Energy Requirement Is Higher During Weight-Loss Maintenance in Adults Consuming a Low- Compared with High-Carbohydrate Diet.

BACKGROUND: Longer-term feeding studies suggest that a low-carbohydrate diet increases energy expenditure, consistent with the carbohydrate-insulin model of obesity. However, the validity of methodology utilized in these studies, involving doubly labeled water (DLW), has been questioned. OBJECTIVE: The aim of this study was to determine whether dietary energy requirement for weight-loss maintenance is higher on a low- compared with high-carbohydrate diet. METHODS: The study reports secondary outcomes from a feeding study in which the primary outcome was total energy expenditure (TEE). After attaining a mean Run-in weight loss of 10.5%, 164 adults (BMI ≥25 kg/m2; 70.1% women) were randomly assigned to Low-Carbohydrate (percentage of total energy from carbohydrate, fat, protein: 20/60/20), Moderate-Carbohydrate (40/40/20), or High-Carbohydrate (60/20/20) Test diets for 20 wk. Calorie content was adjusted to maintain individual body weight within ± 2 kg of the postweight-loss value. In analyses by intention-to-treat (ITT, completers, n = 148) and per protocol (PP, completers also achieving weight-loss maintenance, n = 110), we compared the estimated energy requirement (EER) from 10 to 20 wk of the Test diets using ANCOVA. RESULTS: Mean EER was higher in the Low- versus High-Carbohydrate group in models of varying covariate structure involving ITT [ranging from 181 (95% CI: 8-353) to 246 (64-427) kcal/d; P ≤0.04] and PP [ranging from 245 (43-446) to 323 (122-525) kcal/d; P ≤0.02]. This difference remained significant in sensitivity analyses accounting for change in adiposity and possible nonadherence. CONCLUSIONS: Energy requirement was higher on a low- versus high-carbohydrate diet during weight-loss maintenance in adults, commensurate with TEE. These data are consistent with the carbohydrate-insulin model and lend qualified support for the validity of the DLW method with diets varying in macronutrient composition. This trial was registered at clinicaltrials.gov as NCT02068885.

Atenolol versus losartan in children and young adults with Marfan's syndrome.

BACKGROUND: Aortic-root dissection is the leading cause of death in Marfan's syndrome. Studies suggest that with regard to slowing aortic-root enlargement, losartan may be more effective than beta-blockers, the current standard therapy in most centers. METHODS: We conducted a randomized trial comparing losartan with atenolol in children and young adults with Marfan's syndrome. The primary outcome was the rate of aortic-root enlargement, expressed as the change in the maximum aortic-root-diameter z score indexed to body-surface area (hereafter, aortic-root z score) over a 3-year period. Secondary outcomes included the rate of change in the absolute diameter of the aortic root; the rate of change in aortic regurgitation; the time to aortic dissection, aortic-root surgery, or death; somatic growth; and the incidence of adverse events. RESULTS: From January 2007 through February 2011, a total of 21 clinical centers enrolled 608 participants, 6 months to 25 years of age (mean [±SD] age, 11.5±6.5 years in the atenolol group and 11.0±6.2 years in the losartan group), who had an aortic-root z score greater than 3.0. The baseline-adjusted rate of change in the mean (±SE) aortic-root z score did not differ significantly between the atenolol group and the losartan group (-0.139±0.013 and -0.107±0.013 standard-deviation units per year, respectively; P=0.08). Both slopes were significantly less than zero, indicating a decrease in the aortic-root diameter relative to body-surface area with either treatment. The 3-year rates of aortic-root surgery, aortic dissection, death, and a composite of these events did not differ significantly between the two treatment groups. CONCLUSIONS: Among children and young adults with Marfan's syndrome who were randomly assigned to losartan or atenolol, we found no significant difference in the rate of aortic-root dilatation between the two treatment groups over a 3-year period. (Funded by the National Heart, Lung, and Blood Institute and others; ClinicalTrials.gov number, NCT00429364.).

Characteristics of children and young adults with Marfan syndrome and aortic root dilation in a randomized trial comparing atenolol and losartan therapy.

BACKGROUND: The Pediatric Heart Network designed a clinical trial to compare aortic root growth and other short-term cardiovascular outcomes in children and young adults with Marfan syndrome randomized to receive atenolol or losartan. We report here the characteristics of the screened population and enrolled subjects. METHODS AND RESULTS: Between 2007 and 2011, 21 clinical sites randomized 608 subjects, aged 6 months to 25 years who met the original Ghent criteria and had a body surface area-adjusted aortic root diameter z-score >3.0. The mean age at study entry was 11.2 years, 60% were male, and 25% were older teenagers and young adults. The median aortic root diameter z-score was 4.0. Aortic root diameter z-score did not vary with age. Mitral valve prolapse and mitral regurgitation were more common in females. Among those with a positive family history, 56% had a family member with aortic surgery, and 32% had a family member with a history of aortic dissection. CONCLUSIONS: Baseline demographic, clinical, and anthropometric characteristics of the randomized cohort are representative of patients in this population with moderate to severe aortic root dilation. The high percentage of young subjects with relatives who have had aortic dissection or surgery illustrates the need for more definitive therapy; we expect that the results of the study and the wealth of systematic data collected will make an important contribution to the management of individuals with Marfan syndrome.

Lessons learned from a pediatric clinical trial: the Pediatric Heart Network angiotensin-converting enzyme inhibition in mitral regurgitation study.

BACKGROUND: Mitral regurgitation is the most common indication for reoperation in children following repair of atrioventricular septal defect (AVSD). We hypothesized that angiotensin-converting enzyme inhibitor therapy would decrease the severity of mitral regurgitation and limit left ventricular volume overload in children following AVSD repair. METHODS: The Pediatric Heart Network designed a placebo-controlled randomized trial of enalapril in this population. The primary aim was to test the effect of enalapril on the change in left ventricular end-diastolic dimension body surface area-adjusted z score. Before the launch of the trial, a feasibility study was performed to estimate the number of patients with at least moderate mitral regurgitation following AVSD repair. TRIAL EXPERIENCE: Seventeen months after the start of the study, 349 patients were screened, 8 were trial eligible, and only 5 were enrolled. The study was subsequently terminated because of low patient accrual. Several factors led to the problems with patient accrual, including (1) the use of criteria to assess disease severity in the feasibility study that were not identical to those used in the trial, (2) failure to achieve equipoise for the study among clinicians and referring physicians, (3) reliance on methodology developed in adult populations with different disease mechanisms, and (4) absence of adequate data to define the natural history of the disease process under study. Progress in the treatment of children with cardiovascular disease will depend on the future of multicenter collaborative clinical trials. The lessons learned from this study may contribute to improvements in this research.

Randomized trial of pulsed corticosteroid therapy for primary treatment of Kawasaki disease.

BACKGROUND: Treatment of acute Kawasaki disease with intravenous immune globulin and aspirin reduces the risk of coronary-artery abnormalities and systemic inflammation, but despite intravenous immune globulin therapy, coronary-artery abnormalities develop in some children. Studies have suggested that primary corticosteroid therapy might be beneficial and that adverse events are infrequent with short-term use. METHODS: We conducted a multicenter, randomized, double-blind, placebo-controlled trial to determine whether the addition of intravenous methylprednisolone to conventional primary therapy for Kawasaki disease reduces the risk of coronary-artery abnormalities. Patients with 10 or fewer days of fever were randomly assigned to receive intravenous methylprednisolone, 30 mg per kilogram of body weight (101 patients), or placebo (98 patients). All patients then received conventional therapy with intravenous immune globulin, 2 g per kilogram, as well as aspirin, 80 to 100 mg per kilogram per day until they were afebrile for 48 hours and 3 to 5 mg per kilogram per day thereafter. RESULTS: At week 1 and week 5 after randomization, patients in the two study groups had similar coronary dimensions, expressed as z scores adjusted for body-surface area, absolute dimensions, and changes in dimensions. As compared with patients receiving placebo, patients receiving intravenous methylprednisolone had a somewhat shorter initial period of hospitalization (P=0.05) and, at week 1, a lower erythrocyte sedimentation rate (P=0.02) and a tendency toward a lower C-reactive protein level (P=0.07). However, the two groups had similar numbers of days spent in the hospital, numbers of days of fever, rates of retreatment with intravenous immune globulin, and numbers of adverse events. CONCLUSIONS: Our data do not provide support for the addition of a single pulsed dose of intravenous methylprednisolone to conventional intravenous immune globulin therapy for the routine primary treatment of children with Kawasaki disease. (ClinicalTrials.gov number, NCT00132080 [ClinicalTrials.gov].)

Effects of Dietary Carbohydrate Content on Circulating Metabolic Fuel Availability in the Postprandial State.

CONTEXT: According to the carbohydrate-insulin model of obesity, an elevated insulin-to-glucagon ratio in response to a high-carbohydrate diet directs metabolic fuels toward storage, resulting in lower circulating energy. OBJECTIVE: To determine differences in total circulating energy post-meal related to dietary carbohydrate. DESIGN: Ancillary study within the Framingham State Food Study. SETTING: University community. PARTICIPANTS: 29 adults (aged 20 to 65 years) with overweight or obesity (body mass index ≥25 kg/m2). INTERVENTION: After achieving 10% to 14% weight loss on a run-in diet, participants were randomized to weight-loss-maintenance test diets varying in carbohydrate content (high-carbohydrate, 60% of total energy, n = 11; moderate-carbohydrate, 40%, n = 8; low-carbohydrate, 20%, n = 10) and controlled for protein (20%). During 24-hour metabolic ward admissions between 10 and 15 weeks on the test diets, metabolic fuels and hormones were measured. MAIN OUTCOME MEASURE: Energy availability (EA) based on energy content of blood glucose, beta-hydroxybutyrate, and free fatty acids, in the late postprandial period (180 to 300 minutes). Insulin at 30 minutes into the test meal (Meal Insulin-30) was measured as an effect modifier. RESULTS: Insulin-to-glucagon ratio was 7-fold higher in participants on the high- vs low-carbohydrate diet (2.5 and 0.36, respectively). Late postprandial EA was 0.58 kcal/L lower on the high- vs low-carbohydrate diet (P < 0.0001), primarily related to suppression of free fatty acids. Early postprandial EA (30 to 180 minutes) declined fastest in the high-carbohydrate group, and Meal Insulin-30 modified this diet effect. CONCLUSIONS: During weight-loss maintenance on a high-carbohydrate diet, late postprandial EA is reduced, consistent with the carbohydrate-insulin model.

Associated symptoms in the ten days before diagnosis of Kawasaki disease.

OBJECTIVE: To describe common associated symptoms within the 10 days before diagnosis in subjects enrolled in the Pediatric Heart Network's trial of steroid therapy in Kawasaki disease (KD). STUDY DESIGN: Patients with acute KD were enrolled between days 4 and 10 of illness at 8 centers between 2002 and 2004. We defined common associated symptoms as those occurring in >or=10% of patients. Principal clinical criteria for KD were not included in this analysis. RESULTS: Among 198 patients, irritability was reported in 98 (50%), vomiting in 88 (44%), decreased food/fluid intake in 73 (37%), cough in 55 (28%), diarrhea in 52 (26%), rhinorrhea in 37 (19%), weakness in 37 (19%), abdominal pain in 35 (18%), and joint pain (arthralgia or arthritis) in 29 (15%). One or more gastrointestinal symptom (vomiting, diarrhea, or abdominal pain) was present in 120 patients (61%) and 69 patients (35%) had >or= 1 respiratory symptom (rhinorrhea or cough). CONCLUSIONS: Nonspecific symptoms occur commonly in children with KD. To reduce delays in diagnosis, clinicians should be educated that such symptoms may comprise a significant component in the chief complaint.

Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial.

OBJECTIVE: To determine the effects of diets varying in carbohydrate to fat ratio on total energy expenditure. DESIGN: Randomized trial. SETTING: Multicenter collaboration at US two sites, August 2014 to May 2017. PARTICIPANTS: 164 adults aged 18-65 years with a body mass index of 25 or more. INTERVENTIONS: After 12% (within 2%) weight loss on a run-in diet, participants were randomly assigned to one of three test diets according to carbohydrate content (high, 60%, n=54; moderate, 40%, n=53; or low, 20%, n=57) for 20 weeks. Test diets were controlled for protein and were energy adjusted to maintain weight loss within 2 kg. To test for effect modification predicted by the carbohydrate-insulin model, the sample was divided into thirds of pre-weight loss insulin secretion (insulin concentration 30 minutes after oral glucose). MAIN OUTCOME MEASURES: The primary outcome was total energy expenditure, measured with doubly labeled water, by intention-to-treat analysis. Per protocol analysis included participants who maintained target weight loss, potentially providing a more precise effect estimate. Secondary outcomes were resting energy expenditure, measures of physical activity, and levels of the metabolic hormones leptin and ghrelin. RESULTS: Total energy expenditure differed by diet in the intention-to-treat analysis (n=162, P=0.002), with a linear trend of 52 kcal/d (95% confidence interval 23 to 82) for every 10% decrease in the contribution of carbohydrate to total energy intake (1 kcal=4.18 kJ=0.00418 MJ). Change in total energy expenditure was 91 kcal/d (95% confidence interval -29 to 210) greater in participants assigned to the moderate carbohydrate diet and 209 kcal/d (91 to 326) greater in those assigned to the low carbohydrate diet compared with the high carbohydrate diet. In the per protocol analysis (n=120, P<0.001), the respective differences were 131 kcal/d (-6 to 267) and 278 kcal/d (144 to 411). Among participants in the highest third of pre-weight loss insulin secretion, the difference between the low and high carbohydrate diet was 308 kcal/d in the intention-to-treat analysis and 478 kcal/d in the per protocol analysis (P<0.004). Ghrelin was significantly lower in participants assigned to the low carbohydrate diet compared with those assigned to the high carbohydrate diet (both analyses). Leptin was also significantly lower in participants assigned to the low carbohydrate diet (per protocol). CONCLUSIONS: Consistent with the carbohydrate-insulin model, lowering dietary carbohydrate increased energy expenditure during weight loss maintenance. This metabolic effect may improve the success of obesity treatment, especially among those with high insulin secretion. TRIAL REGISTRATION: ClinicalTrials.gov NCT02068885.

An Academia-Industry Partnership for Planning and Executing a Community-Based Feeding Study.

A research team from Boston Children's Hospital and Harvard Medical School conducted a community-based feeding study in collaboration with Framingham State University (FSU) and Sodexo, the food service contractor at FSU. The study was a randomized controlled trial, implemented on the FSU campus. For the final year of the study, a satellite feeding site was established at Assabet Valley Regional Technical High School. The purpose of the study was to assess the biological effects of different macronutrient diets. An academia-industry partnership was developed to overcome common challenges associated with hospital-based feeding studies. Benefits included the following: a study site outside of Boston (reducing inconvenience for participants), access to a large commercial kitchen and study-specific kiosk (promoting efficiency), collaboration with Sodexo chefs (ensuring palatability of meals), and opportunity to procure food from contracted vendors. The research (academia) and food service (industry) teams worked together to design, plan, and execute intervention protocols using an integrated approach. During execution, the research team was primarily responsible for overseeing treatment fidelity, whereas the food service team provided culinary expertise, with a strong focus on hospitality and food quality. The study was conducted in 3 cohorts between August 2014 and May 2017. Participants received all of their food for ∼30 wk, totaling >160,000 meals. For all 3 cohorts combined, 234 participants provided informed consent, 229 started a standard run-in weight-loss diet, 164 lost a mean ± SD 12% ± 2% of baseline body weight and were randomly assigned to different macronutrient diets for weight-loss maintenance, and 148 completed the study. During the final and largest cohort, as many as 114 participants received daily meals concurrently. The daily cost per participant for preparation and service of weighed meals and snacks was ∼$65. This academia-industry partnership provides a model for controlled feeding protocols in nutrition research, potentially with enhanced cost-effectiveness, practicality, and generalizability. This trial was registered at http://www.clinicaltrials.gov as NCT02068885.

A randomized study of dietary composition during weight-loss maintenance: Rationale, study design, intervention, and assessment.

BACKGROUND: While many people with overweight or obesity can lose weight temporarily, most have difficulty maintaining weight loss over the long term. Studies of dietary composition typically focus on weight loss, rather than weight-loss maintenance, and rely on nutrition education and dietary counseling, rather than controlled feeding protocols. Variation in initial weight loss and insufficient differentiation among treatments confound interpretation of results and compromise conclusions regarding the weight-independent effects of dietary composition. The aim of the present study was to evaluate three test diets differing in carbohydrate-to-fat ratio during weight-loss maintenance. DESIGN AND DIETARY INTERVENTIONS: Following weight loss corresponding to 12±2% of baseline body weight on a standard run-in diet, 164 participants aged 18 to 65years were randomly assigned to one of three test diets for weight-loss maintenance through 20weeks (test phase). We fed them high-carbohydrate (60% of energy from carbohydrate, 20% fat), moderate-carbohydrate (40% carbohydrate, 40% fat), and low-carbohydrate (20% carbohydrate, 60% fat) diets, controlled for protein content (20% of energy). During a 2-week ad libitum feeding phase following the test phase, we assessed the effect of the test diets on body weight. OUTCOMES: The primary outcome was total energy expenditure, assessed by doubly-labeled water methodology. Secondary outcomes included resting energy expenditure and physical activity, chronic disease risk factors, and variables to inform an understanding of physiological mechanisms by which dietary carbohydrate-to-fat ratio might influence metabolism. Weight change during the ad libitum feeding phase was conceptualized as a proxy measure of hunger.

Rationale and design of a randomized clinical trial of beta-blocker therapy (atenolol) versus angiotensin II receptor blocker therapy (losartan) in individuals with Marfan syndrome.

BACKGROUND: Cardiovascular disease, including aortic root dilation, dissection, and rupture, is the leading cause of mortality in patients with Marfan syndrome (MFS). The maximal aortic root diameter at the sinuses of Valsalva is considered the best predictor of adverse cardiovascular outcome. Although advances in therapy have improved life expectancy, affected individuals continue to suffer cardiovascular morbidity and mortality. Recent studies in an FBN1-targeted mouse model of MFS with aortic disease similar to that seen in humans showed that treatment with losartan normalized aortic root growth and aortic wall architecture. METHODS: The Pediatric Heart Network designed a randomized clinical trial to compare aortic root growth and other short-term cardiovascular outcomes in subjects with MFS receiving atenolol or losartan. Individuals 6 months to 25 years of age with a body surface area-adjusted aortic root z score >3.0 will be eligible for inclusion. The primary aim is to compare the effect of atenolol therapy with that of losartan therapy on the rate of aortic root growth over 3 years. Secondary end points include progression of aortic regurgitation; incidence of aortic dissection, aortic root surgery, and death; progression of mitral regurgitation; left ventricular size and function; echocardiographically derived measures of central aortic stiffness; skeletal and somatic growth; and incidence of adverse drug reactions. CONCLUSION: This randomized trial should make a substantial contribution to the management of individuals with MFS and expand our understanding of the mechanisms responsible for the aortic manifestations of this disorder.

Partial and transitional atrioventricular septal defect outcomes.

BACKGROUND: Surgical and perioperative improvements permit earlier repair of partial and transitional atrioventricular septal defects (AVSD). We sought to describe contemporary outcomes in a multicenter cohort. METHODS: We studied 87 patients undergoing primary biventricular repair of partial or transitional AVSD between June 2004 and February 2006 across seven North American centers. One-month and 6-month postoperative data included weight-for-age z-scores, left atrioventricular valve regurgitation (LAVVR) grade, residual shunts, and left ventricular ejection fraction. Paired methods were used to assess 6-month change. RESULTS: Median age at surgery was 1.8 years; median weight z-score was -0.88. Median days for ventilation were 1, intensive care 2, and hospitalization 5, all independent of age, with 1 in-hospital death. At 1 month, 27% (16 of 73) had ejection fraction less than 55%; 20% (17 of 87) had significant LAVVR; 2 had residual shunts; 1 each had subaortic stenosis and LAVV stenosis. At 6 months (n = 60), there were no interim deaths, reinterventions, or new development of subaortic or LAVV stenosis. Weight z-score improved by a median 0.4 units (p < 0.001), especially for underweight children less than 18 months old. Left atrioventricular valve regurgitation occurred in 31% (change from baseline, p = 0.13), occurring more frequently in patients repaired at 4 to 7 years (p = 0.01). Three patients had ejection fraction less than 55%, and 1 had a residual atrial shunt. CONCLUSIONS: Surgical repair for partial/transitional AVSD is associated with low morbidity and mortality, short hospital stays, and catch-up growth, particularly in underweight children repaired between 3 and 18 months of age. Left atrioventricular valve regurgitation remains the most common residual defect, occurring more frequently in children repaired after 4 years of age.

Delayed diagnosis of Kawasaki disease: what are the risk factors?

OBJECTIVE: Because late diagnosis of Kawasaki disease increases the risk for coronary artery abnormalities, we explored the prevalence of and possible risk factors for delayed diagnosis by using the database of the Pediatric Heart Network trial of corticosteroid treatment for Kawasaki disease. METHODS: We collected sociodemographic and clinical data at presentation for all patients who were treated for presumed Kawasaki disease at 8 centers (7 in the United States, 1 in Canada). Delayed diagnosis was evaluated by total number of illness days to diagnosis and by the percentage of patients who were treated after day 10 of illness. Independent predictors of delayed diagnosis were identified by using multivariate linear and logistic regression. RESULTS: Of the 589 patients who received intravenous immunoglobulin, 27 were treated before screening for the trial and excluded; 562 patients formed the cohort for analysis. Kawasaki disease was diagnosed at 7.9 +/- 3.9 days, 92 (16%) cases after day 10. Centers were similar with respect to patient age and gender. Centers differed in the patient percentage with incomplete Kawasaki disease; clinical criteria of cervical adenopathy, oral changes, and conjunctivitis; and distance of residence from the center. Independent predictors of greater number of illness days at diagnosis included center, age of <6 months, incomplete Kawasaki disease, and greater distance from the center. Independent predictors of diagnosis after day 10 were age of <6 months, incomplete Kawasaki disease, and greater distance). Socioeconomic variables had no association with delayed diagnosis. CONCLUSIONS: Even after adjustment for patient factors, illness duration at diagnosis varies by center. These findings underscore the need to maintain a high index of suspicion of Kawasaki disease in the infant who is younger than 6 months and has prolonged fever even with incomplete criteria. Outreach educational programs may be useful in promoting earlier recognition and treatment of Kawasaki disease.