Handgrip Strength as a Reflection of General Muscle Strength in Chronic Obstructive Pulmonary Disease.

Muscle dysfunction is one of the main features in individuals with chronic obstructive pulmonary disease (COPD). Handgrip strength (HS) has been used as a representation of general muscle strength in various populations, and a few studies found correlation between HS and other measures of upper and lower limbs' muscle strength in the general population, although this was not yet studied in depth in COPD. The aims of this study were to verify if HS is cross-sectionally well correlated with upper and lower limbs' muscle strength in individuals with COPD, and to identify a new cutoff for handgrip weakness in this population. HS was assessed by a dynamometer, whereas other muscle strength assessments comprised maximal voluntary contraction (MVC) of the quadriceps femoris and 1-repetition maximum (1RM) of biceps and triceps brachii, pectoralis major, latissimus dorsi and quadriceps femoris. Additional assessments included pulmonary function and volumes, body composition and exercise capacity. Fifty individuals with COPD were studied (65 ± 7 years; FEV1 51 ± 14%pred). HS showed moderate-to-strong correlations with all 1-RM assessments (0.62

Are the Effects of High-Intensity Exercise Training Different in Patients with COPD Versus COPD+Asthma Overlap?

PURPOSE: This study aimed to investigate whether patients with chronic obstructive pulmonary disease (COPD) presenting asthma overlap (ACO) benefit similarly in comparison to patients with only COPD after a 12-week high-intensity exercise training (ET) program. METHODS: Subjects with a diagnosis of COPD alone or ACO were evaluated and compared before and after a high-intensity ET program composed of walking and cycling plus strengthening exercises of the upper and lower limbs (3 days/week, 3 months, 36 sessions). Assessments included spirometry, bioelectrical impedance, 6-min walk test (6MWT), London Chest Activity of Daily Living Scale (LCADL), Hospital anxiety and depression Scale, modified Medical Research Council Scale (mMRC), Saint George Respiratory Questionnaire (SGRQ), and respiratory and peripheral muscle strength [manovacuometry and 1-repetition maximum test (quadriceps femoris, biceps and triceps brachialis), respectively]. ACO was defined according to Sin et al. (Eur Respir J 48(3):664-673, 2016). RESULTS: The sample was composed of 74 subjects (57% male, age 67 ± 8 years, BMI 26 (21-32) kg/m2, FEV1 47 ± 17%predicted), and 12 (16%) of them were classified as presenting ACO. Both groups improved pulmonary function, 6MWT, peripheral and inspiratory muscle strength, LCADL, and SGRQ after ET (p < 0.005 for all). There were no significant interactions between ACO and COPD on ET effects (p > 0.05 for all). Likewise, there was no difference in the proportion of patients achieving the minimum clinical important difference for 6MWT and mMRC. CONCLUSION: High-intensity exercise training generates similar benefits in patients with COPD regardless of whether presenting asthma overlap or not.

The Gini Coefficient: A New Approach to Assess Physical Activity Inequality in COPD.

Increasing physical activity (PA) is a complex and challenging task in patients with chronic obstructive pulmonary disease (COPD). However, some questions are raised regarding the evaluation of PA in these patients: Have all aspects of PA evaluation in patients with COPD already been explored in the scientific literature and clinical practice? What is the clinical importance of assessing PA inequality? PA inequality is defined as the Gini coefficient (Ginicoef) of the PA distribution of a population and is already shown to have implications for public health in the general population. It is a simple tool that might allow a better understanding of PA disparities among different COPD populations, although to our knowledge there is no previous investigation of PA inequality in patients with COPD using the Ginicoef. In this perspective study we have provided examples of the Ginicoef use in different scenarios. Future studies might try to apply it in order to identify subpopulations with higher PA inequality, and perhaps are therefore more prone to benefit most from interventions specifically tailored to promote PA. In summary, we propose the quantification of PA inequality with the Ginicoef as a tool that might allow us to see PA even more comprehensively than we already do, expanding our perspective on PA in patients with COPD.

Functional Status of Patients with COPD Assessed by London Chest Activity of Daily Living Scale: Gender Association and Validity of a Cutoff Point.

PURPOSE: Whether the difference in the impact of chronic obstructive pulmonary disease (COPD) on the functional status of men and women stems from clinical distinctions or to the measuring instrument used is unclear. Like most instruments for assessing functional limitation in COPD, the interpretation of the results of the London Chest Activity of Daily Living (LCADL) scale is limited because a lack of a valid cutoff point to this scale. For that, this study sought to compare the functional status between men and women with COPD; and propose a cutoff point for LCADL capable of discriminating the prognosis of these individuals. METHODS: A sample of 138 subjects with moderate-severe COPD was evaluated by the LCADL. The percentage of the individual maximum score was used to obtain a cutoff point capable of discriminating patients with the worse prognosis according to the BODE Index. The cutoff point was also tested in an independent sample (n = 70). RESULTS: Regarding the total score, domestic and leisure domains of the LCADL, men had better scores than women (P ≤ 0.01). The cutoff point found was 37% (area under the curve = 0.70, 95% confidence interval = 0.60-0.80, sensitivity = 0.55 and specificity = 0.74). Individuals who scored ≥ 37% had a worse prognosis and level of physical activities of daily living than those who scored below (P ≤ 0.02). CONCLUSION: When evaluated by the LCADL, men and women with COPD present difference in the functional status. The established cutoff point (37%) adequately discriminates individuals regarding the prognosis, contributing to improve the interpretation capacity of the LCADL.

Cluster analysis identifying patients with COPD at high risk of 2-year all-cause mortality.

The objective of the article is to identify clusters of patients with COPD according to factors known to be associated with mortality and to verify whether clusters' assignment is associated with 2-year mortality. Patients ( n = 141) were evaluated by bioelectrical impedance, maximal inspiratory pressure (MIP), one-repetition maximum test of the quadriceps femoris (1RMQF) and BODE index (body mass index; airflow obstruction (spirometry); dyspnea (modified Medical Research Council scale); and exercise capacity (6-minute walk test (6MWT) distance). Vital status was retrospectively checked 2 years after the assessments, and time to death was quantified for those deceased in this period. K-means analysis identified two clusters. Patients in cluster one (CL I, n = 69) presented an impaired clinical status in comparison to cluster two (CL II, n = 72). Receiver operating characteristics curves identified the cutoffs discriminating patients composing CL I: forced expiratory volume in the first second <44%pred; 6MWT <479 m; 1RMQF <19 kg; and maximum inspiratory pressures <73 cmH2O (area under the curve range 0.750-0.857). During the follow-up, 19 (13%) patients deceased, 15 in CL I (22%) and 4 in CL II (0.06%) ( p = 0.005). CL I was associated with a higher risk of 2-year mortality (hazard ratio (95% confidence interval): 4.3 (1.40-12.9), p = 0.01). A cluster of patients with COPD highly associated with 2-year mortality was statistically identified, and cutoffs to identify these subjects were provided.

Physical Activity of Patients with COPD from Regions with Different Climatic Variations.

Seasonal changes in physical activity in daily life (PADL) of patients with Chronic Obstructive Pulmonary Disease (COPD) living in regions of the world with contrasting (i.e., mild or marked) weather variations have not been yet investigated. We aimed to quantify PADL and compare its variability caused by seasonality in patients with COPD who live in world regions with different summer-winter climatic variations (i.e. Londrina, Brazil and Leuven, Belgium). In a longitudinal, prospective and observational study, patients with COPD from Brazil and Belgium wore the SenseWear Armband for 7 days in summer and 7 days in winter. Active time (≥2METs) was the primary outcome. PADL data were matched day-by-day with weather information. Regarding the two assessment moments, median (min;max) temperatures were 11 (-5.5;27.2)°C in Leuven and 21 (7;27)°C in Londrina. Patients in Brazil (n = 19, 69 ± 7 years, FEV1 47 ± 15%pred) and Belgium (n = 18, 69 ± 6 years, FEV1 50 ± 15%pred) decreased their active time in winter compared to summer (p < 0.05), and this reduction was more pronounced in Brazil (p = 0.01, between group). Mean, minimum and maximum temperature, daylight duration and relative humidity were significantly related to active time. Patients with COPD decrease their PADL in winter even in a region with milder climatic variation.

Simple Lower Limb Functional Tests in Patients With Chronic Obstructive Pulmonary Disease: A Systematic Review.

OBJECTIVES: To evaluate the characteristics and available evidence on the measurement properties of the gait speed (GS) test, timed Up and Go test (TUG), sit-to-stand (STS) test, and step test; to investigate their relation with clinical outcomes in chronic obstructive pulmonary disease (COPD); and to provide recommendations for clinical practice and future research. DATA SOURCES: Studies were systematically identified from a literature search using PubMed, PEDro, CINAHL, and Cochrane Library databases and the reference lists of the included articles. STUDY SELECTION: Studies including ≥1 of these 4 lower limb functional tests (GS test, TUG, STS test, and step test) as an outcome in patients with COPD were selected. No limits were applied for language and study design. DATA EXTRACTION: Two researchers independently performed data extraction and, by using the COnsensus-based standards for the Selection of health status measurement INstruments, assessed the quality of those studies that described measurement properties. DATA SYNTHESIS: Forty-two articles met the selection criteria. GS test, STS test, and step test are valid, reproducible, and responsive tests, especially the 4-meter GS, 5-repetition STS test, and 6-minute step test (6MST). The TUG is reliable; however, studies on other measurement properties of this test are lacking. Outcomes of these tests are correlated with mortality, physical activity in daily life, exercise capacity, dyspnea, and quality of life. CONCLUSIONS: Simple and functional lower limb tests provide information about important clinical outcomes in patients with COPD. The 4-meter GS, 5-repetition STS test, and 6MST are tests with well-established psychometric properties, whereas the properties of the TUG need to be studied further.

Relationship between sniff nasal inspiratory pressure and BODE index in patients with COPD.

PURPOSE: The aims of this study were to investigate the relationship between sniff nasal inspiratory pressure (SNIP) and severity of chronic obstructive pulmonary disease (COPD) as defined by the BODE index, and to investigate the capacity of different SNIP cutoffs to predict a BODE index score ≥5 (i.e., worse disease severity). METHODS: Thirty-eight subjects with COPD (21 men, 66 ± 8 years, forced expiratory volume in the first second (FEV(1)) 42 ± 16 % predicted) underwent assessments of SNIP, airflow limitation, body mass index (BMI), dyspnea (Medical Research Council scale), and exercise capacity (6-min walking test, 6MWT). The BODE index was calculated, and patients were separated into two groups according to the BODE quartiles (1 and 2, or 3 and 4). RESULTS: Patients from quartiles 3 and 4 presented lower values of SNIP than patients from quartiles 1 and 2 (73 ± 18 vs 56 ± 21 cmH(2)O, respectively; p = 0.01). There was significant and inverse correlation between SNIP and the BODE index (r = -0.62; p<0.001). A logistic regression model revealed that a SNIP value below 63 cmH(2)O presented higher sensitivity and specificity (70 and 67 %, respectively) for predicting a BODE score equivalent to quartiles 3 or 4. CONCLUSION: SNIP is moderately and significantly related to COPD severity as assessed by the BODE index. Moreover, the cutoff point of 63 cmH2O showed the best combination of sensitivity and specificity for predicting worse scores in the BODE index.

The Brazilian-Portuguese version of the Upper Extremity Functional Index (UEFI): Translation, cross-cultural adaptation and measurement properties for Brazilian adults after a burn injury.

OBJECTIVES: To translate, cross-culturally adapt, validate, verify the reliability and estimate the minimal detectable change (MDC) of the UEFI to Brazilian Portuguese (UEFI-Br) for burns. METHODS: The study was carried out with 131 Brazilian burn cases at two time points, at discharge and at the first outpatient follow-up (15-21 days after discharge) in a Burn Treatment Center. The adaptation process of the UEFI was based on international recommendations. The Burn Specific Health Scale-Brief-Br (BSHS-B-Br) was also applied in order to analyze construct validity of the UEFI-Br and distribution-based methods were used to estimate its MDC. RESULTS: Intra- and inter-rater reliability were good with ICC of 0.986 (CI 95 %: 0.98-0.99) and 0.969 (CI 95 %: 0.955-0.979), respectively, at discharge and 0.997 (CI 95 %: 0.996-0.998) and 0.987 (CI 95 %: 0.981-0.991), respectively, at the first outpatient follow-up appointment. We found good internal consistency with Cronbach's α values of 0.987 and 0.996, respectively, at the two times. The SEM was 4.42 and 2.31 at the first and second time points, respectively. The UEFI-Br scores demonstrated strong correlation with the Burn Specific Health Scale-Brief-Br (BSHS-B-Br) function domain scores (r = 0.87-0.90). No significant correlation was found between UEFI-Br scores and participants' characteristics. The MDC of the UEFI-Br lies between 11 and 13 points. CONCLUSION: The Brazilian version of the UEFI-Br, a useful tool to assess upper limb function and disability, is a valid and reliable tool for use with Brazilian burn survivors. The MDC for the instrument was determined to be 11-13 points.

Assessment of sedentary behaviour in individuals with COPD: how many days are necessary?

Objective: The objective of the present study was to define the minimum number of monitoring days required for the adequate cross-sectional assessment of sedentary behaviour in individuals with chronic obstructive pulmonary disease (COPD). Methods: In this cross-sectional study, the sedentary behaviour of individuals with COPD was assessed using two physical activity monitors during awake time for seven consecutive days. Time spent per day in activities requiring ≤1.5 metabolic equivalents (METs) and in sitting, lying and sitting+lying positions was calculated taking into account the average of 7 days (as a reference in all analyses) and of all 119 possible combinations of 2---6 days. Intraclass correlation coefficients (ICCs) and linear regression analyses were performed for all combinations. Results: 91 individuals were analysed (47 female, 66±9 years, forced expiratory volume in 1 s 50±15% predicted). For the variables time spent per day in activities ≤1.5METs and sitting, the average of any combination of at least four assessment days was sufficient to adequately reflect the average of 7 days (adjusted R2≥0.929, ICC≥0.962, p<0.0001 for all). For time spent per day lying and sitting+lying, only two assessment days were enough (adjusted R2≥0.937, ICC≥0.968, p<0.0001 for all). Results were maintained independently of patient sex, disease severity, day of the week, daylight time or daytime naps. Conclusions: The average of 4 days of objective monitoring was sufficient to adequately reflect the results of a 1-week assessment of the main outcomes related to sedentary behaviour in individuals with moderate to very severe COPD, regardless of sex, disease severity, day of the week, daylight time and occurrence of daytime naps.

Comparison of Physical Activity Patterns among Three Major Chronic Respiratory Diseases.

Although the level of physical activity in daily life (PADL) plays a vital role concerning the health of subjects with chronic lung diseases, it remains uncertain how PADL patterns compare among different conditions. This study's objective was to compare the PADL levels of subjects with COPD, asthma and idiopathic pulmonary fibrosis (IPF); and to investigate PADL behaviour in different diseases' severity. Stable subjects who had not undergone pulmonary rehabilitation in the previous year were included. Subjects were divided into two subgroups according to disease severity: mild/moderate and severe/very severe. The primary outcome was time spent in moderate-to-vigorous physical activities (MVPA) (Actigraph GT3x) measured during one week over 12 h/day; other assessments included pulmonary function, peripheral muscle strength and exercise capacity. Comparisons among subgroups were corrected for age, BMI and sex. The analysis involved 119 subjects (47 asthma, 48 COPD and 24 IPF). Subjects with asthma had higher PADL levels than those with COPD and IPF (MVPA 18(14-22) vs. 8(4-12) vs. 7(1-12) min/day, respectively; p ancova = 0.002). Subjects with severe/very severe IPF had the lowest PADL level among all subgroups. Adult subjects with asthma have higher PADL levels than those with COPD and IPF, whereas patients with severe and very severe IPF are the most physically inactive subjects.

Cultural adaptation and validation of the Brazilian Portuguese version of the PROactive Physical Activity in COPD-clinical visit instrument for individuals with COPD.

OBJECTIVE: To adapt the PROactive Physical Activity in COPD-clinical visit (C-PPAC) instrument to the cultural setting in Brazil and to determine the criterion validity, test-retest reliability agreement, and internal consistency of this version. METHODS: A protocol for cultural adaptation and validation was provided by the authors of the original instrument and, together with another guideline, was applied in a Portuguese-language version developed by a partner research group from Portugal. The adapted Brazilian Portuguese version was then cross-sectionally administered twice within a seven-day interval to 30 individuals with COPD (57% were men; mean age was 69 ± 6 years; and mean FEV1 was 53 ± 18% of predicted) to evaluate internal consistency and test-retest reliability. Participants also completed the International Physical Activity Questionnaire (IPAQ), the modified Medical Research Council scale, the COPD Assessment Test, and Saint George's Respiratory Questionnaire to evaluate criterion validity. RESULTS: The C-PPAC instrument showed good internal consistency and excellent test-retest reliability: "amount" domain = 0.87 (95% CI, 0.73-0.94) and "difficulty" domain = 0.90 (95% CI, 0.76-0.96). Bland & Altman plots, together with high Lin's concordance correlation coefficients, reinforced that agreement. Criterion validity showed moderate-to-strong correlations of the C-PPAC with all of the other instruments evaluated, especially with the IPAQ (rho = -0.63). CONCLUSIONS: The Brazilian Portuguese version of the C-PPAC is a reliable and valid instrument for evaluating the experience of Brazilian individuals with COPD with their physical activity in daily life.

Use of different reference values for handgrip strength in individuals with COPD: analysis of agreement, discriminative capacity, and main clinical implications.

OBJECTIVE: To identify reference values for handgrip strength through a literature search and compare the agreement of reference values from Brazil with others for handgrip strength in a sample of COPD patients in Brazil, as well as to determine which set of reference values is more discriminative regarding differences in clinical characteristics between individuals with low handgrip strength and normal handgrip strength. METHODS: To identify reference values for handgrip strength, a literature search was performed; a retrospective cross-sectional analysis of baseline-only data from two unrelated studies was then performed. Individuals were evaluated for handgrip strength, peripheral muscle strength, respiratory muscle strength, pulmonary function, body composition, exercise capacity, dyspnea, and functional status. RESULTS: Of the 45 studies that were initially selected, 9 met the criteria for inclusion in the analysis, which included 99 COPD patients in Brazil (52% of whom were male with GOLD stage II-IV COPD). The prevalence of low handgrip strength varied across studies (from 9% to 55%), the set of reference values for handgrip strength in a sample of individuals in Brazil having classified 9% of the study sample as having low handgrip strength. The level of agreement between the reference values for a sample of individuals in Brazil and the other sets of reference values varied from weak to excellent. The reference values for a sample of individuals in Brazil showed the highest number of significantly different characteristics between individuals with low and normal handgrip strength. CONCLUSIONS: The level of agreement between national and international sets of reference values for handgrip strength varied from weak to excellent in COPD patients in Brazil. Reference values for handgrip strength with higher discriminative capacity are not necessarily those that identify more individuals as having low handgrip strength.

Instruments to assess function or functionality in adults after a burn injury: A systematic review.

INTRODUCTION: Assessment of functionality or function, through valid and reliable instruments, is essential during rehabilitation of adults after a burn injury. Currently, there is no consensus in the literature regarding the most appropriate tool that should be used to assess function or functionality; there is also no synthesis of the current studies published in this area. OBJECTIVES: To investigate and report the instruments used to assess function or functionality in adults after a burn injury; to identify the characteristics and evidence on their measurement properties; and to evaluate their clinical utility. METHODS: We systematically searched the literature via six electronic databases and via screening reference lists of relevant studies. The review was registered in PROSPERO (CRD42016048065) and reported according to the PRISMA statement. Studies in which function or functionality of upper and/or lower limbs of adults after a burn injury was assessed were included. Exclusion criteria comprised studies in pediatric populations and conference abstracts. RESULTS: Thirty-four studies were included. Twelve questionnaires and seven objective tests for function or functionality were identified. Three specific tools were found; four generic instruments have been validated in burns. Nine studies evaluated the instruments' measurement properties, presenting at least one property classified as 'fair' quality. Finally, 18 instruments demonstrated clinical utility. CONCLUSION: This systematic review demonstrated that most instruments used to assess function or functionality in adults with a burn injury have not been specifically developed for this population and had their measurement properties poorly studied. Conversely, almost all instruments had clinical utility.

Estimation of maximal work rate based on the 6-minute walk test and fat-free mass in chronic obstructive pulmonary disease.

OBJECTIVE: To propose a predictive equation of the maximal work rate (Wmax) in patients with chronic obstructive pulmonary disease (COPD) based on the product of 6-minute walking test (6MWT) and fat-free mass (FFM) and to compare it with a previously proposed equation based on the product of 6MWT and body weight (BW). DESIGN: Descriptive (cross-sectional) study. SETTING: University-based rehabilitation center. PARTICIPANTS: Patients with COPD (N=53; 30 men; forced expiratory volume in 1 second, 45%±15% predicted). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Three Wmax were produced: Wmax_real (obtained from the maximal cycle ergometry test), Wmax_BW (estimated from the product of 6MWT and BW), previously proposed by Hill et al. (Arch Phys Med Rehabil 2008; 89(9):1782-7); and Wmax_FFM (estimated from the product of 6MWT and FFM). RESULTS: The equation derived from a regression model to estimate Wmax_FFM was as follows: -27.9717+3.7792*(6MWT*FFM). Wmax_real correlated better with Wmax_FFM (r=.64) than with Wmax_BW (r=.54). There was no difference between Wmax_FFM (median [interquartile range], 41 [29-50] W) and Wmax_real (40 [20-50] W, P=.88), whereas Wmax_BW (60 [52-69] W) significantly overestimated Wmax_real (P<.0001). CONCLUSIONS: In patients with COPD, Wmax is better estimated by an equation including the product of 6MWT and FFM than by a previously proposed equation including the product of 6MWT and body weight.

Six-minute walk test in burned subjects: Applicability, reproducibility and performance at hospital discharge.

INTRODUCTION: Despite its clinical relevance in several populations, there is no evidence on applicability of the 6-min walk test (6MWT) in burned subjects. OBJECTIVES: To verify the applicability and reproducibility of the 6MWT in burned individuals and to analyze patients' performance in this test at hospital discharge. METHODS: In a cross-sectional study, burned individuals performed two 6MWT at hospital discharge, according to international standardization. In addition to walked distance, physiological and symptomatic variables were collected. Clinical history and demographic data were also recorded. RESULTS: One hundred individuals were evaluated (70 men, 10 [6-18]% total body surface area burned). There was excellent agreement between the two 6MWT (ICC = 0.97). However, 73% of subjects increased the walked distance in the second test (23 [-9-47]m or 5 [-2-10]%; P = 0.001). Considering the best 6MWT, the walked distance was 488 [396-718]m (80 [65-92]%pred), and 51% of the individuals had limited functional exercise capacity. Additionally, participants without lower limb involvement presented better 6MWT than others (P < 0.0001). CONCLUSION: The 6MWT was applicable, well tolerated and reproducible at hospital discharge in burned individuals. However, there was considerable learning effect between the first and second test. Finally, the reduced exercise capacity observed reinforces need for early rehabilitation in this population.

Which is the best protocol and cut-off point in the 4-metre gait speed test to discriminate exercise capacity in COPD? / Qual o melhor protocolo e ponto de corte no teste 4-metre gait speed para discriminar capacidade de exercício na Doença Pulmonar Obstrutiva Crônica?

Objective To determine the discriminative capacity and cut-off point of different 4-metre gait speed test (4MGS) protocols in identifying preserved or reduced exercise capacity using the six-minute walk test (6MWT) in patients with Chronic Obstructive Pulmonary Disease (COPD); also, to compare 4MGS protocols and characteristics of individuals according to the best cut-off point. Methods We evaluated fifty-six patients with COPD, all of which were submitted to the assessment of anthropometric characteristics, pulmonary function (spirometry) and functional exercise capacity (6MWT and four protocols of the 4MGS). In the 4MGS test, patients were instructed to walk at normal pace and at maximum speed in a 4 meters course (4MGS 4m - usual pace and at maximum) and 8 meters course (4MGS 8m - usual pace and at maximum). Results Only the 4MGS 4m-maximum protocol was able to identify preserved exercise capacity in the 6MWT (AUC=0.70) with moderate correlation between them (r=0.52; P=0<0.0001). The cut-off point found in the 4MGS 4m-maximum was 1.27 m/s. Patients with preserved exercise capacity (4MGS 4m-maximum ≥1.27m/s) walker greater distances on the 6MWT in %pred (91±2 vs 76±3; P<0.0001). In the other comparisons involving gender, BMI, FEV1% pred and GOLD index there were no significant differences between the groups. In addition, the agreement of individuals classified as preserved and reduced exercise capacity in the 6MWT and 4MGS 4m-maximum was significant (P = 0.008). Conclusion The 4MGS 4m-maximum test can be used to discriminate preserved exercise capacity in patients with COPD and correlates with the 6MWT.

Tossing and turning: association of sleep quantity-quality with physical activity in COPD.

The association between characteristics of sleep and physical activity in daily life (PADL) has not yet been investigated in depth in subjects with COPD. This study evaluated whether time spent per day in physical activity (PA) and sedentary behaviour are associated with sleep quantity and quality in this population. Sleep and PADL were objectively assessed by an activity monitor for 7 days and analysed on a minute-by-minute basis. Subjects also underwent spirometry and 6-min walking test (6MWT). Fifty-five subjects with moderate-to-severe COPD (28 male, 67±8 years) were studied. Subjects with total time in bed (TIB) per night ≥9 h had higher wake-after-sleep onset than TIB 7-9 h and TIB ≤7 h (195 (147-218) versus 117 (75-167) and 106 (84-156) min) and more fragmented sleep than TIB ≤7 h (8.2 (6.7-14.3) versus 6.3 (5.6-6.9) sleeping bouts; p<0.05 for all). Subjects with TIB ≥9 h also spent more time per day in sedentary behaviour and less time per day in PA of light and moderate-to-vigorous intensity than those with TIB 7-9 h and ≤7 h. In multiple linear regression, TIB ≥9 h was the only significant predictor of physical inactivity (ß=-3.3 (-5.1, -1.6), p≤0.0001), accounting for 20% of its variation. Sleep fragmentation was frequent and more pronounced in physically inactive than active patients (7.5 (6.3-9.6) versus 6.4 (5.5-7.3) sleeping bouts; p=0.027). In summary, subjects with COPD with TIB ≥9 h·night-1 have more fragmented sleep, are more sedentary and less physically active than those with <9 h·night-1, independently of the awake time. Sleep quality is frequently poor and even worse in patients classified as physically inactive.

Physiopathological relationship between chronic obstructive pulmonary disease and insulin resistance.

PURPOSE: Chronic obstructive pulmonary disease (COPD) is characterized by persistent and progressive airflow obstruction that is associated with an abnormal chronic inflammatory response in the airways and lungs to noxious particles. COPD often leads to physical inactivity and deconditioning that added to inappropriate/excessive inflammatory responses leads to systemic consequences. Studies have shown that metabolic syndrome and manifested diabetes are more frequent in COPD than in healthy subjects; a possible explanation is that different pathophysiological aspects of COPD can lead to insulin resistance. Thus, this mini-review aims to present the main studies suggesting a pathophysiological relationship between COPD and insulin resistance. METHODS: A review of literature was conducted using PubMed and Web of Science databases with the aim of searching for studies supporting a relationship between COPD and insulin resistance. RESULTS: A physiopathological relationship between COPD and insulin resistance was found, supported in part due to common risk factors presented by these two conditions, such as smoking and physical inactivity. Also, systemic effects (worsening of physical inactivity and sedentary behavior, inflammation and oxidative stress, body composition abnormalities) and the corticosteroid treatment of patients with COPD may play a role. CONCLUSION: Patients with COPD should be screened for abnormalities in insulin sensitivity in order to reduce morbidity and improve health status in this population.

4-Meter Gait Speed Test in Chronic Obstructive Pulmonary Disease: INTERRATER RELIABILITY USING A STOPWATCH.

PURPOSE: 4-meter gait speed (4MGS) is increasingly used to assess functional performance in patients with chronic obstructive pulmonary disease. However, the current literature lacks information regarding some technical standards for this test. Therefore, the purpose of this study was to compare and to evaluate the interrater reliability between a stopwatch and video recording used as timing systems for the 4MGS in patients with chronic obstructive pulmonary disease, as well as to verify the interrater reliability between 2 observers measuring the 4MGS time using a manual stopwatch. METHODS: Fifty-one patients performed the 4MGS using 4 different protocols (random order): walking at the usual and maximum speed in a 4-meter course and walking at the same 2 speeds on an 8-m course using a 2-m acceleration zone, a 4-meter timing area, and a 2-m deceleration zone. Gait speed was measured simultaneously using a stopwatch and a video recording. In a subanalysis (n = 24), 2 independent observers timed the 4MGS using a stopwatch. RESULTS: There was no significant difference in comparison between the 2 timing methods (P > .05 for all), and the reliability between video recording and stopwatch was excellent in all 4MGS studied protocols (intraclass correlation coefficient ≥ 0.91). Moreover, when comparing gait speed measured by 2 observers using a stopwatch, no significant difference was found among all proposed protocols (P > .05 for all), and there was also excellent reliability between the 2 independent observers (intraclass correlation coefficient ≥ 0.94). CONCLUSION: The stopwatch, a low-cost and feasible tool, is reliable as a timing device for the 4MGS in patients with chronic obstructive pulmonary disease.