Dataset Information

Left ventricular mass normalization for body size in children based on an allometrically adjusted ratio is as accurate as normalization based on the centile curves method.

ABSTRACT:

Background

Normalization for body size is required for reliable left ventricular mass (LVM) evaluation, especially in children due to the large variability of body size. In clinical practice, the allometrically adjusted ratio of LVM to height raised to the power of 2.7 is often used. However, studies presenting normative LVM data for children recommend centile curves as optimal for the development of normative data. This study aimed to assess whether the allometrically adjusted LVM-to-height ratio can reliably reproduce the results of LVM normalization for height based on the centile curves method.

Methods

Left ventricular mass was computed for 464 boys and 327 girls, 5-18 years old, based on echocardiographic examination. Normalized data representing LVM for height were developed using the centile curves construction method and two variants of the allometrically adjusted ratio method: one variant with the allometric exponents specific to the study groups, and one variant with the universal exponent of 2.7. The agreement between the allometric methods and the centile curves method was analyzed using the concordance correlation coefficient, sensitivity, and specificity.

Results

For both the specific allometric variant and the universal variant, the analysis of concordance has indicated high reproducibility compared to the centile curves method. The respective coefficient values were 0.9917 and 0.9916 for girls, and 0.9886 and 0.9869 for boys. The sensitivity and specificity test has also shown high agreement. However, for girls, the sensitivity was higher for the specific variant (100% vs. 90.9%).

Conclusion

The results of the study show that allometric scaling of LVM for height can very reliably reproduce the results of LVM normalization for height based on the centile curves method. However, the analysis of sensitivity and specificity indicates greater agreement for the allometric normalization with the group-specific allometric exponents.

SUBMITTER: Krysztofiak H

PROVIDER: S-EPMC6872180 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Publications

Left ventricular mass normalization for body size in children based on an allometrically adjusted ratio is as accurate as normalization based on the centile curves method.

Krysztofiak Hubert H Młyńczak Marcel M Małek Łukasz A ŁA Folga Andrzej A Braksator Wojciech W

PloS one 20191121 11

<h4>Background</h4>Normalization for body size is required for reliable left ventricular mass (LVM) evaluation, especially in children due to the large variability of body size. In clinical practice, the allometrically adjusted ratio of LVM to height raised to the power of 2.7 is often used. However, studies presenting normative LVM data for children recommend centile curves as optimal for the development of normative data. This study aimed to assess whether the allometrically adjusted LVM-to-he ...[more]

PMID: 31751386

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Project description:ObjectiveIdentifying muscle weakness and probable sarcopenia using strength tests requires reference data. This study aimed to provide age- and sex-specific normative data for grip strength and common variations of the Sit-to-Stand (STS) test: time to complete 5 stands (5x-STS) and number of stands completed in 30 seconds (30s-STS). Predictors of test performance were also explored.MethodsDominant hand grip strength was assessed in adults (age = 18-80 years) using a digital dynamometer, and 5x-STS and 30s-STS performance were assessed synchronously during a single 30-second test. Sex-specific centile curves were generated using the lambda-mu-sigma method.ResultsData from 2301 participants (female = 1682, male = 619) were included. Peak median grip strength occurred in female participants at 33.9 years of age (27.9 kg) and in male participants at 37.6 years of age (47.2 kg). 5x-STS and 30s-STS performance peaked at the youngest age (18.0 years) in both female participants (8.16 seconds and 17.2 repetitions) and male participants (8.02 seconds and 17.7 repetitions). Test performances were lowest for all tests at the oldest age in the database. Predictors of better test performance included lower age and higher self-reported physical functioning and appendicular skeletal muscle mass, to name a few. White participants had better performance than Black participants on the STS tests.ConclusionThe generated centile curves reveal the pattern of change in muscle strength for tests recommended to identify probable sarcopenia. The curves can be used in rehabilitation to assess an individual's performance relative to sex- and age-specific norms. To aid use of the data, a downloadable Excel-based calculator is provided to compute participant-specific percentiles, z scores, and t scores for each outcome and plot performance on the centile curves.ImpactPhysical therapists have an important role in identifying and treating individuals with sarcopenia and other causes of muscle weakness. The reference data provided for common clinical muscle strength tests provide therapists an ability to assess an individual's relative performance.Lay summaryKnowing the normal or expected strength for an individual's age and sex is essential to identifying muscle weakness. This study provides age- and sex-specific normal values for hand grip strength and sit-to-stand tests in adults aged 18 to 80 years.

Project description:BACKGROUND:Left ventricular mass normalization for body size is recommended, but a question remains: what is the best body size variable for this normalization-body surface area, height or lean body mass computed based on a predictive equation? Since body surface area and computed lean body mass are derivatives of body mass, normalizing for them may result in underestimation of left ventricular mass in overweight children. The aim of this study is to indicate which of the body size variables normalize left ventricular mass without underestimating it in overweight children. METHODS:Left ventricular mass assessed by echocardiography, height and body mass were collected for 464 healthy boys, 5-18 years old. Lean body mass and body surface area were calculated. Left ventricular mass z-scores computed based on reference data, developed for height, body surface area and lean body mass, were compared between overweight and non-overweight children. The next step was a comparison of paired samples of expected left ventricular mass, estimated for each normalizing variable based on two allometric equations-the first developed for overweight children, the second for children of normal body mass. RESULTS:The mean of left ventricular mass z-scores is higher in overweight children compared to non-overweight children for normative data based on height (0.36 vs. 0.00) and lower for normative data based on body surface area (-0.64 vs. 0.00). Left ventricular mass estimated normalizing for height, based on the equation for overweight children, is higher in overweight children (128.12 vs. 118.40); however, masses estimated normalizing for body surface area and lean body mass, based on equations for overweight children, are lower in overweight children (109.71 vs. 122.08 and 118.46 vs. 120.56, respectively). CONCLUSION:Normalization for body surface area and for computed lean body mass, but not for height, underestimates left ventricular mass in overweight children.

Dataset Information

Left ventricular mass normalization for body size in children based on an allometrically adjusted ratio is as accurate as normalization based on the centile curves method.

Background

Methods

Results

Conclusion

Publications

Left ventricular mass normalization for body size in children based on an allometrically adjusted ratio is as accurate as normalization based on the centile curves method.

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