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result(s) for
"Test methods"
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Accuracy of the Cosmed K5 portable calorimeter
The purpose of this study was to assess the accuracy of the Cosmed K5 portable metabolic system dynamic mixing chamber (MC) and breath-by-breath (BxB) modes against the criterion Douglas bag (DB) method.
Fifteen participants (mean age±SD, 30.6±7.4 yrs) had their metabolic variables measured at rest and during cycling at 50, 100, 150, 200, and 250W. During each stage, participants were connected to the first respiratory gas collection method (randomized) for the first four minutes to reach steady state, followed by 3-min (or 5-min for DB) collection periods for the resting condition, and 2-min collection periods for all cycling intensities. Collection periods for the second and third methods were preceded by a washout of 1-3 min. Repeated measures ANOVAs were used to compare metabolic variables measured by each method, for seated rest and each cycling work rate.
For ventilation (VE) and oxygen uptake (VO2), the K5 MC and BxB modes were within 2.1 l/min (VE) and 0.08 l/min (VO2) of the DB (p≥0.05). Compared to DB values, carbon dioxide production (VCO2) was significantly underestimated by the K5 BxB mode at work rates ≥150W by 0.12-0.31 l/min (p<0.05). K5 MC and BxB respiratory exchange ratio values were significantly lower than DB at cycling work rates ≥100W by 0.03-0.08 (p<0.05).
Compared to the DB method, the K5 MC and BxB modes are acceptable for measuring VE and VO2 across a wide range of cycling intensities. Both K5 modes provided comparable values to each other.
Journal Article
The agreement of the various distance walkway in the 6-minute walk test in healthy adults
Despite a practical guideline of 30-meter walking path during 6-minute walk test (6MWT), such walking course length is not possible in every clinical setting due to unavailable sufficient space. Existing evidence has investigated using several shorter course lengths, it remains unclear whether a walking course length shorter than the standard walking course length is appropriate for 6MWD testing. This study aimed (i) to compare maximum walking distances at various shorter walking course lengths (i.e., 10, 20, and 25 meters) and 30 meters, and (ii) to assess agreements in maximum walking distances achieved at intervals below 30 meters, specifically 10, 15, 20, and 25 meters.
This study was a cross-sectional with cross-over design. Forty-eight healthy participants were randomly ordered to perform 6MWT with five different walkways (10, 15, 20, 25, 30 meters). The maximum walking distance (six-minute walk distance, 6MWD) covered was recorded.
Eligible participants aged 41.0 ± 17.2 years, with equal sex (24 males) participated in this study. The 6MWD at 10, 15, and 20-meter walkways significantly shorter than the 30-meter standard walkway (489.6 ± 59.3 m, 513.1 ± 62.6 m, 524.7 ± 63.7 m vs 539.1 ± 63.1 m, respectively (P<0.01)). Very strong agreement was observed at 15, 20, and 25 meters with the standard 30 meters (0.819-0.875, P<0.001). Subgroup analysis showed strong to very strong agreement in 10-meter walkway length onwards with the standard walkway length among older adults (0.757-0.918, P<0.001).
Testing on 20 meters walkway and shorter yielded varied results compared to the standard 30-meter walk, with exceptional congruence observed at 15 meters onwards. In particular, a minimum walkway of 10 meters had strong agreement with a standard 30-meter walkway in elderly.
Journal Article
A comparison of new cardiovascular endurance test using the 2-minute marching test vs. 6-minute walk test in healthy volunteers: A crossover randomized controlled trial
This was a 2×2 randomized crossover control trial.
To compare the cardiovascular endurance of healthy volunteers using a 2-minute marching test (2MMT) and a 6-minute walk test (6MWT).
This study included 254 participants of both sexes, aged 20-50 years, with a height and body mass index (BMI) of ≥150 cm and ≤25 kg/m2, respectively. Participants were hospital staff who could perform activities independently and had normal annual chest radiographs and electrocardiograms. A group-randomized design was used to assign participants to Sequence 1 (AB) or 2 (BA). The tests were conducted over 2 consecutive days, with a 1-day washout period. On day 1, the participants randomly underwent either a 6MWT or 2MMT in a single-anonymized setup, and on day 2, the tests were performed in reverse order. We analyzed maximal oxygen consumption (VO2max) as the primary outcome and heart rate (HR), respiratory rate (RR), blood pressure (BP), oxygen saturation, dyspnea, and leg fatigue as secondary outcomes.
Data were collected from 127 participants, categorized into two groups for different testing sequences. The first (AB) and second groups had 63 and 64 participants, respectively. The estimated VO2max was equivalent between both groups. The 2MMT and 6MWT estimated VO2max with a mean of 41.00 ± 3.95 mL/kg/min and 40.65 ± 3.98 mL/kg/min, respectively. The mean difference was -0.35 mL/kg/min (95% confidence interval: -1.09 to 0.38; p <0.001), and no treatment and carryover effect were observed. No significant changes were observed in HR, RR, and systolic BP (p = 0.295, p = 0.361 and p = 0.389, respectively). However, significant changes were found in the ratings of perceived exertion (p <0.001) and leg fatigue scale (p <0.001).
The 2MMT is practical, simple, and equivalent to the 6MWT in estimating VO2max.
TCTR20220528004 https://www.thaiclinicaltrials.org.
Journal Article
Enhancing dentate gyrus function with dietary flavanols improves cognition in older adults
This study provides causal evidence demonstrating that consuming a high flavanol diet improves dentate gyrus function and dentate gyrus–dependent cognitive functions in aged humans.
The dentate gyrus (DG) is a region in the hippocampal formation whose function declines in association with human aging and is therefore considered to be a possible source of age-related memory decline. Causal evidence is needed, however, to show that DG-associated memory decline in otherwise healthy elders can be improved by interventions that enhance DG function. We addressed this issue by first using a high-resolution variant of functional magnetic resonance imaging (fMRI) to map the precise site of age-related DG dysfunction and to develop a cognitive task whose function localized to this anatomical site. Then, in a controlled randomized trial, we applied these tools to study healthy 50–69-year-old subjects who consumed either a high or low cocoa flavanol–containing diet for 3 months. A high-flavanol intervention was found to enhance DG function, as measured by fMRI and by cognitive testing. Our findings establish that DG dysfunction is a driver of age-related cognitive decline and suggest non-pharmacological means for its amelioration.
Journal Article
Blinded, randomized trial of sonographer versus AI cardiac function assessment
Artificial intelligence (AI) has been developed for echocardiography
1
–
3
, although it has not yet been tested with blinding and randomization. Here we designed a blinded, randomized non-inferiority clinical trial (ClinicalTrials.gov ID: NCT05140642; no outside funding) of AI versus sonographer initial assessment of left ventricular ejection fraction (LVEF) to evaluate the impact of AI in the interpretation workflow. The primary end point was the change in the LVEF between initial AI or sonographer assessment and final cardiologist assessment, evaluated by the proportion of studies with substantial change (more than 5% change). From 3,769 echocardiographic studies screened, 274 studies were excluded owing to poor image quality. The proportion of studies substantially changed was 16.8% in the AI group and 27.2% in the sonographer group (difference of −10.4%, 95% confidence interval: −13.2% to −7.7%,
P
< 0.001 for non-inferiority,
P
< 0.001 for superiority). The mean absolute difference between final cardiologist assessment and independent previous cardiologist assessment was 6.29% in the AI group and 7.23% in the sonographer group (difference of −0.96%, 95% confidence interval: −1.34% to −0.54%,
P
< 0.001 for superiority). The AI-guided workflow saved time for both sonographers and cardiologists, and cardiologists were not able to distinguish between the initial assessments by AI versus the sonographer (blinding index of 0.088). For patients undergoing echocardiographic quantification of cardiac function, initial assessment of LVEF by AI was non-inferior to assessment by sonographers.
The impact of artificial intelligence in cardiac function assessment is evaluated by a blinded, randomized non-inferiority trial of artificial intelligence versus sonographer initial assessment of the left ventricular ejection fraction.
Journal Article
Causal relationships among the gut microbiome, short-chain fatty acids and metabolic diseases
Microbiome-wide association studies on large population cohorts have highlighted associations between the gut microbiome and complex traits, including type 2 diabetes (T2D) and obesity
1
. However, the causal relationships remain largely unresolved. We leveraged information from 952 normoglycemic individuals for whom genome-wide genotyping, gut metagenomic sequence and fecal short-chain fatty acid (SCFA) levels were available
2
, then combined this information with genome-wide-association summary statistics for 17 metabolic and anthropometric traits. Using bidirectional Mendelian randomization (MR) analyses to assess causality
3
, we found that the host-genetic-driven increase in gut production of the SCFA butyrate was associated with improved insulin response after an oral glucose-tolerance test (
P
= 9.8 × 10
−5
), whereas abnormalities in the production or absorption of another SCFA, propionate, were causally related to an increased risk of T2D (
P
= 0.004). These data provide evidence of a causal effect of the gut microbiome on metabolic traits and support the use of MR as a means to elucidate causal relationships from microbiome-wide association findings.
Mendelian randomization analyses using genotyping data, gut metagenomic sequence and fecal short-chain-fatty-acid levels from 952 individuals combined with GWAS data show evidence of a causal effect of the gut microbiome on metabolic traits.
Journal Article
Inhaled Aztreonam Lysine for Chronic Airway Pseudomonas aeruginosa in Cystic Fibrosis
The effectiveness and safety of aztreonam lysine for inhalation (AZLI) in patients with cystic fibrosis (CF) on maintenance treatment for Pseudomonas aeruginosa (PA) airway infection was evaluated in this randomized, double-blind, placebo-controlled study.
To evaluate the safety and efficacy of inhaled aztreonam lysine in controlling PA infection in patients with CF.
After randomization and a 28-day course of tobramycin inhalation solution (TIS), patients (n = 211; > or =6 yr; > or =3 TIS courses within previous year; FEV(1) > or = 25% and < or =75% predicted values) were treated with 75 mg AZLI or placebo, twice or three times daily for 28 days, then monitored for 56 days. The primary efficacy endpoint was time to need for additional inhaled or intravenous antipseudomonal antibiotics. Secondary endpoints included changes in respiratory symptoms (CF Questionnaire-Revised [CFQ-R] Respiratory Scale), pulmonary function (FEV(1)), and sputum PA density. Adverse events and minimum inhibitory concentrations of aztreonam for PA were monitored.
AZLI treatment increased median time to need for additional antipseudomonal antibiotics for symptoms of pulmonary exacerbation by 21 days, compared with placebo (AZLI, 92 d; placebo, 71 d; P = 0.007). AZLI improved mean CFQ-R respiratory scores (5.01 points, P = 0.02), FEV(1) (6.3%, P = 0.001), and sputum PA density (-0.66 log(10) cfu/g, P = 0.006) compared with placebo; no AZLI dose-response was observed. Adverse events reported for AZLI and placebo were comparable and consistent with CF lung disease. Susceptibility of PA to aztreonam at baseline and end of therapy were similar.
AZLI was effective in patients with CF using frequent TIS therapy. AZLI delayed time to need for inhaled or intravenous antipseudomonal antibiotics, improved respiratory symptoms and pulmonary function, and was well tolerated. Clinical trial registered with www.clinicaltrials.gov (NCT 00104520).
Journal Article
A Pragmatic, Randomized Clinical Trial of Gestational Diabetes Screening
In this pragmatic, randomized trial comparing one-step screening for gestational diabetes mellitus with two-step screening, one-step screening resulted in more diagnoses of gestational diabetes mellitus but did not affect the incidence of adverse perinatal and maternal outcomes.
Journal Article