1. Kalra, Sanjay MD
  2. Roitman, Jeffrey L. EdD

Article Content


Porszasz J, Cao R, Morishige R, van Eykern LA, Stenzler A, Casaburi R


Am J Respir Crit Care Med. 2013;188:334-342.


Rationale: Exercise intolerance limits the ability of patients with chronic obstructive pulmonary disease (COPD) to perform daily living activities. Noninvasive ventilation reduces dyspnea and improves exercise performance, but current systems are unsuitable for ambulatory use.


Objectives: In patients with COPD experiencing exercise-induced desaturation, we evaluated improvements in exercise tolerance facilitated by a wearable, 1-lb, noninvasive open ventilation (NIOV) system featuring a nasal pillow interface during constant work rate (CWR) cycle ergometer exercise and associated effects on dyspnea, respiratory muscle activation, and pulmonary gas exchange efficiency.


Methods: Fifteen men with COPD (FEV1 = 32.2 +/- 12.0% predicted; FEV1/FVC = 31.6 +/- 7.1%; exercise oxygen saturation as measured by pulse oximetry [SpO2] = 86.5 +/- 2.9%) participated. After incremental testing establishing peak work rate, subjects completed three visits in which they performed CWR exercise to tolerance at 80% peak work rate: (1) unencumbered breathing room air, (2) using NIOV + compressed air, (3) using NIOV + compressed O2, or (4) using O2 via nasal cannula. Assessments included exercise duration, surface inspiratory muscle EMG, SpO2, transcutaneous PCO2, and Borg dyspnea scores.


Measurements and Main Results: Exercise endurance was 17.6 +/- 5.7 minutes using NIOV + O2, greatly prolonged compared with unencumbered (5.6 +/- 1.9 min), nasal O2 (11.4 +/- 6.8 min), and NIOV + Air (6.3 +/- 4.1 min). Isotime SpO2 was higher and intercostal, scalene, and diaphragmatic EMG activity was reduced using NIOV + O2 compared with unencumbered, nasal O2, and NIOV + Air, signifying respiratory muscle unloading. Isotime dyspnea reduction correlated with isotime EMG reduction (r = 0.42, P = 0.0053). There were no significant differences in isotime VD/VT or transcutaneous PCO2 among treatments.


Conclusions: NIOV + O2 yielded substantial exercise endurance improvements accompanied by respiratory muscle unloading and dyspnea reductions in patients with severe hypoxemic COPD.


Editor's Comment: Exercise intolerance and dyspnea are the most frequent symptoms in chronic obstructive pulmonary disease (COPD) and a major barrier to the implementation of exercise programs in these patients. Various studies have shown an improvement in both of these symptoms with the use of various ventilator devices, but these devices have been too heavy and cumbersome for use in routine treatment. This study reports on the results while using a new 1lb (BT-V2S System, Breathe Technologies) device that allows non-invasive open ventilation (NIOV) without requiring a nasal seal and can augment tidal volumes by 50-250 ml and allow adjustment of the inspiratory time between 10 and 40% of the breath cycle.


Fifteen patients with severe COPD (forced expiratory volume in 1 second % predicted = 32.2 +/- 12.0) underwent constant work rate exercise (set at 80% of peak work rate determined from an incremental exercise test) under 4 conditions: Unencumbered, NIOV + room air, NIOV + oxygen, and oxygen delivered through nasal cannula. They had the usual exercise parameters measured but also had surface electrode inspiratory muscle electromyography studies.


Although the results are somewhat expected, with exercise tolerance increasing from the unencumbered state through NIOV + air, nasal oxygen, and NIOV + oxygen, the magnitude of improvement in all measures with NIOV + oxygen was most compelling. NIOV with just air was not greatly different from the unencumbered state (exercise time = 6.3 +/- 4.1 vs 5.6 +/- 1.9 min), nasal oxygen produced a near doubling to 11.4 +/- 6.8 min, but NIOV + oxygen increased it substantially more to 17.6 +/- 5.7 min. This occurred with less dyspnea and electromyography activity, suggesting inspiratory muscle unloading, all without any major negative impact on either SpO2 or transcutaneous PCO2 (all isotime measurements).


This is the first device that, even when combined with a portable oxygen system, may be portable enough to be carried by patients during normal daily activities. It certainly appears to be sufficiently lightweight to be easily used during exercise sessions and can therefore allow exercise training to be more aggressive and potentially less uncomfortable. Its ability to reduce exercise related symptoms alone may have sufficient impact on patients' willingness to exercise and may even impact the adherence to exercise programs, something that remains abysmally low in real life. Cost will inevitably be an early obstacle, but as in all such situations, this tends to decrease as the economies of scale kick in, with a widening user base.-SK



Suissa S


Thorax. 2013;68:540-543.


Background: Several recent trials in chronic obstructive pulmonary disease (COPD) have assessed the effectiveness of the fluticasone-salmeterol combination inhaler in preventing COPD exacerbations, while finding an increased risk of pneumonia. The number needed to treat (NNT) is a simple measure to perform the comparative benefit-risk impact, but its calculation involving repeated outcome events such as COPD exacerbations has been incorrect. We describe the proper methods to calculate the NNT and, using data from published trials, apply them to evaluate the relative impact of fluticasone-salmeterol treatment on exacerbations and pneumonias in patients with COPD.


Methods: We review the fundamental definition of NNT and quantify it for situations with varying follow-up times. We review the 'event-based' NNT, proposed and used for repeated event outcomes, show its inaccuracy, describe its proper use and provide an approximate formula for its application.


Results: We show that a 1-year trial of the fluticasone-salmeterol combination versus salmeterol used the incorrect event-based approach to calculate the NNT as two patients that need to be treated for 1 year to prevent one COPD exacerbation, when the proper calculation results in a NNT of 14. In contrast, 20 patients need to be treated to induce one pneumonia case. For the TORCH trial, the NNT is 44 patients treated for 3 years with fluticasone-salmeterol versus salmeterol to prevent one exacerbation compared with 16 patients to induce one pneumonia case.


Conclusions: The NNT is a useful measure of the effect of drugs, but its proper calculation is essential to prevent misleading clinical practice guidelines.


Editor's Comment: The negative impact of certain types of drugs used in chronic obstructive pulmonary disease (COPD), especially the reported increase in pneumonias in patients receiving inhaled corticosteroids, leads to considerable patient anxiety and frequent questions directed at providers. In a not insignificant number, it even leads to patients, informed by widely available data, declining to take such treatment. It therefore becomes especially important that the risk estimate is reliable; this requires not only valid study data but, as this particular study attempts to show, a statistically valid analysis of those data.


An easily understood and user-friendly statistic is the number needed to treat (NNT) which is the inverse of the difference in event frequency between the active and control arms. This calculation is considerably less simple if multiple events occur in the same patient, and the author contends that the statistic has been misapplied in 2 major recent studies examining the treatment of COPD. In the first (Calverley et al., N Engl J Med. 2007;356:775-789), the reported NNT to prevent 1 COPD exacerbation per year is 2, in favor of inhaled corticosteroids; however, the recalculated NNT using the author's method yields a figure of 14, a huge difference which, if correct, would change any population based treatment recommendations. A reanalysis of data obtained from 2 other similar studies yields similar differences between the reported and recalculated rates. A similar calculation, using Kaplan Meir Cumulative Incidence curves, measuring the risk of pneumonia with the use of inhaled corticosteroids, also indicates major differences between the numbers reported in the original papers compared to the recalculated risk in both the Calverley study above and in another large study reported the following year (Wedzicha et al., Am J Respir Crit Care Med. 2008;177:19-26).


This reworking of published data suggests that although the risk of pneumonia is increased and the frequency of exacerbations decreased with the use of inhaled corticosteroids, both may be less impressive than initially reported. Any population-based recommendations therefore depend on which analytic technique is correct, and the subsequent exchange of letters (Keene et al., Thorax. 2013;68:88, and Suissa, Thorax 2013;68:882-883) suggests that these newly recalculated results may well represent the real risk estimate. Regardless, it remains clear the use of inhaled corticosteroids does reduce COPD exacerbations but at an increased risk of pneumonia, even though the magnitude of both the benefit and risk remains contentious.-SK



Fletcher GF, Ades PA, Kligfield, P, et al


Circulation. 2013;128:873-934.


No abstract.


Editor's Comment: The American Heart Association last published this set of "Exercise Standards" in 2001. This update is overdue and is significantly different from the 2001 statement in many ways. I have chosen to highlight the information on exercise physiology (the 2001 term) and exercise prescription. The current statement has several excellent sections that exercise and cardiac rehabilitation professionals may want to read and review simply for the updated information provided by the document. More specifically, the following sections are all worth a close review, simply for the wealth of information provided.


* Cardiovascular Responses to Exercise in Normal Subjects


* Clinical and Cardiopulmonary Responses During Exercise


* Exercise Training (several excellent subsections contained therein)


* Evaluation and Exercise Prescription in Patients with CVD


* Prognostic Benefits of Exercise in Patients with CVD


* Targeting Exercise Prescription to Relevant Outcomes



This is a long document with an impressive writing team, many of whom are AACVPR members. The document has been updated and the resource and background information that is provided is as current as could be expected for a "Statement" of this type from a highly respected organization such as the American Heart Association.-JR



Bennett GG, Foley P, Levine E, et al


JAMA Intern Med. Published online first August 26, 2013, doi:10.1001/jamainternmed.2013.9263.


Importance: Few weight loss treatments produce clinically meaningful weight loss outcomes among black women, particularly in the primary care setting. New weight management strategies are necessary for this population. Weight gain prevention might be an effective treatment option, with particular benefits for overweight and class 1 obese black women.


Objective: To compare changes in weight and cardiometabolic risk during a 12-month period among black women randomized to a primary care-based behavioral weight gain prevention intervention, relative to usual care.


Design, Setting, and Participants: Two-arm randomized clinical trial (the Shape Program). We recruited patients from a 6-site community health center system. We randomized 194 overweight and class 1 obese (body mass index [calculated as weight in kilograms divided by height in meters squared], 25-34.9) premenopausal black women aged 25 to 44 years. Enrollment began on December 7, 2009; 12- and 18-month assessments were completed in February and October 2, 2012.


Interventions: The medium-intensity intervention included tailored behavior change goals, weekly self-monitoring via interactive voice response, monthly counseling calls, tailored skills training materials, and a gym membership.


Main Outcomes and Measures: Twelve-month change in weight and body mass index and maintenance of change at 18 months.


Results: Participants had a mean age of 35.4 years, a mean weight of 81.1 kg, and a mean body mass index of 30.2 at baseline. Most were socioeconomically disadvantaged (79.7% with educational level less than a college degree; 74.3% reporting annual income <$30 000). The 12-month weight change was larger among intervention participants (mean [SD], -1.0 [0.5] kg), relative to usual care (0.5 [0.5] kg; mean difference, -1.4 kg [95% CI, -2.8 to -0.1 kg]; P = .04). At month 12, 62% of intervention participants were at or below their baseline weights compared with 45% of usual-care participants (P = .03). By 18 months, intervention participants maintained significantly larger changes in weight (mean difference, -1.7 kg; 95% CI, -3.3 to -0.2 kg).


Conclusions and Relevance: A medium-intensity primary care-based behavioral intervention demonstrated efficacy for weight gain prevention among socioeconomically disadvantaged black women. A "maintain, don't gain" approach might be a useful alternative treatment for reducing obesity-associated disease risk among some premenopausal black women.



Wing RR, Tate D, Espeland M, et al


BMC Public Health. 2013;13:300, doi:10.1186/1471-2458-13-300.


Background: Weight gain during young adulthood is common and is associated with increased cardiovascular risk. Preventing this weight gain from occurring may be critical to improving long-term health. Few studies have focused on weight gain prevention, and these studies have had limited success. SNAP (Study of Novel Approaches to Weight Gain Prevention) is an NIH-funded randomized clinical trial examining the efficacy of two novel self-regulation approaches to weight gain prevention in young adults compared to a minimal treatment control. The interventions focus on either small, consistent changes in eating and exercise behaviors, or larger, periodic changes to buffer against expected weight gains.


Methods/Design: SNAP targets recruitment of six hundred young adults (18-35 years) with a body mass index between 21.0-30.0 kg/m2, who will be randomly assigned with equal probability to: (1) minimal intervention control; (2) self-regulation with Small Changes; or (3) self-regulation with Large Changes. Both interventions receive 8 weekly face-to-face group sessions, followed by 2 monthly sessions, with two 4-week refresher courses in each of subsequent years. Participants are instructed to report weight via web at least monthly thereafter, and receive monthly email feedback. Participants in Small Changes are taught to make small daily changes (~100 calorie changes) in how much or what they eat and to accumulate 2000 additional steps per day. Participants in Large Changes are taught to create a weight loss buffer of 5-10 pounds once per year to protect against anticipated weight gains. Both groups are encouraged to self-weigh daily and taught a self-regulation color zone system that specifies action depending on weight gain prevention success. Individualized treatment contact is offered to participants who report weight gains. Participants are assessed at baseline, 4 months, and then annually. The primary outcome is weight gain over an average of 3 years of follow-up; secondary outcomes include diet and physical activity behaviors, psychosocial measures, and cardiovascular disease risk factors.


Discussion: SNAP is unique in its focus on weight gain prevention in young adulthood. The trial will provide important information about whether either or both of these novel interventions are effective in preventing weight gain.


Trial Registration:, NCT01183689.


Editor's Comment: I included 2 additional abstracts (a research article and a design article for an upcoming trial) in this issue, despite the significant amount of reading called for in the American Heart Association Statement above, simply because they focus on a little used, but not necessarily new, principle in weight management-specifically, the prevention of weight gain rather than weight loss. Both groups focus on "small" or "slight" energy deficits (200 and 100 calories per day, respectively). In the study by Wing et al, participants were also asked to increase steps by 2000 steps per day, while in the study by Bennett et al, increases in physical activity level were not specified. In the study by Bennett et al, weight gain was prevented over the course of the 18 month study, and the cumulative difference in weight between the usual care and the intervention groups was almost 4 pounds over the study period. Though the difference may seem inconsequential, it is clear that weight loss programs over the same time course have distinctly marginal outcomes, with 1-2 year weight loss in such programs commonly averaging less than 5-7 pounds. So, preventing weight gain may, in fact, be an excellent strategy for some overweight and obese people who may not be active enough, motivated, or even sufficiently informed to undertake even a moderate weight loss program that requires significant calorie deficit and increase in exercise and physical activity.


I present these articles simply as alternatives for weight loss programs that have a long-standing record of being marginally efficacious for many participants. The 12-24 month data for these programs demonstrates an average weight loss of 5-8 kg. Here are 2 examples of programs that have been implemented for overweight and obesity that focus on the prevention of weight gain, apparently with some success. Perhaps this is an approach that will take on some momentum as it becomes more refined. The literature certainly is worth following, and such programs are, perhaps, worth consideration for implementation, at some level in cardiovascular rehabilitation programs.-JR