Physical activity and the frequency of acute exacerbations in patients with chronic obstructive pulmonary disease.

PURPOSE: Acute exacerbations (AE) in patients with COPD are associated with a decline in lung function, increased risk of hospitalization, and mortality. In this cross-sectional study we tested whether the level of objectively measured daily physical activity and exercise capacity are associated with the number of COPD exacerbations. METHODS: In 210 patients with COPD (67 % men; mean (SD) age: 63 (8) years) enrolled in The Obstructive Pulmonary Disease Outcomes Cohort of Switzerland (TOPDOCS) physical activity (PA) (steps per day, physical activity level, (PAL)), exercise capacity (6-min walking distance, (6MWD)), comorbidities, lung function, and medication were assessed. Differences between COPD patients with frequent (≥2 year) and infrequent (0-1 year) exacerbations were assessed. Univariate and multivariate analyses were performed to investigate whether the level of objectively measured daily physical activity and exercise capacity are associated with the number of COPD exacerbations. RESULTS: Patients with frequent AE had a significantly lower FEV1 and 6MWD compared to patients with infrequent AE. In univariate analysis, the number of exacerbations was inversely associated with FEV1, 6MWD, BMI, and smoking status while there was a positive association with RV/TLC and combined inhaled medication. However, there was no significant association with PAL and steps per day. In multivariate analysis, FEV1 and the use of combined inhaled medication were independently associated with the number of AE, after correction for covariates. CONCLUSIONS: The findings of this study imply that FEV1, independent of inhaled medication, is significantly associated with COPD exacerbations. Neither physical activity nor exercise capacity was independently associated with COPD exacerbations.

Prevalence and prediction of exercise-induced oxygen desaturation in patients with chronic obstructive pulmonary disease.

BACKGROUND: Previous studies with small sample sizes reported contradicting findings as to whether pulmonary function tests can predict exercise-induced oxygen desaturation (EID). OBJECTIVE: To evaluate whether forced expiratory volume in one second (FEV(1)), resting oxygen saturation (SpO(2)) and diffusion capacity for carbon monoxide (DLCO) are predictors of EID in chronic obstructive pulmonary disease (COPD). METHODS: We measured FEV(1), DLCO, SpO(2) at rest and during a 6-min walking test as well as physical activity by an accelerometer. A drop in SpO(2) of >4 to <90% was defined as EID. To evaluate associations between measures of lung function and EID univariate and multivariate analyses were used and positive/negative predictive values were calculated. Receiver operating characteristic curve analysis was performed to determine the most useful threshold in order to predict/exclude EID. RESULTS: We included 154 patients with COPD (87 females). The mean FEV(1) was 43.0% (19.2) predicted and the prevalence of EID was 61.7%. The only independent predictor of EID was FEV(1) and the optimal cutoff value of FEV(1) was at 50% predicted (area under ROC curve, 0.85; p < 0.001). The positive predictive value of a threshold of FEV(1) <50% was 0.83 with a likelihood ratio of 3.03 and the negative predicting value of a threshold of FEV(1) ≥80% was 1.0. The severity of EID was correlated with daily physical activity (r = -0.31, p = 0.008). CONCLUSIONS: EID is highly prevalent among patients with COPD and can be predicted by FEV(1). EID seems to be associated with impaired daily physical activity which supports its clinical importance.

[Is COPD a Cardiovascular Risk Factor?]. / Ist die COPD ein kardiovaskulärer Risikofaktor?

Chronic obstructive pulmonary disease (COPD) is an inflammatory disease of the lungs mainly caused by smoking and characterized by chronic airflow limitation. COPD is the fifth leading cause of death worldwide and up to 50% of COPD patients die of a cardiovascular event. Cohort studies demonstrated that airflow limitation is a predictor of cardiovascular risk, even after adjusting for known risk factors such as smoking and cholesterol levels. Various mechanisms of vascular damage have been suggested in COPD including systemic inflammation, hypoxia, oxidative stress, activation of the sympathetic nervous system and changes of the vascular connective tissue. The evidence of a causal relationship between COPD and cardiovascular disease is yet insufficient. Data from controlled trials investigating the postulated pathomechanisms are awaited with interest.

Disability and survival in Duchenne muscular dystrophy.

BACKGROUND: Duchenne muscular dystrophy (DMD) leads to progressive impairment of muscle function, respiratory failure and premature death. Longitudinal data on the course of physical disability and respiratory function are sparse. OBJECTIVES: To assess prospectively physical impairment and disability, respiratory function and survival in patients with DMD over several years to describe the course of the disease with current care. METHODS: In 43 patients with DMD, aged 5-35 years, yearly assessments of physical disability by the Duchenne muscular dystrophy physical Impairment and Dependence on care (DID) score, ranging from 9 (no disability) to 80 (complete dependence), and forced vital capacity (FVC), were obtained over a mean time interval of 5.4 (SD 2.1) years. RESULTS: DID scores were correlated with age according to a hyperbolic function (f = 85.3 x age/(10.05+age), R = 0.62, p<0.0001). FVC declined exponentially with age (f = 139.1 x exp(-0.08 x age), R = 0.52, p<0.0001). Mean age at which patients lost their ambulation was 9.4 (SD 2.4) years and they became dependent on an electric wheelchair at 14.6 (4.0) years. Age at the beginning of assisted ventilation was 19.8 (3.9) years, Three patients died during the observation period. The estimated probability of survival to age 30 years was 85% (median survival was 35 years). CONCLUSIONS: Our detailed observations of the progression of physical disability, dependence on care and respiratory impairment in patients with DMD from childhood to adult life is valuable for predicting the clinical course with current medical care. Compared with historical data, survival has improved considerably.

Periodic whole body acceleration: a novel therapy for cardiovascular disease.

BACKGROUND: Periodic whole body acceleration in the spinal axis (pGz) applied by a motion platform is a novel treatment modality that induced endothelial nitric oxide release into the circulation of animals, healthy subjects and patients with inflammatory diseases during single treatment sessions in previous studies. We hypothesized that patients with advanced arteriosclerotic diseases who are not candidates for a surgical intervention would clinically benefit from repeated pGz treatments over several weeks through improvement of endothelial function. PATIENTS AND METHODS: 11 patients, 5 men (37 to 71 y) with stable ischemic heart disease, LVEF < 35%, NYHA stage > II, and 6 patients (51 to 83 y, 1 woman) with intermittent leg claudication, Fontaine stage II, were enrolled after optimization of pharmacological therapy. PGz was applied for 40 min, 5 days/week during 5 weeks. Quality of life (SF-36 questionnaire), exercise performance, and endothelial function were assessed at baseline, during the treatment period, and 4 weeks after discontinuation of pGz. RESULTS: PGz was well tolerated. In heart failure paitents, pGz therapy improved quality of life, increased 6 min walking distance by a mean +/- SE of 105 +/- 24 m, and improved postischemic skin hyperemia (p < .05 in all instances). In 4 of 6 patients with intermittent claudication, quality of life, treadmill walking distance and post-ischemic skin hyperemia improved with pGz therapy (p < .05). Four weeks after discontinuation of pGz, most therapeutic effects had vanished in both patient groups. CONCLUSIONS: In patients with severe heart failure and with leg claudication who remain symptomatic despite maximal medical therapy and who were not candidates for surgery, periodic acceleration applied over several weeks improved quality of life and exercise capacity. The clinical benefits appear to be mediated through improved endothelial function.

Auto-CPAP therapy based on the forced oscillation technique.

Autoadjusting CPAP devices (APAP) are designed to continuously adjust the positive pressure to the required levels, and thus increase treatment quality and patient compliance. The results of APAP treatment strongly depend on the control mechanism of the respective APAP device. In agreement with other working groups, we have recently shown that the forced oscillation technique (FOT) is capable of detecting incipient upper airway obstruction prior to physiological reactions such as the onset of increasing esophageal pressure swings or microarousals. Therefore we studied efficacy and acceptance of a novel APAP device controlled exclusively by FOT. 100 consecutive patients with OSAS confirmed by polysomnography (mean AHI 47.9 +/- 22.6) and daytime sleepiness (Epworth sleepiness scale, ESS 12.6 +/- 3.9) were randomized to either APAP treatment (n = 50) or conventional CPAP treatment (n = 50). Polysomnographies were performed at the second treatment night and subjective sleepiness (modified ESS) was established in the morning. The respiratory disturbance was largely normalized in both treatment groups in the second treatment night (AHI 4.7 +/- 5.3 vs. 3.7 +/- 3.4; n.s.). Both groups showed largely improved sleep profiles and had markedly reduced ESS-scores (6.6 +/- 3.6 vs. 7.0 +/- 3.4; n.s.). The mean treatment pressure during APAP was significantly lower than during CPAP treatment (6.0 +/- 2.0 vs. 9.0 +/- 1.8 mbar; p < 0.001). There were no significant differences between APAP and CPAP treatment in any parameter of efficacy or acceptance. APAP treatment with this device controlled exclusively by FOT is well accepted by the patients and permits an adequate treatment of OSAS without the need for invidiual CPAP titration.