Rapid point-of-care test for diagnosis of peritonitis in peritoneal dialysis patients

BACKGROUND

Periplex® is a rapid point-of-care test based on the detection of interleukin-6 (IL-6) or matrix metalloproteinase-8 (MMP-8) to diagnose peritonitis in peritoneal dialysis (PD) patients.

METHODS

This single-centre study was conducted in Singapore General Hospital from 2019 to 2022. The study recruited PD patients suspected of having peritonitis. Periplex was performed at the presentation and recovery of peritonitis. Primary outcomes were sensitivity and specificity of Periplex at presentation. The positive and negative predictive values of tests were also performed.

RESULTS

A total of 120 patients were included in the study. The mean age was 60.9 ± 14.9 years, 53% were male, 79% were Chinese and 47.5% had diabetes mellitus. Periplex was positive in all patients with peritonitis (n = 114); sensitivity of 100%; 95% confidence interval (CI): 100-100%. Periplex was falsely positive in three patients with non-infective eosinophilic peritonitis, resulting in a low specificity of 50%; 95% CI: 41.1-59.0%. Periplex had a positive predictive value of 97.4% and a negative predictive value of 100%. During recovery from peritonitis, Periplex had high specificity (93.6%) and negative predictive value (98.7%) to indicate the resolution of infection. MMP-8 was more sensitive than IL-6 in detecting peritonitis. Periplex was positive in all patients with peritonitis regardless of the types of PD solutions used.

CONCLUSIONS

Periplex had high sensitivity, and positive and negative predictive values in the diagnosis of peritonitis can be considered as a screening tool for peritonitis. Given its high specificity and negative predictive value, it may also be used to document the resolution of peritonitis.

The use of medium cutoff dialyzers in patients with multiple myeloma and acute kidney injury requiring hemodialysis: A systematic review

BACKGROUND

Patients with multiple myeloma and high serum levels of circulating free light chains (FLC) have increased risk of acute kidney injury (AKI) secondary to cast nephropathy and is associated with poor survival. Despite removal of FLC by medium cutoff (MCO) dialyzer, the role of MCO hemodialysis (HD) in the treatment of cast nephropathy and its clinical benefits remain unknown.

METHODS

A systematic review was conducted to establish the effectiveness of MCO dialyzer and clinical outcomes, compared to other forms of dialyzers in the removal of FLC, in myeloma patients with AKI. The primary outcome was effectiveness of MCO-HD in reducing serum FLC. The secondary outcomes were HD independence, estimated glomerular filtrate rate, mortality rates, length of hospitalization, rebound of serum FLC before the next dialysis, removal of other molecules during dialysis, and adverse events.

RESULTS

We identified three case series, with a total of 17 patients. There were no randomized controlled trials (RCTs) or cohort studies. These case series showed that MCO dialyzer was effective in the removal of FLC and led to a reduction in FLC concentration post-dialysis. The majority of the case series did not have comparator arm and renal and/or other clinical outcomes.

CONCLUSION

MCO dialyzer appeared to be effective in the removal of FLC based on the existing limited data. However, more data, particularly large-scale RCTs, are needed to assess the use of MCO dialyzer in reducing serum FLC and its effect on clinical outcomes in patients with multiple myeloma and AKI.

MO114: Incidence and Spectrum of Biopsy-Proven Dysproteinemic Kidney Diseases: A Single-Centre Experience

BACKGROUND AND AIMS

We aimed to evaluate the incidence and clinical features of patients with biopsy-proven dysproteinemic kidney diseases (group 1), as well as spectrum of biopsy-proven kidney diseases of patients with monoclonal gammopathy (MG) or abnormal free light chain (FLC) ratio (group 2) at our institution.

METHOD

This was a single-centre retrospective study of all patients who had native kidney biopsies at the Singapore General Hospital between October 2015 and December 2021. Demographic, clinical, laboratory and histological data were retrieved from electronic medical records to identify patients with biopsy-proven dysproteinemic kidney diseases (group 1) and patients with positive MG and/or abnormal FLC (κ to λ) ratio who underwent kidney biopsy (group 2). Patients were considered to have MG if they tested positive on any of the following tests: serum protein electrophoresis, serum immunofixation, urine protein electrophoresis or urine immunofixation. Abnormal FLC ratio is defined as a ratio outside the range of 0.27–1.65 in patients with eGFR ≥60 mL/min/m2 or 0.37–3.10 in patients with eGFR <60 mL/min/m2.

RESULTS

Out of 1066 patients who underwent kidney biopsy between October 2015 and December 2021, 25 (2.3%) patients were diagnosed with dysproteinemic kidney diseases (group 1). The median age of the patients at diagnosis was 65.6 years (IQR 58.6, 68.2), and majority was male (17/25; 68.0%). Haematological diagnoses present in this cohort include multiple myeloma (5/25; 20.0%), chronic lymphocytic leukaemia (2/25; 8.0%), Waldenstrom's macroglobulinaemia (2/25; 8.0%) and mantle cell lymphoma (1/25; 4.0%).

Two-thirds of the patients had acute kidney injury (AKI) at time of biopsy (17/25; 68.0%). All patients presented with proteinuria, and nephrotic syndrome was noted in approximately half of the patients (15/25; 60.0%). Hypocomplementemia was present in a third (7/21; 33.3%) of the patients who had complement levels performed prior to biopsy, with low C3 and low C3/C4 observed in 5 and 2 patients, respectively. The most common histological lesion is immunoglobulin-related amyloidosis (8/25; 32.0%), followed by proliferative glomerulonephritis with monoclonal immune deposits (PGNMID) (6/25; 24.0%) and light-chain cast nephropathy (4/25; 16.0%). Sixteen (64%) patients fulfilled criteria for monoclonal gammopathy of renal significance (MGRS). All patients with PGNMID had undetectable MG and normal FLC ratio at diagnosis.

Among these 1066 patients who underwent kidney biopsy, 396 patients had serum/urine electrophoresis, serum/urine immunofixation and/or FLC performed prior to biopsy. A total of 44 (11.1%) patients with detectable MG and/or abnormal FLC ratio were identified (group 2), 5 of whom had previously known haematological conditions. Dysproteinemic kidney diseases were diagnosed in 14 (31.8%) patients. Amongst patients with non-dysproteinemic diagnosis, diabetic/hypertensive nephropathy was the most frequent (15/30; 50.0%). Majority of the remaining patients had a variety of glomerulonephritides and renal vasculitides (10/30; 33.3%), or tubulointerstitial diseases (2/30; 6.7%). In univariate analysis, non-diabetic status (P < .001), presence of AKI (P = .032) and abnormal FLC ratio (P = .005) increased the likelihood of diagnosing dysproteinemic kidney disease in this group of patients.

CONCLUSION

AKI and proteinuria are common in dysproteinemia kidney diseases. Non-diabetic status, presence of AKI and abnormal FLC ratio increased the likelihood of diagnosing dysproteinemic kidney disease.

Development and validation of an interpretable clinical score for early identification of acute kidney injury at the emergency department

Acute kidney injury (AKI) in hospitalised patients is a common syndrome associated with poorer patient outcomes. Clinical risk scores can be used for the early identification of patients at risk of AKI. We conducted a retrospective study using electronic health records of Singapore General Hospital emergency department patients who were admitted from 2008 to 2016. The primary outcome was inpatient AKI of any stage within 7 days of admission based on the Kidney Disease Improving Global Outcome (KDIGO) 2012 guidelines. A machine learning-based framework AutoScore was used to generate clinical scores from the study sample which was randomly divided into training, validation and testing cohorts. Model performance was evaluated using area under the curve (AUC). Among the 119,468 admissions, 10,693 (9.0%) developed AKI. 8491 were stage 1 (79.4%), 906 stage 2 (8.5%) and 1296 stage 3 (12.1%). The AKI Risk Score (AKI-RiSc) was a summation of the integer scores of 6 variables: serum creatinine, serum bicarbonate, pulse, systolic blood pressure, diastolic blood pressure, and age. AUC of AKI-RiSc was 0.730 (95% CI 0.714–0.747), outperforming an existing AKI Prediction Score model which achieved AUC of 0.665 (95% CI 0.646–0.679) on the testing cohort. At a cut-off of 4 points, AKI-RiSc had a sensitivity of 82.6% and specificity of 46.7%. AKI-RiSc is a simple clinical score that can be easily implemented on the ground for early identification of AKI and potentially be applied in international settings.

Death and cardiovascular outcomes in end-stage renal failure patients on different modalities of dialysis

INTRODUCTION

Cardiovascular morbidity and mortality in end-stage renal failure (ESRF) patients are high. We examined the incidence and predictors of death and acute myocardial infarction (AMI) in ESRF patients on different modalities of dialysis.

METHOD

Data were obtained from a population-based database (National Registry Disease Offices) in Singapore. The study cohort comprised all adult patients initiated on dialysis between 2007 and 2012 who were closely followed for the development of death and AMI until September 2014. Cox regression methods were used to identify predictors of death and AMI.

RESULTS

Of 5,309 patients, 4,449 were on haemodialysis and 860 on peritoneal dialysis (PD). Mean age of the cohort was 61 (±13) years (44% women), of Chinese (67%), Malay (25%) and Indian (7%) ethnicities. By September 2014, the incidence of all-cause death was 34%; close to a third of the patients died from a cardiovascular cause. Age >60 years and the presence of ischaemic heart disease, diabetes, stroke, peripheral vascular disease and PD were identified as independent predictors of all-cause death. PD patients had lower odds of survival compared to patients on haemodialysis (hazard ratio 1.51, 95% confidence interval 1.35-1.70, P<0.0001). Predictors of AMI in this cohort were older age (>60 years) and the presence of ischaemic heart disease, diabetes, stroke, peripheral vascular disease and current/ex-smokers. There were no significant differences in the incidence of AMI between patients on PD and haemodialysis.

CONCLUSION

The short-term incidence of death and AMI remains high in Singapore. Future studies should investigate the benefits of a tighter control of cardiovascular risk factors among ESRF patients on dialysis.

Description of parallel and sequential configurations for concurrent therapeutic plasma exchange and continuous kidney replacement therapy in adults

Therapeutic plasma exchange (TPE) and continuous kidney replacement therapy (CKRT) are extracorporeal therapeutic procedures often implemented in management of patients. Critically ill patients may be afflicted with disease processes that require both TPE and CKRT. Performing TPE discontinuous with CKRT is technically easier, however, it disrupts CKRT and may compromise with CKRT efficiency or hemofilter life. Concurrent TPE with CKRT offers several advantages including simultaneous control of disease process and correction of electrolyte, fluid, and acid-base disturbances that may accompany TPE. Additionally, TPE may be performed by either centrifugation method or membrane plasma separation method. The technical specifications of these methods may influence the methodology of concurrent connections. This report describes and reviews two different approaches to circuit arrangements when establishing concurrent TPE and CKRT.

Comparison of outcomes of urgent-start and conventional-start peritoneal dialysis: a single-centre experience

BACKGROUND

There has been a growing interest in urgent-start peritoneal dialysis (PD) in patients with end-stage kidney disease to avoid central venous catheter use and its complications. This study aimed to compare clinical outcomes between urgent-start PD (defined as PD commencement within 2 weeks of PD catheter insertion) and conventional-start PD.

METHODS

This was a single-centre retrospective cohort study of all incident PD patients at Singapore General Hospital between January 2017 and February 2018. The primary outcome was dialysate leak. Secondary outcomes included catheter malfunction, catheter readjustment, exit-site infection, peritonitis, technique and patient survival.

RESULTS

A total of 187 incident PD patients were included. Of these, 66 (35%) initiated urgent-start PD. Dialysate leak was significantly higher in urgent-start PD compared with conventional-start PD groups (7.6% versus 0.8%; p = 0.02) whilst catheter malfunction (4.5% vs. 3.3%; p  = 0.70) and catheter readjustment (1.5% vs. 2.5%; p  = 1.00) were comparable between the two groups. Exit-site infection was comparable (IRR: 0.66 95% CI 0.25-1.74) whilst peritonitis was significantly higher in urgent-start PD compared with conventional-start PD (incidence risk ratio (IRR) 3.10, 95% confidence interval (CI) 1.29-7.44). Time to first episode of peritonitis, particularly Gram-positive peritonitis was significantly shorter with urgent-start PD. Technique survival (hazards ratio (HR) 1.95, 95% CI 0.89-4.31) and patient survival (HR 1.46, 95% CI 0.44-4.87) were comparable between the two groups.

CONCLUSION

Urgent-start PD was associated with higher risks of dialysate leak and peritonitis but comparable technique and patient survival compared to conventional-start PD.

Early technique failure in peritoneal dialysis patients in a multi-ethnic Asian country

PURPOSE

Early technique failure is a serious complication for peritoneal dialysis (PD) patients. The study aimed to examine the incidence, causes, and risk factors associated with early technique failure.   METHODS: This retrospective study included all incident PD patients in a hospital in Singapore from 2013 to 2017. The primary outcome was early technique failure, which was defined as transfer to hemodialysis for ≥ 30 days or death, within the first year of PD initiation. Secondary outcomes were death, technique failure due to PD infection, and death-censored technique failure.

RESULTS

Overall, 517 patients were included in the study. Of these, 98 patients (19.0%) developed early technique failure. The common causes of early technique failure were death (41.8%) and infection (40.8%). Peripheral vascular disease was significantly associated with a higher hazard of early technique failure [hazard ratio (HR) 1.95, 95% confidence interval (CI) 1.04-3.63] and death (HR 3.75, 95% CI 1.71-8.21), whilst glomerulonephritis as a cause of end-stage kidney disease (compared with hypertension) was associated with a lower hazard of early technique failure (HR 0.38, 95% CI 0.18-0.77) and death (HR 0.08, 95% CI 0.02-0.37). Male gender was associated with early technique failure due to PD infection (HR 2.55, 95% CI 1.32-4.95). No specific factor was associated with death-censored early technique failure.

CONCLUSION

Technique failure in the first year of PD initiation occurs in one-fifth of PD patients and is associated with peripheral vascular disease and cause of end-stage kidney disease.

Renal outcomes of intensive care burn patients in an Asian tertiary centre

INTRODUCTION

Acute kidney injury (AKI) is a frequent complication of severe burn injury and is associated with a high mortality rate of up to 80%. We aimed to establish the incidence, mortality rate, and factors related to mortality in adult patients with severe burn injury and AKI with renal replacement therapy (RRT) in Singapore.

METHODS

We performed a retrospective cohort study of severely burned patients who were admitted to the Burns Intensive Care Unit (BICU) at the Singapore General Hospital (SGH) from January 2008 to December 2016. We compared patients with AKI with RRT who survived with those who did not survive. As there were changes in the protocol for burns management after 2013, we also compared patients with AKI with RRT who survived with non-survivors in each of the 2008-2012 and 2013-2016 cohorts.

RESULTS

Data of 201 patients were studied. The incidence of AKI with RRT use in severe burn injury was 21.9% and their mortality rate was 50.0%. The non-survivors had significantly higher median burned total body surface area (p = 0.043), earlier AKI (p = 0.046), earlier use of RRT (p = 0.035), lower rate of renal recovery (p = <0.0001), higher rates of adult respiratory distress syndrome (ARDS) (p = 0.005) and shock with vasopressors (p = 0.009) compared to the survivors. The survival rate was 36.8% in the 2008-2012 cohort, but improved to 60.0% in the 2013-2016 cohort. In the 2008-2012 cohort, the non-survivors developed AKI earlier (day 0 admission vs. day 3 admission, p = 0.039), and were initiated on RRT at lower serum creatinine level (173.5 μmol/L vs. 254.0 μmol/L, p = 0.042), when compared to the survivors in this same cohort. On the other hand, there were no significant differences in the renal status and fluid balance parameters between the non-survivors and survivors in the 2013-2016 cohort.

CONCLUSIONS

The incidence of AKI with RRT in the Singapore study cohort was high, but their mortality rate was relatively lower compared to other study cohorts. Severity of AKI and use of RRT were associated with poor prognosis. Large scale study is required to further study the risk factors for mortality in this group of patients and establish cause-and-effect relationship.

A prospective study of clinical characteristics and outcomes of acute kidney injury in a tertiary care Centre

Background

Acute kidney injury (AKI) is a major global health problem. We aim to evaluate the epidemiology, risk factors and outcomes of AKI episodes in our single centre.

Methodology

We prospectively identified 422 AKI and acute on chronic kidney disease episodes in 404 patients meeting KDIGO definitions using electronic medical records and clinical data from 15th July to 22nd October 2016, excluding patients with baseline estimated GFR (eGFR) of < 15 mL/min. Patients were followed up till 6 months after AKI diagnosis.

Results

The mean age was 65.8 ± 14.1. Majority of patients were male (58.2%) of Chinese ethnicity (68.8%). One hundred and thirty-two patients (32.6%) were diagnosed in acute care units. Seventy-five percent of patients developed AKI during admission in a non-Renal specialty. Mean baseline eGFR was 50.2 ± 27.7 mL/min. Mean creatinine at AKI diagnosis was 297 ± 161 μmol/L. Renal consultations were initiated at KDIGO Stages 1, 2 and 3 in 58.9, 24.5 and 16.6% of patients, respectively. Three hundred and ten (76.7%) patients had a single etiology of AKI with the 3 most common etiologies of AKI being pre-renal (27.7%), sepsis-associated (25.5%) and ischemic acute tubular necrosis (15.3%). One hundred and nine (27%) patients received acute renal replacement therapy. In-hospital mortality was 20.3%. Six-month mortality post-AKI event was 9.4%. On survival analysis, patients with KDIGO Stage 3 AKI had significantly shorter survival than other stages.

Conclusion

AKI is associated with significant in-hospital to 6-month mortality. This signifies the pressing need for AKI prevention, early detection and intervention in mitigating reversible risk factors in order to optimize clinical outcomes.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1466-z) contains supplementary material, which is available to authorized users.

A matched patient-sibling study on the usage of paracetamol and the subsequent development of allergy and asthma

A number of studies have suggested that intake of paracetamol during pregnancy and during the first months of life is associated with an increased risk of childhood asthma. We aimed to determine the association between paracetamol usage during pregnancy and the first 6 months of life, and childhood allergy (i.e. positive skin prick tests), allergic asthma, and asthma, using a matched patient-sibling study comparing patients with allergic asthma with their healthy siblings without any symptoms of allergic diseases. Allergy in patients and their siblings was determined by skin prick tests. Children having at least one positive skin prick test were considered to be allergic. Intake of paracetamol was assessed by standardized, interviewer-administered, questionnaire. Nineteen pairs of allergic asthma patients vs. non-allergic siblings were compared to determine the risk factors for allergic asthma, while 15 pairs of allergic asthma patients vs. allergic siblings were compared to determine the risk factors for asthma. Moreover, 33 pairs of allergic asthma patients vs. non-asthmatic siblings (with and without allergy) were compared to determine the risk factors for asthma. In addition, 17 allergic siblings (without asthma) were compared with 19 non-allergic siblings (without asthma) to determine the risk factors for allergy. Usage of paracetamol during pregnancy was associated with allergic asthma (p = 0.03). Furthermore, usage of paracetamol between birth and 6 months of age, and between 4 and 6 months of age, was also found to be associated with non-allergic asthma (p = 0.008 and p = 0.03 respectively). Usage of paracetamol during pregnancy and during the early months of life may play a role in the development of allergic and non-allergic asthma in children. However, due to obvious ethical reasons, direct evidence for this association (i.e. a double-blind, prospective study) is not available.