Group-based trajectory analysis of physical activity change in a U.S. weight loss intervention

Background: The obesity epidemic is a global concern. Standard behavioral treatment including increased physical activity, reduced energy intake, and behavioral change counseling is an effective lifestyle intervention for weight loss. Purpose: To identify distinct step count patterns among weight loss intervention participants, examine weight loss differences by trajectory group, and examine baseline factors associated with trajectory group membership. Methods: Both groups received group-based standard behavioral treatment while the experimental group received up to 30 additional, one-on-one self-efficacy enhancement sessions. Data were analyzed using group-based trajectory modeling, analysis of variance, chi-square tests, and multinomial logistic regression. Results: Participants (N = 120) were mostly female (81.8%) and white (73.6%) with a mean (SD) body mass index of 33.2 (3.8) kg/m2. Four step count trajectory groups were identified: active (>10,000 steps/day; 11.7%), somewhat active (7500–10,000 steps/day; 28.3%), low active (5000–7500 steps/day; 27.5%), and sedentary (<5000 steps/day; 32.5%). Percent weight loss at 12 months increased incrementally by trajectory group (5.1% [5.7%], 7.8% [6.9%], 8.0% [7.4%], and 13.63% [7.0%], respectively; P = .001). At baseline, lower body mass index and higher perceived health predicted membership in the better performing trajectory groups. Conclusions: Within a larger group of adults in a weight loss intervention, 4 distinct trajectory groups were identified and group membership was associated with differential weight loss

The SELF Trial: A self-efficacy based behavioral intervention trial for weight loss maintenance.

The SELF Trial examined the effect of adding individual self‐efficacy (SE) enhancement sessions to standard behavioral weight loss treatment (SBT). Participants were randomly assigned to SBT or SBT plus SE sessions (SBT+SE). Outcome measures were weight loss maintenance, quality of life, intervention adherence, and self‐efficacy at 12 and 18 months. The sample (N = 130) was female (83.08%) with a mean (SD) body mass index of 33.15 (4.11) kg m2. There was a significant time effect for percent weight change (P = 0.002) yet no significant group or group‐by‐time effects. The weight loss for the SBT+SE group was 8.38% (7.48) at 12 months and 8.00% (7.87) at 18 months, with no significant difference between the two time points (P = 0.06). However, weight loss for the SBT group was 6.95% (6.67) at 12 months and 5.96% (7.35) at 18 months, which was significantly different between the two time points (P = 0.005), indicating that the SBT group had significant weight regain. Both groups achieved clinically significant weight loss. The group receiving an intervention targeting enhanced self‐efficacy had greater weight loss maintenance whereas the SBT group demonstrated significant weight regain possibly related to the greater attention provided to the SBT+SE group

The Use of mHealth to Deliver Tailored Messages Reduces Reported Energy and Fat Intake.

Evidence supports the role of feedback in reinforcing motivation for behavior change. Feedback that provides reinforcement has the potential to increase dietary self-monitoring and enhance attainment of recommended dietary intake. The aim of this study was to examine the impact of daily feedback (DFB) messages, delivered remotely, on changes in dietary intake. This was a secondary analysis of the Self- Monitoring And Recording using Technology (SMART) Trial, a single-center, 24-month randomized clinical trial of behavioral treatment for weight loss. Participants included 210 obese adults (mean body mass index, 34.0 kg/m2) who were randomized to either a paper diary (PD), personal digital assistant (PDA), or PDA plus daily tailored feedback messages (PDA + FB). To determine the role of daily tailored feedback in dietary intake, we compared the self-monitoring with DFB group (DFB group; n = 70) with the self-monitoring without DFB group (no-DFB group, n = 140). All participants received a standard behavioral intervention for weight loss. Self-reported changes in dietary intake were compared between the DFB and no-DFB groups and were measured at baseline and at 6, 12, 18, and 24 months. Linear mixed modeling was used to examine percentage changes in dietary intake from baseline. Compared with the no-DFB group, the DFB group achieved a larger reduction in energy (−22.8% vs −14.0%; P = .02) and saturated fat (−11.3% vs −0.5%; P = .03) intake and a trend toward a greater decrease in total fat intake (−10.4% vs −4.7%; P = .09). There were significant improvements over time in carbohydrate intake and total fat intake for both groups (P values < .05). Daily tailored feedback messages designed to target energy and fat intake and delivered remotely in real time using mobile devices may play an important role in the reduction of energy and fat intake

Sociodemographic, Anthropometric, and Psychosocial Predictors of Attrition across Behavioral Weight-Loss Trials.

Preventing attrition is a major concern in behavioral weight loss intervention studies. The purpose of this analysis was to identify baseline and six-month predictors associated with participant attrition across three independent clinical trials of behavioral weight loss interventions (PREFER, SELF, and SMART) that were conducted over 10 years. Baseline measures included body mass index, Barriers to Healthy Eating, Beck Depression Inventory-II (BDI), Hunger Satiety Scale (HSS), Binge Eating Scale (BES), Medical Outcome Study Short Form (MOS SF-36 v2) and Weight Efficacy Lifestyle Questionnaire (WEL). We also examined early weight loss and attendance at group sessions during the first 6 months. Attrition was recorded at the end of the trials. Participants included 504 overweight and obese adults seeking weight loss treatment. The sample was 84.92% female and 73.61% white, with a mean (± SD) age of 47.35 ± 9.75 years. After controlling for the specific trial, for every one unit increase in BMI, the odds of attrition increased by 11%. For every year increase in education, the odds of attrition decreased by 10%. Additional predictors of attrition included previous attempts to lose 50–79 lbs, age, not possessing health insurance, and BES, BDI, and HSS scores. At 6 months, the odds of attrition increased by 10% with reduced group session attendance. There was also an interaction between percent weight change and trial (p < .001). Multivariate analysis of the three trials showed education, age, BMI, and BES scores were independently associated with attrition (ps ≤ .01). These findings may inform the development of more robust strategies for reducing attrition

Left ventricular dysfunction and duration of mechanical ventilatory support in the chronically critically ill: A survival analysis

Objective: The purpose of this study was to determine whether there was a greater risk for prolonged duration of mechanical ventilatory support (MVS) for those who demonstrated left ventricular dysfunction (LVD) compared to those without evidence of LVD when controlling for nutritional and general health status and spontaneous breathing pattern. Design: A secondary analysis was used on data obtained in a retrospective survey of patient records. Setting: Five adult critical care units at an academic medical center in the Midwest. Subjects: Twenty-seven chronically critically ill adults requiring MVS who later successfully weaned from MVS. Outcome Measure: Duration of MVS. Instrumentation: LVD was determined with use of a criterion-based checklist. Serum albumin level as determined by the hospital's clinical laboratory served as the indicator of nutritional and general health status. The rapid shallow breathing index was used to describe the spontaneous breathing pattern. Results: Adjusted survival function estimates were obtained on fitting a Cox proportional hazards model. When adjusting for the known covariates, serum albumin level and rapid shallow breating index, the duration of MVS was significantly longer for those who demonstrated LVD when compared to those without evidence of LVD [X2(Wald) (1) = 4.72, p < 0.05]. Conclusions: The findings of this secondary analysis lend support to the fact that when controlling for serum albumin level and rapid shallow breathing index, LVD is related to the duration of MVS in patients who successfully wean

Relationship among serum albumin, TNF-α and IL-6 levels in adults requiring mechanical ventilatory support

Introduction: Serum albumin levels have been shown to be decreased in adults requiring mechanical ventilatory support (MVS). TNF-α and IL-6 have been shown to decrease gene expression for albumin synthesis in hepatocytes. The purpose of this study is to examine the relationship between levels of inflammatory markers and albumin levels during MVS. Methods: A total of 57 specimens (blood) were obtained from 39 subjects (23 men, 16 women), age 21-89 yrs. Serum albumin level was measured using the bromocresol green basic method. TNF-α and IL-6 analyses were performed by ELISA. Results were classified as normal or elevated. Normal was defined as < 15.6 pg/mL for TNF-α and < 12.5 pg/mL for IL-6. Results: Serum albumin levels ranged from 12 to 40 g/L. TNF-α ranged from 0.0 to 82.5 pg/mL IL-6 ranged from 2.03 to 349.5 pg/mL. TNF-α was elevated in 12 (31%), while IL-6 was elevated in 35 (90%) of the subjects at one or more points in time. Serum albumin level is inversely related to IL-6 but not TNF-α. Significant differences in albumin [(mean = 29.4 ± 7.0 g/L, n = 7) (mean = 24-6 ± 5.8 g/L, n = 49)] exist between those with normal and elevated levels of IL-6[(t = 2.024, df =54)]. Expressed as an regression equation: [serum albumin level] = [-5.184] [IL-6 group] + 29.429. Conclusion: We speculate that inflammation, as evidenced by the large proportion of patients with elevated IL-6, may be an important cause of ventilatory dependency. Since many patients requiring MVS frequently have serum albumin levels in the 24 g/L range and tend to wean once albumin levels begin to rise, weaning may be related to decreased inflammation. The role that inflammatory processes play in ventilator dependency warrants further examination

Biochemical indicators of LV function during mechanical ventilatory support in critically ill adults

Introduction: The role of cardiac function is emerging as a poorly explored but potentially significant factor in ventilator dependence. Measuring LV function in the ICU is difficult. Therefore, surrogate biochemical markers were evaluated to determine if they correlate with standard measures and whether these surrogates can be used to predict duration of MVS especially in the absence of PA catheter. Methods: Blood samples for plasma norepmephnne levels (PNL) and atrial natnureuc peptade (ANP) were collected while hemodynamic parameters were observed using standard methods on the day following the initiation of mechanical ventilatory support. Results: PNL was significantly correlated with systemic vascular resistance (r - .57, p 900 pg/L did so. Conclusions: Biochemical indicators such as PNL and ANP may be useful in categorizing hemodynamic status in mechanically ventilated adults when a PA catheter IB not in place

Noninvasrve estimation of paop during mechanical ventilatory support in critically ill adults

Introduction: At a time when there is renewed controversy about the use of flow-directed balloon-tipped pulmonary artery catheters and increasing hesitation in their use, the ability to estimate the PAOP nomnvasively is welcome. Methods: Twenty mechanically ventilated, critically ill adults with flowdirected, balloon-tipped pulmonary artery catheters were recruited to evaluate a nomnvasive device (VenCor, CVP Diagnostics, Laguna Beach CA) estimates PAOP based on the pulse pressure response to Valsalva as measured by finger plethysmography. Results: Twenty subjects (8 men, 12 women) ranging in age from 49 to 89 years (median- 61 ), had first day APACHE III acute physiology scores that ranged from 24 to 92 (median= 52 ). The PAOP measures ranged from 9 to 24 mm Hg. There is no significant difference (paired t - -0.91, df = 19, p>.05) between the two measures and they are significantly correlated (r=.90, p<.05) with each other. Conclusions: The VeriCor provides the means to estimate PAOP noninvasively

Elevated Troponin-T levels in patients requiring prolonged mechanical ventdlatory support (MVS)

Introduction: Identifying non-pulmonary determinants is essential in liberating those ventilator-dependent patients, who despite demonstrating good pulmonary mechanics, are unable to resume unassisted, spontaneous ventilation. Prior research suggests heart function is one of these non-pulmonary determinants. Methods: As part of a larger study, blood was obtained from 19 subjects (10 men, 9 women)on Day 1 of MVS. They ranged in age from 21 to 89 years (mean=62.5). There were 11 medical and 8 surgical patients. Myocardial injury was evaluated using Troponin-T level (TnT). Results: Of 19 subjects, 6 had elevated TnT. Three of those with elevated TnT (>0.10 μg/L) had CK-MB and ECG evidence of MI, 3 did not. There was a significant difference in the duration of MVS between those who had elevated TnT (mean-18 days, median=20 days) and those who did not (mean=4 days, median = 3 days) and survival distribution functions as demonstrated by Kaplan Meier survival function plot [Generalized Savage log-rank test=6.55, df=1, p<.05]. Conclusions: Clinically recognized as well as unrecognized myocardial injury (ischemia or infarction) is related to prolonged MVS

Impact of left ventricular function on duration of mechanical ventilatory support

Introduction: The primary focus on predicting ability to wean from mechanical ventilatory support (MVS) has been on ventilatory capacity, lung pathology, diaphragmatic strength and nutrition. While this focus has not been incorrect, results have been disappointing. Clinicians continue to be challenged by patients requiring prolonged MVS. Left ventricular (LV) function is emerging as a poorly explored but potentially significant factor impacting ventilator dependence. Methods: A prospective, comparative design was used to follow 53 critically ill adults requiring MVS until completely weaned up to 4 weeks following initiation of MVS. Subjects were male (n=27, 51%), white (n=50, 94%) and aged 21 to 89 years (mean=63.9, SD=12.9). LV function was measured weekly using surrogate indicators of preload [pulmonary artery occlusion pressure (PAOP) and atrial natriuretic peptide levels (ANP)] and afterload (plasma norepinephrine). Cox proportional hazards regression was used to develop predictive models of MVS duration, treating the longitudinally measured indicators of LV function as time-dependent covariates. Hypotheses were tested using likelihood-ratio statistics. Results: Most subjects (n=40, 75.5%) exhibited compromised LV function based on either PAOP (mean= 16.6 mmHg, SD=5.2) or plasma norepinephrine (median=957pg/mL, SQR=562) levels at MVS initiation. Within 4 weeks, 69.8% (n=37) had weaned completely from MVS. Examination of the surrogate indicators of LV function revealed that subjects having a relative decrease in plasma norepinephrine levels since MVS initiation [χ2(1)=2.73, p<.05] and having lower absolute plasma norepinephrine levels [χ2(1)=3.65, p<.05] were more likely to wean; however, neither absolute or relative change since MVS initiation in either PAOP or ANP predicted MVS duration. Conclusions: These findings suggest LV function may play a role in ventilator dependence and that decreasing afterload may shorten duration of MVS