Body surface area formulae: an alarming ambiguity

Simultaneous, Seconds-Resolved Doxorubicin Measurements in the Blood and Subcutaneous Interstitial Fluid Identify Quantitative Pharmacokinetic Relationships between the Two

The kinetics with which chemotherapeutics distribute into solid tissues, including their sites of both action and toxicity, remains poorly characterized. This is due to the limited temporal resolution of traditional methods of measuring drug concentrations in the body, all of which employ sample collection (e.g., via a blood draw or microdialysis) followed by benchtop analysis. Here, we have used electrochemical aptamer-based (EAB) sensors to perform simultaneous, 12 s resolution, nanomolar-precision measurements of the chemotherapeutic doxorubicin in the jugular vein (plasma) and subcutaneous space (interstitial fluid) of live rats. The resulting data sets identify predictively strong correlations between its plasma and solid-tissue pharmacokinetics in terms of both cumulative (area under the curve) and maximum exposure. In contrast, the correlations between delivered body-mass-adjusted and body-surface-area-adjusted doses and drug exposure in both the plasma and solid tissue are relatively poor. The latter observation highlights the need for therapeutic drug monitoring, and the former observation shows the potential value of employing subcutaneous EAB sensors as a convenient, minimally invasive, high-precision means of performing such monitoring. The high time density of our two-compartment data sets also provides unprecedented opportunities to model the distribution of a drug from the central compartment to a distal physiological compartment. We find that the preferred description of doxorubicin transport into the solid tissues for five of our six data sets is a three-compartment model composed of the vein (plasma), the interstitial fluid, and an unobserved third compartment distal to the interstitial fluid, with this additional compartment presumably representing intracellular fluid.

Measuring Biventricular Function and Left Atrial Volume in a Single 5D Whole-Heart CMR Scan at 0.55T

BACKGROUND

CMR has not seen widespread adoption beyond large urban academic centers. The reasons for this limited uptake include the cost, time-intensive nature and special expertise of CMR. Self-navigated 5D, x-y-z-cardiac-respiratory, free-funning whole-heart CMR using self-navigation (5D CMR) implemented on a low-field clinical scanner may help bridge this gap for bi-ventricular function assessment and left atrium volume index measurement.

METHODS

Whole-heart 3D radial phyllotaxis bSSFP data were collected in 10 healthy adult subjects. Self-navigation was used to extract respiratory and cardiac motion signals and to generate motion-resolved 5D CMR datasets. The right- and left-ventricular ejection fraction (RVEF and LVEF), left atrial volume index (LAVI), contrast ratio, sharpness, perceived image quality, and total scan durations were ascertained and compared to those obtained with the reference 2D cine images.

RESULTS

5D CMR allowed for time-efficient and concordant measurements when compared to the 2D reference method. The 5D CMR images resulted in lower CR on 5D CMR images (3.3 ± 2.9) than on 2D cines (4.7 ± 1.2), and similarly lower perceived image quality (1.8 ± 0.8 for 5D CMR and 3.6 ± 0.9 for the 2D cines). However, the LVEF measurements were similar with no statistically significant differences (Mean: 58 ± 5% for 5D CMR and 59 ± 5% for 2D cine, p = 0.49) and the LoA were low (-2.81% to 3.81%). For the RVEF, the measurements were also in good agreement when RVEF was measured on the axial views (60 ± 3% for 5D CMR and 60 ± 4% for 2D cine, p = 0.85) and the LoA were also low (-2.87% to 3.07%).

CONCLUSION

5D CMR without the need for ECG, breath-holding, navigators, or complex scan planning enables a highly simplified and time-efficient assessment of bi-ventricular cardiac function on a 0.55T clinical system in 7:50min.

Synergy of Body Composition, Exercise Oncology, and Pharmacokinetics: A Narrative Review of Personalizing Paclitaxel Treatment for Breast Cancer

BACKGROUND/OBJECTIVES

Paclitaxel is a type of small molecule chemotherapy widely used for breast cancer, but its clinical efficacy is often hindered by dose-limiting toxicities such as chemotherapy-induced peripheral neuropathy and neutropenia. Traditional dosing based on body surface area does not account for variations in body composition, which may influence paclitaxel metabolism, toxicity, and treatment outcomes. This review explores the interplay between body composition, physical activity, and paclitaxel pharmacokinetics, emphasizing the potential for personalized dosing strategies.

METHODS

A comprehensive narrative review was conducted by analyzing the literature on body composition, small molecule chemotherapy-related toxicities, pharmacokinetics, and exercise oncology. Studies examining the role of skeletal muscle mass, adipose tissue, and physical activity in modulating paclitaxel metabolism and side effects were included.

RESULTS

Evidence suggests that patients with low skeletal muscle mass are at a higher risk of paclitaxel-induced toxicities due to altered drug distribution and clearance. Sarcopenic obesity, characterized by low muscle and high-fat levels, further exacerbates these risks. Exercise, particularly resistance and aerobic training, has been shown to improve muscle mass, mitigate toxicities, and enhance chemotherapy tolerance. However, the precise mechanisms by which exercise influences paclitaxel pharmacokinetics remain underexplored.

CONCLUSIONS

Personalized chemotherapy dosing, considering body composition and physical activity, may optimize paclitaxel treatment outcomes. Future research should focus on integrating exercise interventions into oncology care and refining dosing models that account for interindividual differences in drug metabolism. These advancements could improve treatment efficacy while minimizing toxicities in breast cancer patients.

The Creeping Creatinine in a Growing Child With a Kidney Transplant: Distinguishing Progressive Graft Dysfunction From Normal Growth in Pediatric Kidney Transplant Recipients

BACKGROUND

Pediatric kidney transplant recipients experience creeping creatinine, which is a slow increase in serum creatinine over time. Distinguishing between normal growth-related changes and possible allograft dysfunction becomes challenging when interpreting the increase in serum creatinine. We hypothesized that changes in BSA-indexed measured glomerular filtration rate (mGFR) or creatinine-estimated GFR (eGFR) might not be a true reflection of the renal function post-transplant and that for longitudinal follow-up a stable absolute mGFR is better.

METHODS

In total, 115 pediatric kidney transplant recipients transplanted between 2000 and 2021, with 319 measured GFR values (each subject had at least 2 values) were enrolled in this retrospective study. We analyzed after stratifying based on the height and BSA changes (< 5% change, 5%-14.9% change, and > 15% change in height and BSA) between measured GFR tests. The agreement between absolute mGFR and both BSA-indexed mGFR or eGFR was analyzed by Bland and Altman analysis and nonparametric Spearman's rank order correlation analysis.

RESULTS

The bias between absolute mGFR and either BSA-indexed mGFR or eGFR increased as the % change in height and the BSA increased. Spearman's rank order correlation showed a strong correlation when the BSA and height changes were < 5% and the correlation weakened as the % changes increased.

CONCLUSIONS

In children who grew more, the BSA-indexed mGFR dropped more than the absolute mGFR. We propose that a stable absolute mGFR can be used to infer stable allograft function in the presence of height growth.

Improving Individualized Salbutamol Treatment: A Population Pharmacokinetic Model for Oral Salbutamol in Virtual Patients

BACKGROUND

Salbutamol, a short-acting β2-agonist used in asthma treatment, is available in multiple formulations, including inhalers, nebulizers, oral tablets, and intravenous, intramuscular, and subcutaneous routes. Each formulation exhibits distinct pharmacokinetic (PK) and pharmacodynamic (PD) profiles, influencing therapeutic outcomes and adverse effects. Although asthma management predominantly relies on inhaled salbutamol, understanding how these formulations interact with patient-specific characteristics could improve personalized medicine approaches, potentially uncovering the therapeutic benefits of alternative formulations for an individual patient. Herein, this study aims to analyze how covariates-such as age, weight, gender, body surface area (BSA), cytochrome P450 (CYP) expression, race, and health status-affect the therapeutic regime of orally administered salbutamol using population PK (popPK) modeling. The final model is intended as a tool to support the selection of optimal formulation and dosage regimen based on individual patient profiles.

METHODS

A dataset of 40 virtual patients derived from a physiologically based PK (PBPK) model of oral salbutamol was included in the popPK model.

RESULTS

A two-compartment model with first-order elimination and absorption, with a transit compartment, best described the plasma concentration-time profile following a 4 mg dose. Relationships were identified between gender and mean transit time (Mtt) and clearance (Cl), as well as the effects of weight and BSA on the volume of distribution of the central compartment (V1) and Cl, and a significant impact of health status on Cl.

CONCLUSIONS

Despite current contraindications for oral salbutamol, our findings suggest that certain individuals, particularly children, may benefit from oral treatment over inhalation. We also identified individual characteristics associated with increased salbutamol toxicity risk, indicating the need for dose adjustment or alternative administration. This study further highlights the potential of popPK modeling in personalized therapy through a fully in silico approach.

Dose-Limiting Toxicities of Paclitaxel in Breast Cancer Patients: Studying Interactions Between Pharmacokinetics, Physical Activity, and Body Composition-A Protocol for an Observational Cohort Study

Background/Objectives: Paclitaxel (PTX), a commonly used chemotherapy for breast cancer (BC), is associated with dose-limiting toxicities (DLTs) such as peripheral neuropathy and neutropenia. These toxicities frequently lead to dose reductions, treatment delays, or therapy discontinuation, negatively affecting patients' quality of life and clinical outcomes. Current dosing strategies based on body surface area (BSA) fail to account for individual variations in body composition (skeletal muscle mass (SMM) and adipose tissue (AT) mass) and physical activity (PA), which can influence drug metabolism and toxicity. This study aims to explore the relationships between PTX pharmacokinetics, body composition, and PA to predict DLTs. Methods: This single-group observational cohort study will recruit 40 female BC patients undergoing PTX treatment. Data collection will include plasma PTX concentrations, body composition assessments (using dual X-ray absorptiometry and bioelectrical impedance analysis), PA measurements (via accelerometers), and questionnaires to assess BC-related health-related quality of life, chemotherapy-induced peripheral neuropathy, and neutropenia during the PTX schedule using validated questionnaires. Dose-limiting toxicities will be graded according to the Common Terminology Criteria for Adverse Events v5.0 (grade 3 or higher). This protocol is designed to develop a population-based PK-PD model that predicts the occurrence of chemotherapy-induced peripheral neuropathy and neutropenia in women with stage II or III BC undergoing PTX therapy, focusing on explanatory outcomes related to SMM, AT mass, and PA.

Determining pulmonary artery diameter on CT scans as basis for performing transthoracic echocardiography to screen for pulmonary hypertension in patients with pulmonary artery enlargement

BACKGROUND

The current guidelines recommend patient stratification based on transthoracic echocardiography (TTE) to identify individuals with potential pulmonary hypertension (PH). We validated the relationship between PH and the pulmonary artery diameter (PAD) on computed tomography (CT) with peak tricuspid regurgitant velocity (TRV) measured by TTE for referral of patients with suspected PH for TTE screening.

METHODS

We performed a retrospective analysis of CT-based PAD of 2356 patients who underwent TTE from February 2, 2013 to December 25, 2019 at our institution. The thresholds for suspected PH based on TRV were determined using receiver operating characteristic curves based on PAD. Pearson's rank correlation coefficient was used to assess the relationship between PAD and TRV.

RESULTS

The area under the curve (AUC) of the PAD for suspected PH was statistically greater or comparable to others. The sex-specific PAD threshold for high PH probability were 29.4 mm (male: AUC, 0.86; sensitivity, 84.9%; specificity, 72.3%) and 27.8 mm (female: AUC, 0.83; sensitivity, 78%; specificity, 75.6%). Pearson's rank correlation coefficient showed a correlation between the PAD and TRV (male: ρ = 0.40, P < 0.001, female: ρ = 0.43, P < 0.001).

CONCLUSIONS

The main PAD on CT findings served as a suitable marker for referral of patients with suspected PH for TTE screening. Patients exceeding the CT-derived PAD threshold, even incidentally, should undergo additional TTE for a comprehensive PH assessment.

Comparison of the Effectiveness of Body Surface Area Estimation Formulas in Predicting the Risk of Death in Patients with Heart Failure

Background/Objectives: Body surface area is one of the most important anthropometric parameters in medicine. The study's primary objective is to compare the consistency of the BSA estimation results through applying available formulas. Other objectives include determining the ability of these formulas to discriminate between death and survival in patients, comparing the formulas' diagnostic features, and investigating whether the risk associated with a low BSA is independent of BMI. Methods: This study included 1029 patients (median age, 54 years; female, 13.7%; NYHA I/II/III/IV, 6.3%/36.5%/47.7%/9.5%) diagnosed with heart failure. For each patient, BSA was calculated using 25 formulas. Over the 3-year observation period, 31.2% of the patients died. Results: The average BSA value of the optimal discrimination thresholds was 1.79 m2 ± 0.084 m2 and the BSA difference between the estimators with the lowest (BSAMeeh1879) and the highest (BSANwoye1989) optimal discrimination thresholds was 0.42 m2. The lowest mortality rate was 35.2% and occurred in the subgroup of individuals with BSA values below the optimal discrimination threshold using the BSASchlich2010 estimator. The highest mortality was predicted when the estimator BSAMeeh1879 or BSALivingston&Lee2001 was used. Conclusions: Our study showed a relatively good concordance of 25 BSA estimators in BSA assessment in patients, without extremes of weight or height being known to disrupt it. All BSA estimators presented a significant, although weak, ability to discriminate death from survival at 3-year follow-up; however, BSA is not a very good predictor of HF mortality at 3 years. The higher risk of death in smaller patients, as shown by BSA, was independent of BMI in all but two BSA estimators.

Model-informed dose optimization of mycophenolic acid in pediatric kidney transplant patients

PURPOSE

We aimed to develop and evaluate a population PK model of mycophenolic acid (MPA) in pediatric kidney transplant patients to aid MPA dose optimization.

METHODS

Data were collected from pediatric kidney transplant recipients from a Dutch academic hospital (Radboudumc, the Netherlands). Pharmacokinetic model-building and model-validation analyses were performed using NONMEM. Subsequently, we externally evaluated the final model using data from another academic hospital. The final model was used to develop an optimized dosing regimen.

RESULTS

Thirty pediatric patients were included of whom 266 measured MPA plasma concentrations, including 20 full pharmacokinetic (PK) curves and 24 limited sampling curves, were available. A two-compartment model with a transition compartment for Erlang-type absorption best described the data. The final population PK parameter estimates were Ktr (1.48 h-1; 95% CI, 1.15-1.84), CL/F (16.0 L h-1; 95% CI, 10.3-20.4), Vc/F (24.9 L; 95% CI, 93.0-6.71E25), Vp/F (1590 L; 95% CI, 651-2994), and Q/F (36.2 L h-1; 95% CI, 9.63-74.7). The performance of the PK model in the external population was adequate. An optimized initial dose scheme based on bodyweight was developed. With the licensed initial dose, 35% of patients were predicted to achieve the target AUC, compared to 42% using the optimized scheme.

CONCLUSION

We have successfully developed a pharmacokinetic model for MPA in pediatric renal transplant patients. The optimized dosing regimen is expected to result in better target attainment early in treatment. It can be used in combination with model-informed follow-up dosing to further individualize the dose when PK samples become available.

Assessment of body mass-related covariates for rifampicin pharmacokinetics in healthy Caucasian volunteers

PURPOSE

Currently, body weight-based dosing of rifampicin is recommended. But lately, fat-free mass (FFM) was reported to be superior to body weight (BW). The present evaluation aimed to assess the influence of body mass-related covariates on rifampicin's pharmacokinetics (PK) parameters in more detail using non-linear mixed effects modeling (NLMEM).

METHODS

Twenty-four healthy Caucasian volunteers were enrolled in a bioequivalence study, each receiving a test and a reference tablet of 600 mg of rifampicin separated by a wash-out period of at least 9 days. Monolix version 2023R1 was used for NLMEM. Monte Carlo simulations (MCS) were performed to visualize the relationship of body size descriptors to the exposure to rifampicin.

RESULTS

A one-compartment model with nonlinear (Michaelis-Menten) elimination and zero-order absorption kinetics with a lag time best described the data. The covariate model including fat-free mass (FFM) on volume of distribution (V/F) and on maximum elimination rate (Vmax/F) lowered the objective function value (OFV) by 56.4. The second-best covariate model of sex on V/F and Vmax/F and BW on V/F reduced the OFV by 51.2. The decrease in unexplained inter-individual variability on Vmax/F in both covariate models was similar. For a given dose, MCS showed lower exposure to rifampicin with higher FFM and accordingly in males compared to females with the same BW and body height.

CONCLUSION

Our results indicate that beyond BW, body composition as reflected by FFM could also be relevant for optimized dosing of rifampicin. This assumption needs to be studied further in patients treated with rifampicin.

Sex as a Biological Variable in Early-Phase Oncology Clinical Trials: Enhancing the Path to Personalised Medicine

Sex is an essential biological variable that influences the development, progression and response to treatment in cancer. Despite this, early-phase cancer clinical trials frequently neglect to consider sex as a variable, creating a barrier to the development of personalised medicine. This article argues that failure to identify and infer sex differences in early-phase clinical trials may result in suboptimal dosing, underestimation of toxicity, and the failure to identify potential sex-specific responses to new systemic anticancer therapies. There should be a greater focus on sex as a biological variable in drug development so that thoughtful and deliberate study design can bring precision to the development of new systemic cancer therapies.

Reporting on patient's body mass index (BMI) in recent clinical trials for patients with breast cancer: a systematic review

BACKGROUND

The proportion of patients with breast cancer and obesity is increasing. While the therapeutic landscape of breast cancer has been expanding, we lack knowledge about the potential differential efficacy of most drugs according to the body mass index (BMI). Here, we conducted a systematic review on recent clinical drug trials to document the dosing regimen of recent drugs, the reporting of BMI and the possible exclusion of patients according to BMI, other adiposity measurements and/or diabetes (leading comorbidity of obesity). We further explored whether treatment efficacy was evaluated according to BMI.

METHODS

A search of Pubmed and ClinicalTrials.gov was performed to identify phase I-IV trials investigating novel systemic breast cancer treatments. Dosing regimens and exclusion based on BMI, adiposity measurements or diabetes, documentation of BMI and subgroup analyses according to BMI were assessed.

RESULTS

495 trials evaluating 26 different drugs were included. Most of the drugs (21/26, 81%) were given in a fixed dose independent of patient weight. BMI was an exclusion criterion in 3 out of 495 trials. Patients with diabetes, the leading comorbidity of obesity, were excluded in 67/495 trials (13.5%). Distribution of patients according to BMI was mentioned in 8% of the manuscripts, subgroup analysis was performed in 2 trials. No other measures of adiposity/body composition were mentioned in any of the trials. Retrospective analyses on the impact of BMI were performed in 6 trials.

CONCLUSIONS

Patient adiposity is hardly considered as most novel drug treatments are given in a fixed dose. BMI is generally not reported in recent trials and few secondary analyses are performed. Given the prevalence of patients with obesity and the impact obesity can have on pharmacokinetics and cancer biology, more attention should be given by investigators and study sponsors to reporting patient's BMI and evaluating its impact on treatment efficacy and toxicity.

An improvement of body surface area formulas using the 3D scanning technique

OBJECTIVES

Body surface area (BSA) is one of the major parameters used in several medical fields. However, there are concerns raised about its usefulness, mostly due to the ambiguity of its estimation.

MATERIAL AND METHODS

Authors have conducted a voluntary study to investigate BSA distribution and estimation in a group of 179 adult people of various sex, age, and physique. Here, there is provided an extended analysis of the majority of known BSA formulas. Furthermore, it was supplement with a comparison with the authors' propositions of enhanced formulas coefficients for known formulas models as well as with new power models based on an increased number of anthropometric data.

RESULTS

Introduction of the enhanced formulas coefficients cause a reduction of at least 30.5% in mean absolute error and 21.1% in maximum error in comparison with their known counterparts.

CONCLUSIONS

In the context of the analysis presented it can be stated that the development of a single universal body surface area formula, based on a small number of state variables, is not possible. Therefore, it is necessary and justified to search for new estimation models that allow for quick and accurate calculation of body surface area for the entire population, regardless of individual body variations. The new formulas presented are such an alternative, which achieves better results than the previously known methods. Int J Occup Med Environ Health. 2024;37(2):205-19.

Optimizing cancer patient care with a robust assay for 5-fluorouracil quantification and in-vitro stability in human blood for therapeutic drug monitoring

Background

The plasma concentration of 5-Fluorouracil (5-FU) is affected by numerous factors, thereby limiting its efficacy. The current therapeutic regimen's doses based on body surface area (BSA) are linked to increased toxicity and sometimes inadequate drug exposure.

Aim and objectives

The study aims to develop an in-vitro assay to monitor 5-Fluorouracil's therapeutic efficacy in cancer patients' blood samples, focusing on pharmacokinetics to improve therapy precision.

Materials and methods

Drug levels were determined from standards, quality controls, and experimental samples using protein precipitation, liquid-liquid extraction, and separation using a C18 analytical column with an isocratic program.

Result

In EXP-1A, the mean concentration of 5-Fluorouracil was 1.15 μg/ml; in EXP-1B, it was 1.16 μg/ml, while in EXP-1C, the mean concentration was 0.9 μg/ml. The percentage difference in mean 5-Fluorouracil concentration between the experiment sample containing a DPD inactivator and EXP-1C (without a DPD inactivator) was 21.5 % higher for EXP-1A and 0.68 % higher for EXP-1B. In the second phase of the experiment, the overall stability of 5-Fluorouracil in samples containing a DPD inactivator was 24.5 % superior compared to samples without a DPD inactivator.

Conclusion

A modified extraction technique has been developed to accurately measure 5-Flourouracil concentration in blood, preserving its stability and concentration by adding a DPD inactivator.

Anthropometric measures of obesity in patients with knee joint pathology: Body surface area versus body mass index

BACKGROUND

Obesity is quantified using body mass index. Body surface area may provide a superior and more anthropometric method of quantifying obesity in patients with musculoskeletal knee disease. This study compares the effect of weight, height, age and gender on body mass index and body surface area in a population with orthopaedic knee disease.

METHODS

An observational cohort study was conducted of patients presenting with musculoskeletal knee disease. Associations between body mass index, body surface area, age, gender, height, weight and operative versus non-operative management were analysed.

RESULTS

A total of 151 patients were included. Body surface area was more strongly correlated to weight than body mass index (r = 0.98, p < 0.001 versus r = 0.84, p < 0.001). Body surface area also reflects height which body mass index under presents (r = 0.65, p < 0.001 versus r = -0.08, p = 0.35). Body mass index and body surface area were correlated with one another (r = 0.70, p < 0.001). Age was inversely correlated with body surface area (r = -0.20, p = 0.013) but not body mass index (r = 0.05, p = 0.585). Body mass index did not differ between males and females (30.1 versus 30.9, p = 0.37); however, BSA scores were significantly higher in males than females (2.11 versus 1.91, p < 0.001). Neither body surface area nor body mass index scores influenced operative versus non-operative treatment.

CONCLUSION

Body surface area could be a useful alternative to body mass index when considering obesity in patients with musculoskeletal knee pathology. Body surface area better reflects the effects of height, weight, age and gender than body mass index.

Predicting fluid responsiveness using esophagus Doppler monitoring and pulse oximetry derived pleth variability index; retrospective analysis of a hemodynamic study

BACKGROUND

Fluid therapy during major surgery can be managed by providing repeated bolus infusions until stroke volume no longer increases by ≥ 10%. However, the final bolus in an optimization round increases stroke volume by < 10% and is not necessary. We studied how different cut-off values for the hemodynamic indications given by esophagus Doppler monitoring, as well as augmentation by pulse oximetry, are associated with a higher or smaller chance that stroke volume increases by ≥ 10% (fluid responsiveness) before fluid is infused.

METHODS

An esophagus Doppler and a pulse oximeter that displayed the pleth variability index were used to monitor the effects of a bolus infusion in 108 patients undergoing goal-directed fluid therapy during major open abdominal surgery.

RESULTS

The analyzed data set comprised 266 bolus infusions. The overall incidence of fluid responsiveness was 44%, but this varied greatly depending on pre-infusion hemodynamics. The likelihood of being fluid-responsive was 30%-38% in the presence of stroke volume > 80 mL, corrected flow time > 360 ms, or pleth variability index < 10%. The likelihood was 21% if stroke volume had decreased by <8% since the previous optimization, which decreased to 0% if combined with stroke volume > 100 mL. By contrast, the likelihood of fluid responsiveness increased to 50%-55% when stroke volume ≤ 50 mL, corrected flow time ≤ 360 ms, or pleth variability index ≥ 10. A decrease in stroke volume by > 8% since the previous optimization was followed by a 58% likelihood of fluid responsiveness that, in combination with any of the other hemodynamic variables, increased to 66%-76%.

CONCLUSIONS

Single or combined hemodynamic variables provided by esophagus Doppler monitoring and pulse oximetry derived pleth variability index could help clinicians avoid unnecessary fluid bolus infusions.

Prospective clinical study testing the efficacy and safety of a new formula to increase the precision of oxygen therapy in the initiation phase of cardiopulmonary bypass

INTRODUCTION

During cardiopulmonary bypass (CPB), supranormal concentrations of oxygen are routinely administered with the intention to prevent cellular hypoxia. However, hyperoxemia may have adverse effects on patient outcome. Oxygen settings are based on the perfusionist's individual work experience rather than profound recommendations and studies analyzing the effect of oxygen levels are in need of methodological improvement. We aimed to advance perfusion technique by developing and clinically applying a formula for tailored oxygen therapy in CPB.

METHODS

A formula to precalculate the oxygenator setting before CPB was developed. The newly-derived formula was then evaluated in a prospective, single-center pilot study to test whether a predefined arterial partial oxygen pressure (PaO2) of 150-250 mmHg could be reached. 80 patients were enrolled in the study between April and September 2021.

RESULTS

The mean oxygen fraction calculated for the setting of the gas blender was 52% ±0,12. The mean PaO2 after initiation of the CPB was 193 ± 99 mmHg (min-max: 61-484, median 163 mmHg). 38.75% of the values were in the desired PaO2 corridor of 150 to 250 mmHg. 8.75% of all PaO2 values were below <79.9 mmHg, 31.25% between 80 and 149.9 mmHg, 38.75% between 150 and 249.9 mmHg and 21.25%>250 mmHg.

CONCLUSIONS

Conceptually, perfusion technique should be goal-directed, guided by objective parameters and formulas. Although the optimal CPB oxygenation target remains unknown, it is nevertheless important to develop strategies to tailor oxygen therapy to aid in creating evidence as to what level of oxygen is best for patients during CPB. The formula we derived needs further adjustments to increase results in the target range.

Growth Hormone Dosing Estimations Based on Body Weight Versus Body Surface Area

Objective

Both body weight (BW)- and body surface area (BSA)-based dosing regimens have been recommended for growth hormone (rhGH) replacement. The aim was to compare the two regimens to determine if either resulted in inadequate treatment depending on anthropometric factors.

Methods

The retrospective study included children diagnosed with idiopathic isolated growth hormone deficiency. BW-based dosing in mcg/kg/day was converted to BSA in mg/m2/day to determine the equivalent amounts of the given rhGH. Those with a BW-to-BSA ratio of more than 1 were allocated to the “relatively over-dosed group”, while the remaining patients with a ratio of less than 1 were assigned to the “relatively under-dosed” group. Patients with a height gain greater than 0.5 standard deviation score (SDS) at the end of one year were classified as the height gain at goal (HAG), whereas those with a height gain of less than 0.5 SDS were assigned as the height gain not at goal (NHAG).

Results

The study included 60 patients (18 girls, 30%). Thirty-six (60%) patients were classified as HAG. The ratio of dosing based on BW-to-BSA was positively correlated both with the ages and body mass index (BMI) levels of the patients, leveling off at the age of 11 at a BMI of 18 kg/m2. The relative dose estimations (over- and under-dosed groups) differed significantly between the patients classified as HAG or NHAG. Fifty-six percent of NHAG compared to 44% of HAG patients received relatively higher doses, while 79% of HAG compared to 21% of NHAG received relatively lower doses (p=0.006). When the patients were subdivided according to their pubertal status, higher doses were administrated mostly to the pubertal patients in both the NHAG and HAG groups. In the pre-pubertal age group, 73% of NHAG compared to 27% of HAG received relatively higher doses, while 25% of NHAG compared to 75% of HAG received relatively lower doses (p=0.01).

Conclusion

Dosing based on BW may be preferable in both prepubertal and pubertal children who do not show adequate growth responses. In prepubertal children, relatively lower doses calculated based on BW rather than BSA provide similar efficacy at lower costs.

Application of multiple deep learning models for automatic burn wound assessment

PURPOSE

Accurate assessment of the percentage of total body surface area (%TBSA) burned is crucial in managing burn injuries. It is difficult to estimate the size of an irregular shape by inspection. Many articles reported the discrepancy of estimating %TBSA burned by different doctors. We set up a system with multiple deep learning (DL) models for %TBSA estimation, as well as the segmentation of possibly poor-perfused deep burn regions from the entire wound.

METHODS

We proposed boundary-based labeling for datasets of total burn wound and palm, whereas region-based labeling for the dataset of deep burn wound. Several powerful DL models (U-Net, PSPNet, DeeplabV3+, Mask R-CNN) with encoders ResNet101 had been trained and tested from the above datasets. With the subject distances, the %TBSA burned could be calculated by the segmentation of total burn wound area with respect to the palm size. The percentage of deep burn area could be obtained from the segmentation of deep burn area from the entire wound.

RESULTS

A total of 4991 images of early burn wounds and 1050 images of palms were boundary-based labeled. 1565 out of 4994 images with deep burn were preprocessed with superpixel segmentation into small regions before labeling. DeeplabV3+ had slightly better performance in three tasks with precision: 0.90767, recall: 0.90065 for total burn wound segmentation; precision: 0.98987, recall: 0.99036 for palm segmentation; and precision: 0.90152, recall: 0.90219 for deep burn segmentation.

CONCLUSION

Combining the segmentation results and clinical data, %TBSA burned, the volume of fluid for resuscitation, and the percentage of deep burn area can be automatically diagnosed by DL models with a pixel-to-pixel method. Artificial intelligence provides consistent, accurate and rapid assessments of burn wounds.

Obesity and breast cancer prognosis: pre-diagnostic anthropometric measures in relation to patient, tumor, and treatment characteristics

PURPOSE

Examine the association between obesity and clinical outcomes in early breast cancer and assess if patient, tumor, and treatment characteristics modify such associations in Malmö Diet and Cancer Study patients (MDCS).

METHODS

The MDCS enrolled 17,035 Swedish women from 1991 to 1996. At enrollment, participants' body mass index (BMI), waist circumference and body fat percentage measures were collected. We identified all female MDCS participants with invasive breast cancer from 1991 to 2014. Follow-up began at breast cancer diagnosis and ended at breast cancer recurrence (BCR), death, emigration, or June 8, 2020. The World Health Organization guidelines were used to classify BMI, waist circumference, and body fat percentage into three categories of healthy weight, overweight, and obesity. We fit Cox regression models to compute adjusted hazard ratios (HRs) with 95% confidence intervals (CI) of BCR according to body composition. To evaluate effect measure modification, we stratified Cox models by patient, tumor, and treatment characteristics.

RESULTS

In total, 263 BCRs were diagnosed over 12,816 person-years among 1099 breast cancer patients with a median follow-up of 11.1 years. Obesity according to BMI (HR = 1.44 [95%CI 1.00-2.07]), waist circumference (HR = 1.31 [95%CI 0.98-1.77]), and body fat percentage (HR = 1.41 [95%CI 1.02-1.98]) was associated with increased risk of BCR compared with healthy weight. Obesity was stronger associated with BCR in patients with low socioeconomic position (HR = 2.55 [95%CI 1.08-6.02]), larger tumors > 20 mm (HR = 2.68 [95%CI 1.42-5.06]), estrogen-receptor-negative breast cancer (HR = 3.13 [95%CI 1.09-8.97]), and with adjuvant chemotherapy treatment (HR = 2.06 [95%CI 1.08-4.31]).

CONCLUSION

Higher pre-diagnostic BMI, waist circumference, and body fat percentage was associated with increased risk of BCR. The association between obesity and BCR appears dependent on patient, tumor, and treatment characteristics.

Change in Growth Status and Obesity Rates among Saudi Children and Adolescents Is Partially Attributed to Discrepancies in Definitions Used: A Review of Anthropometric Measurements

Anthropometric measurements are the first step in determining the health status in children and adolescents. Clinicians require standardized protocols for proper assessment and interpretation. Therefore, this study aims to review the literature of international and Saudi national guidelines and studies previously conducted in Saudi children and adolescents to provide recommendations to establish Saudi guidelines in line with the Saudi 2030 Vision. Systematic search was conducted in several databases: Medline, PubMed, Saudi Digital Library and Google Scholar from January 1990 to January 2021. Further, 167 studies measured anthropometrics in Saudi children/adolescents; 33 of these studies contributed to the establishment/adjustment of Saudi growth charts or specific cutoffs or studied the trend of growth in representative samples or adjusted the international curves to be used in Saudis. This review warrants updating growth charts and establishing the standard cutoffs of Saudi adolescent anthropometrics to avoid over/underreporting. This review provides insights and recommendations regarding the resources that can be used to establish national guidelines in anthropometric measurements for Saudi children/adolescents. This review will help policymakers and the Ministry of Health to establish standardized protocols to be used in Saudi Arabia for anthropometric measurements that may assist in detecting malnutrition.

Oxygen Uptake Efficiency Slope in South American Healthy Adults: COMPREHENSIVE REFERENCE VALUES AND INTERNATIONAL COMPARISONS

PURPOSE

The purpose of this study is to provide comprehensive reference values for oxygen uptake efficiency slope (OUES) in healthy adults. International heterogeneity was also explored through published databases.

METHODS

A cross-sectional study was conducted with treadmill cardiopulmonary exercise testing (CPX) from a Brazilian healthy adult sample, in which absolute OUES and values normalized by weight and body surface area (BSA) were calculated. Data were stratified by sex and age group. Prediction equations were calculated using age and anthropometric variables. International data were pooled and differences were explored using factorial analysis of variance or the t test, as appropriate. The OUES age-related patterns were calculated using regression analysis.

RESULTS

A total of 3544 CPX were included (1970 males and 1574 females) and the age ranged from 20-80 yr. Males had higher values than females for OUES, OUES/kg, and OUES/BSA. Lower values were found with aging and the data followed a quadratic regression curve. Reference value tables and predictive equations were provided for absolute and normalized OUES in both sexes. International comparisons of absolute OUES values among Brazilian, European, and Japanese data revealed substantial heterogeneity. The OUES/BSA measure minimized the discrepancies between Brazilian and European data.

CONCLUSIONS

Our study provided comprehensive OUES reference values in a large healthy adult sample from South America with a wide age range and included absolute and normalized values. Differences observed between Brazilian and European data were reduced in the BSA-normalized OUES.

Body surface area equations for physically active men and women

OBJECTIVES

To improve predictive formulae for estimating body surface area (BSA) in healthy men and women using a modern three-dimensional scanner technology.

METHODS

Body surface areas were obtained from a convenience sample of 1267 US Marines (464 women and 803 men) using a whole body surface scanner (Size Stream SS20). The reliability of SS20 measures of total and regional BSA within participants was compared across triplicate scans. We then derived a series of formulae to estimate SS20-measured BSA using various combinations of sex, height, and mass. We also assessed relationships between percent body fat measured by dual-energy x-ray absorptiometry and sex-specific formulae errors in Marines.

RESULTS

Body surface areas recorded by the SS20 were highly reliable whether measured for the total body or by region (ICC ≥ .962). Formulae estimates of BSA from sex, height, and mass were precise (root-mean-square deviation, 0.031 m² ). Errors from the Marine Corps formulae were positively associated with percent body fat for men (p = .001) but not women (p = .843).

CONCLUSIONS

Clinicians, military leaders, and researchers can use the newly developed BSA formulae for precise estimates in healthy physically active men and women. Users should be aware that height- and mass-based BSA estimates are less accurate for individuals with extremely low or high percent body fat.

Premature Death in Bodybuilders: What Do We Know?

Premature deaths in bodybuilders regularly make headlines and are cited as evidence that bodybuilding is a dangerous activity. A wealth of research has revealed elite athletes typically enjoy lower mortality rates than non-athletes, but research on bodybuilder lifespan is surprisingly limited. Anabolic androgenic steroid (AAS) use is commonly cited as a key contributor to morbidity and premature mortality in bodybuilders, but this area of research is highly nuanced and influenced by numerous confounders unique to bodybuilding. It is quite possible that bodybuilders are at elevated risk and that AAS use is the primary reason for this, but there remains much unknown in this realm. As global participation in bodybuilding increases, and healthcare providers play a more active role in monitoring bodybuilder health, there is a need to identify how numerous factors associated with bodybuilding ultimately influence short- and long-term health and mortality rate. In this Current Opinion, we discuss what is currently known about the bodybuilder lifespan, identify the nuances of the literature regarding bodybuilder health and AAS use, and provide recommendations for future research on this topic.

Real-Time, Seconds-Resolved Measurements of Plasma Methotrexate In Situ in the Living Body

Dose-limiting toxicity and significant patient-to-patient pharmacokinetic variability often render it difficult to achieve the safe and effective dosing of drugs. This is further compounded by the slow, cumbersome nature of the analytical methods used to monitor patient-specific pharmacokinetics, which inevitably rely on blood draws followed by post-facto laboratory analysis. Motivated by the pressing need for improved "therapeutic drug monitoring", we are developing electrochemical aptamer-based (EAB) sensors, a minimally invasive biosensor architecture that can provide real-time, seconds-resolved measurements of drug levels in situ in the living body. A key advantage of EAB sensors is that they are generalizable to the detection of a wide range of therapeutic agents because they are independent of the chemical or enzymatic reactivity of their targets. Three of the four therapeutic drug classes that have, to date, been shown measurable using in vivo EAB sensors, however, bind to nucleic acids as part of their mode of action, leaving open questions regarding the extent to which the approach can be generalized to therapeutics that do not. Here, we demonstrate real-time, in vivo measurements of plasma methotrexate, an antimetabolite (a mode of action not reliant on DNA binding) chemotherapeutic, following human-relevant dosing in a live rat animal model. By providing hundreds of drug concentration values, the resulting seconds-resolved measurements succeed in defining key pharmacokinetic parameters, including the drug's elimination rate, peak plasma concentration, and exposure (area under the curve), with unprecedented 5 to 10% precision. With this level of precision, we easily identify significant (>2-fold) differences in drug exposure occurring between even healthy rats given the same mass-adjusted methotrexate dose. By providing a real-time, seconds-resolved window into methotrexate pharmacokinetics, such measurements can be used to precisely "individualize" the dosing of this significantly toxic yet vitally important chemotherapeutic.

Exercise capacity in a cohort of children with congenital heart disease

In patients with congenital heart disease (CHD), reduced exercise capacity can be a predictor for late complications and may be used to guide interventions. Yet, the interpretation of exercise capacity is challenged by changes in body composition during growth. Our aim was to create an overview of disease-specific exercise capacity in children with CHD. We performed a multicentre retrospective study of exercise capacity of CHD patients, aged 6-18 years, tested between January 2001 and October 2018. Sex-specific distribution graphs were made using the LMS method and height to relate to body size. We included all CHD with N > 50, including severe defects (e.g., univentricular heart, tetralogy of Fallot) and "simple" lesions as ventricular septum defect and atrial septum defect. We included 1383 tests of 1208 individual patients for analysis. The peak oxygen uptake (VO₂peak, 37.3 ml/min/kg (25th-75th percentile 31.3-43.8)) varied between specific defects; patients with univentricular hearts had lower VO_2peak compared with other CHD. All groups had lower VO_2peak compared to healthy Dutch children. Males had higher VO_2peak, W_peak and O₂pulse_peak than females. Sex- and disease-specific distribution graphs for VO_2peak, W_peak and O2pulse_peak showed increase in variation with increase in height.   Conclusion: Disease-specific distribution graphs for exercise capacity in children with CHD from a large multicentre cohort demonstrated varying degrees of reduced VO_2peak and W_peak. The distribution graphs can be used in the structured follow-up of patients with CHD to predict outcome and identify patients at risk. What is Known: • Children with congenital heart disease (COnHD) are at risk to develop heart failure, arrhytmia's and other complications. Exercise capacity may be an important predictor for outcome in children with ConHD. In children, the interpretation of exercise capacity poses an additional challenge related to physical changes during growth. What is New: • In this report of a multi-center cohort >1300 childrewn with ConHD, we related the changes in exercise capacity to length. We demonstrated that exercise capacity was reduced as compared with healthy children and we observed variation between disease groups. Patients with a univentricular circulation (Fontan) had worse exercise capacity. We constructed disease specific charts of development of exercise capacity throughout childhood, accessible via a web-site. These graphs may help practitioner to guide children with ConHD.

Chemotherapy and Anticancer Drugs Adjustment in Obesity: A Narrative Review

BACKGROUND

Obese individuals have higher rates of cancer incidence and cancer- related mortality. The worse chemotherapy outcomes observed in this subset of patients are multifactorial, including the altered physiology in obesity and its impact on pharmacokinetics, the possible increased risk of underdosing, and treatment-related toxicity.

AIMS

The present review aimed to discuss recent data on physiology, providing just an overall perspective and pharmacokinetic alterations in obesity concerning chemotherapy. We also reviewed the controversies of dosing adjustment strategies in adult and pediatric patients, mainly addressing the use of actual total body weight and ideal body weight.

METHODS

This narrative review tried to provide the best evidence to support antineoplastic drug dosing strategies in children, adolescents, and adults.

RESULTS

Cardiovascular, hepatic, and renal alterations of obesity can affect the distribution, metabolism, and clearance of drugs. Anticancer drugs have a narrow therapeutic range, and variations in dosing may result in either toxicity or underdosing. Obese patients are underrepresented in clinical trials that focus on determining recommendations for chemotherapy dosing and administration in clinical practice. After considering associated comorbidities, the guidelines recommend that chemotherapy should be dosed according to body surface area (BSA) calculated with actual total body weight, not an estimate or ideal weight, especially when the intention of therapy is the cure.

CONCLUSION

The actual total body weight dosing appears to be a better approach to dosing anticancer drugs in both adults and children when aiming for curative results, showing no difference in toxicity and no limitation in treatment outcomes compared to adjusted doses.

The past, present, and future of chemotherapy with a focus on individualization of drug dosing

While there have been rapid advances in developing new and more targeted drugs to treat cancer, much less progress has been made in individualizing dosing. Even though the introduction of immunotherapies such as CAR T-cells and checkpoint inhibitors, as well as personalized therapies that target specific mutations, have transformed clinical treatment of cancers, chemotherapy remains a mainstay in oncology. Chemotherapies are typically dosed on either a body surface area (BSA) or weight basis, which fails to account for pharmacokinetic differences between patients. Drug absorption, distribution, metabolism, and excretion rates can vary between patients, resulting in considerable differences in exposure to the active drugs. These differences result in suboptimal dosing, which can reduce efficacy and increase side-effects. Therapeutic drug monitoring (TDM), genotype guided dosing, and chronomodulation have been developed to address this challenge; however, despite improving clinical outcomes, they are rarely implemented in clinical practice for chemotherapies. Thus, there is a need to develop interventions that allow for individualized drug dosing of chemotherapies, which can help maximize the number of patients that reach the most efficacious level of drug in the blood while mitigating the risks of underdosing or overdosing. In this review, we discuss the history of the development of chemotherapies, their mechanisms of action and how they are dosed. We discuss substantial intraindividual and interindividual variability in chemotherapy pharmacokinetics. We then propose potential engineering solutions that could enable individualized dosing of chemotherapies, such as closed-loop drug delivery systems and bioresponsive biomaterials.

Human body radiation area factors for diverse adult population

Radiation accounts for a significant fraction of the human body and environment heat exchange and strongly impacts thermal comfort and safety. The direct radiative exchange between an individual and a source or sink can be quantified using the effective (f_eff) and projected radiation area factors (f_p). However, these factors have not been quantified for half of the population of the USA with an above-average body mass index (BMI). Here, we address this gap by developing thirty male and thirty female computational manikin models that cover the 1 to 99 percentile variation in height and BMI of adults in the USA. The radiative simulations reveal that the f_eff and the f_p angular distributions are nearly independent of gender, height, and BMI. Appreciable relative differences from the average models only emerge for manikins with BMI above 80th percentile. However, these differences only occur at low zenith angles and, in absolute terms, are small as compared to variations induced by, for example, the zenith angle increase. We also use the manikin set to evaluate whether the body shape impacts the quality of human representation with several levels of geometrical simplification. We find that the "box/peg" body representation, which is based on the hemispherical f_p average, is independent of the body shape. In turn, the f_p distributions averaged over the azimuth angle range, representing the rotationally symmetric humans, are only impacted to the same degree as for the anatomical manikins. We also show that the anatomical manikins can be closely approximated by the multi-cylinder and sphere representation, at least from a radiation perspective. The developed anatomical manikin set is freely available and can be used to compute how body shape impacts a variety of external heat transport processes.

Non-obese NAFLD had no better cardio-metabolic risk profile than obese NAFLD in type 2 diabetic patients

BACKGROUND

Non-obese non-alcoholic fatty liver disease (NAFLD) has been reported to share clinical outcomes with its obese counterpart in the general population. However, conflicting results have been observed regarding the cardio-metabolic risk profile of non-obese NAFLD as compared to obese NAFLD. Moreover, in the context of type 2 diabetes mellitus (T2DM), this issue has been even less addressed. We hence aimed to examine the association of NAFLD with the cardio-metabolic risk profile in patients with T2DM according to their obesity status.

METHODS

A total of 2,708 patients with T2DM who were hospitalized between June 2018 and May 2021 were cross-sectionally assessed.

RESULTS

The prevalence of NAFLD was 49.3%. NAFLD was found in 34.1% of non-obese patients and 66.0% of obese patients. Non-obese NAFLD patients had more and worse metabolic disorders than obese patients without NAFLD in both men and women. Comparable cardio-metabolic risk profiles were noted between non-obese and obese NAFLD subjects. The associations of worse cardio-metabolic risk profiles with NAFLD were overall stronger in non-obese than in obese subjects among women with T2DM, while more pronounced in obese than in non-obese subjects among men with T2DM.

CONCLUSION

In patients with T2DM, non-obese NAFLD had no better cardio-metabolic risk profile than obese NAFLD. The associations of metabolic disorders with NAFLD were stronger in non-obese than in obese patients in women patients with T2DM.

Body Surface Area (BSA) is a Better Osteoporosis Associated Anthropometric Parameter Than Other Anthropometric Parameters in Elderly Population

Body surface area (BSA) is widely used for adjusting drug dose, while few studies have yet systematically evaluated its association with osteoporosis and compared its advantage with other anthropometric parameters in osteoporotic risk prediction. A total of 10,021 Chinese individuals aged over 65 years were enrolled in our study. Bone mineral density (BMD) was measured, and demographic information was also collected. Pearson correlation analysis, receiver operating characteristic (ROC) curves and predictive analysis were performed to assess the clinical practice of BSA for osteoporosis. BSA had the strongest correlation with BMD (0.544, p &lt; 0.001) compared with conventional anthropometric indices. Besides, BSA had the highest power in osteoporosis prediction, with an area under the curve (AUC) reaching 0.81. After incorporating BSA into the osteoporosis risk prediction model, the AUC improved from 0.82 to 0.83 (p &lt; 0.01). We found BSA provided additional diagnostic value beyond conventional anthropometric information with continuous and category NRIs were 30.40% (p &lt; 0.01) and 3.29% (p &lt; 0.01), respectively, and the IDI was 1.85% (p &lt; 0.01). BSA was positively associated with osteoporosis and showed superior discriminative ability for osteoporosis risk prediction compared with other anthropometric parameters in the Chinese elderly population.

Sex and Gender Differences in Anticancer Treatment Toxicity: A Call for Revisiting Drug Dosing in Oncology

The practice of oncology has dramatically changed in the last decade with the introduction of molecular tumor profiling into routine tumor diagnostics and the extraordinary progress in immunotherapies. However, there remains an unmet need to explore personalized dosing strategies that take into account the patient's sex and gender to optimize the balance between efficacy and toxicity for each individual patient. In this mini-review, we summarize the evidence on sex and gender differences in toxicity of anticancer therapies and present data on dose reduction and dose discontinuation rates for selected chemotherapies and targeted therapies. Finally, we propose the investigation of body composition (specifically fat-free muscle mass) as a viable approach for personalized treatment dosage.

Predicting Approximate Clinically Effective Doses in Oncology Using Preclinical Efficacy and Body Surface Area Conversion: A Retrospective Analysis

The correlation between efficacious doses in human tumor-xenograft mouse models and the human clinical doses of approved oncology agents was assessed using published preclinical data and recommended clinical doses. For 90 approved small molecule anti-cancer drugs, body surface area (BSA) corrected mouse efficacious doses were strongly predictive of human clinical dose ranges with 85.6% of the predictions falling within three-fold (3×) of the recommended clinical doses and 63.3% within 2×. These results suggest that BSA conversion is a useful tool for estimating human doses of small molecule oncology agents from mouse xenograft models from the early discovery stage. However, the BSA based dose conversion poorly predicts for the intravenous antibody and antibody drug conjugate anti-cancer drugs. For antibody-based drugs, five out of 30 (16.7%) predicted doses were within 3× of the recommended clinical dose. The body weight-based dose projection was modestly predictive with 66.7% of drugs predicted within 3× of the recommended clinical dose. The correlation was slightly better in ADCs (77.7% in 3×). The application and limitations of such simple dose estimation methods in the early discovery stage and in the design of clinical trials are also discussed in this retrospective analysis.

Cardiac Structure and Function in Junior Athletes: A Systematic Review of Echocardiographic Studies

Background

In young athletes, the level of competitiveness in sports is increasing, as well as frequency and intensity of exercise training. Adaptations of the cardiac system to this increased workload imposed by exercise has not yet been studied sufficiently. In adults, studies point towards a shift from the functional athlete's heart towards pathological cardiac remodelling, with ventricular arrythmia and impaired cardiac function, that is exercise-related. This systematic review investigates cardiac adaptations to exercise in junior athletes compared to inactive controls.

Methods

Three electronic databases (PubMed/Medline, ScienceDirect and Web of Science) were searched for studies assessing 2-dimensional transthoracic echocardiography (2D TTE) and 2-dimensional speckle tracking echocardiography (2D STE) parameters in junior athletes, aged 7-19 years, compared to inactive controls. Data was screened and extracted by two reviewers; study quality and risk of bias was assessed by three reviewers.

Results

Eight out of 1460 studies met all inclusion criteria, with all studies reporting results on 2D TTE and six studies reporting results on 2D STE parameters in 540 (51 girls) junior athletes and 270 (18 girls) controls. There is evidence for structural cardiac adaptations of the left ventricle and both atria in junior athletes. Results regarding left ventricular function are controversial with a tendency to improved function in dynamic exercising athletes. Left ventricular mass and relative wall thickness point towards higher values in static exercising athletes.

Conclusions

Cardiac adaptations to exercise occur in children and adolescents. These adaptations are more pronounced in structural left ventricular parameters. Functional parameters are preserved or slightly improved in junior athletes but not impaired by exercise.

DXA-Based Detection of Low Muscle Mass Using the Total Body Muscularity Assessment Index (TB-MAXI): A New Index with Cutoff Values from the NHANES 1999-2004

The aims of this study were to investigate age-related changes in total body skeletal muscle mass (TBSMM) and the between-limb asymmetry in lean mass in a large sample of adults. Demographic, anthropometric, and DXA-derived data of National Health and Nutrition Examination Survey participants were considered. The sample included 10,014 participants of two ethnic groups (Caucasians and African Americans). The age-related decline of TBSMM absolute values was between 5% and 6% per decade in males and between 4.5% and 5.0% per decade in females. The adjustment of TBSMM for body surface area (TB-MAXI) showed that muscle mass peaked in the second decade and decreased progressively during the subsequent decades. The following thresholds were identified to distinguish between low and normal TB-MAXI: (i) 10.0 kg/m2 and 11.0 kg/m2 in Caucasian and African American females; and (ii) 12.5 kg/m2 and 14.5 kg/m2 in Caucasian and African American males. The lean asymmetry indices were higher for the lower limbs compared with the upper limbs and were higher for males compared with females. In conclusion, the present study proposes the TB-MAXI and lean asymmetry index, which can be used (and included in DXA reports) as clinically relevant markers for muscle amount and lean distribution.

Deep Learning-Assisted Burn Wound Diagnosis: Diagnostic Model Development Study

BACKGROUND

Accurate assessment of the percentage total body surface area (%TBSA) of burn wounds is crucial in the management of burn patients. The resuscitation fluid and nutritional needs of burn patients, their need for intensive unit care, and probability of mortality are all directly related to %TBSA. It is difficult to estimate a burn area of irregular shape by inspection. Many articles have reported discrepancies in estimating %TBSA by different doctors.

OBJECTIVE

We propose a method, based on deep learning, for burn wound detection, segmentation, and calculation of %TBSA on a pixel-to-pixel basis.

METHODS

A 2-step procedure was used to convert burn wound diagnosis into %TBSA. In the first step, images of burn wounds were collected from medical records and labeled by burn surgeons, and the data set was then input into 2 deep learning architectures, U-Net and Mask R-CNN, each configured with 2 different backbones, to segment the burn wounds. In the second step, we collected and labeled images of hands to create another data set, which was also input into U-Net and Mask R-CNN to segment the hands. The %TBSA of burn wounds was then calculated by comparing the pixels of mask areas on images of the burn wound and hand of the same patient according to the rule of hand, which states that one's hand accounts for 0.8% of TBSA.

RESULTS

A total of 2591 images of burn wounds were collected and labeled to form the burn wound data set. The data set was randomly split into training, validation, and testing sets in a ratio of 8:1:1. Four hundred images of volar hands were collected and labeled to form the hand data set, which was also split into 3 sets using the same method. For the images of burn wounds, Mask R-CNN with ResNet101 had the best segmentation result with a Dice coefficient (DC) of 0.9496, while U-Net with ResNet101 had a DC of 0.8545. For the hand images, U-Net and Mask R-CNN had similar performance with DC values of 0.9920 and 0.9910, respectively. Lastly, we conducted a test diagnosis in a burn patient. Mask R-CNN with ResNet101 had on average less deviation (0.115% TBSA) from the ground truth than burn surgeons.

CONCLUSIONS

This is one of the first studies to diagnose all depths of burn wounds and convert the segmentation results into %TBSA using different deep learning models. We aimed to assist medical staff in estimating burn size more accurately, thereby helping to provide precise care to burn victims.

Estimation of body surface area in neonates, infants, and children using body weight alone

BACKGROUND

The aim of this study was to use Body Surface Area (BSA) data calculated with the Mosteller equation to test potential new equations that estimate BSA using Body Weight (BW) alone in children aged 0-18 years.Mosteller's equation, the golden standard at our hospital, was used to calculate the BSA in infants and children aged 0-18 years using BW and height data from 27,440 hospital visits by 20,635 patients over one year.

METHODS

The best fit of three nonlinear regression equations (third-order polynomial, Meeh-type, and modified Boyd self-adjusting-type) to a plot of the calculated Mosteller BSA values versus BW was then investigated. The correlation between the BSA values estimated by these equations and the Mosteller BSA values was established by the Spearman rank correlation test. Bias and precision were evaluated as outlined by Sheiner and Beal. Measured and estimated BSA values were compared using the Eksborg plot.

RESULTS

The estimated BSA values from all three equations and the BSA values from the Mosteller equation were closely correlated (P < .0001). The third-order polynomial and Meeh-type equations overestimated BSA by 0.13% and 0.40%, respectively, while the Boyd self-adjusted-type equation underestimated BSA by 0.060%. For the entire pediatric population, the best fit was obtained with the Meeh-type equation: 99.2% of the Meeh/Mosteller BSA ratios were within the range of 0.9-1.1 when compared with 98.3% and 97.2% for the polynomial and Boyd-type equations, respectively.

CONCLUSION

A single Meeh-type equation can be used to predict the results of Mosteller equation when H is not available with high precision and accuracy in children aged 0-18 years, including term neonates. We now plan to include the results of this study in CPOE systems in Sweden to improve drug dosage in all children.

Analgesic Effect of Electroacupuncture on Postherpetic Neuralgia: A Trial Protocol for a Multicenter Randomized Controlled Trial

INTRODUCTION

The chronic neuropathic pain associated with postherpetic neuralgia (PHN) can last for several months or even many years, seriously affecting the affected person's work, sleep, mood, and daily life activities. In generaly, current treatments for PHN are at best limited and unsatisfactory, and adverse reactions are common, especially in elderly patients. Electroacupuncture (EA) is widely used clinically to manage painful diseases, but there remains a lack of evidence to support the effectiveness of EA on PHN. This study is designed to assess the efficacy and safety of EA on PHN, and to provide evidence-based medical evidence for EA treatment of PHN.

METHODS

This multicenter, prospective, randomized controlled trial will recruit 448 patients with PHN at seven clinical centers. Multicenter stratified variable block randomization will be used, and the eligible patients will be randomly allocated in a ratio of 1:1 to the EA group or sham EA group. The EA group will receive 4 weeks of EA treatment, given as 30-min treatment sessions, once daily, 5 times per week, for a total of 20 treatments; the sham EA group will receive sham EA treatment under the same conditions.

PLANNED OUTCOMES

The primary outcome measure is the 11-point Numeric Rating Scale pain score at week 4. The secondary outcome measures, including mechanical pain threshold, pain area of PHN, average number of pain episodes, the short-form McGill Pain Questionnaire 2, Zoster Brief Pain Inventory, the Depression, Anxiety, and Positive Outlook Scale, Patient Global Impression of Change, safety of EA, and use of concomitant medications, among others. The primary analysis of the outcomes will be the mixed-effect model with repeated measurement between groups on an intent-to-treat population.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT04560361. Registered 23 September 2020 ( https://clinicaltrials.gov/ct2/show/NCT04560361?term=NCT04560361&draw=2&rank=1 ).

The Influence of Surgical Weight Reduction on Left Atrial Strain

BACKGROUND

Obesity increases and surgical weight reduction decreases the risk of atrial fibrillation (AF) and heart failure (HF). We hypothesized that surgically induced weight loss may favorably affect left atrial (LA) mechanical function measured by longitudinal strain, which has recently emerged as an independent imaging biomarker of increased AF and HF risk.

METHODS

We retrospectively evaluated echocardiograms performed before and 12.2 ± 2.2 months after bariatric surgery in 65 patients with severe obesity (mean age 39 [36; 47] years, 72% of females) with no known cardiac disease or arrhythmia. The LA mechanical function was measured by the longitudinal strain using the semi-automatic speckle tracking method.

RESULTS

After surgery, body mass index decreased from 43.72 ± 4.34 to 30.04 ± 4.33 kg/m2. We observed a significant improvement in all components of the LA strain. LA reservoir strain (LASR) and LA conduit strain (LASCD) significantly increased (35.7% vs 38.95%, p = 0.0005 and - 19.6% vs - 24.4%, p < 0.0001) and LA contraction strain (LASCT) significantly decreased (- 16% vs - 14%, p = 0.0075). There was a significant correlation between an increase in LASR and LASCD and the improvement in parameters of left ventricular diastolic and longitudinal systolic function (increase in E' and MAPSE). Another significant correlation was identified between the decrease in LASCT and an improvement in LA function (decrease in A').

CONCLUSIONS

The left atrial mechanical function improves after bariatric surgery. It is partially explained by the beneficial effect of weight reduction on the left ventricular diastolic and longitudinal systolic function. This effect may contribute to decreased risk of AF and HF after bariatric surgery.

Age-specific normal reference ranges for 99mTc-DTPA glomerular filtration rate to use with two-sample slope-intercept method and Jodal Brochner-Mortensen correction

Glomerular filtration rate (GFR) varies with age, the calculation method, and the correction factor for slope-intercept overestimation. Hence, any normal reference range accompanying the results should be suitably adapted to the method used. For Nuclear Medicine Departments using a two-sample slope-intercept method, the lack of appropriate age-specific normal reference range has been a hindrance to adopting the recently updated Jodal Brochner-Mortensen (JBM) correction over other older and more widely used methods. A retrospective analysis of the routine GFR calculation and clinical reports generated locally from 2006 to 2020 was carried out. GFR was calculated with ^99mTc-DTPA plasma clearance using a two-sample slope-intercept method with JBM correction. Age-specific normal range equations were developed from normal healthy subjects. Published normal reference ranges were modified with appropriate correction reversal and compared with the locally developed reference ranges. Age-specific normal GFR reference ranges for ^99mTc-DTPA with slope-intercept method and JBM correction were developed and validated with current literature. Normal reference range (Mean ± 2SD) for Normalised GFR (ml min^-1 (1.73m²)^-1) within 95% confidence limits suitable for use with JBM correction is 100.6 ± 35.2 for children above 2 years and 102.9 - 0.00629 × (Age)² ± 19.4 for adults. Availability of age-specific normal GFR reference ranges applicable to the target population and appropriately tailored to the calculation method and correction factor enables Nuclear Medicine Departments to update their calculation methods in line with the current literature and also facilitates accurate reporting and evaluation of the calculated GFR results.

Establishing an appropriate Z score regression equation for Chinese pediatric coronary artery echocardiography: a multicenter prospective cohort study

BACKGROUND

Z score utility is emphasized in classifying coronary artery lesions in Kawasaki disease patients. The present study is the largest such multicenter Chinese pediatric study about coronary artery diameter reference values and Z score regression equation to date. It is useful in Chinese pediatric echocardiography.

METHODS

A multicenter cohort was assembled, which consisted of 852 healthy children between 1 month and 17 years of age, ten children were excluded because their ultrasound images were not clear, or lost in following up. Diameters of the right coronary artery, left coronary artery, and left anterior descending coronary artery were assessed using echocardiography. Data were body surface area (BSA)-corrected using BSA calculated via either the Stevenson BSA formula or the Haycock BSA formula. Coronary artery diameter reference values and Z score regression equations were established for use in the Chinese pediatric population.

RESULTS

No difference was observed between coronary artery diameter data corrected using BSAste or BSAhay. Of the five assessed regression models, the exponential model exhibited the best fit and was therefore selected as the basis for derivation of the SZ method. When comparing Z scores, those produced by the SZ method conformed to the standard normal distribution, while those produced by the D method did not. In addition, there was a statistically significant difference between Z scores produced by the SZ and D methods (P < 0.05).

CONCLUSIONS

Coronary artery diameter reference values for echocardiography were successfully established for use in the Chinese pediatric population, and a Z score regression equation more suitable for clinical use in this population was successfully developed.

Overweight and prognosis in triple-negative breast cancer patients: a systematic review and meta-analysis

We conducted a systematic review and meta-analysis investigating the association between overweight and outcome in triple-negative breast cancer (TNBC) patients. We searched PubMed and Embase using variations of the search terms triple-negative breast cancer (population), overweight and/or obesity (exposure), and prognosis (outcome). Based on the World Health Organization guidelines for defining overweight, we included longitudinal observational studies, which utilized survival statistics with hazard ratios (HRs) in our analysis. The included studies measured body mass index at the time of diagnosis of TNBC and reported disease-free survival and/or overall survival. Study quality was assessed with the Newcastle-Ottawa Scale and study data were extracted using the Meta-analysis of Observational Studies in Epidemiology (MOOSE) checklist, independently by two authors. Random-effects models were used to combine the effect sizes (HRs), and the results were evaluated and adjusted for possible publication bias. Thirteen studies of 8,944 TNBC patients were included. The meta-analysis showed that overweight was associated with both shorter disease-free survival (HR = 1.26; 95%CI: 1.09–1.46) and shorter overall survival (HR = 1.29; 95%CI: 1.11c1.51) compared to normal-weight. Additionally, our Bayesian meta-analyses suggest that overweight individuals are 7.4 and 9.9 times more likely to have shorter disease-free survival and overall survival, respectively. In conclusion, the available data suggest that overweight is associated with shorter disease-free and overall survival among TNBC patients. The results should be interpreted with caution due to possible publication bias.

Optimal injection interval for testosterone undecanoate treatment of hypogonadal and transgender men

OBJECTIVE

To define the optimized inter-injection interval of injectable testosterone undecanoate (TU) treatment for hypogonadal and transmen based on individual dose titration in routine clinical practice.

DESIGN AND METHODS

A prolective observational study of consecutive TU injections in men undergoing testosterone replacement therapy for pathological hypogonadism or masculinization of female-to-male transgender (transmen) subject to individual dosing titration to achieve a stable replacement regimen.

RESULTS

From 2006 to 2019, 6899 injections were given to 325 consecutive patients. After excluding the 6-week loading dose, 6300 injections were given to 297 patients who had at least three and a median of 14 injections. The optimal injection interval (mean of last three injection intervals) had a median of 12.0 weeks (interquartile range 10.4-12.7 weeks). The interval was significantly influenced by age and body size (body surface area, BSA) but not by diagnosis or trough serum LH, FSH, and SHBG. Longer (≥14 weeks; 68/297, 23%), but not shorter (≤10 weeks; 22/297, 7.4%), intervals were weakly correlated with age but not diagnosis or other covariables. Low blood hemoglobin increased with trough serum testosterone to reach plateau once testosterone was about 10 nmol/L or higher.

CONCLUSION

Optimal intervals between TU injection after individual titration resulted in the approved 12-week interval in 70% of patients with only minor influence for clinical application of BSA and not of trough serum LH, FSH, and SHBG. Individually optimized inter-injection interval did not differ between men with primary or secondary hypogonadism or transmen.

Evaluation of body-surface-area adjusted dosing of high-dose methotrexate by population pharmacokinetics in a large cohort of cancer patients

Background

The aim of this study was to identify sources of variability including patient gender and body surface area (BSA) in pharmacokinetic (PK) exposure for high-dose methotrexate (MTX) continuous infusion in a large cohort of patients with hematological and solid malignancies.

Methods

We conducted a retrospective PK analysis of MTX plasma concentration data from hematological/oncological patients treated at the University Hospital of Cologne between 2005 and 2018. Nonlinear mixed effects modeling was performed. Covariate data on patient demographics and clinical chemistry parameters was incorporated to assess relationships with PK parameters. Simulations were conducted to compare exposure and probability of target attainment (PTA) under BSA adjusted, flat and stratified dosing regimens.

Results

Plasma concentration over time data (2182 measurements) from therapeutic drug monitoring from 229 patients was available. PK of MTX were best described by a three-compartment model. Values for clearance (CL) of 4.33 [2.95–5.92] L h^− 1 and central volume of distribution of 4.29 [1.81–7.33] L were estimated. An inter-occasion variability of 23.1% (coefficient of variation) and an inter-individual variability of 29.7% were associated to CL, which was 16 [7–25] % lower in women. Serum creatinine, patient age, sex and BSA were significantly related to CL of MTX. Simulations suggested that differences in PTA between flat and BSA-based dosing were marginal, with stratified dosing performing best overall.

Conclusion

A dosing scheme with doses stratified across BSA quartiles is suggested to optimize target exposure attainment. Influence of patient sex on CL of MTX is present but small in magnitude.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08443-x.

A Systematic Review of Scaling Left Atrial Size: Are Alternative Indexation Methods Required for an Increasingly Obese Population?

BACKGROUND

Left atrial (LA) size indexed to body surface area (BSA) is a clinically important marker of cardiovascular prognosis. However, indexation using a scaling variable such as BSA has inherent flaws, particularly in an obese population. The aim of this study was to determine whether alternative indexation methods may more accurately scale for LA size.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used to execute a structured search of medical databases, to identify articles discussing alternative methods of LA indexation in echocardiography. Articles that stratified indexed LA size by obesity class were also included. Two independent reviewers identified relevant articles and extracted baseline characteristics, alternative indexation methods, scaling variables, obesity class characteristics, and correlation coefficients.

RESULTS

A total of 3,804 articles were found in the database search after removing duplicates. After abstract and full-text screening, 13 relevant articles were identified. Twelve studies used alternative methods of LA indexation, of which nine reported allometric indices. Seven of the included studies reported LA size by obesity class, of which six reported alternative indices. Correlation coefficients plotted for indexed LA size against absolute measured LA size showed that allometric indices (specifically to height) were more likely to maintain proportionality to body size compared with isometric indices such as BSA. Allometric indices were less likely to overcorrect for body size compared with isometric indices.

CONCLUSIONS

Compared with isometric indexation to BSA, allometric indexation (specifically to height) improves scaling of LA volumes to maintain proportionality and avoid overcorrection for body size.

Steroid Sensitive Nephrotic Syndrome: Revised Guidelines

JUSTIFICATION

Steroid sensitive nephrotic syndrome (SSNS) is one of the most common chronic kidney diseases in children. These guidelines update the existing Indian Society of Pediatric Nephrology recommendations on its management.

OBJECTIVE

To frame revised guidelines on diagnosis, evaluation, management and supportive care of patients with the illness.

PROCESS

The guidelines combine evidence-based recommendations and expert opinion. Formulation of key questions was followed by review of literature and evaluation of evidence by experts in two face-to-face meetings.

RECOMMENDATIONS

The initial statements provide advice for evaluation at onset and follow up and indications for kidney biopsy. Subsequent statements provide recommendations for management of the first episode of illness and of disease relapses. Recommendations on the use of immunosuppressive strategies in patients with frequent relapses and steroid dependence are accompanied by suggestions for step-wise approach and plan of monitoring. Guidance is also provided regarding the management of common complications including edema, hypovolemia and serious infections. Advice on immunization and transition of care is given. The revised guideline is intended to improve the management and outcomes of patients with SSNS, and provide directions for future research.

Diet-Related Inflammation is Associated with Major Depressive Disorder in Bahraini Adults: Results of a Case-Control Study Using the Dietary Inflammatory Index

PURPOSE

This case-control study aimed to examine the association between the inflammation potential of the diet and depression.

PATIENTS AND METHODS

Ninety-six patients with major depression disorder were matched with 96 age- and sex-matched healthy controls. Energy-adjusted DII (E-DIITM) scores were calculated based on the participants' responses to a detailed nutritional assessment using a quantitative food frequency questionnaire. Descriptive results were reported. Logistic regression was used to estimate odds ratios and 95% confidence intervals associated with E-DII scores and depression adjusting for covariates including age, sex, body mass index, comorbidities, level of education, and employment.

RESULTS

The mean E-DII score of participants in the study was 1.32±1.08, indicating a generally pro-inflammatory diet. Patients with depression had elevated E-DII scores compared to age- and sex-matched controls with E-DII scores of 1.72± 1.09 vs 0.90±0.90, respectively (P=0.001). Results of logistic regression analysis revealed that patients with depression were nearly three times more likely to be in the extreme ends of pro-inflammatory diet (OR 2.75; 95% CI 1.82-4.15).

CONCLUSION

Adult Bahraini patients with depression have higher dietary inflammation potential compared to the general population controls. Further research is needed to confirm these results and provide effective interventions to reduce the burden of this dietary inflammation.