The epidemiology of primary FSGS including cluster analysis over a 20-year period

INTRODUCTION

Focal segmental glomerulosclerosis (FSGS) is one of the leading causes of nephrotic syndrome in adults. This epidemiological study describes a renal centre's 20-year experience of primary FSGS.

METHODS

Patients were identified with a diagnosis of primary FSGS after exclusion of known secondary causes. In this retrospective observational study, data was collected for baseline demographics, immunosuppression and outcomes. A two-step cluster analysis was used to identify natural groupings within the dataset.

RESULTS

The total cohort was made up of 87 patients. Those who received immunosuppression had lower median serum albumin than those who did not- 23g/L vs 40g/L (p<0.001) and higher median urine protein creatinine ratios (uPCR)- 795mg/mmol vs 318mg/mmol (p <0.001). They were more likely to achieve complete remission (62% vs 40%, p=0.041), but relapsed more 48.6% vs 22% (p=0.027). Overall 5 year mortality was 10.3% and 5 year progression to RRT was seen in 17.2%. Complete remission was observed in 49.4%. The 2-step cluster analysis separated the cohort into 3 clusters: cluster 1 (n=26) with 'nephrotic-range proteinuria'; cluster 2 (n=43) with 'non-nephrotic-range proteinuria'; and cluster 3 (n=18) with nephrotic syndrome. Immunosuppression use was comparable in clusters 1 and 3, but lower in cluster 2 (77.8% and 69.2% vs 11.6%, p<0.001). Rates of complete remission were greatest in clusters 1 and 3 vs cluster 2: 57.7% and 66.7% vs 37.2%.

CONCLUSION

People who received immunosuppression had lower serum albumin and achieved remission more frequently, but were also prone to relapse. Our cluster analysis highlighted 3 FSGS phenotypes: a nephrotic cluster that clearly require immunosuppression; a cohort with preserved serum albumin and non-nephrotic range proteinuria who will benefit from supportive care; and lastly a cluster with heavy proteinuria but serum albumin > 30g/L. This group may still have immune mediated disease and thus could potentially benefit from immunosuppression.

TRIAL REGISTRATION

This study protocol was reviewed and approved by the 'Research and Innovation committee of the Northern Care Alliance NHS Group', study approval number (Ref: ID 22HIP54).

Improving outpatient clinic experience: the future of chronic kidney disease care and associated multimorbidity

BACKGROUND

Chronic kidney disease (CKD) is estimated to affect more than 2.5 million adults in England, and this is expected to rise to 4.2 million by 2036 (1). Population-level digital healthcare systems have the potential to enable earlier detection of CKD providing an opportunity to introduce interventions that attenuate progression and reduce the risk of end-stage kidney disease (ESKD) and cardiovascular diseases (CVD). Services that can support patients with CKD, CVD, and diabetes mellitus (DM) have the potential to reduce fragmented clinical care and optimise pharmaceutical management.

METHODS AND RESULTS

The Salford renal service has established an outpatient improvement programme which aims to address these issues via two projects. Firstly, the development of a CKD dashboard that can stratify patients by their kidney failure risk equation (KFRE) risk. High-risk patients would be invited to attend an outpatient clinic if appropriate. Specialist advice and guidance would be offered to primary care providers looking after patients with medium risk. Patients with lower risk would continue with standard care via their primary care provider unless there was another indication for a nephrology referral. The CKD dashboard identified 11546 patients (4.4% of the total adult population in Salford) with T2DM and CKD. The second project is the establishment of the Metabolic CardioRenal (MRC) clinic. It provided care for 209 patients in the first 8 months of its establishment with a total of 450 patient visits. Initial analysis showed clustering of cardiorenal metabolic diseases with 85% having CKD stages 3 and 4 and 73.2% having DM. In addition, patients had a significant burden of CVD with 50.2% having hypertension and 47.8% having heart failure.

CONCLUSION

There is a pressing need to create new outpatient models of care to tackle the rising epidemic of cardio-renal metabolic diseases. This model of service has potential benefits at both organisational and patient levels including improving patient management via risk stratification, increased care capacity and reduction of variation of care. Patients will benefit from earlier intervention, appropriate referral for care, reduction in CKD-related complications, and reduction in hospital visits and cardiovascular events. In addition, this combined digital and patient-facing model of care will allow rapid translation of advances in cardio-renal metabolic diseases into clinical practice.

A low rate of end-stage kidney disease in membranous nephropathy: A single centre study over 2 decades

INTRODUCTION

Membranous nephropathy is the commonest cause of nephrotic syndrome in non-diabetic Caucasian adults over the age of 40 years. Primary membranous nephropathy is limited to the kidneys. Clinical management aims to induce remission, either spontaneously with supportive care, or with immunosuppression. Here, we describe the natural history of this condition in a large tertiary centre in the UK.

METHODS

178 patients with primary membranous nephropathy were identified over 2 decades. We collected data on demographics, baseline laboratory values, treatment received and outcomes including progression to renal replacement therapy and death. Analysis was performed on the whole cohort and specific subgroups. Univariate and multivariate Cox regression was also performed.

RESULTS

Median age was 58.3 years with 63.5% male. Median baseline creatinine was 90μmol/L and urine protein-creatinine ratio 664g/mol. Remission (partial or complete) was achieved in 134 (75.3%), either spontaneous in 60 (33.7%) or after treatment with immunosuppression in 74 (41.6%), and of these 57 (42.5%) relapsed. Progression to renal replacement therapy was seen in 10.1% (much lower than classically reported) with mortality in 29.8%. Amongst the whole cohort, those who went into remission had improved outcomes compared to those who did not go into remission (less progression to renal replacement therapy [4.5% vs 28%] and death [20.1% vs 67%]. Those classified as high-risk (based on parameters including eGFR, proteinuria, serum albumin, PLA2R antibody level, rate of renal function decline) also had worse outcomes than those at low-risk (mortality seen in 52.6% vs 10.8%, p<0.001). The median follow-up period was 59.5 months.

CONCLUSION

We provide a comprehensive epidemiologic analysis of primary membranous nephropathy at a large tertiary UK centre. Only 10.1% progressed to renal replacement therapy. For novelty, the KDIGO risk classification was linked to outcomes, highlighting the utility of this classification system for identifying patients most likely to progress.

Peptide GAM immunoadsorption in anti-PLA2 R positive autoimmune membranous nephropathy. The PRISM trial

Membranous nephropathy associated with anti-PLA₂ R autoantibody is a significant cause of nephrotic syndrome worldwide. Treatment remains empiric with a significant side-effect burden despite an increase in our understanding of the disease. We studied the effect of selectively removing this pathogenic autoantibody using immunoadsorption in adult patients with biopsy proven anti-PLA₂ R membranous nephropathy. This was a multicenter, single-arm prospective clinical trial carried out in the United Kingdom. Twelve patients underwent five consecutive sessions of peptide GAM immunoadsorption with 12 months follow-up. Primary outcome was anti-PLA₂ R titer at week 2. Secondary outcomes were safety and tolerability of therapy, antibody profile, and change in proteinuria, renal excretory function, serum albumin, total immunoglobulin, and quality of life at weeks 12, 24, and 52. Patients were also stratified by the presence or absence of the high-risk allele (heterozygous or homozygous for HLA-DQA1*05). Median pretreatment anti-PLA₂ R was 702.50 U/mL, 1045.00 U/mL at week 2 (P-value .023) and 165.00 U/mL at week 52 (P-value .017). The treatment was well tolerated and safe. Two patients required rescue immunosuppression during the follow-up period. There was a significant improvement in serum albumin with a median at baseline of 20.50 g/L rising to 25.00 g/L at week 52 (P-value <.001). There was no statistical difference over the follow-up period in proteinuria or renal function. Patients in possession of a high-risk allele saw improvement in anti-PLA₂ R titers, possibly representing a cohort more likely to benefit from immunoadsorption. Immunoadsorption therapy is a safe treatment and well-tolerated treatment in anti-PLA₂ R positive autoimmune membranous nephropathy.

Safely reducing haemodialysis frequency during the COVID-19 pandemic

BACKGROUND

Patients undergoing haemodialysis (HD) are at higher risk of developing worse outcomes if they contract COVID-19. In our renal service we reduced HD frequency from thrice to twice-weekly in selected patients with the primary aim of reducing COVID 19 exposure and transmission between HD patients.

METHODS

Dialysis unit nephrologists identified 166 suitable patients (38.4% of our HD population) to temporarily convert to twice-weekly haemodialysis immediately prior to the peak of the COVID-19 pandemic in our area. Changes in pre-dialysis weight, systolic blood pressure (SBP) and biochemistry were recorded weekly throughout the 4-week project. Hyperkalaemic patients (serum potassium > 6.0 mmol/L) were treated with a potassium binder, sodium bicarbonate and received responsive dietary advice.

RESULTS

There were 12 deaths (5 due to COVID-19) in the HD population, 6 of which were in the twice weekly HD group; no deaths were definitively associated with change of dialysis protocol. A further 19 patients were either hospitalised and/or developed COVID-19 and thus transferred back to thrice weekly dialysis as per protocol. 113 (68.1%) were still receiving twice-weekly HD by the end of the 4-week project. Indications for transfer back to thrice weekly were; fluid overload (19), persistent hyperkalaemia (4), patient request (4) and compliance (1). There were statistically significant increases in SBP and pre-dialysis potassium during the project.

CONCLUSIONS

Short term conversion of a large but selected HD population to twice-weekly dialysis sessions was possible and safe. This approach could help mitigate COVID-19 transmission amongst dialysis patients in centres with similar organisational pressures.

Differing commissioning arrangements may contribute to geographic variation in clinical management of digital ulcers in systemic sclerosis

Phosphodiesterase inhibitors (such as sildenafil) and endothelin receptor antagonist, bosentan, are effective for digital ulcer disease in systemic sclerosis (SSc-DU) and are endorsed in international treatment recommendations. Commissioning of high-cost drugs, such as bosentan, however, differs across devolved nations of the UK. We report a multicentre service evaluation project to examine 'real world' management of SSc-DU before and following the 2015 UK Scleroderma Study Group (UKSSG) guidance, across south-west (SW) England and Wales. Results showed that iloprost and sildenafil use for SSc-DU was higher in patients in Wales prior to 2015. Between 2015-2017, sildenafil use for SSc-DU increased in SW England while remaining stable in Wales. Bosentan use for SSc-DU after 2015 in SW England increased, while remaining stable and proportionately lower in Wales. These findings demonstrate that differing commissioning guidance across devolved nations of the UK seems to contribute to geographic variation in patient care.

Association between non-malignant monoclonal gammopathy and adverse outcomes in chronic kidney disease: A cohort study

BACKGROUND

In studies including the general population, the presence of non-malignant monoclonal gammopathy (MG) can be causally associated with kidney damage and shorter survival. We assessed whether the presence of an MG is associated with a higher risk of kidney failure or death in individuals with chronic kidney disease (CKD).

METHODS AND FINDINGS

Data were used from 3 prospective cohorts of individuals with CKD (not on dialysis or with a kidney transplant): (1) Renal Impairment in Secondary Care (RIISC, Queen Elizabeth Hospital and Heartlands Hospital, Birmingham, UK, N = 878), (2) Salford Kidney Study (SKS, Salford Royal Hospital, Salford, UK, N = 861), and (3) Renal Risk in Derby (RRID, Derby, UK, N = 1,739). Participants were excluded if they had multiple myeloma or any other B cell lymphoproliferative disorder with end-organ damage. Median age was 71.0 years, 50.6% were male, median estimated glomerular filtration rate was 42.3 ml/min/1.73 m2, and median urine albumin-to-creatinine ratio was 3.4 mg/mmol. All non-malignant MG was identified in the baseline serum of participants of RIISC. Further, light chain MG (LC-MG) was identified and studied in participants of RIISC, SKS, and RRID. Participants were followed up for kidney failure (defined as the initiation of dialysis or kidney transplantation) and death. Associations with the risk of kidney failure were estimated by competing-risks regression (handling death as a competing risk), and associations with death were estimated by Cox proportional hazards regression. In total, 102 (11.6%) of the 878 RIISC participants had an MG. During a median follow-up time of 74.0 months, there were 327 kidney failure events and 202 deaths. The presence of MG was not associated with risk of kidney failure (univariable subhazard ratio [SHR] 0.97 [95% CI 0.68 to 1.38], P = 0.85; multivariable SHR 1.16 [95% CI 0.80 to 1.69], P = 0.43), and although there was a higher risk of death in univariable analysis (hazard ratio [HR] 2.13 [95% CI 1.49 to 3.02], P < 0.001), this was not significant in multivariable analysis (HR 1.37 [95% CI 0.93 to 2.00], P = 0.11). Fifty-five (1.6%) of the 3,478 participants from all 3 studies had LC-MG. During a median follow-up time of 62.5 months, 564 of the 3,478 participants progressed to kidney failure, and 803 died. LC-MG was not associated with risk of kidney failure (univariable SHR 1.07 [95% CI 0.58 to 1.96], P = 0.82; multivariable SHR 1.42 [95% CI 0.78 to 2.57], P = 0.26). There was a higher risk of death in those with LC-MG in the univariable model (HR 2.51 [95% CI 1.59 to 3.96], P < 0.001), but not in the multivariable model (HR 1.49 [95% CI 0.93 to 2.39], P = 0.10). An important limitation of this work was that only LC-MG, rather than any MG, could be identified in participants from SKS and RRID.

CONCLUSIONS

The prevalence of MG was higher in this CKD cohort than that reported in the general population. However, the presence of an MG was not independently associated with a significantly higher risk of kidney failure or, unlike in the general population, risk of death.

The influence of multiple episodes of acute kidney injury on survival and progression to end stage kidney disease in patients with chronic kidney disease

Background

Acute kidney injury (AKI) and chronic kidney disease (CKD) are common syndromes associated with significant morbidity, mortality and cost. The extent to which repeated AKI episodes may cumulatively affect the rate of progression of all-cause CKD has not previously been investigated. In this study, we explored the hypothesis that repeated episodes of AKI increase the rate of renal functional deterioration loss in patients recruited to a large, all-cause CKD cohort.

Methods

Patients from the Salford Kidney Study (SKS) were considered. Application of KDIGO criteria to all available laboratory measurements of renal function identified episodes of AKI. A competing risks model was specified for four survival events: Stage 1 AKI; stage 2 or 3 AKI; dialysis initiation or transplant before AKI event; death before AKI event. The model was adjusted for patient age, gender, smoking status, alcohol intake, diabetic status, cardiovascular co-morbidities, and primary renal disease. Analyses were performed for patients’ first, second, and third or more AKI episodes.

Results

A total of 48,338 creatinine measurements were available for 2287 patients (median 13 measures per patient [IQR 6–26]). There was a median age of 66.8years, median eGFR of 28.4 and 31.6% had type 1 or 2 diabetes. Six hundred and forty three (28.1%) patients suffered one or more AKI events; 1000 AKI events (58% AKI 1) in total were observed over a median follow-up of 2.6 years [IQR 1.1–3.2]. In patients who suffered an AKI, a second AKI was more likely to be a stage 2 or 3 AKI than stage 1 [HR 2.04, p 0.01]. AKI events were associated with progression to RRT, with multiple episodes of AKI progressively increasing likelihood of progression to RRT [HR 14.4 after 1 episode of AKI, HR 28.4 after 2 episodes of AKI]. However, suffering one or more AKI events was not associated with an increased risk of mortality.

Conclusions

AKI events are associated with more rapid CKD deterioration as hypothesised, and also with a greater severity of subsequent AKI. However, our study did not find an association of AKI with increased mortality risk in this CKD cohort.

Harmonization of Busulfan Plasma Exposure Unit (BPEU): A Community-Initiated Consensus Statement

Busulfan therapeutic drug monitoring (TDM) is often used to achieve target plasma exposures. Variability in busulfan plasma exposure units (BPEU) is a potential source for misinterpretation of publications and protocols and is a barrier to data capture by hematopoietic cell transplantation (HCT) registry databases. We sought to harmonize to a single BPEU for international use. Using Delphi consensus methodology, iterative surveys were sent to an increasing number of relevant clinical stakeholders. In survey 1, 14 stakeholders were asked to identify ideal properties of a BPEU. In survey 2, 52 stakeholders were asked (1) to evaluate BPEU candidates according to ideal BPEU properties established by survey 1 and local position statements for TDM and (2) to identify potential facilitators and barriers to adoption of the harmonized BPEU. The most frequently used BPEU identified, in descending order, were area under the curve (AUC) in μM × min, AUC in mg × h/L, concentration at steady state (Css) in ng/mL, AUC in μM × h, and AUC in μg × h/L. All respondents conceptually agreed on the ideal properties of a BPEU and to adopt a harmonized BPEU. Respondents were equally divided between selecting AUC in μM × min versus mg × h/L for harmonization. AUC in mg × h/L was finally selected as the harmonized BPEU, because it satisfied most of the survey-determined ideal properties for the harmonized BPEU and is read easily understood in the clinical practice environment. Furthermore, 10 major professional societies have endorsed AUC in mg × h/L as the harmonized unit for reporting to HCT registry databases and for use in future protocols and publications.

The importance of acute kidney injury in suspected community acquired infection

Background

Most sepsis and acute kidney injury (AKI) cases are community acquired (CA). The aim of this study was to evaluate the characteristics of suspected community acquired infection (sCA-I) and CA-AKI and their impact upon patient outcomes.

Methods

All adult creatinine blood tests from non-elective, non-dialysis attendances to a single centre over a 29-month period were analysed retrospectively. We defined sCA-I and CA-AKI cases as antibiotic prescription and AKI alert within 48 hours of attendance respectively. Binary logistic regression models were created to determine associations with 30-day mortality, intensive care unit (ICU) admission and length of stay (LOS) dichotomised at median.

Results

Of 61,471 attendances 28.1% and 5.7% suffered sCA-I or CA-AKI in isolation respectively, 3.4% suffered both. sCA-I was present in 58.8% of CA-AKI cases and CA-AKI was present in 11.9% of CA-I cases. The combination of sCA-I and CA-AKI was associated with a higher risk for all outcomes compared to sCA-I or CA-AKI in isolation. The 30-day mortality was 8.1%, 11.8% and 26.2% in patients with sCA-I, CA-AKI and when sCA-I and CA-AKI occurred in combination respectively. The adjusted odds ratios (OR) and 95% confidence intervals (CI) for 30-day mortality, ICU admission and LOS for sCA-I combined with CA-AKI stage 1 were OR 6.09:CI: 5.21–7.12, OR 12.52 CI: 10.54–14.88 and OR 8.97 CI: 7.62–10.56, respectively, and for combined sCA-I and CA-AKI stage 3 were OR 9.23 CI: 6.91–12.33, OR 29.26 CI: 22.46–38.18 and OR 9.48 CI: 6.82–13.18 respectively.

Conclusion

The combination of sCA-I and CA-AKI is associated with worse outcomes.

Association of novel biomarkers with major clinical outcomes in a cohort of patients with atherosclerotic renovascular disease

Introduction

In this study, we investigate whether the addition of biomarkers to a model based on traditional risk factors improves risk prediction and patient selection for revascularization in atherosclerotic renovascular disease.

Methods

Patients in the Salford Renovascular Study who had the following biomarkers analysed on a baseline sample were included in this study: FGF-23, Cystatin C, kidney injury molecule-1, myeloperoxidase, neutrophil gelatinase-associated lipocalin, N-terminal prohormone of brain natriuretic peptide (NT-proBNP), high-sensitivity Troponin T and anti-apolipoprotein A1 IgG. Cox proportional hazards models and net reclassification index were used to study the effects of either individual or a panel of biomarkers on predicting death, end-stage kidney disease and cardiovascular events.

Results

A total of 112 patients were followed up for a median 59.9 months (IQR 33.6–86.9). In total, 75 patients died, 21 reached end-stage kidney disease and 36 suffered a cardiovascular event. Only NT-proBNP maintained a statistically significant association with all end-points (death: HR 1.62 [95% CI 1.26–2.10], P < 0.0005; end-stage kidney disease: HR 1.51 [95% 1.19–1.91], P = 0.001; cardiovascular event: HR 1.56 [95% CI 1.23–1.97], P < 0.0005). Risk reclassification improved with addition of all biomarkers as a panel to the base model. Only patients with NT-proBNP concentrations above 300 ng/L gained benefit from revascularization with regard to all adverse end-points compared with medically managed patients.

Conclusions

NT-proBNP is independently associated with increased risk for all adverse events in atherosclerotic renovascular disease. Novel biomarkers may have an incremental risk predictive value when used in combination with traditional risk factors, and NT-proBNP may have value in patient selection for revascularization. Given the small size of this study, larger multicentre studies are required to validate these findings.

Improved management of acute kidney injury in primary care using e-alerts and an educational outreach programme

PURPOSE

Acute kidney injury (AKI) detected in primary care is associated with increased morbidity and mortality. AKI electronic alerts (e-alerts) and educational programmes have recently been implemented but their contribution to improve AKI care is unknown. This project aimed to improve response to AKI detected in primary care and used a factorial design to evaluate the impact of the UK National Health Service (NHS) AKI e-alert and AKI educational outreach sessions on time to response to primary care AKI stages 2 and 3 between April and August 2016.

METHODS

A total of 46 primary care practices were randomized into four groups. A 2 × 2 factorial design exposed each group to different combinations of two interventions. The primary outcome was 'time to repeat test' or hospitalization following AKI e-alert for stages 2 and 3. Yates algorithm was used to evaluate the impact of each intervention. Time to response and mortality pre- and post-intervention were analysed using Mann-Whitney U test and chi-square test respectively. The factorial design included two interventions: an AKI educational outreach programme and the NHS AKI e-alerts.

RESULTS

1807 (0.8%) primary care blood tests demonstrated AKI 1-3 (78.3% stage 1, 14.8% stage 2, 6.9% stage 3). There were 391 stage 2 and 3 events from 251 patients. E-alerts demonstrated a reduction in mean response time (-29 hours). Educational outreach had a smaller effect (-3 hours). Median response time to AKI 2 and 3 pre- and post-interventions was 27 hours versus 16 hours respectively (P = 0.037). Stage 2 and 3 event-related 30-day all-cause mortality decreased following the interventions (15.6% versus 3.9% P = 0.036).

CONCLUSION

AKI e-alerts in primary care hasten response to AKI 2 and 3 and reduce all-cause mortality. Educational outreach sessions further improve response time.

Extensions to Online Feature Selection Using Bagging and Boosting

Feature subset selection can be used to sieve through large volumes of data and discover the most informative subset of variables for a particular learning problem. Yet, due to memory and other resource constraints (e.g., CPU availability), many of the state-of-the-art feature subset selection methods cannot be extended to high dimensional data, or data sets with an extremely large volume of instances. In this brief, we extend online feature selection (OFS), a recently introduced approach that uses partial feature information, by developing an ensemble of online linear models to make predictions. The OFS approach employs a linear model as the base classifier, which allows the $l_{0}$ -norm of the parameter vector to be constrained to perform feature selection leading to sparse linear models. We demonstrate that the proposed ensemble model typically yields a smaller error rate than any single linear model, while maintaining the same level of sparsity and complexity at the time of testing.

Calcium and Bone Turnover Markers in Acromegaly: A Prospective, Controlled Study

CONTEXT

Acromegaly has been associated with calcium-phosphate and bone turnover alterations. Controlled studies of these interactions are sparse.

OBJECTIVE

To evaluate calcium and bone metabolism in active and treated acromegaly.

DESIGN/SETTING/PATIENTS

We conducted a controlled, prospective study at a tertiary referral center. We studied 22 patients with acromegaly referred for surgical or medical therapy (ACM) and 22 with nonfunctioning pituitary adenomas referred for surgery (control).

MAIN OUTCOME MEASURES

Calcium (serum and urine), phosphorus, parathyroid hormone (PTH), 25-hydroxy- and 1,25-dihydroxy-vitamin D, bone turnover markers [serum C-terminal telopeptide of type 1 collagen (CTX) and procollagen type 1 N-terminal propeptide (P1NP)], and cytokines [receptor activator of nuclear factor κB ligand (RANK-L) and osteoprotegerin (OPG)] at baseline and 3 to 6 months after treatment.

RESULTS

At baseline, the ACM group had lower PTH levels than controls (36.3 ± 13.9 pg/mL vs 56.0 ± 19.9 pg/mL) and higher phosphorus (4.34 ± 0.71 mg/dL vs 3.55 ± 0.50 mg/dL) (P < 0.01). Groups had similar levels of serum and urine calcium and 25-hydroxy- and 1,25-dihydroxy-vitamin D. The ACM group had higher bone turnover markers than control; P1NP and CTX were strongly correlated (r2 = 0.82, P < 0.05). CTX was dependent on age and disease group but not on sex or gonadal status. After treatment of acromegaly, serum calcium (9.52 ± 0.43 mg/dL to 9.26 ± 0.28 mg/dL), phosphorus (4.34 ± 0.71 mg/dL to 3.90 ± 0.80 mg/dL), and CTX (0.91 ± 0.75 ng/mL to 0.63 ± 0.68 ng/mL) decreased, while PTH increased (36.3 ± 13.9 pg/mL to 48.9 ± 16.7 pg/mL) (P < 0.01). 25-hydroxy-vitamin D, P1NP, and RANK-L/OPG ratio did not change significantly.

CONCLUSION

Acromegaly patients exhibited PTH-independent calcium-phosphate alterations and enhanced coupled bone formation and resorption. Within 6 months of treatment, bone resorption decreased, whereas RANK-L/OPG changes were inconsistent.

Kidney volume to GFR ratio predicts functional improvement after revascularization in atheromatous renal artery stenosis

BACKGROUND

Randomized controlled trials (RCT) have shown no overall benefit of renal revascularization in atherosclerotic renovascular disease (ARVD). However, 25% of patients demonstrate improvement in renal function. We used the ratio of magnetic resonance parenchymal volume (PV) to isotopic single kidney glomerular filtration rate (isoSKGFR) ratio as our method to prospectively identify "improvers" before revascularization.

METHODS

Patients with renal artery stenosis who were due revascularization were recruited alongside non-ARVD hypertensive CKD controls. Using the controls, 95% CI were calculated for expected PV:isoSK-GFR at given renal volumes. For ARVD patients, "improvers" were defined as having both >15% and >1ml/min increase in isoSK-GFR at 4 months after revascularization. Sensitivity and specificity of PV:isoSK-GFR for predicting improvers was calculated.

RESULTS

30 patients (mean age 68 ±8 years), underwent revascularization, of whom 10 patients had intervention for bilateral RAS. Stented kidneys which manifested >15% improvement in function had larger PV:isoSK-GFR compared to controls (19±16 vs. 6±4ml/ml/min, p = 0.002). The sensitivity and specificity of this equation in predicting a positive renal functional outcome were 64% and 88% respectively. Use of PV:isoSK-GFR increased prediction of functional improvement (area under curve 0.93). Of note, non-RAS contralateral kidneys which improved (n = 5) also demonstrated larger PV:isoSK-GFR (15.2±16.2 ml/ml/min, p = 0.006).

CONCLUSION

This study offers early indicators that the ratio of PV:isoSK-GFR may help identify patients with kidneys suitable for renal revascularization which could improve patient selection for a procedure associated with risks. Calculation of the PV:isoSK-GFR ratio is easy, does not require MRI contrast agent.

Effect of renal artery revascularization upon cardiac structure and function in atherosclerotic renal artery stenosis: cardiac magnetic resonance sub-study of the ASTRAL trial

Background

Cardiac abnormalities are frequent in patients with atherosclerotic renovascular disease (ARVD). The Angioplasty and Stenting for Renal Artery Lesions (ASTRAL) trial studied the effect of percutaneous renal revascularization combined with medical therapy compared with medical therapy alone in 806 patients with ARVD.

Methods

This was a pre-specified sub-study of ASTRAL (clinical trials registration, current controlled trials number: ISRCTN59586944), designed to consider the effect of percutaneous renal artery angioplasty and stenting on change in cardiac structure and function, measured using cardiac magnetic resonance (CMR) imaging. Fifty-one patients were recruited from six selected ASTRAL centres. Forty-four completed the study (medical therapy n = 21; revascularization n = 23). Full analysis of CMR was possible in 40 patients (18 medical therapy and 22 revascularization). CMR measurements of left and right ventricular end systolic (LV and RVESV) and diastolic volume (LV and RVEDV), ejection fraction (LVEF) and mass (LVM) were made shortly after recruitment and before revascularization in the interventional group, and again after 12 months. Reporting was performed by CMR analysts blinded to randomization arm.

Results

Groups were well matched for mean age (70 versus 72 years), blood pressure (148/71 versus 143/74 mmHg), degree of renal artery stenosis (75 versus 75%) and comorbid conditions. In both randomized groups, improvements in cardiac structural parameters were seen at 12 months, but there were no significant differences between treatment groups. Median left ventricular changes between baseline and 12 months (medical versus revascularization) were LVEDV -1.9 versus -5.8 mL, P = 0.4; LVESV -2.1 versus 0.3 mL, P = 0.7; LVM -5.4 versus -6.3 g, P = 0.8; and LVEF -1.5 versus -0.8%, P = 0.7. Multivariate regression also found that randomized treatment assignment was not associated with degree of change in any of the CMR measurements.

Conclusions

In this sub-study of the ASTRAL trial, renal revascularization did not offer additional benefit to cardiac structure or function in unselected patients with ARVD.

Population-based cohort study of variation in the use of emergency cholecystectomy for benign gallbladder diseases

Background

The aims of this prospective population-based cohort study were to identify the patient and hospital characteristics associated with emergency cholecystectomy, and the influences of these in determining variations between hospitals.

Methods

Data were collected for consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing the performance of emergency cholecystectomy were analysed by means of multilevel, multivariable logistic regression modelling using a two-level hierarchical structure with patients (level 1) nested within hospitals (level 2).

Results

Data were collected on 4744 cholecystectomies from 165 hospitals. Increasing age, lower ASA fitness grade, biliary colic, the need for further imaging (magnetic retrograde cholangiopancreatography), endoscopic interventions (endoscopic retrograde cholangiopancreatography) and admission to a non-biliary centre significantly reduced the likelihood of an emergency cholecystectomy being performed. The multilevel model was used to calculate the probability of receiving an emergency cholecystectomy for a woman aged 40 years or over with an ASA grade of I or II and a BMI of at least 25·0 kg/m2, who presented with acute cholecystitis with an ultrasound scan showing a thick-walled gallbladder and a normal common bile duct. The mean predicted probability of receiving an emergency cholecystectomy was 0·52 (95 per cent c.i. 0·45 to 0·57). The predicted probabilities ranged from 0·02 to 0·95 across the 165 hospitals, demonstrating significant variation between hospitals.

Conclusion

Patients with similar characteristics presenting to different hospitals with acute gallbladder pathology do not receive comparable care.

Short-term and long-term effects of acute kidney injury in chronic kidney disease patients: A longitudinal analysis

We use data from an ongoing cohort study of chronic kidney patients at Salford Royal NHS Foundation Trust, Greater Manchester, United Kingdom, to investigate the influence of acute kidney injury (AKI) on the subsequent rate of change of kidney function amongst patients already diagnosed with chronic kidney disease (CKD). We use a linear mixed effects modelling framework to enable estimation of both acute and chronic effects of AKI events on kidney function. We model the fixed effects by a piece-wise linear function with three change-points to capture the acute changes in kidney function that characterise an AKI event, and the random effects by the sum of three components: a random intercept, a stationary stochastic process with Matérn correlation structure, and measurement error. We consider both multivariate Normal and multivariate t versions of the random effects. For either specification, we estimate model parameters by maximum likelihood and evaluate the plug-in predictive distributions of the random effects given the data. We find that following an AKI event the average long-term rate of decline in kidney function is almost doubled, regardless of the severity of the event. We also identify and present examples of individual patients whose kidney function trajectories diverge substantially from the population-average.

Three Decades of Atherosclerotic Reno-vascular Disease Management - Changing Outcomes in an Observational Study

BACKGROUND/AIMS

Optimized medical therapy has improved cardiovascular outcomes in the general population. To investigate whether changes in the management of atherosclerotic renovascular disease (ARVD) have had an impact on clinical outcomes.

METHODS

Recruitment into this single-center prospective cohort study started in 1986. Data was analyzed retrospectively. Patients were divided into four groups based on relationship of diagnosis year to landmark randomized controlled trials (RCT); group 1 - pre-large RCT data (1986-2000); group 2 - post-early RCT (2001-2004); group 3 - ASTRAL study recruitment era (2004-2009); group 4 - post-ASTRAL (2009-2014).

RESULTS

In total, 872 patients were followed for a median 54.9 months (IQR 20.2-96.2). Over successive time-periods, there was an increase in baseline utilization of renin angiotensin blockade (RAB) (group 4: 69% vs. group 1: 31%, p<0.001), statins (74% vs 20%, p<0.001) and beta-blockers (43% vs 30%, p=0.024). Median time to death, end-stage kidney disease and cardiovascular events improved except in group 4, which displayed more baseline cardiovascular comorbidities. The number of investigative angiograms performed decreased from 139 per year between 2006 and 2008 to 74 per year in group 4.

CONCLUSIONS

Although fewer patients are being investigated for ARVD in our center, these have more cardiovascular comorbidities. Nonetheless, optimized medical therapy may have contributed towards improved proteinuria, renal function and clinical outcomes in patients diagnosed with ARVD.

Associations of antiplatelet therapy and beta blockade with patient outcomes in atherosclerotic renovascular disease

Randomized trials have shown a neutral effect of percutaneous revascularization compared with optimal medical therapy in patients with atherosclerotic renovascular disease (ARVD). However, there are few data to define what constitutes optimal medical therapy. We present a retrospective analysis of 529 ARVD patients. Separate analyses were performed comparing outcomes in patients prescribed/not prescribed beta blocker and antiplatelet agents. Analyses were adjusted for effects of baseline covariates on probability of treatment and on clinical outcome. Over a median follow-up period of 3.8 years, antiplatelet therapy was associated with a reduced risk for death (relative risk, 0.52 [95% confidence interval {CI}: 0.31-0.89]; P = .02). Beta blocker therapy was associated with a reduced for death (relative risk, 0.45 [95% CI: 0.21-0.97]; P = .04) and nonfatal cardiovascular events (relative risk, 0.74 [95% CI: 0.60-0.90]; P = .003). Although limited by small patient numbers, this study suggests that in ARVD, treatment with antiplatelet therapy and beta blockade may associate with a prognostic benefit.

Post-transplant lymphoproliferative disorder in adult renal transplant recipients: survival and prognosis

Post-transplant lymphoproliferative disorder (PTLD) is a rare, serious complication following solid organ transplantation, with an incidence of 2.6 cases per 1000 patient years. Optimal treatment strategies and risk stratifications specific to kidney transplantation are lacking and PTLD mortality remains high. This study investigated survival and prognosis in 89 cases of PTLD presenting over 44 years at Manchester Royal Infirmary. Patient survival following diagnosis was 72% at 6 months, 67% at 1 year and 54% at 3 years. In multivariate analysis, a poorer 3 year survival was associated with acute kidney injury at diagnosis (p = 0.0001), impaired renal function (p = 0.04), early onset (p = 0.02), T cell disease (p = 0.02) and previous treatment with anti-thymocyte globulin (p = 0.04). The inclusion of graft function adds prognostic value to risk stratification and should be explored further. Strategies to improve survival should include timing and choice of immuno-chemotherapy, preparation for dialysis and aggressive surveillance for sepsis and treatment toxicity.