Susan O'Connell

Can ventilation-feedback training augment exercise tolerance in patients with chronic obstructive pulmonary disease?

RATIONALE Exercise-induced dynamic hyperinflation contributes to decreased exercise tolerance in chronic obstructive pulmonary disease (COPD). It is unknown whether respiratory retraining (ventilation-feedback [VF] training) can affect exercise-induced dynamic hyperinflation and increase exercise tolerance. OBJECTIVES To determine whether patients with COPD would achieve longer exercise duration if randomized to a combination of exercise training plus VF training than either form of training on its own. METHODS A total of 64 patients randomized to 1 of 3 groups: VF plus exercise (n = 22), exercise alone (n = 20), and VF alone (n = 22). MEASUREMENTS AND MAIN RESULTS Exercise duration before and after 36 training sessions and exercise-induced dynamic hyperinflation and respiratory pattern before and after training were measured. In the 49 patients who completed training, duration of constant work-rate exercise was 40.0 (+/- 20.4) minutes (mean +/- SD) with VF plus exercise, 31.5 (+/- 17.3) minutes with exercise alone, and 16.1 (+/- 19.3) minutes with VF alone. Exercise duration was longer in VF plus exercise than in VF alone (P < 0.0001), but did not reach predetermined statistical significance when VF plus exercise was compared with exercise alone (P = 0.022) (because of multiple comparisons, P </= 0.0167 was used for statistical significance). After training, exercise-induced dynamic hyperinflation, measured at isotime, in VF plus exercise was less than in exercise alone (P = 0.014 for between-group changes) and less than in VF alone (P = 0.019 for between-group changes). After training, expiratory time was longer in VF plus exercise training (P < 0.001), and it was not significantly changed in the other two groups. CONCLUSIONS The combination of VF plus exercise training decreases exercise-induced dynamic hyperinflation and increases exercise duration more than VF alone. An additive effect to exercise training from VF was not demonstrated by predetermined statistical criteria.

Relationship between depression and functional measures in overweight and obese persons with osteoarthritis of the knee

Depression is common in overweight and obese individuals with chronic illness. The purpose of this study was to determine the relationship between depression and functional status. Baseline data were used from 105 overweight/obese participants who enrolled in a clinical trial for overweight and obese adults with osteoarthritis of the knee. Forty-two percent of the sample was classified as depressed according to the Center for Epidemiologic Studies Depression Scale. A moderate relationship was seen between perceived physical function and physical performance in patients who were not depressed that did not exist in patients reporting depressive symptoms. In a stepwise regression analysis, poorer function (as measured by the Western Ontario and MacMaster Universities (Osteoarthritis Index) function subscale) and younger age accounted for 29 percent of the variance in depressive symptoms.

The effects of smoking status on walking ability and health-related quality of life in patients with peripheral arterial disease.

BACKGROUND Smoking is a leading risk factor for peripheral arterial disease (PAD), yet little is known about the interrelationships among smoking status, walking endurance, calf muscle tissue oxygenation, and quality of life in patients with PAD. OBJECTIVE The aim of this study was to explore the differences in factors associated with walking endurance including walk distance, perceived walking ability, measures of skeletal muscle tissue oxygenation (StO2), claudication pain, peak oxygen consumption per unit time, and quality of life in smokers versus nonsmokers. METHODS A total of 105 patients with PAD performed progressive, symptom-limited treadmill test. Ankle-brachial index was measured at baseline. Calf muscle tissue oxygenation measures were obtained during testing. The RAND Short Form-36 and Walking Impairment Questionnaire were used to measure health-related quality of life (HR-QoL). RESULTS In the total sample (36 current smokers, 69 nonsmokers), smokers had steeper declines in StO2 from baseline to 2 minutes (42.3% vs 33%, P = .05) and shorter distance walked to onset of claudication pain (142.6 vs 247.7 m) than did nonsmokers (P < .0125), despite having no differences in ankle-brachial index, peak oxygen consumption per unit time, or any momentary measure of StO2 during walking. Smokers reported significantly lower HR-QoL on the Short Form-36 in several domains but no differences in the Walking Impairment Questionnaire measures. The smokers were younger than the nonsmokers; however, when age was entered as a covariate in the analyses, the results remained unchanged. CONCLUSIONS These findings suggest that smokers have lower HR-QoL than do nonsmokers with PAD and that smoking confers risks for disrupted tissue oxygenation above those seen in patients who do not smoke.

Predictors of weight loss in overweight veterans with knee osteoarthritis who participated in a clinical trial

Individuals with osteoarthritis (OA) of the knee have a high prevalence of obesity. The objective of this study was to determine predictors of weight loss among participants with knee OA in a clinical trial. A secondary analysis of data from a randomized clinical trial was used. Multiple regression analysis was used to predict weight loss after identification of predictor variables from the data. Hypothesized predictors of weight loss included demographic, clinical, and behavioral characteristics. The only baseline variable that was significantly related to weight loss was the Center for Epidemiologic Studies Depression Scale (CES-D) score. The CES-D score was an independent predictor of weight loss at 16 (p < 0.01) and 32 weeks (p < 0.05). Receiving nutrition counseling was also predictive of weight loss at 16 weeks (p < 0.03). These two variables explained 24% and 22% of the variance in weight loss for weeks 16 and 32, respectively. Being less depressed and receiving nutritional counseling appeared predictive of weight loss in this group of veterans.

The Effects of Walking or Walking-with-Poles Training on Tissue Oxygenation in Patients with Peripheral Arterial Disease

This randomized trial proposed to determine if there were differences in calf muscle StO2 parameters in patients before and after 12 weeks of a traditional walking or walking-with-poles exercise program. Data were collected on 85 patients who were randomized to a traditional walking program (n = 40) or walking-with-poles program (n = 45) of exercise training. Patients walked for 3 times weekly for 12 weeks. Seventy-one patients completed both the baseline and the 12-week follow-up progressive treadmill tests (n = 36 traditional walking and n = 35 walking-with-poles). Using the near-infrared spectroscopy measures, StO2 was measured prior to, during, and after exercise. At baseline, calf muscle oxygenation decreased from 56 ± 17% prior to the treadmill test to 16 ± 18% at peak exercise. The time elapsed prior to reaching nadir StO2 values increased more in the traditional walking group when compared to the walking-with-poles group. Likewise, absolute walking time increased more in the traditional walking group than in the walking-with-poles group. Tissue oxygenation decline during treadmill testing was less for patients assigned to a 12-week traditional walking program when compared to those assigned to a 12-week walking-with-poles program. In conclusion, the 12-week traditional walking program was superior to walking-with-poles in improving tissue deoxygenation in patients with PAD.

Evaluation of psychometric properties of Walking Impairment Questionnaire in overweight patients with osteoarthritis of knee

This study tested the psychometric properties of the Walking Impairment Questionnaire (WIQ) in overweight patients with osteoarthritis (OA) of the knee. Internal consistency, test-retest reliability, and concurrent validity of the WIQ were measured. Used in a randomized clinical trial, the WIQ was one of the instruments completed by overweight adults with OA of the knee. A total of 105 patients completed the WIQ. Internal consistency of the WIQ was supported in this population with a Cronbach alpha total score of 0.97. Test-retest reliability scores were not different when subjects completed the WIQ 14 days apart (p > 0.05). The relationships were moderate between the WIQ subscales and other established measures, such as the 6-minute walk distance, stair climb and descend, and the Western Ontario and McMaster Universities (OA Index) questionnaire. After evaluating the psychometric properties of the WIQ, we found that it is a valid and reliable instrument to use in overweight patients with symptomatic OA of the knee.

Structured Exercise in Obese Diabetic Patients with Chronic Kidney Disease: A Randomized Controlled Trial

Background: Patients with type 2 diabetes mellitus (DM), obesity, and chronic kidney disease (CKD) are generally physically inactive and may benefit from exercise. Our objective was to determine the effects of structured exercise on physical fitness, kidney function, endothelial function, inflammation, and body composition in such patients. Methods: In this randomized, controlled trial, 36 male patients (age 49-81) were randomly assigned to exercise + diet management (n = 18) or diet alone (n = 18). Participants were eligible if they had type 2 DM, body mass index >30 kg/m2, CKD stages 2-4, and persistent proteinuria (>200 mg/g creatinine for >3 months). The exercise intervention was a 12-week (3 days per week) program of aerobic and resistance training followed by 40 weeks of home exercise. The primary outcome measure was change from baseline in urine protein to creatinine ratio (UPCR) at 12 and 52 weeks. Results: Thirty-two participants completed the study (14 exercise + diet, 18 diet-alone group). The change from baseline in UPCR was slightly greater in the diet-alone group at 12 weeks but not at 52 weeks. Changes in both symptom-limited and constant-workrate treadmill times were significantly higher in the exercise + diet group at 12 weeks but not at 52 weeks. There were no significant differences in urine albumin to creatinine ratio, estimated glomerular filtration rate, endothelial function, inflammation, or body composition between the groups. Conclusions: In obese diabetic subjects with CKD, structured exercise improved exercise capacity but not body composition or renal function. This is a work of the US Government and is not subject to copyright protection in the USA. Foreign copyrights may apply. Published by S. Karger AG, Basel