scholarly journals Estimates of Within-Subject Biological Variation Derived from Pathology Databases: An Approach to Allow Assessment of the Effects of Age, Sex, Time between Sample Collections, and Analyte Concentration on Reference Change Values

2019 ◽  
Vol 65 (4) ◽  
pp. 579-588 ◽  
Author(s):  
Graham Ross Dallas Jones
Keyword(s):  
Clinical Laboratory ◽  
Biological Variation ◽  
Clinical Environment ◽  
Analyte Concentration ◽  
Regression To The Mean ◽  
Statistical Process ◽  
Reference Change Value ◽  
First Results ◽  
The Mean ◽  
Number Of Individuals

Abstract BACKGROUND Within-subject biological variation data (CVI) are used to establish quality requirements for assays and allow calculation of the reference change value (RCV) for quantitative clinical laboratory tests. The CVI is generally determined using a large number of samples from a small number of individuals under controlled conditions. The approach presented here is to use a small number of samples (n = 2) that have been collected for routine clinical purposes from a large number of individuals. METHODS Pairs of sequential results from adult patients were extracted from a routine pathology database for 29 common chemical and hematological tests. Using a statistical process to identify a central gaussian distribution in the ratios of the result pairs, the total result variation for individual results was determined for 26 tests. The CVI was then calculated by removing the effect of analytical variation. RESULTS This approach produced estimates of CVI that, for most of the analytes in this study, show good agreement with published values. The data demonstrated minimal effect of sex, age, or time between samples. Analyte concentration was shown to affect the distributions with first results more distant from the population mean more likely to be followed by a result closer to the mean. DISCUSSION The process described here has allowed rapid and simple production of CVI data. The technique requires no patient intervention and replicates the clinical environment, although it may not be universally applicable. Additionally, the effect of regression to the mean described here may allow better interpretation of sequential patient results.

scholarly journals Models to estimate biological variation components and interpretation of serial results: strengths and limitations

2020 ◽  
Vol 1 (3) ◽  
Author(s):  
Jorge Díaz-Garzón Marco ◽  
Pilar Fernández-Calle ◽  
Carmen Ricós
Keyword(s):  
Clinical Laboratory ◽  
Direct Methods ◽  
Biological Variation ◽  
European Federation ◽  
Mixed Effect ◽  
Mixed Effect Models ◽  
Reference Change Value ◽  
Large Databases ◽  
The One

AbstractBiological variation (BV) has multiple applications in a variety of fields of clinical laboratory. The use of BV in statistical modeling is twofold. On the one hand, some models are used for the generation of BV estimates (within- and between-subject variability). Other models are built based on BV in combination with other factors to establish ranges of normality that will help the clinician interpret serial results for the same subject. There are two types of statistical models for the calculation of BV estimates: A. Direct methods, prospective studies designed to calculate BV estimates; i. Classic model: developed by Harris and Fraser, revised by the Working Group on Biological Variation of the European Federation of Laboratory Medicine. ii. Mixed-effect models. iii. Bayesian model. B. Indirect methods, retrospective studies to derive BV estimates from large databases of results. Big data. Understanding the characteristics of these models is crucial as they determine their applicability in different settings and populations. Models for defining ranges that help in the interpretation of individual serial results include: A. Reference change value and B. Bayesian data network. In summary, this review provides an overview of the models used to define BV components and others for the follow-up of patients. These models should be exploited in the future to personalize and improve the information provided by the clinical laboratory and get the best of the resources available.

Creation of physiologic rhythm by closed loop stimulation in heart failure patients with severe chronotropic incompetence: worldwide first results of a pilot study

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
J Proff ◽  
B Merkely ◽  
R Papp ◽  
C Lenz ◽  
P.J Nordbeck ◽  
...  
Keyword(s):  
Heart Rate ◽  
Closed Loop ◽  
Funding Source ◽  
Chronotropic Incompetence ◽  
First Results ◽  
The Mean ◽  
Group 2 ◽  
Group 1

Abstract Background The prevalence of chronotropic incompetence (CI) in heart failure (HF) population is high and negatively impacts prognosis. In HF patients with an implanted cardiac resynchronisation therapy (CRT) device and severe CI, the effect of rate adaptive pacing on patient outcomes is unclear. Closed loop stimulation (CLS) based on cardiac impedance measurement may be an optimal method of heart rate adaptation according to metabolic need in HF patients with severe CI. Purpose This is the first study evaluating the effect of CLS on the established prognostic parameters assessed by the cardio-pulmonary exercise (CPX) testing and on quality of life (QoL) of the patients. Methods A randomised, controlled, double-blind and crossover pilot study has been performed in CRT patients with severe CI defined as the inability to achieve 70% of the age-predicted maximum heart rate (APMHR). After baseline assessment, patients were randomised to either DDD-CLS pacing (group 1) or DDD pacing at 40 bpm (group 2) for a 1-month period, followed by crossover for another month. At baseline and at 1- and 2-month follow-ups, a CPX was performed and QoL was assessed using the EQ-5D-5L questionnaire. The main endpoints were the effect of CLS on ventilatory efficiency (VE) slope (evaluated by an independent CPX expert), the responder rate defined as an improvement (decrease) of the VE slope by at least 5%, percentage of maximal predicted heart rate reserve (HRR) achieved, and QoL. Results Of the 36 patients enrolled in the study, 20 fulfilled the criterion for severe CI and entered the study follow-up (mean age 68.9±7.4 years, 70% men, LVEF=41.8±9.3%, 40%/60% NYHA class II/III). Full baseline and follow-up datasets were obtained in 17 patients. The mean VE slope and HRR at baseline were 34.4±4.4 and 49.6±23.8%, respectively, in group 1 (n=7) and 34.5±12.2 and 54.2±16.1% in group 2 (n=10). After completing the 2-month CPX, the mean difference between DDD-CLS and DDD-40 modes was −2.4±8.3 (group 1) and −1.2±3.5 (group 2) for VE slope, and 17.1±15.5% (group 1) and 8.7±18.8% (group 2) for HRR. Altogether, VE slope improved by −1.8±2.95 (p=0.31) in DDD-CLS versus DDD-40, and HRR improved by 12.9±8.8% (p=0.01). The VE slope decreased by ≥5% in 47% of patients (“responders to CLS”). The mean difference in the QoL between DDD-CLS and DDD-40 was 0.16±0.25 in group 1 and −0.01±0.05 in group 2, resulting in an overall increase by 0.08±0.08 in the DDD-CLS mode (p=0.13). Conclusion First results of the evaluation of the effectiveness of CLS in CRT patients with severe CI revealed that CLS generated an overall positive effect on well-established surrogate parameters for prognosis. About one half of the patients showed CLS response in terms of improved VE slope. In addition, CLS improved quality of life. Further clinical research is needed to identify predictors that can increase the responder rate and to confirm improvement in clinical outcomes. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Biotronik SE & Co. KG

scholarly journals Clinical Implications of Polymicrobial Synergism Effects on Antimicrobial Susceptibility

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 144
Author(s):  
William Little ◽  
Caroline Black ◽  
Allie Clinton Smith
Keyword(s):  
Antimicrobial Susceptibility ◽  
Chronic Wounds ◽  
Clinical Laboratory ◽  
Patient Treatment ◽  
Clinical Implications ◽  
Clinical Environment ◽  
Tolerance Mechanisms ◽  
Sequencing Technologies ◽  
Generation Sequencing ◽  
Polymicrobial Infections

With the development of next generation sequencing technologies in recent years, it has been demonstrated that many human infectious processes, including chronic wounds, cystic fibrosis, and otitis media, are associated with a polymicrobial burden. Research has also demonstrated that polymicrobial infections tend to be associated with treatment failure and worse patient prognoses. Despite the importance of the polymicrobial nature of many infection states, the current clinical standard for determining antimicrobial susceptibility in the clinical laboratory is exclusively performed on unimicrobial suspensions. There is a growing body of research demonstrating that microorganisms in a polymicrobial environment can synergize their activities associated with a variety of outcomes, including changes to their antimicrobial susceptibility through both resistance and tolerance mechanisms. This review highlights the current body of work describing polymicrobial synergism, both inter- and intra-kingdom, impacting antimicrobial susceptibility. Given the importance of polymicrobial synergism in the clinical environment, a new system of determining antimicrobial susceptibility from polymicrobial infections may significantly impact patient treatment and outcomes.

scholarly journals Clinical, Laboratory and Histological Features of Dipeptidyl Peptidase-4 Inhibitor Related Noninflammatory Bullous Pemphigoid

2021 ◽  
Vol 10 (9) ◽  
pp. 1916
Author(s):  
Ágnes Kinyó ◽  
Anita Hanyecz ◽  
Zsuzsanna Lengyel ◽  
Dalma Várszegi ◽  
Péter Oláh ◽  
...  
Keyword(s):  
Bullous Pemphigoid ◽  
Clinical Laboratory ◽  
Case Series ◽  
Dipeptidyl Peptidase ◽  
Area Index ◽  
Histological Features ◽  
Dipeptidyl Peptidase 4 ◽  
First Case ◽  
Dipeptidyl Peptidase 4 Inhibitor ◽  
The Mean

Bullous pemphigoid (BP) is an autoimmune blistering disease of elderly patients that has shown increasing incidence in the last decades. Higher prevalence of BP may be due to more frequent use of provoking agents, such as antidiabetic dipeptidyl peptidase-4 inhibitor (DPP4i) drugs. Our aim was to assess DPP4i-induced bullous pemphigoid among our BP patients and characterize the clinical, laboratory and histological features of this drug-induced disease form. In our patient cohort, out of 127 BP patients (79 females (62.2%), 48 males (37.7%)), 14 (9 females and 5 males) were treated with DPP4i at the time of BP diagnosis. The Bullous Pemphigoid Disease Area Index (BPDAI) urticaria/erythema score was significantly lower, and the BPDAI damage score was significantly higher in DPP4i-BP patients compared to the nonDPP4i group. Both the mean absolute eosinophil number and the mean periblister eosinophil number was significantly lower in DPP4i-BP patients than in nonDPP4i cases (317.7 ± 0.204 vs. 894.0 ± 1.171 cells/μL, p < 0.0001; 6.75 ± 1.72 vs. 19.09 ± 3.1, p = 0.0012, respectively). Our results provide further evidence that DPP4i-associated BP differs significantly from classical BP, and presents with less distributed skin symptoms, mild erythema, normal or slightly elevated peripheral eosinophil count, and lower titers of BP180 autoantibodies. To our knowledge, this is the first case series of DPP4i-related BP with a non-inflammatory phenotype in European patients.

scholarly journals Biological variation and reference change value data for serum copper, zinc and selenium in Turkish adult population

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ceylan Bal ◽  
Serpil Erdogan ◽  
Gamze Gök ◽  
Cemil Nural ◽  
Betül Özbek ◽  
...  
Keyword(s):  
Adult Population ◽  
Reference Intervals ◽  
Serum Copper ◽  
Biological Variation ◽  
Serum Samples ◽  
Reference Change Value ◽  
Index Of Individuality ◽  
Copper Zinc ◽  
Clinically Significant ◽  
Analytical Variation

Abstract Objectives Calculation of biological variation (BV) components is very important in evaluating whether a test result is clinically significant. The aim of this study is to analyze BV components for copper, zinc and selenium in a cohort of healthy Turkish participants. Methods A total of 10 serum samples were collected from each of the 15 healthy individuals (nine female, six male), once a week, during 10 weeks. Copper, zinc and selenium levels were analyzed by atomic absorption spectrometer. BV parameters were calculated with the approach suggested by Fraser. Results Analytical variation (CVA), within-subject BV (CVI), between-subject BV (CVG) values were 8.4, 7.1 and 4.3 for copper; 4.2, 9.1 and 13.7 for zinc; 7.6, 2.5 and 6.9 for selenium, respectively. Reference change values (RCV) were 30.46, 27.56 and 22.16% for copper, zinc and selenium, respectively. The index of individuality (II) values were 1.65, 0.66 and 0.36 for copper, zinc and selenium, respectively. Conclusions According to the results of this study, traditional reference intervals can be used for copper but we do not recommend using it for zinc and selenium. We think that it would be more accurate to use RCV value for zinc and selenium in terms of following significant changes in recurrent results of a patient.

Mines in the End Zone: Are there Downsides to Team Performance?

2020 ◽  
Vol 23 ◽  
Author(s):  
Troy V. Mumford ◽  
M. Travis Maynard
Keyword(s):  
Team Performance ◽  
Role Overload ◽  
Future Research ◽  
Negative Consequences ◽  
Regression To The Mean ◽  
Occupational Psychology ◽  
Team Success ◽  
The Mean ◽  
Overconfidence Bias

Abstract Research on teams in organizations tends to focus on understanding the causes of team performance with a focus on how to enjoy the benefits of team success and avoid the negative consequences of team failure. This paper instead asks the question, ‘what are some of the negative consequences of team success?’ A review of the literature on teams is augmented with research from cognitive science, sociology, occupational psychology, and psychology to explore the potential negative long-term consequences of teamwork success. The general topics of groupthink, overconfidence bias, regression to the mean, role overload, and strategy calcification are reviewed while discussing the implications for future research streams and practical team management.

scholarly journals Are the Effects of Homeopathy Attributable to a Statistical Artefact? A Reanalysis of an Observational Study

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Rainer Lüdtke ◽  
Stefan N. Willich ◽  
Thomas Ostermann
Keyword(s):  
Quality Of Life ◽  
Cohort Studies ◽  
Summary Score ◽  
Regression To The Mean ◽  
Sf 36 ◽  
The Mean ◽  
Component Scores ◽  
True Population ◽  
Respective Standard Deviation

Background. Cohort studies have reported that patients improve considerably after individualised homeopathic treatment. However, these results may be biased by regression to the mean (RTM).Objective. To evaluate whether the observed changes in previous cohort studies are due to RTM and to estimate RTM adjusted effects.Methods. SF-36 quality-of-life (QoL) data from a German cohort of 2827 chronically diseased adults treated by a homeopath were reanalysed by Mee and Chua’s modifiedt-test.Results. RTM adjusted effects, standardized by the respective standard deviation at baseline, were 0.12 (95% CI: 0.06–0.19,P<0.001) in the mental and 0.25 (0.22–0.28,P<0.001) in the physical summary score. Small-to-moderate effects were confirmed for the most individual diagnoses in physical, but not in mental component scores. Under the assumption that the true population mean equals the mean of all actually diseased patients, RTM adjusted effects were confirmed for both scores in most diagnoses.Conclusions. Changes in QoL after treatment by a homeopath are small but cannot be explained by RTM alone. As all analyses made conservative assumptions, true RTM adjusted effects are probably larger than presented.

Empirical methods for assessing meaningful neuropsychological change following epilepsy surgery

1996 ◽  
Vol 2 (6) ◽  
pp. 556-564 ◽  
Author(s):  
Stephen M. Sawrie ◽  
Gordon J. Chelune ◽  
Richard I. Naugle ◽  
Hans O. Lüders
Keyword(s):  
Epilepsy Surgery ◽  
Intractable Epilepsy ◽  
Practice Effects ◽  
Cutoff Score ◽  
Regression To The Mean ◽  
Neuropsychological Battery ◽  
Reliable Change ◽  
Medical Interventions ◽  
The Mean ◽  
Test Retest Reliability

AbstractTraditional methods for assessing the neurocognitive effects of epilepsy surgery are confounded by practice effects, test-retest reliability issues, and regression to the mean. This study employs 2 methods for assessing individual change that allow direct comparison of changes across both individuals and test measures. Fifty-one medically intractable epilepsy patients completed a comprehensive neuropsychological battery twice, approximately 8 months apart, prior to any invasive monitoring or surgical intervention. First, a Reliable Change (RC) index score was computed for each test score to take into account the reliability of that measure, and a cutoff score was empirically derived to establish the limits of statistically reliable change. These indices were subsequently adjusted for expected practice effects. The second approach used a regression technique to establish “change norms” along a common metric that models both expected practice effects and regression to the mean. The RC index scores provide the clinician with a statistical means of determining whether a patient's retest performance is “significantly” changed from baseline. The regression norms for change allow the clinician to evaluate the magnitude of a given patient's change on 1 or more variables along a common metric that takes into account the reliability and stability of each test measure. Case data illustrate how these methods provide an empirically grounded means for evaluating neurocognitive outcomes following medical interventions such as epilepsy surgery. (JINS, 1996, 2, 556–564.)

Sign in / Sign up

Export Citation Format

Share Document