Prevalence and causes of chronic cough in Japan.

BACKGROUND: Chronic cough is one of the most common symptoms of respiratory diseases and can adversely affect patients' quality of life and interfere with social activities, resulting in a significant social burden. A survey is required to elucidate the frequency and treatment effect of chronic cough. However, clinical studies that cover all of Japan have not yet been conducted. METHODS: Patients who presented with a cough that lasted longer than 8 weeks and visited the respiratory clinics or hospitals affiliated with the Japan Cough Society during the 2-year study period were registered. RESULTS: A total of 379 patients were enrolled, and those who did not meet the definition of chronic cough were excluded. A total of 334 patients were analyzed: 201 patients had a single cause, and 113 patients had two or more causes. The main causative diseases were cough variant asthma in 92 patients, sinobronchial syndrome (SBS) in 36 patients, atopic cough in 31 patients, and gastroesophageal reflux (GER)-associated cough in 10 patients. The time required to treat undiagnosed patients and those with SBS was significantly longer and the treatment success rate for GER-associated cough was considerably poor. CONCLUSIONS: We confirmed that the main causes of chronic cough were cough variant asthma, SBS, atopic cough, and their complications. We also showed that complicated GER-associated cough was more likely to become refractory. This is the first nationwide study in Japan of the causes and treatment effects of chronic cough.

Changes in sleep profile on exposure to sodium chloride and artificially carbonated springs: a pilot study.

[Purpose] Herein, we aimed to investigate the effects of bathing in a sodium chloride spring and an artificially carbonated spring on core body temperature and electroencephalograms, to assess whether the springs facilitate sleep. [Participants and Methods] This randomized, controlled, crossover study evaluated the effects of a sodium chloride spring, an artificially carbonated spring, a plain hot bath, and no bath on sleep. The subjective evaluations and recording of temperature were performed before/after bathing at 40 °C for 15 min at 22:00 h, before nocturnal sleep (0:00-7:00 h), and after the participants (n=8) woke up in the morning. [Results] Bathing significantly increased the core body temperature, with significant subsequent declines observed until bedtime. Participants in the sodium chloride spring group had the highest average core body temperature, while participants in the no-bath group had the lowest average core body temperature before bedtime (23:00-0:00 h). During bedtime (1:00-2:00 h), the participants in the no bath group had the highest average core body temperature, while participants in the artificially carbonated spring group had the lowest average core body temperature. The amount of delta power/min in the first sleep cycle significantly increased in the bathing groups, with the highest value during bedtime being recorded in the artificially carbonated spring group, followed by the sodium chloride spring, plain hot bath, and no-bath groups. These sleep changes were associated with significant declines in the elevated core body temperature. Increased heat dissipation and decreased core body temperature were observed in the artificially carbonated spring and sodium chloride spring groups, which increased the delta power during the first sleep cycle compared with that observed in the plain hot bath group, followed by the no-bath group. [Conclusion] An artificially carbonated spring would be the most appropriate given each circumstance because it did not cause fatigue, as observed with the sodium chloride spring.

Objective physical activity level is associated with rectus femoris muscle echo-intensity in patients with chronic obstructive pulmonary disease.

INTRODUCTION: Skeletal muscle dysfunction is one of the major extrapulmonary complications of chronic obstructive pulmonary disease (COPD). Some studies have reported a relationship between physical activity (PA) level and skeletal muscle quality assessed by echo-intensity (EI) in healthy individuals but not in patients with COPD. OBJECTIVES: The aim of this study is to investigate the relationships between PA level and both skeletal muscle EI and skeletal muscle mass in patients with COPD. METHODS: We employed a cross-sectional design. Forty male outpatients with stable COPD were enrolled. Using B-mode ultrasonography, we measured the rectus femoris muscle cross-sectional area (RF-CSA) and EI (RF-EI). The RF-CSA and RF-EI were measured on frozen images using an electronic caliper and 8-bit gray-scale analysis, respectively. The objective PA level was determined by monitoring daily step counts and moderate-to-vigorous physical activity time (MVPA) with an activity monitor. A general regression model was used to assess the relationships between PA level and both RF-CSA and RF-EI. Age and body mass index (BMI) were adopted as confounding variables. RESULTS: Twenty-five outpatients with stable COPD (age, 70 ± 7 years old; forced expiratory volume in 1 s, 55.0 ± 24.9% of predicted values) were finally enrolled in the present study. Even after adjusting for age and BMI, the daily step counts and MVPA were significantly associated with RF-EI, and knee extensor force was associated with RF-CSA. CONCLUSION: The present study showed that PA level was associated with RF-EI in patients with COPD. In addition, RF-CSA was associated with knee extensor force. When assessing skeletal muscle using ultrasonography in patients with COPD, we should also assess EI.

Residual effects of low dose of suvorexant, zolpidem, and ramelteon in healthy elderly subjects: A randomized double-blind study.

INTRODUCTION: Current hypnotic agents have next-day residual effects. The new orexin antagonist, suvorexant, has little muscle relaxation effect on the physical and cognitive function in the following morning and daytime. In this study, the effects of suvorexant, zolpidem, ramelteon and placebo in elderly subjects were evaluated. METHODS: Six men and eight women aged 63-75 years received a single tablet and lights were then turned off. Subjects were instructed to sleep from 23:00-6:00 with an interruption from 4:00-4:30 for evaluations. Suvorexant 10 mg, zolpidem 5 mg, ramelteon 4 mg or placebo was administered single time in a randomized, double-blind and crossover design with a one-week drug holiday in between each drug. Measures of objective parameters and subjective ratings were obtained every 2 h from 4:00 to 16:00. RESULT: No subjects showed serious side effects from physical observations and vital sign checks before and after hypnotics were taken. During the first sleep period, the REM sleep time with suvorexant was especially longer than that with zolpidem. During the second sleep period, suvorexant had shorter sleep latency and longer stage2 sleep time than ramelteon and zolpidem, respectively. During the whole entire sleep, the REM sleep time with suvorexant was longer than zolpidem and placebo. For the body sway test with closed eye, the main effects of the medicines and zolpidem were significantly better than suvorexant and ramelteon. CONCLUSION: The changes of physical and cognitive functions in healthy elderly after taking hypnotics were not remarkable. Therefore, these three hypnotics maybe appropriate for the elderly people with insomnia for single-time low dose administration.

Prediction of Low-intensity Physical Activity in Stable Patients with Chronic Obstructive Pulmonary Disease.

OBJECTIVE: To develop an equation of the predicted amount of low-intensity physical activity (LPA) by analyzing clinical parameters in patients with chronic obstructive pulmonary disease (COPD). METHODS: In this cross-sectional study, we analyzed the assessments of clinical parameters evaluated every 6 months from the start of pulmonary rehabilitation in 53 outpatients with stable COPD (age 77 ± 6 yrs; 46 men; body mass index 21.8 ± 4.1 kg/m2; forced expiratory volume in one second 63.0 ± 26.4% pred). An uniaxial accelerometer was used to measure the number of steps and the time spent in LPA of 1.8-2.3 metabolic equivalents during 14 consecutive days. We also evaluated body composition, respiratory function, skeletal muscle strength, inspiratory muscle strength, exercise capacity, and gait speed. Factors associated with the time spent in LPA were examined by multivariate regression analysis. Internal validity between the predicted amount of LPA obtained by the equation and the measured amount was examined by regression analysis. RESULTS: Multivariate regression analysis revealed that gait speed (ß = 0.369, p = 0.007) and maximum inspiratory mouth pressure (PImax) (ß = 0.329, p = 0.016) were significant influence factors on LPA (R2 = 0.354, p <0.001). The stepwise regression analysis showed a moderate correlation between the measured amount and predicted amount of LPA calculated by the regression equation (r = 0.609, p <0.001; LPA = 31.909 × gait speed + 0.202 × PImax - 20.553). CONCLUSION: Gait speed and PImax were extracted as influence factors on LPA, suggesting that the regression equation could predict the amount of LPA.

Functionally relevant threshold of inspiratory muscle strength in patients with chronic obstructive pulmonary disease.

OBJECTIVES: We aimed to identify the inspiratory muscle strength thresholds below which exercise capacity is compromised in men with chronic obstructive pulmonary disease (COPD). METHODS: We measured the maximum static inspiratory mouth pressure (PImax) and the percentage of predicted values (%PImax) in 113 patients with COPD. Six-minute walk distance (6-MWD) was measured as an indicator of functional exercise capacity, and a 6-MWD of <350 m was defined as functional exercise intolerance. Thresholds were determined as values with high specificity (>0.90) and maximal sensitivity. Statistical significance was set at P < 0.01. RESULTS: The data of 96 patients (74 ± 6 years old; forced expiratory volume in 1-s [FEV1], 56.5 ± 26.2% predicted) were analyzed; three women and 14 participants with missing data were excluded. Multivariate logistic regression models identified significant associations of PImax (odds ratio at 99% confidence interval [CI]: 0.95 [0.92-0.98]) and %PImax (odds ratio at 99% CI: 0.97 [0.95-0.99]) with 6-MWD, after adjustments for height and FEV1. C-statistics showed that the area under the curves (99% CI) of PImax and %PImax were comparable (0.87 [0.77-0.96] and 0.83 [0.72-0.94]). The thresholds of PImax and %PImax were 45.1 cmH2O and 66%; PImax and %PImax also had moderate positive likelihood ratios of 4.44 and 5.00. CONCLUSIONS: Thresholds of inspiratory muscle strength in men with COPD could help clinicians evaluate whether their patient's inspiratory muscle strength is inadequate to achieve a 6-MWD of ≥350 m, and identify patients who should be targeted for inspiratory muscle training.

Estimation of minimal clinically important difference for quadriceps and inspiratory muscle strength in older outpatients with chronic obstructive pulmonary disease: a prospective cohort study.

OBJECTIVE: To estimate the minimal clinically important difference (MCID) of quadriceps and inspiratory muscle strength after a home-based pulmonary rehabilitation program (PRP) in chronic obstructive pulmonary disease (COPD). METHOD: Eighty-five COPD patients were included. Quadriceps maximal voluntary contraction (QMVC) was measured. We measured maximal inspiratory mouth pressure (PImax), the 6-minute walk distance (6MWD), the chronic respiratory questionnaire (CRQ) and the modified Medical Research Council dyspnoea score (mMRC). All measurements were conducted at baseline and at the end of the PRP. The MCID was calculated using anchor-based (using 6MWD, CRQ, and mMRC as possible anchor variables) and distribution-based (half standard deviation and 1.96 standard error of measurement) approaches. Changes in the five variables were compared in patients with and without changes in QMVC or PImax >MCID for each variable. RESULTS: Sixty-nine COPD patients (age 75±6 years) were analysed. QMVC improved by 2.4 (95%CI 1.1-3.7) kgf, PImax by 5.8 (2.7-8.8) cmH2O, 6MWD by 21 (11-32) meters and CRQ by 3.9 (1.6-6.3) points. The MCID of QMVC and PImax was 3.3-7.5 kgf and 17.2-17.6 cmH2O, respectively. The MCID of QMVC (3.3 kgf) could differentiate individuals with significant improvement in 6MWD and PImax from those without. CONCLUSION: The MCID of QMVC (3.3 kgf) can identify a meaningful change in quadriceps muscle strength after a PRP. The MCID of PImax (17.2 cmH2O) should be used with careful consideration, because the value is estimated using distributionbased method.

Functionally Relevant Threshold of Quadriceps Muscle Strength in Patients with Chronic Obstructive Pulmonary Disease.

OBJECTIVES: We aimed to identify the quadriceps muscle strength (QMS) thresholds below which exercise capacity is compromised in men with chronic obstructive pulmonary disease (COPD). METHODS: We measured the quadriceps isometric maximum voluntary contraction (QMVC) and calculated the QMVC values normalized to weight (QMVC-BW), height squared (QMVC-H2), and body mass index (QMVC-BMI) in 113 patients with COPD. The functional exercise capacity was evaluated using the 6-minute walk distance (6MWD), and 6MWD <350 m was defined as functional exercise intolerance. Thresholds were determined for QMVC and its normalized values to achieve high specificity (>0.90) with maximal sensitivity. P-values <0.01 were considered statistically significant. RESULTS: Data from 99 male patients (age, 74 ± 6 years; percentages of predicted forced expiratory volume in 1-s, 56.9 ± 26.4%) were analyzed; 3 women and 11 participants with the missing data were excluded. Multivariate logistic regression models identified significant associations of QMVC and QMVC-H2 with 6MWD, after adjustment for age and dyspnea. C-statistics showed that the area under the curves of all QMVC parameters were comparable. The thresholds of QMVC and QMVC-H2 for predicting compromised exercise capacity were 26.2 kg and 9.6 kg/m2, respectively. CONCLUSIONS: QMS thresholds in men with COPD could help clinicians evaluate whether QMS is insufficient to achieve 6MWD ≥350 m and thereby identify patients who should be specifically targeted for muscle strengthening training during their pulmonary rehabilitation program.

The association between systemic inflammation and the time spent in posture and movement during daytime in patients with chronic obstructive pulmonary disease and lower weight.

[Purpose] The effect of physical activity on systemic inflammation remains unclear and might be negative in patients with chronic obstructive pulmonary disease (COPD) and lower weight. We investigated the amount of physical activity as the time spent in posture and movement and its association with systemic inflammation. [Participants and Methods] In this retrospective cross-sectional pilot study, we evaluated 11 patients with COPD (age, 73 ± 7 years; body mass index, 18.9 ± 2.9 kg/m2). A recently developed triaxial accelerometer was used to measure the time spent in posture and movement. We also evaluated body composition, physiological indexes, and serum levels of inflammatory cytokines. Single correlation coefficients were calculated as the association between physical activity and other outcomes. [Results] The walking time was 36 ± 32 min/d, and the standing time was 151 ± 118 min/d. The time spent walking significantly correlated with the fat-free mass index (r=0.73) and interleukin (IL)-8 level (r=0.76). The time spent standing significantly correlated with the C-reactive protein (r=0.80) and IL-6 levels (r=0.74). [Conclusion] These data indicate that increased physical activity is associated with higher systematic inflammation. We should consider that the systemic inflammation may have been affected by the increased physical activity of the patients with COPD and lower weight in this study.

Diaphragm thickening assessed by ultrasonography is lower than healthy adults in patients with chronic obstructive pulmonary disease.

BACKGROUND: Ultrasound imaging has been widely used for imaging of the diaphragm thickness (Tdi) and thickening. Few studies assessed the Tdi using ultrasonography in patients with chronic obstructive pulmonary disease (COPD). We measured the Tdi and thickening in patients with COPD compared with healthy younger and healthy older adults to reveal the influence of ageing and/or COPD. METHODS: Thirty-eight male patients with COPD (age 72 ± 8 years), 15 healthy younger (age 22 ± 1 years) and 15 healthy older (age 72 ± 5 years) male volunteers were recruited. We measured Tdi at total lung capacity (TdiTLC ), functional residual capacity (TdiFRC ) and residual volume (TdiRV ) using B-mode ultrasonography. We calculated the change ratio of TdiTLC and TdiRV (ΔTdi%). We used a one-way analysis of variance and multiple comparison test for the comparison analysis. RESULTS: The TdiTLC and the ΔTdi% were significantly lower in patients with COPD compared to the healthy adults. There was no significant difference in these values with age. There was no between group difference in the TdiFRC or TdiRV . CONCLUSIONS: Our results indicate significant differences in TdiTLC and ΔTdi% between patients with COPD and healthy adults. Therefore, diaphragm ultrasonography can assess diaphragm dysfunction associated with COPD. We suggest that it is better to use TdiTLC and ΔTdi% (not only Tdi at rest) to assess diaphragm function.

Gait characteristics and their associations with clinical outcomes in patients with chronic obstructive pulmonary disease.

BACKGROUND: Abnormalities of spatiotemporal gait parameters are frequently observed in chronic obstructive pulmonary disease (COPD). However, associations of gait parameters with clinical outcomes and their implementation into clinical practice have not been established. RESEARCH QUESTION: To investigate gait abnormalities and their association with clinical outcomes of COPD. METHODS: This study included 34 male outpatients with COPD and 16 community-dwelling healthy men aged ≥65 years. The subjects underwent a ten-metre walk test wearing an accelerometer. Data on gait speed, step length, cadence, walk ratio, acceleration magnitude, and standard deviation of step time (step time SD) were collected. Forced expiratory volume in 1-second, modified Medical Research Council dyspnoea score, six-minute walk distance (6MWD), quadriceps muscle strength (QMVC), and physical activity (daily steps and time spent in moderate to vigorous physical activity per day) were measured in the COPD group as clinical outcomes of COPD. We tested group differences in gait parameters, associations between gait parameters and COPD clinical outcomes, and predictive capability of gait parameters for reductions in 6MWD, QMVC, and daily steps in COPD. RESULTS: All gait parameters except walk ratio deteriorated in COPD. Step time SD and gait speed were significant independent predictors of 6MWD in COPD (B=-0.440, p = 0.001, B = 0.339, p = 0.007, respectively). Step length was a significant independent predictor of QMVC (B=-0.609, p < 0.001) and daily steps (B=-0.453, p = 0.006). Step length was a significant predictor of muscle weakness and physical inactivity, and step time SD was significant in predicting poor 6MWD in COPD. SIGNIFICANCE: Significant associations between gait abnormalities measured by an accelerometer and deficits in extra-pulmonary features of COPD were observed. An accelerometer-based gait analysis could be an alternative approach to assessing gait abnormalities and screening of functional decline in COPD.

New evaluation of trunk movement and balance during walking in COPD patients by a triaxial accelerometer.

BACKGROUND: Individuals with COPD may experience ambulatory difficulty due to both effort intolerance arising from respiratory dysfunction and impaired balance control during walking. However, the trunk movement during walking has not been evaluated or adjusted for patients with COPD. The Lissajous index (LI) visually and numerically evaluates the left-right symmetry of the trunk movement during walking and is useful in clinical practice. In COPD patients, the LI is used as an indicator of the left-right symmetry of the trunk during walking. Here, we used the LI to evaluate the symmetry of COPD patients based on bilateral differences in mediolateral and vertical accelerations, and we investigated the correlation between the patients' symmetry evaluation results and their physical function. PATIENTS AND METHODS: Sixteen stable COPD patients (all males; age 71.3±9.2 years) and 26 healthy control subjects (15 males; age 68.2±6.9 years) participated in this study. They performed the 10-minute walk test at a comfortable gait speed wearing a triaxial accelerometer, and we measured their trunk acceleration for the evaluation of symmetry. Motor functions were also evaluated in the patients with COPD. RESULTS: The average mediolateral bilateral difference and LI values of the COPD patients were significantly larger than those of the healthy subjects. The COPD patients' LI values were significantly correlated with their static balance. CONCLUSION: The LI measured using a triaxial accelerometer during walking is useful in balance assessments of patients with COPD.

Approaches to Cough Peak Flow Measurement With Duchenne Muscular Dystrophy.

BACKGROUND: Manually-assisted coughing and mechanical insufflation-exsufflation (MI-E) are commonly used in patients with Duchenne muscular dystrophy (DMD). Few studies have compared cough peak flow (CPF) with manually-assisted coughing to other methods, such as MI-E + manually-assisted coughing. In addition, few studies have reported the reliability of the measured CPF values. This study aimed to compare CPF with different cough-assistance methods and to examine the reliability of CPF data. METHODS: The study included 12 subjects with DMD (mean age, 34 ± 8 y). CPF, CPF + manually-assisted coughing (assisted CPF), maximum insufflation capacity (MIC) + CPF (MIC-CPF), MIC + manually-assisted coughing (MIC+assisted CPF), MI-E (MI-E-CPF), and MI-E + assisted CPF were measured. A spirometer was used to compare CPF measurements obtained with each of the cough-assist techniques. The reliability of the measured CPF values was analyzed using Bland-Altman analysis. RESULTS: CPF was 59 ± 34 L/min, assisted CPF was 113 ± 32 L/min, MIC-CPF was 170 ± 30 L/min, MIC+assisted CPF was 224 ± 62 L/min, MI-E-CPF was 199 ± 40 L/min, and MI-E + assisted CPF was 240 ± 38 L/min. A fixed and proportional bias was found in the CPF measurements made with the peak flow meter and the spirometer. The average 95% CI in the difference between peak flow meter, MI-E, and CPF obtained using the spirometer were -7.45 to -1.95 and -1.45 to 4.95, respectively. Test for correlation was r = 0.54 (P < .001) for CPF (peak flow meter) and CPF (spirometer) and r = 0.17 (P = .17) in CPF (MI-E) and CPF (spirometer), respectively. CONCLUSION: MI-E + assisted CPF was the highest. The CPF measured with the peak flow meter suggested underestimation.

Improvement of physical activity in chronic obstructive pulmonary disease by pulmonary rehabilitation and pharmacological treatment.

Physical activity (PA) is defined as bodily movement produced by skeletal muscles with energy expenditure beyond resting levels. PA is closely related to reduced morbidity and mortality in chronic obstructive pulmonary disease (COPD). Self-report questionnaires are often subject to recall bias, correlating poorly with objectively qualified PA, and do not provide an accurate estimate of free-living energy expenditure. PA may be objectively evaluated by newly developed tri-axial accelerometers by quantifying steps or body movements over a period of time. Low-intensity, home-based pulmonary rehabilitation (PR) using pedometer feedback improves PA. Improvement in physiological factors correlates with increased walking time in stable elderly COPD patients. This review focuses on the effects of PR and pharmacological treatment on PA in COPD patients. We selected 32 studies from our literature search evaluating the effects of PR and 11 studies examining the effects of pharmacological treatment on PA. Findings in both categories were inconsistent. Nineteen studies showed a positive effect with PR whereas 13 showed no effect. Eight studies showed a positive effect, while three revealed no effect from pharmacological intervention. As both interventions increase exercise capacity without a consistent effect on PA, counseling with behavioral changes may be necessary to achieve a significant and lasting increase in PA. Changing PA behavior in COPD patients requires an interdisciplinary approach involving specialists in respiratory medicine, rehabilitation, social, and behavioral sciences. Future research in this area is warranted to advance our knowledge in this area, specifically with regard to the interaction of pharmacological and non-pharmacological interventions.

Evaluation of gait symmetry using a tri-axial accelerometer in stroke patients.

OBJECTIVES: The purpose of this study was to confirm the intra-rater reliability and absolute reliability of Lissajous Index (LI) in evaluating the symmetry of trunk movement during gait in patients with stroke and to examine the relation between LI and body function in patients with stroke. METHODS: Twenty-one healthy subjects (11 males and 10 females, age 63.3±2.0 yrs) and 45 patients with stroke (33 males and 12 females, age 58.7±13.4 yrs) were included in the study. The accelerometer was fixed to a belt at the level of the L3 spinous process. The 10-m walk test was performed twice to record definitive data on trunk acceleration. LI was calculated from trunk accelerations. We confirmed the intra-rater reliability and absolute reliability of LI in patients with stroke and we examined the relation between LI and body function in patients with stroke. RESULTS: There was no fixed bias and proportional bias in the LI of patients with stroke. It was found that BBS significantly correlated with LI in stroke patients (p < 0.05, r = -0.413). CONCLUSIONS: It was clear that LI during gait was effective at evaluating gait symmetry and balance. LI was indicated to be useful in evaluating gait in patients with stroke.

Association Between Endothelial Progenitor Cells and Treatment Response in Non-Squamous Non-small Cell Lung Cancer Treated with Bevacizumab.

BACKGROUND/AIM: To investigate the association between the number of circulating endothelial progenitor cells (EPCs) in non-squamous non-small cell lung cancer (NSCLC) and disease outcome, in combination chemotherapy with and without bevacizumab. MATERIALS AND METHODS: We retrospectively identified 25 non-squamous NSCLC cases, and divided them into high-EPC and low-EPC groups. Within each group, we compared disease outcomes, with or without the administration of bevacizumab. RESULTS: In the high-EPC group, chemotherapy with bevacizumab produced a significantly higher tumor reduction rate and objective response rate, with significantly longer progression-free survival, compared to chemotherapy without bevacizumab (p<0.001, p=0.010, and p<0.001, respectively). However, in the low-EPC group, there were no significant differences in disease outcomes in groups with versus those without bevacizumab. CONCLUSION: The number of EPCs may be a useful biomarker to guide decision-making in the use of bevacizumab in non-squamous NSCLC.

Contractile capability of the diaphragm assessed by ultrasonography predicts nocturnal oxygen saturation in COPD.

BACKGROUND AND OBJECTIVE: Diaphragm function might be useful to predict nocturnal oxygen desaturation in COPD. Ultrasonography has been widely used for the assessment of the diaphragm. We aimed to investigate the relationship between the contractile capability of the diaphragm assessed by ultrasonography and the nocturnal percutaneous arterial oxygen saturation (NSpO2 ) in COPD. METHODS: Twenty-eight male patients with COPD (age, 73 ± 7 years; forced expiratory volume in 1 s (FEV1 ), 54.2 ± 17.0% predicted) were included. The thickness of the diaphragm (Tdi) was assessed by ultrasonography. We calculated the change ratio of Tdi at the end of maximal inspiration and expiration (%ΔTdi). The mean value of NSpO2 (NSpO2mean ), the percentage of total sleep time (TST) with desaturation above 4% (DA4%) and the percentage of TST with saturation below 90% (SB90%) were measured by overnight oximetry. Daytime arterial oxygen pressure (PaO2 ) and maximal inspiratory mouth pressure (PImax ) were also measured. RESULTS: All participants had mild or no daytime hypoxaemia (PaO2 , 77.3 ± 8.6 mm Hg). The NSpO2mean , DA4% and SB90% were significantly correlated with %ΔTdi, PaO2 , %PImax of the predicted value and the Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage. The %ΔTdi and PaO2 were predictors of NSpO2 mean by multiple regression analysis. CONCLUSION: This study suggested a close relationship between the NSpO2 and the contractile capability of the diaphragm assessed by ultrasonography in COPD. The %ΔTdi combined with PaO2 might predict NSpO2 in COPD patients with mild or no daytime hypoxaemia.

Relationship between balance and physical activity measured by an activity monitor in elderly COPD patients.

BACKGROUND: Little is known regarding the relationship between balance impairments and physical activity in COPD. There has been no study investigating the relationship between balance and objectively measured physical activity. Here we investigated the association between balance and physical activity measured by an activity monitor in elderly COPD patients. MATERIALS AND METHODS: Twenty-two outpatients with COPD (mean age, 72±7 years; forced expiratory volume in 1 second, 53%±21% predicted) and 13 age-matched healthy control subjects (mean age, 72±6 years) participated in the study. We assessed all 35 subjects' balance (one-leg standing test [OLST] times, Short Physical Performance Battery total scores, standing balance test scores, 4 m gait speed, and five-times sit-to-stand test [5STST]) and physical activity (daily steps and time spent in moderate-to-vigorous physical activity per day [MV-PA]). Possible confounders were assessed in the COPD group. The between-group differences in balance test scores and physical activity were analyzed. A correlation analysis and multivariate regression analysis were conducted in the COPD group. RESULTS: The COPD patients exhibited significant reductions in OLST times (P=0.033), Short Physical Performance Battery scores (P=0.013), 4 m gait speed (P<0.001), five-times sit-to-stand times (P=0.002), daily steps (P=0.003), and MV-PA (P=0.022) compared to the controls; the exception was the standing balance test scores. The correlation and multivariate regression analyses revealed significant independent associations between OLST times and daily steps (P<0.001) and between OLST times and MV-PA (P=0.014) in the COPD group after adjusting for possible confounding factors. CONCLUSION: Impairments in balance and reductions in physical activity were observed in the COPD group. Deficits in balance are independently associated with physical inactivity.

[Improvement of physical activity in patients with COPD].

Physical activity (PA) is defined as any bodily movement produced by skeletal muscles that results in energy expenditure beyond resting energy expenditure. Physical activity is an important clinical parameter closely related to morbidity and mortality in COPD. A self-report questionnaire is often subject to recall bias, correlates only poorly with objectively qualified PA, and does not provide an accurate estimate of free-living energy expenditure. In contrast, tri-axial accelerometers generate objective data in terms of quantifying steps or body movements performed over a period of a time. Low-intensity and home-based pulmonary rehabilitation with the feedback from using pedometer was effective in improving PA, and the improvements of physiological factors were correlated with increased walking time in stable elderly patients with COPD.