 and 2010. RESULTS: Twenty-two patients had Crohn's disease and four had ulcerative colitis. Fistulae and abscesses occurred in ten cases, all of whom had Crohn's disease. Amyloidotic proteinuric renal dysfunction occurred in all of the cases. It resolved in five patients with well-controlled inflammation, but was progressive in all of the other patients. Fifteen patients reached end-stage renal disease after a median time of 6.3 years from development of renal dysfunction (by Kaplan-Meier estimate), six of whom subsequently proceeded to renal transplantation. There were five functioning grafts at census 0.8, 3.2, 4.2, 20.1 and 24.6 years after transplantation. One graft failed 14.5 years after renal transplantation because of amyloid recurrence in a patient with sustained chronic inflammatory activity. CONCLUSIONS: AA amyloidosis remains a serious complication of both Crohn's disease and ulcerative colitis, and is characterized by proteinuric renal dysfunction that may resolve following suppression of inflammatory activity. Patient and graft survival are excellent in patients who undergo renal transplantation.

Systemic AA amyloidosis.

Systemic AA amyloidosis is a rare complication of chronic inflammatory disorders. The amyloid fibrils are derived from serum amyloid A protein, an acute phase protein synthesized in the liver. Clinical presentation is most commonly due to the consequences of renal involvement, with proteinuria and progressive renal decline. Progression to end stage renal failure is common. Management is currently centred on reducing the supply of the precursor protein by treating the underlying inflammatory condition, whilst supporting the affected organs. Monitoring of the serum amyloid A protein is vital to assess whether there is adequate suppression of the underlying disease. The level of serum amyloid A protein is a powerful predictor of both patient survival and renal outcome. In patients with adequate suppression of the serum amyloid A protein amyloid deposits can be seen to regress and renal function can be stabilised and even improve.

Cardiac phenotype and clinical outcome of familial amyloid polyneuropathy associated with transthyretin alanine 60 variant.

AIMS: Familial amyloid polyneuropathy (FAP) is a dominantly inherited multi-system disease associated with transthyretin (TTR) mutations. Previous series have predominantly described patients with the TTR variant Val30Met (V30M), which is the most prevalent cause of FAP worldwide. Here, we report the dominant cardiac phenotype and outcome of FAP associated with TTR Thr60Ala (T60A), the most common UK variant. METHODS AND RESULTS: Sixty consecutive patients with FAP associated with TTR T60A (FAP T60A) were prospectively evaluated in two centres between 1992 and 2009. Median (range) age of symptom development was 63 (45-78) years. A family history of amyloidosis was present in only 37%. Autonomic and peripheral neuropathy were present in 44 and 32 patients, respectively, at diagnosis. Cardiac involvement was evident on echocardiography at diagnosis in 56 patients, but was associated with reduced QRS voltages on electrocardiography in only 16% evaluable cases. Seventeen patients received implantable anti-arrhythmic devices. Median survival was 6.6 years following onset of symptoms and 3.4 years from diagnosis, and correlated with serum N-terminal prohormone brain natriuretic peptide (NT-proBNP) concentration and certain echocardiographic parameters at the latter. Orthotopic liver transplantation (OLT), performed to eliminate the predominant hepatic source of variant TTR T60A protein, was performed in eight patients including one who received a concomitant cardiac transplant. Cardiac amyloidosis progressed in all lone OLT recipients, of whom four died within 5 years. CONCLUSION: Cardiac amyloidosis is almost always present at diagnosis in FAP T60A, and is a major determinant of its poor prognosis. Outcome of liver transplantation in FAP T60A has been discouraging.

The electrocardiographic features associated with cardiac amyloidosis of variant transthyretin isoleucine 122 type in Afro-Caribbean patients.

BACKGROUND: About 4% of African Americans possess the isoleucine 122 (V122I) variant of transthyretin, associated with cardiac amyloidosis beyond ages of 55 to 60 years. Transthyretin amyloidosis associated with variant V122I (ATTR V122I) is likely to be an important cause of heart failure in Afro-Caribbean populations, but the high prevalence of left ventricular hypertrophy (LVH) and lack of awareness of this genetic disorder pose diagnostic hurdles. We report the electrocardiographic (ECG) features of ATTR V122I in the largest clinical series to date. METHODS: Patients with ATTR V122I were identified in collaboration with the UK National Amyloidosis Centre. The ECG at presentation was assessed for cardiac rhythm, axis, and voltage complex size. RESULTS: We include 64 patients with ATTR V122I, with a median age of 74 years (range, 57-88 years). Normal or increased ECG voltage was present in 44.3% of patients, and overall 25% met the criteria for LVH. A significant negative correlation between voltage complex size and duration of illness was seen (P < .05). First-degree heart block was evident in 56% of patients in sinus rhythm. During follow-up (n = 17; median, 28 months), 50% of patients with initial first-degree heart block required pacing. CONCLUSION: Electrocardiographic voltages meet the criteria for LVH in one quarter of patients with ATTR V122I cardiac amyloidosis. The widely held belief that cardiac amyloidosis is associated with low-voltage complexes is likely to contribute to underdiagnosis of ATTR V122I. First-degree heart block is common at diagnosis and identifies patients at high risk for subsequent pacing requirement.

Haemodiafiltration versus high-flux haemodialysis: Effects on phosphate control and erythropoietin response.

INTRODUCTION: Haemodiafiltration (HDF) has been reported to improve erythropoietin (EPO) responsiveness and phosphate clearance. We prospectively audited the effect of HDF on EPO dosages, weight and serum phosphate. METHODS: 34 patients dialyzing on Tu/Th/Sa switched to HDF, and 44 dialyzing on M/W/F remained on high-flux haemodialysis (HD) and were followed for 12 months. RESULTS: Dialysis adequacy (Kt/V start HDF 1.56 ± 0.03 vs. HD 1.58 ± 0.04 and 12 months 1.55 ± 0.03 vs. 1.59 ± 0.03), haemoglobin (start 11.7 ± 0.3 vs. 11,8 ± 0.2 g/dl and end 11.5 ± 0.1 vs. 11.3 ± 0.3 g/dl), weight (start 69.8 ± 2.4 vs. 67.8 ± 2.5 kg and end 67.4 ± 2.5 vs. 66.1 ± 2.3 kg), or EPO prescription (start 83 (61-186) vs. 123 (71-225) IU/kg/weeks and 12 months 142 (48-188) vs. 124 (59-223) IU/kg/weeks) did not differ. There were no differences in serum albumin, CRP, calcium and parathyroid hormone. Serum beta-2-microglobulin (B2M) decreased with HDF (32.7 ± 1.9 vs. 28.1 ± 1.1 mg/l, p < 0.01), but not with HD (31.6 ± 1.4 vs. 31.5 ± 1.1 mg/l). Serum phosphate fell with HDF (start 1.48 ± 0.08 vs. 1.57 ± 0.07 mmol/l (p = NS); 3 months 1.35 ± 0.07 vs. 1.61 ± 0.08; 6 months 1.34 ± 0.06 vs. 1.57 ± 0.06, and 12 months 1.36 ± 0.07 vs. 1.67 ± 0.07, all p < 0.05). CONCLUSION: HDF did not lead to weight gain or improved EPO responsiveness in this prospective observational study. However, predialysis serum phosphate and B2M fell with HDF.

Haemodiafiltration does not reduce the frequency of intradialytic hypotensive episodes when compared to cooled high-flux haemodialysis.

INTRODUCTION: Intradialytic hypotension remains the commonest complication of outpatient haemodialysis (HD) treatments. On-line haemodiafiltration (HDF) has been reported to reduce the frequency of intradialytic hypotension. We introduced on-line HDF into our satellite dialysis program, and prospectively audited the effect of HDF on cardiovascular stability. METHODS: 34 patients' dialysis schedules (Tuesday/Thursday/Saturday) were converted to online post-dilutional HDF, and 44 patients' dialysis schedules (Monday/Wednesday/Friday) remained on high-flux HD. Blood pressure and intra-treatment complications were monitored prospectively for 12 months. RESULTS: There was no significant change in pre-treatment mean arterial blood pressure in the HDF group during the 12 months of the study (pre-treatment 113.7 ± 0.7 mm Hg vs. 109.3 ± 2.8 after 12 months), or for the HD cohort (113.9 ± 2.7 vs. 117.9 ± 2.6). However, the frequency of intradialytic hypotensive episodes was greater for the HDF cohort: 25.9 versus 16.5% in the HD cohort, p = 0.0116. During HDF, on average >16 litres of substitution fluid was used and the median temperature was 36°C (35°C-36°C), higher than the dialysate in the HD cohort which was 35°C (35°C-36°C), p < 0.05. CONCLUSION: In this study, HDF did not improve blood pressure control or reduce the frequency of intradialytic hypotensive episodes compared to high-flux HD using cooled dialysate.

Post-transplant Monoclonal Gammopathy of Renal Significance: A Case Series.

Monoclonal gammopathy of renal significance (MGRS) is a new concept with evolving evidence for treatment. MGRS in the transplant kidney is a rare cause of renal transplant dysfunction that can lead to graft loss. Most cases of post-transplant MGRS are due to recurrent disease. Clone-specific chemotherapy is required to target the underlying clone, and this may improve graft survival; however, this can be challenging, as most patients are elderly with age-related comorbidities and may have complications associated with increasing immunosuppression. Here, we report 3 cases of renal allograft MGRS, and each case highlights different challenges in the diagnosis and management of this condition.

Changing epidemiology of AA amyloidosis: clinical observations over 25 years at a single national referral centre.

OBJECTIVE: Systemic AA amyloidosis is a serious complication of chronic inflammation; however, there are relatively few published data on its incidence. We investigated the changing epidemiology of AA amyloidosis over a 25-year period at a single national referral centre. METHODS: We conducted a retrospective study of all patients diagnosed with AA amyloidosis who had attended the centre between 1990 and 2014 inclusive. Six hundred and twenty-five patients were studied in three cohorts: C1: 1990-1997; C2: 1998-2006; C3: 2007-2014. RESULTS: Mean age at presentation increased from 46 in C1 to 56 in C3 (p < .0001). The proportion of South Asian patients increased from 4% in C1 to 17% in C3 (p = .0006). Comparison of underlying diseases between C1 and C3 revealed a reduction in patients with juvenile idiopathic arthritis from 25% to 2% (p < .0001), but an increase in patients with chronic infection due to intravenous recreational drug use from 1% to 13% (p < .0001), and uncharacterized inflammatory disorders from 10% to 27% (p <.0001). More patients were in end-stage renal failure at presentation in C3 (29%) than C1 (15%) (p = .0028). Median age at death was later in C3 (62 years) than C1 (54 years) (p = .0012). CONCLUSION: These data suggest both falling incidence and better outcome in AA amyloidosis over a quarter of a century, reflecting advances in therapeutics and overall management of complex chronic disease in an ageing population. AA amyloidosis of uncertain aetiology presents an emerging major problem. Newer techniques such as next-generation sequencing may aid diagnosis and effective treatment, thereby improving overall survival.

CMR-based differentiation of AL and ATTR cardiac amyloidosis.

OBJECTIVES: This study was devised to describe the different cardiac magnetic resonance (CMR) appearances in light chain amyloid (AL) and transthyretin-related amyloidosis (ATTR). BACKGROUND: CMR is increasingly used to investigate patients with suspected amyloidosis. Global subendocardial late gadolinium enhancement (LGE) has been reported as typical of AL amyloidosis, whereas different patterns have been noted in ATTR amyloidosis. METHODS: We performed de novo analyses on original DICOM magnetic resonance imaging in 46 patients with cardiac AL amyloidosis and 51 patients with ATTR type who had been referred to a specialist amyloidosis center between 2007 and 2012 after CMR. Histological examination was performed in all cases, with immunohistochemistry, to confirm systemic amyloidosis. RESULTS: Patients' median age was 68 ± 10 years, and 74% were male. Left ventricular mass was markedly increased in ATTR amyloidosis (228 g [202 to 267 g]) compared with AL type (167 g [137 to 191 g]) (p < 0.001). LGE was detected in all but 1 cardiac amyloidosis patient (AL type) and was substantially more extensive in ATTR compared with AL amyloidosis. Ninety percent of ATTR patients demonstrated transmural LGE compared with 37% of AL patients (p < 0.001). Right ventricular LGE was apparent in all ATTR patients but in only 33 AL patients (72%) (p < 0.001). Despite these findings, survival was significantly better in cardiac ATTR amyloidosis compared with AL type. We derived an LGE scoring system (Query Amyloid Late Enhancement) that independently differentiated ATTR from AL amyloidosis and, when incorporated into a logistic regression model with age and wall thickness, detected ATTR type with 87% sensitivity and 96% specificity. CONCLUSIONS: Transmural patterns of LGE distinguished ATTR from AL cardiac amyloidosis with high accuracy in this real-world analysis of CMR. Precise diagnosis of cardiac amyloidosis is crucial given the role of chemotherapy in AL type and with novel therapies for ATTR type currently in development.