Improving home haemodialysis: Stability evaluation of routine clinical chemistry analytes in blood samples of haemodialysis patients

Introduction: A growing number of dialysis patients is treated with home haemodialysis. Our current pre-analytical protocols require patients to centrifuge the blood sample and transfer the plasma into a new tube at home. This procedure is prone to errors and precludes accurate bicarbonate measurement, required for determining dialysate bicarbonate concentration and maintaining acid-base status. We therefore evaluated whether cooled overnight storage of gel separated plasma is an acceptable alternative. Materials and methods: Venous blood of 34 haemodialysis patients was collected in 2 lithium heparin blood collection tubes with gel separator (LH PSTTM II, REF 367374; Becton Dickinson, New Jersey, USA). One tube was analysed directly for measurement of bicarbonate, potassium, calcium, phosphate, glucose, urea, lactate, aspartate aminotransferase (AST), and lactate dehydrogenase (LD); whereas the other was centrifuged and stored unopened at 4 °C and analysed 24 h later. To measure analyte stability after 24 h of storage, the mean difference was calculated and compared to the total allowable error (TEa) which was used as acceptance limit. Results: Potassium (Z = - 4.28, P < 0.001), phosphate (Z = - 3.26, P = 0.001), lactate (Z = - 5.11, P < 0.001) and AST (Z = - 2.71, P = 0.007) concentrations were higher, whereas glucose (Z = 4.00, P < 0.001) and LD (Z = 3.13, P = 0.002) showed a reduction. All mean differences were smaller than the TEa and thus not clinically relevant. Bicarbonate (Z = 0.69, P = 0.491), calcium (Z = - 0.23, P = 0.815) and urea (Z = 0.81, P =0.415) concentrations were stable. Conclusions: Our less complex, user-friendly pre-analytical procedure resulted in at least 24 h stability of analytes relevant for monitoring haemodialysis, including bicarbonate. This allows shipment and analysis the next day

Gene signatures from scRNA-seq accurately quantify mast cells in biopsies in asthma

Respiratory disease, characterized by changes in the cells of the lung, can affect molecular phenotype of cells and the intercellular interactions, resulting in a disbalance in the relative proportions of individual cell types. Understanding these changes is essential to understand the pathophysiology of lung disease. Conventional 'bulk' RNA-sequencing (RNA-seq), analyzing the entire transcriptome of the tissue sample, provides information about average expression levels of each gene in the mixed cell population; whereas it does not consider the cellular heterogeneity in samples composed of more than one cell type 1 . Single-cell RNA-seq (scRNA-seq) assesses the transcriptome of a complex biological sample with single-cell resolution, allowing identification of the relative frequency of discrete cell-types and analysis of their transcriptomes 1 . Nevertheless, analyzing the transcriptomic signature in large numbers of patients by scRNA-Seq is currently limited by its high costs. Mast cells are key regulatory cells driving the inflammatory process in asthma2 . Since they can be quantified by immunohistochemical staining for validation purposes, we used mast cells as an example of a rare cell population to assess the validity of our deconvolution approach. Recently, a number of bulk RNA-seq deconvolution methods have become available 3 , for instance of two deconvolution methods, namely support vector regression (SVR) 4 , the machine-learning method implemented in CYBERSORT, and Non-Negative Least Square (NNLS) 5 , using a matrix of cell-type selective genes identified with AutoGeneSc 6 . Both approaches are designed to estimate relative proportion of the main, common cell types present in the sample. When we used these methods to estimate the number of mast cells, we found a poor correlation with the number of mast cells stained by immunohistochemistry in the biopsies, suggesting the CIBERSORT and NNLS are less reliable in the case of rare cell types. We explored the possibility to use scRNA-Seq data from small numbers of subjects to specifically interrogate the relative cell type frequency of a rare cell population in a bulk RNA-Seq dataset obtained from a large asthma cohort

Rate control efficacy in permanent atrial fibrillation:a comparison between lenient versus strict rate control in patients with and without heart failure. Background, aims, and design of RACE II

BACKGROUND: Recent studies demonstrated that rate control is an acceptable alternative for rhythm control in patients with persistent atrial fibrillation (AF). However, optimal heart rate during AF is still unknown. OBJECTIVE: To show that in patients with permanent AF, lenient rate control is not inferior to strict rate control in terms of cardiovascular mortality, morbidity, neurohormonal activation, New York Heart Association class for heart failure, left ventricular function, left atrial size, quality of life, and costs. METHODS: The RACE II study is a prospective multicenter trial in The Netherlands that will randomize 500 patients with permanent AF (< or = 12 months) to strict or lenient rate control. Strict rate control is defined as a mean resting heart rate < 80 beats per minute (bpm) and heart rate during minor exercise < 110 bpm. After reaching the target, a 24-hour Holter monitoring will be performed. If necessary, drug dose reduction and/or pacemaker implantation will be performed. Lenient rate control is defined as a resting heart rate < 110 bpm. Patients will be seen after 1, 2, and 3 months (for titration of rate control drugs) and yearly thereafter. We anticipate a 25% 2.5-year cardiovascular morbidity and mortality in both groups. RESULTS: Enrollment started in January 2005 in 29 centers in The Netherlands and is expected to be concluded in June 2006. Follow-up will be at least 2 years with a maximum of 3 years. CONCLUSION: This study should provide data how to treat patients with permanent AF

Cost Effectiveness of a CYP2C19 Genotype-Guided Strategy in Patients with Acute Myocardial Infarction:Results from the POPular Genetics Trial

INTRODUCTION: The POPular Genetics trial demonstrated that a CYP2C19 genotype-guided P2Y12 inhibitor strategy reduced bleeding rates compared with standard treatment with ticagrelor or prasugrel without increasing thrombotic event rates after primary percutaneous coronary intervention (PCI). OBJECTIVE: In this analysis, we aimed to evaluate the cost effectiveness of a genotype-guided strategy compared with standard treatment with ticagrelor or prasugrel. METHODS: A 1-year decision tree based on the POPular Genetics trial in combination with a lifelong Markov model was developed to compare costs and quality-adjusted life-years (QALYs) between a genotype-guided and a standard P2Y12 inhibitor strategy in patients with myocardial infarction undergoing primary PCI. The cost-effectiveness analysis was conducted from a Dutch healthcare system perspective. Within-trial survival and utility data were combined with lifetime projections to evaluate lifetime cost effectiveness for a cohort of 1000 patients. Costs and utilities were discounted at 4 and 1.5%, respectively, according to Dutch guidelines for health economic studies. Besides deterministic and probabilistic sensitivity analyses, several scenario analyses were also conducted (different time horizons, different discount rates, equal prices for P2Y12 inhibitors, and equal distribution of thrombotic events between the two strategies). RESULTS: Base-case analysis with a hypothetical cohort of 1000 subjects demonstrated 8.98 QALYs gained and €725,550.69 in cost savings for the genotype-guided strategy (dominant). The deterministic and probabilistic sensitivity analysis confirmed the robustness of the model and the cost-effectiveness results. In scenario analyses, the genotype-guided strategy remained dominant. CONCLUSION: In patients undergoing primary PCI, a CYP2C19 genotype-guided strategy compared with standard treatment with ticagrelor or prasugrel resulted in QALYs gained and cost savings. TRIAL REGISTRATION: Clinicaltrials.gov number: NCT01761786, Netherlands trial register number: NL2872

The Impact of a Standardized Pre-visit Laboratory Testing Panel in the Internal Medicine Outpatient Clinic: a Controlled “On-Off” Trial

Background: In several settings, a shorter time to diagnosis has been shown to lead to improved clinical outcomes. The implementation of a rapid laboratory testing allows for a pre-visit testing in the outpatient clinic, meaning that test results are available during the first outpatient visit. Objective: To determine whether the pre-visit laboratory testing leads to a shorter time to diagnosis in the general internal medicine outpatient clinic. Design: An “on-off” trial, allocating subjects to one of two treatment arms in consecutive alternating blocks. Participants: All new referrals to the internal medicine outpatient clinic of a university hospital were included, excluding second opinions. A total of 595 patients were eligible; one person declined to participate, leaving data from 594 patients for analysis. Intervention: In the intervention group, patients had a standardized pre-visit laboratory testing before the first visit. Main Measures: The primary outcome was the time to diagnosis. Secondary outcomes were the correctness of the preliminary diagnosis on the first day, health care utilization, and patient and physician satisfaction. Key Results: There was no difference in time to diagnosis between the two groups (median 35 days vs 35 days; hazard ratio 1.03 [0.87–1.22]; p =.71). The pre-visit testing group had higher proportions of both correct preliminary diagnoses on day 1 (24% vs 14%; p =.003) and diagnostic workups being completed on day 1 (10% vs 3%; p <.001). The intervention group had more laboratory tests done (50.0 [interquartile range (IQR) 39.0–69.0] vs 43.0 [IQR 31.0–68.5]; p <.001). Otherwise, there were no differences between the groups. Conclusions: Pre-visit testing did not lead to a shorter overall time to diagnosis. However, a greater proportion of patients had a correct diagnosis on the first day. Further studies should focus on customizing pre-visit laboratory panels, to improve their efficacy. Trial Registration: NL500

Genome-wide Analyses Identify KIF5A as a Novel ALS Gene

To identify novel genes associated with ALS, we undertook two lines of investigation. We carried out a genome-wide association study comparing 20,806 ALS cases and 59,804 controls. Independently, we performed a rare variant burden analysis comparing 1,138 index familial ALS cases and 19,494 controls. Through both approaches, we identified kinesin family member 5A (KIF5A) as a novel gene associated with ALS. Interestingly, mutations predominantly in the N-terminal motor domain of KIF5A are causative for two neurodegenerative diseases: hereditary spastic paraplegia (SPG10) and Charcot-Marie-Tooth type 2 (CMT2). In contrast, ALS-associated mutations are primarily located at the C-terminal cargo-binding tail domain and patients harboring loss-of-function mutations displayed an extended survival relative to typical ALS cases. Taken together, these results broaden the phenotype spectrum resulting from mutations in KIF5A and strengthen the role of cytoskeletal defects in the pathogenesis of ALS.Peer reviewe

Data-gedreven integrale diagnostiek

In the near future, making a correct medical diagnosis will be increasingly supported by artificial intelligence. The development of algorithms that integrate all data from an individual into the diagnostic process calls for a multidisciplinary approach that includes not only healthcare professionals and patients, but also data scientists. Because of the position of the clinical chemist in the current health care process, this medical specialist is naturally suited to initiate the development of self-learning diagnostic algorithms and to take the lead in the process to take big data to the next level and create value for health care

Quality of life of patients with irritable bowel syndrome is low compared to others with chronic diseases

BACKGROUND: Irritable bowel syndrome (IBS) is a prevalent functional gastrointestinal dysmotility disorder. This study aimed to estimate the burden of illness of a Dutch population of community dwelling patients suffering from IBS. METHODS: Patients identified at community pharmacies, using mebeverine as a proxy for IBS, were administered a questionnaire regarding (1) the Rome II criteria for IBS, (2) predominant type of stool during complaints, (3) severity of symptoms (abdominal pain and discomfort), (4) generic and disease-specific quality of life, (5) current health status (utilities), and (6) loss of productivity. RESULTS: Three hundred and seventy-five users of mebeverine were identified of which 169 patients met the Rome II criteria for IBS, and were included in the study. More than half (58%) of the IBS patients reported severe abdominal pain and complaints. Generic and disease-specific quality of life outcomes showed impairment on all dimensions. Current health status in IBS patients, calculated on the basis of the EQ-5D VAS, was perceived on 62% of full health (95% CI, 60-66%). A calculation of health status in these patients based on the SF-6D algorithm showed a comparable score of 0.67 (1 is full health; 95% CI, 0.65-0.68). The loss in productivity of IBS patients was 1.8 days (95% CI, 1.1-2.5) per month. CONCLUSIONS: This study confirmed that the burden of illness of IBS in the Netherlands is substantial. IBS patients treated with mebeverine experienced low quality of life and suffered from severe pain. Based on these results, more attention for the diagnosis and treatment of IBS seems to be justified