Six Minute Walk Test to assess functional capacity in chronic liver disease patients

Use of pedometer-driven walking to promote physical activity and improve health-related quality of life among meat processing workers: a feasibility trial

BACKGROUND

Current evidence supports the use of pedometers as effective motivational tools to promote physical activity and improve health-related quality of life in the general population. The aims of this study are to examine whether a pedometer-driven walking programme can improve health-related quality of life, and increase ambulatory activity in a population of meat processing workers when compared to a control group receiving educational material alone.

METHODS/DESIGN

A feasibility study employing a randomized controlled trial (RCT) design will collect data at three time points. A sample of up to 60 meat workers will be recruited and randomly assigned to either an intervention group N = 30 (12-week pedometer-driven walking program, brief intervention, and educational material), or control group N = 30 (educational material only). The primary outcomes of ambulatory activity, health-related quality of life, and functional capacity, will be evaluated at baseline, immediately following the 12-week intervention and then at three month post-intervention.

DISCUSSION

This paper describes the design of a feasibility randomized controlled trial, which aims to assess the effectiveness of the introduction of a workplace pedometer-driven walking program compared to normal lifestyle advice in meat processing workers.

TRIAL REGISTRATION NUMBER (ANZCTR)

12613000087752.

Test-retest reliability and developmental evolution of the 6-min walk test in Caucasian boys aged 5-12 years

The 6-min walk test (6MWT) assesses functional capacity and has been used as outcome measure in therapeutic studies in childhood neuromuscular disorders. The objectives were to evaluate test-retest reliability of the 6MWT and to generate normative data for healthy boys aged 5-12 years. Ninety boys (mean age 8 years 10 months) were recruited over four age subcategories (5-6, 7-8, 9-10, 11-12 years). Mean 6MWT distance and velocity (±standard deviation) for the total group were 555.5±93 m and 92.6±16.6 m/min. The 6MWT distance increased significantly with age. Test-retest reliability (mean interval 12 days) was very high for the total group (ICC>0.95) and for all age subcategories (ICC>0.80) a moderately high reliability (ICC>0.75) was found from 3 min onwards for each age subcategory. There was a mean difference of 5.2 m between test and retest without systematic bias. The standard error of measurement and smallest detectable difference were 20.7 and 57.4 m, respectively. These findings demonstrate the reliability of the 6MWT in young children, underscore its evolution with age, and indicate that a shorter version of the test is also reliable.

Comparison of activity level among patients with chronic liver disease

PURPOSE

To determine whether self-reported maximal and daily activity levels are impaired among patients with nonalcoholic fatty liver disease (NAFLD), hepatitis C (HCV) and hepatitis B (HBV).

METHODS

Clinicodemographic, diagnostic, self-report and standard laboratory data were obtained. Univariate, multivariate and regression analyses were performed comparing group maximal (Maximum Activity Score [MAS]) and daily activity scores (Adjusted Activity Score [AAS]), adjusted for age and gender.

RESULTS

Two hundred twenty-two patients completed activity-level self-reports (mean age [52.4 ± 10.0 years], BMI [28.3 ± 6.58], 31.2% NAFLD, 48.3% HCV, 20.3% HBV). On multivariate analysis, significantly higher MAS (p < 0.05) and AAS in HBV patients correlated with absence of cirrhosis, younger age, male gender (higher MAS) and lower BMI (higher AAS). Lowest activity levels were found primarily in obese patients (p < 0.009). Compared with population norms, NAFLD and HCV cohorts scored mildly disabled on MAS; the HBV cohort scored low normal. Mild disability on AAS was observed in patients with HBV; moderate disability in those with NAFLD, HCV.

CONCLUSIONS

All groups had significantly lower activity levels than population norms. Nonobese patients showed significantly less disability than obese patients. Patients with NAFLD and HCV are likely to have lower levels than those with HBV without cirrhosis. This presents an additional risk factor for disability and mortality.

IMPLICATIONS FOR REHABILITATION

• Hepatitis B (HBV), hepatitis C (HCV), and nonalcoholic fatty liver disease (NAFLD) patients had significantly lower activity levels than expected for their age and gender, as measured by the Human Activity Profile (HAP). • Overweight and normal weight chronic liver disease (CLD) patients showed significantly less disability than obese chronic liver disease patients. • Patients with NAFLD and HCV are likely to participate in low levels of activity that require fewer metabolic equivalents for completion, adding an additional risk factor for disability and mortality. • Targeting low activity level in CLD patients, and decreasing BMI below the obesity threshold, may reduce disability and risk of mortality.

Rehabilitation and 6-minute walk test after liver transplantation

BACKGROUND

Measurement of exercise capacity is an integral element to assess patients after surgery. Although the 6-minute walk test (6MWT) provides information regarding functional capacity, response to therapy, and prognosis across a range of conditions, its applicability for liver transplant recipients remains to be established. The aim of our study was to examine whether the 6MWT in combination with a subjective rating of perceived exertion (Borg Scale [BS]) could be used to evaluate exercise capacity among patients after liver transplantation (OLT).

METHODS

Thirteen consecutive subjects were enrolled in this single-center study during routine rehabilitation of the 6MWT and BS. At days 7 and 14 after OLT seeking to assess objective and subjective exercise capacities, we recorded basic clinical parameters, including body weight, blood pressure, heart rate and temperature. The results as compared between days 7 and 14 were related to the reference values for age-, height- and weight-matched healthy subjects.

RESULTS

On day 7, normal 6MWT was achieved by one patient and at day 14-, by three patients. At days 7 and 14, the average distances of 6MWT were 326.7 m and 421 m, respectively (P<.05), indicating a significant increase in exercise capacity. The average BS rating did not change significantly between days 7 and 14, indicating, that the increased exercise capacity was achieved without excessive effort.

CONCLUSIONS

Our study indicated that the 6MWT and BS may represent inexpensive and safe assessment methods for exercise capacity after OLT. This evaluation may be helpful to plan and optimize post-OLT rehabilitation.

Capacidade funcional e força muscular respiratória de candidatos ao transplante hepático

INTRODUÇÃO: A doença hepática crônica resulta em grande impacto funcional, causando perda de massa e função muscular com consequente redução da capacidade funcional. OBJETIVO: Avaliar e comparar a força muscular respiratória e a capacidade funcional dos candidatos ao transplante hepático que possuem classe B ou C segundo o Child-Pugh Score e correlacionar estas variáveis dentro de cada grupo. MÉTODOS: Estudo transversal, com amostra de conveniência composta por 35 pacientes, divididos em dois grupos a partir da pontuação obtida no Child-Pugh Score, sendo B (19 pacientes) e C (16 pacientes). Todos os indivíduos foram avaliados em um único momento, sendo mensuradas as pressões inspiratória máxima (PImáx) e expiratória máxima (PEmáx) e a distância percorrida no teste de caminhada de seis minutos (TC6M). RESULTADOS: Os indivíduos classificados com Child-Pugh Score B apresentaram maiores valores na PImáx (-86,05 ± 23,89 vs. -57,94 ± 14,14), p = 0,001, na PEmáx (84,16 ± 28,26 vs. 72,00 ± 16,94), p = 0,142, e na distância percorrida no TC6M (473,63 ± 55,276 vs. 376,13 ± 39,00), p = 0,001. Encontramos, ainda, correlação positiva entre os valores da PImáx e a distância percorrida no TC6M dentro grupo Child-Pugh Score B, r = 0,64 e p = 0,003. CONCLUSÃO: O progresso da doença hepática contribui para o surgimento de diversas complicações que, em conjunto, parecem contribuir para a redução da capacidade funcional dos indivíduos. Em nosso trabalho, isso ficou evidenciado pelo pior desempenho do grupo Child-Pugh Score C. Isto pode sugerir que a espera para o transplante hepático (TxH) pode agravar a capacidade funcional e a força muscular respiratória desses indivíduos.

Predicting outcomes from 6-minute walk distance in chronic obstructive pulmonary disease

BACKGROUND

Exercise tolerance is an important clinical aspect of chronic obstructive pulmonary disease that can be easily and reliably measured with the 6-minute walking test (6MWT). To improve the utility of the 6MWT for patient and health care system management, the interpretation of the functional status measure in relation to death and hospitalization should be elucidated.

METHODS

Three-year, prospective, multicenter observational study to evaluate the predictive power of 6MWD for death or exacerbation-related hospitalization and to evaluate the factors that help determine 6MWD.

RESULTS

We measured 6MWD at baseline and annually in 2110 patients with clinically stable Global Initiative for Obstructive Lung Disease (GOLD) stage II-IV COPD and recorded exacerbation-related hospitalizations and all-cause mortality. During the study, 200 patients died and 650 were hospitalized. Using receiver operating characteristics, the best predictive thresholds of the 6MWD were 334 m for increased risk of death and 357 m for exacerbation-related hospitalization (area under the curve 0.67 and 0.60 respectively); however, the discriminatory thresholds, especially for mortality, were influenced by age. The mean (SE) 6MWD declined by 1.6 (1.2) m per year in GOLD II, 9.8 (1.3) m per year in GOLD III, and 8.5 (2.4) m per year in GOLD IV.

CONCLUSION

The 6MWD provides prognostic information that may be useful for identifying high-risk patients with COPD.

Body composition, muscle strength, functional capacity, and physical disability risk in liver transplanted familial amyloidotic polyneuropathy patients

BACKGROUND

Familial amyloidotic polyneuropathy (FAP) is a neurodegenerative disease leading to sensory and motor polyneuropathies, and functional limitations. Liver transplantation is the only treatment for FAP, requiring medication that negatively affects bone and muscle metabolism. The aim of this study was to compare body composition, levels of specific strength, level of physical disability risk, and functional capacity of transplanted FAP patients (FAPTx) with a group of healthy individuals (CON).

METHODS

A group of patients with 48 FAPTx (28 men, 20 women) was compared with 24 CON individuals (14 men, 10 women). Body composition was assessed by dual-energy X-ray absorptiometry, and total skeletal muscle mass (TBSMM) and skeletal muscle index (SMI) were calculated. Handgrip strength was measured for both hands as was isometric strength of quadriceps. Muscle quality (MQ) was ascertained by the ratio of strength to muscle mass. Functional capacity was assessed by the six-minute walk test.

RESULTS

Patients with FAPTx had significantly lower functional capacity, weight, body mass index, total fat mass, TBSMM, SMI, lean mass, muscle strength, MQ, and bone mineral density.

CONCLUSION

Patients with FAPTx appear to be at particularly high risk of functional disability, suggesting an important role for an early and appropriately designed rehabilitation program.

The six-minute walk test in patients with pulmonary sarcoidosis

BACKGROUND:

The 6-min walk test (6MWT) is a useful tool to assess prognosis and functional impairment in various pulmonary diseases.

AIMS:

To evaluate functional capacity during various stages of pulmonary sarcoidosis and develop a scoring system clinical radiological physiological score (CRP) that can potentially be used to assess the functional status among patients with sarcoidosis.

MATERIALS AND METHODS:

We performed a retrospective study on 26 patients diagnosed with pulmonary sarcoidosis from 2001 to 2007. All patients completed the 6MWT. The parameters assessed during the test included spirometry, arterial blood gas, 6-min walk distance (6MWD), Borg dyspnea score, and initial and end oxygen saturation.

RESULTS:

Females covered a significantly shorter distance than males (343 m (223–389) vs. 416.5 m (352–500); P < 0.0001). In addition, females had a significantly lower SpO₂ at the end of the 6MWT than males (90.5 (61–99) vs. 96 (75–98); P < 0.03). The 6MWD was inversely correlated with the final Borg score (ρ = −0.603, P = 0.004) and the CRP score (ρ = −0.364, P = 0.047) and positively correlated with forced expiratory volume in 1 s (FEV₁) % (ρ = 0.524, P = 0.006) and forced vital capacity (FVC) % (ρ = 0.407, P = 0.039).

CONCLUSIONS:

Female gender, FEV₁%, final Borg score, FVC%, CRP score, and SpO₂ at the end of the 6MWT are associated with reduced 6MWD. It appears that Saudi patients diagnosed with sarcoidosis have a markedly reduced walking distance compared with other races. The effect of race and ethnicity and the utility of the CRP score as a potential marker to assess functional status require further exploration.

Six-minute walk distance predicts mortality in liver transplant candidates

The 6-minute walk distance (6MWD) is a simple test measuring global physical function. It is commonly used to predict mortality in patients with cardiac and pulmonary diseases, but it is also useful in assessing the functional status of patients with a variety of other medical conditions. We sought to determine (1) the characteristics of the 6MWD in patients listed for liver transplantation (LT), (2) the existence of a relationship between the 6MWD and the quality of life, and (3) the relationship between the 6MWD and survival in LT candidates. The 6MWD was prospectively measured in all patients listed for LT. The 6MWD was determined when the listed Model for End-Stage Liver Disease (MELD) score was ≥ 15. Patients were followed until LT, death, removal from the wait list, or the end of the study period. Quality of life was assessed with the Short Form 36 (SF-36). In 121 patients, the mean 6MWD was 369 ± 122 m; it was not related to age, height, weight, body mass index, albumin level, or etiology of liver disease and showed a moderate correlation with the physical component score (PCS) on the SF-36 (r = 0.4) and a moderate inverse correlation with the native MELD score (r = -0.61). In an unadjusted analysis, a high native MELD score, a low 6MWD, and a low PCS were associated with mortality, with only the 6MWD retaining significance after adjustment for covariates. Each 100-m increase in the 6MWD was significantly associated with increased survival (hazard ratio = 0.48, P = 0.0001), with 6MWD < 250 m being associated with an increased risk of death (P = 0.0001). In conclusion, the 6MWD is significantly reduced in patients awaiting LT and is inversely correlated with the native MELD score. A pretransplant 6MWD < 250 m is a risk for death on the wait list.

Six-minute walk test in patients with Down syndrome: validity and reproducibility

OBJECTIVES

To examine the validity of the six-minute walk test (6MWT) as a tool to evaluate functional exercise performance in patients with Down syndrome (DS).

DESIGN

Comparison of the six-minute walk distance (6MWD) in 2 distinct groups of DS patients: with and without severe cardiac disease. To test reproducibility, a group of patients with DS performed the 6MWT twice.

SETTING

Tertiary referral centers for patients with congenital heart defects and outpatient clinics for people with intellectual disabilities.

PARTICIPANTS

Adult patients with DS with (n=29) and without (n=52) severe cardiac disease categorized by cardiac echocardiography.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

Distance walked on the 6MWT.

RESULTS

The mean 6MWD in the group with severe cardiac disease was 289+/-104 m and in the group without severe cardiac disease 280+/-104 m (P=.70). Older age, female sex, and severe level of intellectual disability were all found to be independently and significantly correlated with a lower 6MWD (r=.67, P<.001). The paired 6MWD was not significantly different (310+/-88 m vs 317+/-85 m; P=.40) in patients who performed the 6MWT twice. The coefficient of variation was 11%.

CONCLUSIONS

The 6MWD between the 2 groups was not significantly different. However, the walking distance inversely correlated with the level of intellectual disability. Therefore, the 6MWT is not a valid test to examine cardiac restriction in adult patients with DS.

Six-minute walk test: functional capacity of severely obese before and after bariatric surgery

BACKGROUND

The 6-minute walk test (6MWT) is a well-known instrument for assessing the functional capacity of a variety of groups, including the obese. It is a simple, low-cost and easily applied method to objectively assess the level of exercise capacity. The aim of the present study was to study the functional capacity of a severely obese population before and after bariatric surgery.

METHODS

A total of 51 patients were studied. Of the 51 patients, 86.2% were women, and the mean age was 40.9 + or - 9.2 years. All 51 patients were evaluated preoperatively and 49 were evaluated 7-12 months postoperatively. The initial body mass index was 51.1 + or - 9.2 kg/m(2), and the final body mass index was 28.2 + or - 8.1 kg/m(2). All patients underwent Roux-en-Y gastric bypass. The 6MWT was performed in a hospital corridor, with patients attempting to cover as much distance as they could, walking back and forth for as long as possible within 6 minutes at their regular pace. The total distance, Borg Scale of perceived exhaustion, modified Borg dyspnea scale for shortness of breath, and physical complaints at the end of the test were recorded. In addition, the heart rate and respiratory frequency were assessed before and after the test.

RESULTS

The tolerance was good, and no injuries occurred at either evaluation. The patients' mean distance for the 6MWT was 381.9 + or - 49.3 m before surgery and 467.8 + or - 40.3 m after surgery (p <.0001). Similar results were observed for the other parameters assessed.

CONCLUSION

The 6MWT provided useful information about the functional status of the obese patients undergoing bariatric surgery. A simple, safe, and powerful method to assess functional capacity of severely obese patients, the 6MWT is an objective test that might replace the conventional treadmill test for these types of patients.