Assessing agreement between two methods of measuring blood glucose level without Bland-Altman limits.

OBJECTIVE: To describe a new method of assessing agreement between two methods of measuring blood glucose level in view of several problems with the currently used Bland-Altman method. METHODS: Study the deficiencies in the Bland-Altman method and propose a simple method that overcomes these deficiencies. The simple method does not require the calculation of Bland-Altman limits. RESULTS: Clinical tolerance limits, which are needed anyway, can be directly used to obtain the agreement by the percentage of differences within these limits. This method is simple, robust, and nonparametric. It is more flexible also as the clinical tolerance limits can be varied for different values of the measurement such as to have close agreement at critical values and relaxed agreement at other values. Non-symmetric limits can also be set up under the simple method. CONCLUSION: The method of assessing agreement between two methods of measuring blood glucose level can be greatly improved by directly using clinical tolerance limits without calculating the Bland-Altman limits.

Comparing human milk macronutrients measured using analyzers based on mid-infrared spectroscopy and ultrasound and the application of machine learning in data fitting.

OBJECTIVE: Fat, carbohydrates (mainly lactose) and protein in breast milk all provide indispensable benefits for the growth of newborns. The only source of nutrition in early infancy is breast milk, so the energy of breast milk is also crucial to the growth of infants. Some macronutrients composition in human breast milk varies greatly, which could affect its nutritional fulfillment to preterm infant needs. Therefore, rapid analysis of macronutrients (including lactose, fat and protein) and milk energy in breast milk is of clinical importance. This study compared the macronutrients results of a mid-infrared (MIR) analyzer and an ultrasound-based breast milk analyzer and unified the results by machine learning. METHODS: This cross-sectional study included breastfeeding mothers aged 22-40 enrolled between November 2019 and February 2021. Breast milk samples (n = 546) were collected from 244 mothers (from Day 1 to Day 1086 postpartum). A MIR milk analyzer (BETTERREN Co., HMIR-05, SH, CHINA) and an ultrasonic milk analyzer (HonÉ¡yanÉ¡ Co,. HMA 3000, Hebei, CHINA) were used to determine the human milk macronutrient composition. A total of 465 samples completed the tests in both analyzers. The results of the ultrasonic method were mathematically converted using machine learning, while the Bland-Altman method was used to determine the limits of agreement (LOA) between the adjusted results of the ultrasonic method and MIR results. RESULTS: The MIR and ultrasonic milk analyzer results were significantly different. The protein, fat, and energy determined using the MIR method were higher than those determined by the ultrasonic method, while lactose determined by the MIR method were lower (all p < 0.05). The consistency between the measured MIR and the adjusted ultrasound values was evaluated using the Bland-Altman analysis and the scatter diagram was generated to calculate the 95% LOA. After adjustments, 93.96% protein points (436 out of 465), 94.41% fat points (439 out of 465), 95.91% lactose points (446 out of 465) and 94.62% energy points (440 out of 465) were within the LOA range. The 95% LOA of protein, fat, lactose and energy were - 0.6 to 0.6 g/dl, -0.92 to 0.92 g/dl, -0.88 to 0.88 g/dl and - 40.2 to 40.4 kj/dl, respectively and clinically acceptable. The adjusted ultrasonic results were consistent with the MIR results, and LOA results were high (close to 95%). CONCLUSIONS: While the results of the breast milk rapid analyzers using the two methods varied significantly, they could still be considered comparable after data adjustments using linear regression algorithm in machine learning. Machine learning methods can play a role in data fitting using different analyzers.

Validation of a Low-Cost Electrocardiography (ECG) System for Psychophysiological Research.

BACKGROUND AND OBJECTIVE: The reliability of low-cost mobile systems for recording Electrocardiographic (ECG) data is mostly unknown, posing questions regarding the quality of the recorded data and the validity of the extracted physiological parameters. The present study compared the BITalino toolkit with an established medical-grade ECG system (BrainAmp-ExG). METHODS: Participants underwent simultaneous ECG recordings with the two instruments while watching pleasant and unpleasant pictures of the "International Affective Picture System" (IAPS). Common ECG parameters were extracted and compared between the two systems. The Intraclass Correlation Coefficients (ICCs) and the Bland-Altman Limits of Agreement (LoA) method served as criteria for measurement agreement. RESULTS: All but one parameter showed an excellent agreement (>80%) between both devices in the ICC analysis. No criteria for Bland-Altman LoA and bias were found in the literature regarding ECG parameters. CONCLUSION: The results of the ICC and Bland-Altman methods demonstrate that the BITalino system can be considered as an equivalent recording device for stationary ECG recordings in psychophysiological experiments.

Parametric and nonparametric improvements in Bland and Altman's assessment of agreement method.

The Bland-Altman method, which assesses agreement via an assessment set constructed by the difference of the measurement variables, has received great attention. Other assessment approaches have been proposed following the same difference-based framework. However, the exact assessment set constructed by the difference is achievable only for measurements with certain joint distributions. To provide a more general assessment framework, we propose two approaches. First, when the measurement distribution is known, we propose a parametric approach that constructs the assessment set through a measure of closeness corresponding to the distribution. Second, when the measurement distribution is unknown, we propose a nonparametric approach that constructs the assessment set through quantile regression. Both approaches quantify the degree of agreement with the presence of both systematic and random measurement errors, and enable one to go beyond the difference-based approach. Results of simulation and data analyses are presented to compare the two approaches.

Validation of a life-logging wearable camera method and the 24-h diet recall method for assessing maternal and child dietary diversity.

Accurate and timely data are essential for identifying populations at risk for undernutrition due to poor-quality diets, for implementing appropriate interventions and for evaluating change. Life-logging wearable cameras (LLWC) have been used to prospectively capture food/beverage consumed by adults in high-income countries. This study aimed to evaluate the concurrent criterion validity, for assessing maternal and child dietary diversity scores (DDS), of a LLWC-based image-assisted recall (IAR) and 24-h recall (24HR). Direct observation was the criterion method. Food/beverage consumption of rural Eastern Ugandan mothers and their 12-23-month-old child (n 211) was assessed, for the same day for each method, and the IAR and 24HR DDS were compared with the weighed food record DDS using the Bland-Altman limits of agreement (LOA) method of analysis and Cohen's κ. The relative bias was low for the 24HR (-0·1801 for mothers; -0·1358 for children) and the IAR (0·1227 for mothers; 0·1104 for children), but the LOA were wide (-1·6615 to 1·3012 and -1·6883 to 1·4167 for mothers and children via 24HR, respectively; -2·1322 to 1·8868 and -1·7130 to 1·4921 for mothers and children via IAR, respectively). Cohen's κ, for DDS via 24HR and IAR, was 0·68 and 0·59, respectively, for mothers, and 0·60 and 0·59, respectively, for children. Both the 24HR and IAR provide an accurate estimate of median dietary diversity, for mothers and their young child, but non-differential measurement error would attenuate associations between DDS and outcomes, thereby under-estimating the true associations between DDS - where estimated via 24HR or IAR - and outcomes measured.

Bland-Altman methods for comparing methods of measurement and response to criticisms.

Introduced in 1983, Bland-Altman methods is now considered the standard approach for assessment of agreement between two methods of measurement. The method is widely used by researchers in various disciplines so that the Bland-Altman 1986 Lancet paper has been named as the 29th mostly highly cited paper ever, over all fields. However, two papers by Hopkins (2004) and Krouwer (2007) questioned the validity of the Bland-Altman analysis. We review the points of critical papers and provide responses to them. The discussions in the critical papers of the Bland-Altman method are scientifically delusive. Hopkins misused the Bland-Altman methodology for research question of model validation and also incorrectly used least-square regression when there is measurement error in the predictor. The problem with Krouwers' paper is making sweeping generalisation of a very narrow and somewhat unrealistic situation. The method proposed by Bland and Altman should be used when the research question is method comparison.

Reliability and Test-Retest Agreement of Mechanical Variables Obtained During Countermovement Jump.

The countermovement jump (CMJ) is often used as performance measure and monitoring tool. Traditionally, jump height (JH) is most often studied and reported, but other variables (e.g. force, velocity, power) can also be obtained during CMJ testing on a force plate. The aim of this study was to determine the intra-rater reliability of mechanical variables obtained during CMJs. For this, 41 physically active men (24 ± 4 years) performed four CMJs on a force plate with an interval of 48 to 168 hours (test-retest design). Six variables were analyzed: 1) jump height (JH), 2) peak force (PF), 3) peak power (PP), 4) velocity at takeoff (VTO), 5) rate of force (RFD) and 6) power (RPD) development. Five variables showed to be reliable (i.e. CV < 10%), except RFD (CV of 12.9%). Although JH exhibited an acceptable level of reliability (r = 0.94 and CV = 5.8%), better scores were observed for PF, VTO, and PP (CV ranging from 2.5 to 5.1%). The PF showed the best reliability scores (r = 0.99 and CV = 2.5%) and RPD, a relatively unexamined variable compared to the others, showed an acceptable level of reliability (r = 0.96 and CV = 7.8%). Therefore, JH, PF, PP, VTO, and RPD demonstrated acceptable scores of reliability. PF seems to be the most appropriate variable to use when small changes in performance are expected. Future studies should investigate the importance of RPD for performance evaluation.

Ecuaciones para la estimación del agua corporal total por el método de análisis de impedancia bioeléctrica a 50 kHz / Equations for the estimate of total body water by the method of bioelectric impedance at 50 kHz

Introducción: El agua mantiene un rango normal en personas aparentemente sanas, el cual se altera ante la existencia de diversas enfermedades. Objetivo: Conocer cuánto se diferencian los valores de agua corporal total estimados por las ecuaciones de agua corporal total, de Kushner, de Deurenberg y de Heitman, con respecto a los obtenidos clínicamente por el método de impedancia bioeléctrica a 50 kHz. Métodos: Se realizó un estudio descriptivo y transversal, de abril a diciembre del 2018, en 62 individuos: 31 adultos aparentemente sanos y 31 niños y adolescentes con diferentes enfermedades, ingresados en el Hospital Infantil Docente Sur Dr. Antonio María Béguez César de Santiago de Cuba (24 en el Servicio de Misceláneas y 7 en el de Oncopediatría). El agua corporal total y los parámetros bioeléctricos se estimaron con el analizador de impedancia bioeléctrica Bodystat® 1500-MDD, a 50 kHz, por el método tetrapolar ipsilateral derecho. Se utilizó el criterio de Bland-Altman, para un 95 % de confianza, a fin de conocer si las ecuaciones de Kushner, de Deurenberg y de Heitman podían sustituir a la ecuación de referencia. Resultados: Las ecuaciones de agua corporal total, de Kushner y de Deurenberg no mostraron diferencias significativas respecto a la ecuación de referencia, mientras que la ecuación de Heitman sí presentó diferencias significativas en relación con el resto de las ecuaciones. El método de Bland-Altman demostró que la ecuación de Kushner posee mayor concordancia con la ecuación de referencia. Conclusiones: La ecuación de Kushner es la de mayor exactitud para la estimación del agua corporal total en personas sanas y en las afectadas por entidades clínicas.

Introduction: The water maintains a normal range in apparently healthy people, which changes with the existence of diverse diseases. Objective: To know how the values of total body water estimated by Kushner, Deurenberg and Heitman equations of total body water, differ regarding those obtained clinically by the method of bioelectric impedance at 50 kHz. Methods: A descriptive and cross-sectional study was carried out, from April to December, 2018, in 62 individuals: 31 apparently healthy adults and 31 children and adolescents with different diseases, admitted to "Dr. Antonio María Béguez César" Southern Teaching Children Hospital in Santiago de Cuba (24 in the Miscellaneous Service and 7 in Oncopediatrics Service). The total body water and the bioelectric parameters were considered with the analyzer of bioelectric impedance Bodystat® 1500-MDD, at 50 kHz, for the right ipsilateral tetrapolar method. The approach of Bland-Altman was used, for 95% of confidence in order to know if Kushner, Deurenberg and Heitman equations could substitute the reference equation. Results: Kushner and Deurenberg equations of total body water didn't show significant differences regarding the reference equation, while Heitman equation presented significant differences related to the rest of the equations. The Bland-Altman method demonstrated that the equation of Kushner has higher concordance with the reference equation. Conclusions: Kushner equation has the highest accuracy for the estimate of total body water in healthy people and in those affected by diseases.

Comparison of Two Different Techniques Of Warfarin Dosing Determination - A Chemometrics Study.

A high prevalence of genetic polymorphisms increases sensitivity to warfarin therapy. In this study, we investigated 47 patients with effective long-term therapy by warfarin well-controlled by monitoring of International Normalised Ratio (INR). All patients were tested for gene polymorphisms VKORC1, CYP2C9*C2, and CYP2C9*C3, which were used for a dose calculation employing a program www.WarfarinDosing.org. The main goal was to investigate whether the warfarin doses determined by INR are in accordance with the doses calculated according to the pharmacogenetic algorithm. For this purpose, several chemometric tools, namely principal component analysis, cluster analysis, correlation analysis, correspondence analysis, Passing-Bablock regression, Bland-Altman method, descriptive statistics, and ANOVA were used. We also analysed the relationship between the dose of warfarin determined by INR and several constitutional and genetic factors. Statistically significant association between clinically optimized warfarin dose and indication for the treatment, age, and warfarin sensitivity determined by VKORC1, CYP2C9 gene polymorphisms were confirmed. Finally, we confirmed a good concordance between the INR determined warfarin doses and pharmacogenetic approach.

Statistical comparative study between the conventional DPPH spectrophotometric and dropping DPPH analytical method without spectrophotometer: Evaluation for the advancement of antioxidant activity analysis.

Recently, new approaches for measuring antioxidant activity have been developed to eliminate or reduce the use of a spectrophotometer. All analytical methods must provide consistent and reliable results, which should be compared with statistical models. Therefore, we compared the conventional and dropping DPPH methods with three widely used standards. We employed and compared with three statistical methods. Good R-squared (R2 = ≥0.96) confirmed the similarity in comparison of using dropping DPPH method compared with the conventional DPPH method and reported lower deviations (ARD = -0.32 to 0.13; RMSD = 0.10 to 1.15). Bland-Altman method (95% CI) demonstrated a good agreement between the two methods using standards and grape extracts (skin and seed). These findings suggested that the dropping DPPH method proved cheaper (without spectrophotometer) and correlated well with the conventional DPPH method. Therefore, this method could be affordably conducted in research laboratories in developing and less developed countries.

Comparison of Self-Reported and Objectively Measured Sedentary Behavior and Physical Activity in Undergraduate Students.

OBJECTIVE: To investigate differences between estimates of sedentary behavior and physical activity (PA) from the International Physical Activity Questionnaire (IPAQ) and accelerometry in undergraduate students. PARTICIPANTS: 91 students participated in the study. METHODS: Sedentary behavior and PA were objectively measured by an accelerometer for 7 days and then self-reported with the IPAQ. Partial correlations were used to assess associations among PA variables and participant characteristics between the methods. Agreement was assessed via the Bland-Altman method. RESULTS: Correlation coefficients between self-reported and objectively measured PA ranged from 0.21 to 0.38 (p≤0.05 for all). A higher proportion of students were classified as meeting PA guidelines via self-report compared to objective measurements. Bland-Altman plots revealed acceptable agreement between methods, however, bias was evident for all PA intensities. Sex and lean body mass impacted these differences. CONCLUSIONS: Researchers should exercise caution when interpreting PA assessed via the IPAQ in undergraduate students.

The accuracy of a handheld "disposable pneumotachograph device" in the spirometric diagnosis of airway obstruction in a Chinese population.

Background and aim: It is desirable to facilitate the use of an affordable, reliable, and portable spirometer, for earlier diagnosis of COPD in China, particularly in rural areas. The aim of this study was to assess the agreement of a handheld "disposable pneumotachograph" (D-PNEU) spirometer with the gold standard spirometer and to evaluate its diagnostic accuracy of spirometric classification of airflow obstruction. Subjects and methods: A total of 241 adult Chinese subjects ranging from healthy to those with mixed levels of pulmonary disease performed spirometry in a conventional body plethysmograph, and using a D-PNEU device in randomized order. The three best spirometric tests were recorded for comparative analysis. A Bland-Altman graph was created to assess the agreement between devices. Using FEV1/FVC <70% as the "gold standard" for obstruction, the accuracy of classifying the severity of airway obstruction for all subjects was assessed. For the specific individuals (n=159) able to exhale for at least 6 seconds, the accuracy of classifying airway obstruction was further assessed. For this purpose, a receiver operating characteristic curve was used to determine an optimal cutoff point of FEV1/FEV6 ratio obtained by the D-PNEU device, which matched the global definition of FEV1/FVC <70% by the traditional spirometer. Results: The Bland-Altman analysis showed that the between-device agreement for key airflow metrics was within clinically acceptable limits. The D-PNEU device had 87.1% accuracy in the classification of severity of obstruction in all 241 subjects, when using FEV1/FVC<70% as the "gold standard" for both devices. The D-PNEU device had 93.7% accuracy in the 159 individuals able to exhale for at least 6 seconds, when a cutoff point of FEV1/FEV6 was 74%. Conclusion: A disposable handheld spirometry device is capable of accurately identifying and quantifying airway obstruction in patients deemed to be at risk, however, caution should be exercised and all available brands should be tested.

Reporting items of agreement evaluation using Bland-Altman Method:RiBAM / 医学研究生学报

With the promotion and application in medicine and sanitary fields,the reporting quality of Bland-Altman agreement evaluation is worrying.This study aimed at developing a set of reporting standards for Bland-Altman agreement evaluation as the guidance for proper application to improve the reporting quality.A research group was launched to work on reporting standards for Bland-Altman agreement evaluation,and all the requirements for personnel on various levels were made clear.Early in the study,we carried out articles reviews,regular meetings,expert consultations,literary evaluation,item integration and extraction.Then,we invited a multi-disciplinary panel of experts to improve overall design,evaluate reporting items and form the first draft by brainstorming method.Multiple rounds of expert consultations were also conducted with reference to Delphi method to integrate expert advice and form the basic framework of reporting items.Finally,through the thorough analysis and demonstration,we proposed the reporting items for the agreement evaluation of Bland-Altman method (RiBAM) as the recommended report.A list of recommended items called RiBAM was formed,which consisted of 17 first-level items and 23 secondary-level items.RiBAM is more comprehensive and systematic as an important reference for improving the quality of reports by avoiding the omission of reporting contents and achieving the clarity,integrity and transparency of the report.RiBAM recommended items can be a guide for authors in reporting Bland-Altman agreement evaluation as well as a basic reference for journal editors,peer reviewers and readers.

A framework for the meta-analysis of Bland-Altman studies based on a limits of agreement approach.

Bland-Altman method comparison studies are common in the medical sciences and are used to compare a new measure to a gold-standard (often costlier or more invasive) measure. The distribution of these differences is summarized by two statistics, the 'bias' and standard deviation, and these measures are combined to provide estimates of the limits of agreement (LoA). When these LoA are within the bounds of clinically insignificant differences, the new non-invasive measure is preferred. Very often, multiple Bland-Altman studies have been conducted comparing the same two measures, and random-effects meta-analysis provides a means to pool these estimates. We provide a framework for the meta-analysis of Bland-Altman studies, including methods for estimating the LoA and measures of uncertainty (i.e., confidence intervals). Importantly, these LoA are likely to be wider than those typically reported in Bland-Altman meta-analyses. Frequently, Bland-Altman studies report results based on repeated measures designs but do not properly adjust for this design in the analysis. Meta-analyses of Bland-Altman studies frequently exclude these studies for this reason. We provide a meta-analytic approach that allows inclusion of estimates from these studies. This includes adjustments to the estimate of the standard deviation and a method for pooling the estimates based upon robust variance estimation. An example is included based on a previously published meta-analysis. Copyright © 2017 John Wiley & Sons, Ltd.

Accuracy of maxillary repositioning by computer-aided orthognathic surgery in patients with normal temporomandibular joints.

Our aim was to assess the accuracy of computer-aided orthognathic surgery for maxillary repositioning in 15 patients with mandibular hyperplasia and normal temporomandibular joints (TMJ). We aligned preoperative and postoperative virtual skulls at the cranium using surface superimposition then recorded and calibrated three 3-dimensional coordinates (maxillary dental landmarks U0, 6R, and 6L) on the skulls. Errors between these preoperative and postoperative landmarks were calculated and the largest error of every patient was chosen for assessment. Landmark errors ranged from 1.00 - 2.49mm, and recording errors from -0.06 - 0.07mm. The superimposition error was mean (SD) 0.036 (0.002)mm. The accuracy of the method is acceptable in patients with a normal TMJ.

Clinically acceptable agreement between the ViMove wireless motion sensor system and the Vicon motion capture system when measuring lumbar region inclination motion in the sagittal and coronal planes.

BACKGROUND: Wireless, wearable, inertial motion sensor technology introduces new possibilities for monitoring spinal motion and pain in people during their daily activities of work, rest and play. There are many types of these wireless devices currently available but the precision in measurement and the magnitude of measurement error from such devices is often unknown. This study investigated the concurrent validity of one inertial motion sensor system (ViMove) for its ability to measure lumbar inclination motion, compared with the Vicon motion capture system. METHODS: To mimic the variability of movement patterns in a clinical population, a sample of 34 people were included - 18 with low back pain and 16 without low back pain. ViMove sensors were attached to each participant's skin at spinal levels T12 and S2, and Vicon surface markers were attached to the ViMove sensors. Three repetitions of end-range flexion inclination, extension inclination and lateral flexion inclination to both sides while standing were measured by both systems concurrently with short rest periods in between. Measurement agreement through the whole movement range was analysed using a multilevel mixed-effects regression model to calculate the root mean squared errors and the limits of agreement were calculated using the Bland Altman method. RESULTS: We calculated root mean squared errors (standard deviation) of 1.82° (±1.00°) in flexion inclination, 0.71° (±0.34°) in extension inclination, 0.77° (±0.24°) in right lateral flexion inclination and 0.98° (±0.69°) in left lateral flexion inclination. 95% limits of agreement ranged between -3.86° and 4.69° in flexion inclination, -2.15° and 1.91° in extension inclination, -2.37° and 2.05° in right lateral flexion inclination and -3.11° and 2.96° in left lateral flexion inclination. CONCLUSIONS: We found a clinically acceptable level of agreement between these two methods for measuring standing lumbar inclination motion in these two cardinal movement planes. Further research should investigate the ViMove system's ability to measure lumbar motion in more complex 3D functional movements and to measure changes of movement patterns related to treatment effects.

Intra-rater reliability and agreement of various methods of measurement to assess dorsiflexion in the Weight Bearing Dorsiflexion Lunge Test (WBLT) among female athletes.

OBJECTIVES: To examine the intra-observer reliability and agreement between five methods of measurement for dorsiflexion during Weight Bearing Dorsiflexion Lunge Test and to assess the degree of agreement between three methods in female athletes. DESIGN: Repeated measurements study design. SETTING: Volleyball club. PARTICIPANTS: Twenty-five volleyball players. MAIN OUTCOME MEASUREMENTS: Dorsiflexion was evaluated using five methods: heel-wall distance, first toe-wall distance, inclinometer at tibia, inclinometer at Achilles tendon and the dorsiflexion angle obtained by a simple trigonometric function. For the statistical analysis, agreement was studied using the Bland-Altman method, the Standard Error of Measurement and the Minimum Detectable Change. Reliability analysis was performed using the Intraclass Correlation Coefficient. RESULTS: Measurement methods using the inclinometer had more than 6° of measurement error. The angle calculated by trigonometric function had 3.28° error. The reliability of inclinometer based methods had ICC values < 0.90. Distance based methods and trigonometric angle measurement had an ICC values > 0.90. Concerning the agreement between methods, there was from 1.93° to 14.42° bias, and from 4.24° to 7.96° random error. CONCLUSION: To assess DF angle in WBLT, the angle calculated by a trigonometric function is the most repeatable method. The methods of measurement cannot be used interchangeably.

The Agreement between Parent-Reported and Directly Measured Child Language and Parenting Behaviors.

Parenting behaviors are commonly targeted in early interventions to improve children's language development. Accurate measurement of both parenting behaviors and children's language outcomes is thus crucial for sensitive assessment of intervention outcomes. To date, only a small number of studies have compared parent-reported and directly measured behaviors, and these have been hampered by small sample sizes and inaccurate statistical techniques, such as correlations. The Bland-Altman Method and Reduced Major Axis regression represent more reliable alternatives because they allow us to quantify fixed and proportional bias between measures. In this study, we draw on data from two Australian early childhood cohorts (N = 201 parents and slow-to-talk toddlers aged 24 months; and N = 218 parents and children aged 6-36 months experiencing social adversity) to (1) examine agreement and quantify bias between parent-reported and direct measures, and (2) to determine socio-demographic predictors of the differences between parent-reported and direct measures. Measures of child language and parenting behaviors were collected from parents and their children. Our findings support the utility of the Bland-Altman Method and Reduced Major Axis regression in comparing measurement methods. Results indicated stronger agreement between parent-reported and directly measured child language, and poorer agreement between measures of parenting behaviors. Child age was associated with difference scores for child language; however, the direction varied for each cohort. Parents who rated their child's temperament as more difficult tended to report lower language scores on the parent questionnaire, compared to the directly measured scores. Older parents tended to report lower parenting responsiveness on the parent questionnaire, compared to directly measured scores. Finally, speaking a language other than English was associated with less responsive parenting behaviors on the videotaped observation compared to the parent questionnaire. Variation in patterns of agreement across the distribution of scores highlighted the importance of assessing agreement comprehensively, providing strong evidence that simple correlations are grossly insufficient for method comparisons. We discuss implications for researchers and clinicians, including guidance for measurement selection, and the potential to reduce financial and time-related expenses and improve data quality. Further research is required to determine whether findings described here are reflected in more representative populations.

Consistency evaluation for quantitative measurements by Bland-Altman method and its clinical application / 医学研究生学报

The Bland-Altman method has been widely used for consistency evaluation in the field of medicine .However, fre-quent errors in the application of the method seriously affect the quality of researches .This review focuses on the studies of the Bland-Altman method , the status quo and common problems in its application , and standards for related reports .

Parámetros bioeléctricos in vitro e in vivo, estimados con los analizadores Bodystat®1500-MDD y BioScan®98 / Bioelectrical parameters in vitro and in vivo estimated with analyzers Bodystat®1500-MDD and BioScan®98

Se efectuó un estudio comparativo de 2 analizadores comerciales de bioimpedancia eléctrica corporal (Bodystat® 1500-MDD y BioScan®98) en el Servicio de Oncopediatría del Hospital Infantil Sur de Santiago de Cuba, desde septiembre hasta octubre del 2009, para lo cual se realizó una simulación in vitro con los calibradores de cada equipo y un estudio in vivo de 32 adultos aparentemente sanos y 32 niños con diferentes afecciones. La resistencia eléctrica y la reactancia capacitiva se estimaron con ambos analizadores; además, se calcularon el módulo de impedancia y el ángulo de fase. La prueba t-student de 2 medias para muestras apareadas y el método de Bland-Altman fueron los criterios estadísticos usados. No existieron diferencias significativas entre ambos analizadores al introducir los factores de corrección para la resistencia eléctrica y la reactancia capacitiva; por tanto, es posible usarlos indistintamente para caracterizar bioeléctricamente a los individuos aparentemente sanos y pacientes con diferentes enfermedades.

A controlled trial with 2 body electrical impedance commercial analyzers was carried out (Bodystat® 1500-MDD and BioScan®98) at the Pediatric Oncology Department of the Southern Children Hospital in Santiago de Cuba, from September to October 2009, for which an in vitro simulation with gauges of each device and an in vivo study in 32 apparently healthy adults and 32 children with different conditions were conducted. Electrical resistance and capacitive reactance were estimated with both analyzers, and impedance module and phase angle were also calculated. The two-means Student's t test for paired samples and the Bland-Altman method were used as statistical criteria. There were not significant differences between the two analyzers by introducing correction factors for electrical resistance and capacitive reactance; therefore, it is possible to use either to characterize bioelectrically apparently healthy individuals and patients with different conditions.