Impairments of muscles and nerves associated with peripheral arterial disease and their relationship with lower extremity functioning: the InCHIANTI Study

Skeletal muscle desmin alterations following revascularization in peripheral artery disease claudicants

Peripheral artery disease (PAD) is characterized by varying severity of arterial stenosis, exercise induced claudication, malperfused tissue precluding normal healing and skeletal muscle dysfunction. Revascularization interventions improve circulation, but post-reperfusion changes within the skeletal muscle are not well characterized. This study investigates if revascularization enhanced hemodynamics increases walking performance with concurrent improvement of mitochondrial function and reverses abnormal skeletal muscle morphological features that develop with PAD. Fifty-eight patients completed walking performance testing and muscle biopsy before and 6 months after revascularization procedures. Muscle fiber morphology, desmin structure, and mitochondria respiration assessments before and after the revascularization were evaluated. Revascularization improved limb hemodynamics, walking function, and muscle morphology. Qualitatively not all participants recovered normal structural architecture of desmin in the myopathic myofibers after revascularization. Heterogenous responses in the recovery of desmin structure following revascularization may be caused by other underlying factors not reversed with hemodynamic improvements. Revascularization interventions clinically improve patient walking ability and can reverse the multiple subcellular functional and structural abnormalities in muscle cells. Further study is needed to characterize desmin structural remodeling with improvements in skeletal muscle morphology and function.

Time-course evolution of functional performance during a 3-month supervised exercise training program in patients with symptomatic peripheral artery disease

INTRODUCTION

Functional performance is impaired in patients with peripheral artery disease (PAD). The effects of a supervised exercise training (SET) program on functional performance have yet to be clearly determined. The aim was to investigate the time-course evolution of functional performance during a 3-month SET program.

METHODS

Patients with chronic symptomatic PAD participating in a 3-month SET program were investigated. Six-minute walking distance (6MWD), the stair climbing test (SCT), and the Short Physical Performance Battery (SPPB) were assessed before SET, after the first and second months of SET, and following the SET program. The ankle- and toe-brachial indices were measured before and after the SET program.

RESULTS

Ninety patients with PAD (age 65.4 ± 10.2 years) were analyzed. The 6MWD significantly improved after the first (+7%, p ⩽ 0.001) and second months (+13%, p ⩽ 0.001) and following SET (+14%, p ⩽ 0.001) compared to before the SET program. The 6MWD significantly improved after the 2nd month (+6%, p ⩽ 0.001) and following SET (+7%, p ⩽ 0.001) compared to after the first month of the SET program. The SPPB score and SCT performance significantly improved after the first (SPPB score: +9%, p ⩽ 0.001; SCT: +17%, p ⩽ 0.001) and second months (SPPB score: +11%, p ⩽ 0.001; SCT: +24%, p ⩽ 0.001) and following SET (SPPB score: +12%, p ⩽ 0.001; SCT: +25%, p ⩽ 0.001) compared to before the SET program. No significant differences were observed following SET compared to the second month of the SET program. Vascular parameters did not change significantly.

CONCLUSIONS

A 3-month SET program improves several components of functional performance, and adaptations mainly occur during the 1st and 2nd months of the SET program.

Energizing Mitochondria to Prevent Mobility Loss in Aging: Rationale and Hypotheses

Based on recent studies from our group and others, we hypothesize that mitochondrial dysfunction during aging may be the root cause of mobility decline through deficits in the musculoskeletal and central nervous systems. Mitochondrial dysfunction could be a therapeutic target to prevent mobility decline in aging.

A Narrative Review of Non-Pharmacological Strategies for Managing Sarcopenia in Older Adults with Cardiovascular and Metabolic Diseases

This narrative review examines the mechanisms underlying the development of cardiovascular disease (CVD) and metabolic diseases (MDs), along with their association with sarcopenia. Furthermore, non-pharmacological interventions to address sarcopenia in patients with these conditions are suggested. The significance of combined training in managing metabolic disease and secondary sarcopenia in type II diabetes mellitus is emphasized. Additionally, the potential benefits of resistance and aerobic training are explored. This review emphasises the role of nutrition in addressing sarcopenia in patients with CVD or MDs, focusing on strategies such as optimising protein intake, promoting plant-based protein sources, incorporating antioxidant-rich foods and omega-3 fatty acids and ensuring sufficient vitamin D levels. Moreover, the potential benefits of targeting gut microbiota through probiotics and prebiotic fibres in sarcopenic individuals are considered. Multidisciplinary approaches that integrate behavioural science are explored to enhance the uptake and sustainability of behaviour-based sarcopenia interventions. Future research should prioritise high-quality randomized controlled trials to refine exercise and nutritional interventions and investigate the incorporation of behavioural science into routine practices. Ultimately, a comprehensive and multifaceted approach is essential to improve health outcomes, well-being and quality of life in older adults with sarcopenia and coexisting cardiovascular and metabolic diseases.

Sit to Stand Muscle Power Is Related to Functional Performance at Baseline and After Supervised Exercise Training in Patients with Lower Extremity Peripheral Artery Disease

OBJECTIVE

Patients with peripheral artery disease (PAD) have decreased muscle power, contributing to functional limitations. The sit to stand (STS) is a validated test to assess muscle power in older individuals; however, it has never been investigated in patients with PAD. The relationship between STS muscle power, and common disease related outcomes was evaluated at baseline and following supervised exercise training (SET) in patients with PAD.

METHODS

This observational study investigated patients with Fontaine stage II. Before and after SET, maximum treadmill walking distance (MWD), functional performance tests (six minute walk, STS, stair climbing, habitual gait speed), and quality of life (Short Form 36 questionnaire) were assessed. Relative (W/kg) STS muscle power was calculated using a validated equation. Multiple regressions models were used.

RESULTS

Ninety-five patients with PAD were included (63.1 ± 12.1 years, 67% male). Relative STS muscle power before: 2.7 W/kg, 95% confidence interval [CI] 2.5 - 2.9; after: 3.3, 95% CI 3.1 - 3.6, MWD before: 367.0 m, 95% CI 302.4 - 431.5; after: 598.4, 95% CI 515.6 - 681.3, six minute walking distance before: 418.3 metres; 95% CI 399.4 - 437.2; after: 468.8; 95% CI 452.7-484.9, stair climbing performance before: 6.8 seconds 95% CI 6.2 - 7.4); after: 5.3; 95% CI 4.9 - 5.7, habitual gait speed before: 1.10 m/s, 95% CI 1.05 - 1.14; after: 1.18, 95% CI 1.14 - 1.22 increased significantly following SET (p < .001). Similarly, physical before: 31.4, 95% CI 29.4 - 33.3; after: 35.8, 95% CI 33.9 - 37.7 and mental before: 39.5, 95% CI 37.0 - 42.0; after: 43.1, 95% CI 40.9 - 45.4 component summaries of the SF-36 also increased significantly (p < .001). Greater relative STS muscle power at baseline was significantly related to greater baseline treadmill (β < .380; p < .002) and functional (β < .597; p < .001) performance, and quality of life (β < .291; p < .050). Larger increases in relative STS muscle power following SET were associated with greater improvements in functional performance (β < .419; p < .009).

CONCLUSION

The STS test is a valid clinical tool to monitor overall functional status in patients with symptomatic PAD.

The effect of resistance training on functional capacity in middle-aged to elderly individuals with peripheral artery disease: a meta-analysis

INTRODUCTION

Peripheral artery disease (PAD) is an ischemic disease of the lower limbs, caused by atherosclerotic plaques, leading to impairments in functional capacity and reduced quality of life. This meta-analysis aimed to assess the effect of 12-week and 24-week resistance training (RT) interventions on 6-minute walking distance (6WMD) and initial claudication distance (ICD) measured during a 6-minute walk test (6MWT).

EVIDENCE ACQUISITION

A meta-analysis was conducted in accordance with PRISMA guidelines, with an electronic search conducted using the online database of PUBMED. Methodological quality of all included studies was completed using a modified version of the Newcastle Ottawa Scale (NOS). The effect sizes (ES) of 6MWD and ICD were calculated, with the 12-week and 24-week interventions analyzed separately.

EVIDENCE SYNTHESIS

An initial literature search yielded 1973 results that were consequently reduced to 7 studies to be included in the final meta-analysis. The pooled effect size for 6MWD for 12-week and 24-week interventions was ES=0.189 [95% CI: -0.074 to 0.451] P=0.159 and ES=0.298 [95% CI: -0.036 to 0.631] P=0.080 respectively. For ICD, ES=0.498 [95% CI: 0.000 to 0.995] P=0.050 and ES: 1.106 [95% CI: 0.120 to 0.428] P=0.001 respectively.

CONCLUSIONS

Short-term RT interventions have a positive effect on functional capacity in middle-aged to elderly individuals with PAD. There was a greater effect on ICD compared to 6MWD, with 24-week interventions showing larger effects for both measures. Improvements in functional capacity in such populations confers significant potential for positive health outcomes.

Associations of Lower Extremity Peripheral Nerve Impairment and Risk of Dementia in Black and White Older Adults

BACKGROUND AND OBJECTIVES

Peripheral nerve impairments and dementia are common among older adults and share risk factors. However, few studies have examined whether peripheral nerve function and dementia are associated. We evaluated whether lower extremity peripheral nerve impairments were associated with higher incidence of dementia and whether associations differed by comorbidity subgroups (diabetes, low vitamin B12, and APOE ε4 allele carriers).

METHODS

We studied Black and White Health, Aging, and Body Composition Study participants 70 to 79 years of age and without dementia at enrollment. Lower extremity sensory and motor peripheral nerve function was measured at year 4 (the analytic baseline of this study). Sensory nerve impairments were measured with monofilament (1.4 g, 10 g) and vibration threshold of the toe. Monofilament insensitivity was defined as unable to detect monofilament (3 of 4 touches), and vibration detection impairment was defined as >130 μm. Fibular motor impairments were defined as <1 mV compound motor action potential (CMAP) amplitude and slow nerve conduction velocity <40 m/s. Incident dementia over the following 11 years was determined from medical records, cognitive scores, and medications. Cox proportional hazard models adjusted for demographics and health conditions assessed associations of nerve impairments with incident dementia.

RESULTS

Among 2,174 participants (52% women, 35% Black), 45% could not detect monofilament 1.4 g, 9% could not detect monofilament 10 g, 6% could not feel vibration, 10% had low CMAP amplitude, and 24% had slow conduction velocity. Monofilament 10 g (hazard ratio [HR] 1.35, 95% CI 0.99-1.84) and vibration detection insensitivity (HR 1.73, 95% CI 1.24-2.40) were associated/borderline associated with a higher risk of dementia after covariate adjustment. Estimates were elevated but not significant for monofilament 1.4 g, CMAP amplitude, and conduction velocity (p > 0.05). Increasing number of peripheral nerve impairments was associated with higher risk of dementia in a graded fashion; for ≥3 impairments, the HR was 2.37 (95% CI 1.29-4.38). In subgroup analyses, effect estimates were generally higher among those with diabetes, low vitamin B12, and APOE ε4 allele except for vibration detection.

DISCUSSION

Peripheral nerve impairments, especially sensory, were associated with a higher risk of dementia even after adjustment for age and other health factors. These associations may represent a shared susceptibility to nervous system degeneration.

Supervised physical activity in patients with symptomatic peripheral arterial disease: protocol for a randomized clinical trial (ARTPERfit Study)

INTRODUCTION

Peripheral arterial disease (PAD) is a marker of cardiovascular morbidity, causing disability, loss of mobility and poor quality of life, manifesting clinically in the form of intermittent claudication (IC). Physical exercise increases the distance walked and improves quality of life. The aim of our study will be increased walking distance prolonging the time of onset of pain in patients with symptomatic PAD (IC).

METHODS AND ANALYSIS

This study will be performed in Mataró Hospital's vascular surgery service and School of Health Sciences, TecnoCampus. This population comes from 15 primary healthcare centres ofNorth Barcelona, Spain (450 000 inhabitants).This study will be a four-group parallel, longitudinal, randomised controlled trial, blind to analysis.The main primary outcome of this study will be the improvement in pain-free walking distance. Others primary objectives are and improvement in functional status, quality of life and Ankle-Brachial Index (ABI). Secondary outcomes will be the analysis of cardiorespiratory fitness, evaluation of muscle fitness, determine the maintenance of primary objectives at 6 and 12 months.We will be included 124 patients (31 per group). The changes of the outcome (Barthel, SF-12, VascQOL-6, ABI) of the three intervention groups vs the control group at 3, 6 and 12 months will be compared, both continuously (linear regression) and categorically (logistic regression). A person who has not performed at least 75% of the training will be considered to have not completed the intervention.

ETHICS AND DISSEMINATION

The study will be conducted according to the Declaration of Helsinki . It was approved by the Ethics Committee of the Research Institute Primary Health IDIAP Jordi Gol (20/035 P),Barcelona 6 October 2020. Informed consent will be obtained from all patients before the start of the study. We will disseminate results through academic papers and conference presentations.

TRIAL REGISTRATION NUMBER

NCT04578990.

Examination of Changes in 6-minute Walk Distance and Related Factors in Patients with Perioperative Peripheral Arterial Disease

OBJECTIVE

This study aimed to clarify the effects of pre- and postoperative physical function on the 6-minute walking distance (6MWD) in patients with peripheral arterial disease (PAD).

METHOD

Forty-two elderly patients with PAD who were hospitalized for revascularization and able to walk independently were included in the study. The 6MWD, ankle brachial index (ABI), weight-bearing index (WBI), gait, and intermittent claudication distance (ICD) were measured before and after the surgery, and skeletal muscle index was measured only before surgery. Analyses were performed by comparing the pre- and postoperative values of each factor using a paired t-test. In addition, multiple regression analysis was performed with 6MWD as the dependent variable before and after surgery.

RESULTS

Postoperatively, pain disappeared in 22 patients, and ABI, ICD, 6MWD, and stride length improved significantly. ICD and stride length were extracted as factors related to 6MWD before and after surgery, and ABI, WBI, and stride length were extracted as factors related to 6MWD after surgery.

CONCLUSION

The improvement of intermittent claudication associated with revascularization suggests a stronger influence of functional aspects on postoperative 6MWD.

Ankle-Brachial Index Is a Good Determinant of Lower Limb Muscular Strength but Not of the Gait Pattern in PAD Patients

The aim of this study was to evaluate the relationship of the ankle-brachial index (ABI) level with kinetic and kinematic parameters of the gait pattern and force-velocity parameters generated by lower limb muscles. Methods: The study group consisted of 65 patients with peripheral arterial disease (PAD). The ABI value, kinetic and kinematic parameters of gait and force-velocity parameters of knee and ankle extensors and flexors were determined in all subjects. The values obtained for right and left limbs as well as the limbs with higher and lower ABI were compared. Results: Regardless of the method of analysis, the values of the gait’s kinematic and kinetic parameters of both lower limbs did not differ significantly. However, significant differences were noted in the values of peak torque, work and power of the extensor muscles of the knee and the flexor muscles of the ankle with the higher and lower ABI. Conclusion: This study demonstrated that a higher degree of ischemia worsened the level of strength, endurance, and performance of ankle flexors and extensors of the knee joint. ABI is not related to the gait pattern. The above-mentioned relationship should be taken into account in the rehabilitation process and methodological assessment.

Diffusion tensor imaging indices of acute muscle damage are augmented after exercise in peripheral arterial disease

PURPOSE

Although it is known that peripheral arterial disease (PAD) is associated with chronic myopathies, the acute muscular responses to exercise in this population are less clear. This study used diffusion tensor imaging (DTI) to compare acute exercise-related muscle damage between PAD patients and healthy controls.

METHODS

Eight PAD patients and seven healthy controls performed graded plantar flexion in the bore of a 3T MRI scanner. Exercise began at 2 kg and increased by 2 kg every 2 min until failure, or completion of 10 min of exercise. DTI images were acquired from the lower leg pre- and post-exercise, and were analyzed for mean diffusivity, fractional anisotropy (FA), and eigenvalues 1-3 (λ1-3) of the medial gastrocnemius (MG) and tibialis anterior (TA).

RESULTS

Results indicated a significant leg by time interaction for mean diffusivity, explained by a significantly greater increase in diffusivity of the MG in the most affected legs of PAD patients (11.1 × 10-4 ± 0.5 × 10-4 mm2/s vs. 12.7 × 10-4 ± 1.2 × 10-4 mm2/s at pre and post, respectively, P = 0.02) compared to healthy control subjects (10.8 × 10-4 ± 0.3 × 10-4 mm2/s vs. 11.2 × 10-4 ± 0.5 × 10-4 mm2/s at pre and post, respectively, P = 1.0). No significant differences were observed for the TA, or λ1-3 (all P ≥ 0.06). Moreover, no reciprocal changes were observed for FA in either group (all P ≥ 0.29).

CONCLUSION

These data suggest that calf muscle diffusivity increases more in PAD patients compared to controls after exercise. These findings are consistent with the notion that acute exercise results in increased muscle damage in PAD.

The Association Between Diabetes Mellitus and Risk of Sarcopenia: Accumulated Evidences From Observational Studies

AIM

We performed a meta-analysis of observational studies to evaluate the association between the presence of sarcopenia and HbA1c, prediabetes, diabetes and diabetic complications.

METHOD

The PubMed, Embase, Cochrane and Web of Science databases were searched from inception to May 2021. We included full-text English language articles that reported the prevalence of sarcopenia in patients with and without diabetes. Quality assessment was performed according to the Newcastle- Ottawa scale for observational studies.

RESULTS

Sixteen studies were included in the meta-analysis. Three studies showed that high HbA1c levels lead to loss of muscle mass, and one study involving prediabetes showed that people with prediabetes had lower muscle mass, strength, and performance than non-diabetic population. Seven studies showed that people with diabetes had a higher risk of sarcopenia than those without diabetes (combined OR: 2.09, 95% CI:1.62-2.70). The remaining five studies suggested that diabetic complications increased the risk of sarcopenia (combined OR: 2.09,95% CI:1.62-2.70).

CONCLUSION

High HbA1c levels, prediabetes, diabetes and diabetes complications were associated with an increased risk of sarcopenia. Therapeutic strategies addressed to avoid the conversion of IGT to diabetes and to optimize glycemic control are warranted to prevent or arrest sarcopenia in the diabetic population.

Myostatin as a Biomarker of Muscle Wasting and other Pathologies-State of the Art and Knowledge Gaps

Sarcopenia is a geriatric syndrome with a significant impact on older patients’ quality of life, morbidity and mortality. Despite the new available criteria, its early diagnosis remains difficult, highlighting the necessity of looking for a valid muscle wasting biomarker. Myostatin, a muscle mass negative regulator, is one of the potential candidates. The aim of this work is to point out various factors affecting the potential of myostatin as a biomarker of muscle wasting. Based on the literature review, we can say that recent studies produced conflicting results and revealed a number of potential confounding factors influencing their use in sarcopenia diagnosing. These factors include physiological variables (such as age, sex and physical activity) as well as a variety of disorders (including heart failure, metabolic syndrome, kidney failure and inflammatory diseases) and differences in laboratory measurement methodology. Our conclusion is that although myostatin alone might not prove to be a feasible biomarker, it could become an important part of a recently proposed panel of muscle wasting biomarkers. However, a thorough understanding of the interrelationship of these markers, as well as establishing a valid measurement methodology for myostatin and revising current research data in the light of new criteria of sarcopenia, is needed.

Sarcopenia Characteristics Are Associated with Incident Mobility Limitations in African Caribbean Men: The Tobago Longitudinal Study of Aging

BACKGROUND

Sarcopenia varies by ethnicity, and has a major impact on health in older adults. However, little is known about sarcopenia characteristics in African ancestry populations outside the United States. We examined sarcopenia characteristics in 2,142 African Caribbean men aged 59.0 ± 10.4 years (range: 40-92 years) in Tobago, and their association with incident mobility limitations in those aged 55+ (n = 738).

METHODS

Body mass index (BMI), grip strength, dual-x-ray absorptiometry (DXA) appendicular lean mass (ALM), and self-reported mobility limitations were measured at baseline, and 6 years later. Change in sarcopenia characteristics, including grip strength, grip strength/BMI, ALMBMI, and ALM/ht2, were determined. Foundations for the National Institutes of Health Sarcopenia Project (FNIH) and European Working Group for Sarcopenia in Older People 2 (EWGSOP2) cut-points were also examined. Odds ratios (OR) and 95% confidence intervals (CI) for mobility limitation were calculated using multivariable linear regression models adjusted for covariates.

RESULTS

Overall, sarcopenia prevalence was quite low using the FNIH (0.3%) and EWGSOP2 (0.6%) operational cut-points, but was higher in those aged 75+ (2.1% [FNIH] and 3.7% [EWGSOP2]). Prevalence was also higher when based on "weakness", versus "low ALM." When sarcopenia markers were examined separately, baseline levels, but not changes, were associated with incident mobility limitations. Baseline grip strength/BMI was a particularly strong risk factor for incident mobility limitations (OR per SD: 0.50; 95% CI: 0.37-0.68).

CONCLUSIONS

Our findings suggest that grip strength normalized to body mass, measured at one time point, may be a particularly useful phenotype for identifying African Caribbean men at risk for future mobility limitations.

Chronic kidney disease and peripheral nerve function in the Health, Aging and Body Composition Study

BACKGROUND

Chronic kidney disease (CKD) is associated with poor mobility. Peripheral nerve function alterations play a significant role in low mobility. We tested the hypothesis that early CKD is associated with altered sensory, motor and autonomic nerve function.

METHODS

Participants in the Health, Aging and Body Composition cohort who had kidney function measures in Year 3 (1999-2000) and nerve function measurements at Year 4 (2000-01) were analyzed (n = 2290). Sensory (vibration threshold, monofilament insensitivity to light and standard touch), motor [compound motor action potentials (CMAPs), nerve conduction velocities (NCVs)] and autonomic (heart rate response and recovery after a 400-m walk test) nerve function as well as participant characteristics were compared across cystatin C- and creatinine-based estimated glomerular filtration rate categorized as ≤60 (CKD) or >60 mL/min/1.73 m2 (non-CKD). The association between CKD and nerve function was examined with logistic regression adjusted for covariates.

RESULTS

Participants with CKD (n = 476) were older (77 ± 3 versus 75 ± 3 years; P < 0.05) and had a higher prevalence of diabetes (20.6% versus 13.1%; P < 0.001). CKD was associated with higher odds for vibration detection threshold {odds ratio [OR] 1.7 [95% confidence interval (CI) 1.1-2.7]} and light touch insensitivity [OR 1.4 (95% CI 1.1-1.7)]. CMAPs and NCVs were not significantly different between CKD and non-CKD patients. In adjusted analyses, participants with CKD had higher odds of an abnormal heart rate response [OR 1.6 (95% CI 1.1-2.2)] and poor heart rate recovery [OR 1.5 (95% CI 1.1-2.0)].

CONCLUSIONS

CKD is associated with changes in sensory and autonomic nerve function, even after adjustment for demographics and comorbidities, including diabetes. Longitudinal studies in CKD are needed to determine the contribution of nerve impairments to clinically important outcomes.

Sleep duration and sarcopenia risk: a systematic review and dose-response meta-analysis

PURPOSE

Present systematic literature review and dose-response meta-analysis were carried out to evaluate the association between sleep duration and sarcopenia risk.

METHODS

Related studies were found by searching ISI Web of science databases, Scopus, and PubMed, up to May, 2019. Data were available from four studies. A total odds ratio of 17551 participants in these studies was pooled for the current study.

RESULTS

Pooled outcomes from random effects model demonstrated that lowest category of sleep duration (under 6 h) versus reference category (6-8 h) was significantly related with increased risk of sarcopenia (OR: 1.71 95% CI, 1.11, 2.64). Pooled OR also indicated that highest category (more than 8 h) of sleep duration versus reference category (6-8 h) was significantly associated with increased risk of sarcopenia (OR: 1.52 95% CI, 1.23, 1.88). Moreover, subgroup analysis by sex showed that women were affected by both short and long sleep while men were only affected by long sleep duration. The nonlinear dose-response meta-analysis revealed a U-shaped association between sleep duration and the risk of sarcopenia, with a nadir at 8 h per day. The linear dose-response meta-analysis illustrated that the risk of sarcopenia did not change significantly nor for a 0.5-h increment neither for 1-h increment in sleep duration per day.

CONCLUSION

The outcomes from this meta-analysis indicate that the public should be made aware of the negative consequences of long and short sleep for sarcopenia especially among women. Further studies should now be undertaken to establish possible links between risk of sarcopenia and sleep duration.

Associations between severe co-morbidity and muscle measures in advanced non-small cell lung cancer patients

BACKGROUND

Studies show that low skeletal muscle index (SMI) and low skeletal muscle density (SMD) are negative prognostic factors and associated with more toxicity from systemic therapy in cancer patients. However, muscle depletion can be caused by a range of diseases, and many cancer patients have significant co-morbidity. The aim of this study was to investigate whether there were associations between co-morbidity and muscle measures in patients with advanced non-small cell lung cancer.

METHODS

Patients in a Phase III trial comparing two chemotherapy regimens in advanced non-small cell lung cancer were analysed (n = 436). Co-morbidity was assessed using the Cumulative Illness Rating Scale for Geriatrics (CIRS-G), which rates co-morbidity from 0 to 4 on 14 different organ scales. Severe co-morbidity was defined as having any grades 3 and 4 CIRS-G score. Muscle measures were assessed from baseline computed tomography slides at the L3 level using the SliceOMatic software.

RESULTS

Complete data were available for 263 patients (60%). Median age was 66, 57.0% were men, 78.7% had performance status 0-1, 25.9% Stage IIIB, 11.4% appetite loss, 92.4% were current/former smokers, 22.8% were underweight, 43.7% had normal weight, 26.6% were overweight, and 6.8% obese. The median total CIRS-G score was 7 (range: 0-16), and 48.2% had severe co-morbidity. Mean SMI was 44.7 cm² /m² (range: 27-71), and the mean SMD was 37.3 Hounsfield units (HU) (range: 16-60). When comparing patients with and without severe co-morbidity, there were no significant differences in median SMI (44.5 vs. 44.1 cm² /m² ; 0.70), but patients with severe co-morbidity had a significantly lower median SMD (36 HU vs. 39 HU; 0.001), mainly due to a significant difference in SMD between those with severe heart disease and those without (32.5 vs. 37.9 HU; 0.002). Linear regression analyses confirmed the association between severe co-morbidity and SMD both in the simple analysis (0.001) and the multiple analysis (0.037) adjusting for baseline characteristics. Stage of disease, gender, and body mass index (BMI) were significantly associated with SMI in both the simple and multiple analyses. Age and BMI were significantly associated with SMD in the simple analysis; and age, gender, and BMI were significantly associated in the multiple analysis.

CONCLUSIONS

There were no significant differences in SMI between patients with and patients without severe co-morbidity, but patients with severe co-morbidity had lower SMD than other patients, mainly due to severe heart disease. Co-morbidity might be a confounder in studies of the clinical role of SMD in cancer patients.

Influence of Mild Peripheral Arterial Obstructive Disease in the Functional Capacity

AbstractThe peripheral arterial obstructive disease (PAOD) is a chronic illnes that has as main symptom intermittent claudication and causes a progressive functional impairment of the patient. The literature is still inconclusive when it addresses the relationship among functional capacity, endurance, muscle contraction speed, and degree of blood flow impairment in patients with PAOD. The objective of this study was to evaluate the physical fitness individuals with bilateral PAOD, claudication and ankle-brachial index between 0.8 and 0.9, to verify the impact of the disease in this outcome and to analyze the association among the tests. Forty individuals, with mean age 56 years were divided in: group PAOD (n=20) and control group (n=20) were subjected to the following tests: Five-Times-Sit-to-Stand Test (FTSST), Heel-rise test (HRT), test of gait speed usual (UV) and maximum (MV), shuttle walking test (SWT). There was a significant difference among the variables obtained through HRT, UV, MV and SWT, showing a worse performance of the group with PAOD compared to the control. The FTSST test showed no differences among the groups. Analyzing the whole sample, the presence of PAOD is an indicator of poor performance in TDBP. This study suggests that people with mild PAOD present reduced performance in functional endurance tests of the lower limbs and that there is a direct relationship between walking speed and patency of local arterial flow, demonstrating in an unprecedented way the need for evaluation of this public, considering the possibility of initial identification of the symptoms and giving greater efficiency in the therapeutic planning of maintenance of the functionality.Keywords: Physical Fitness. Intermittent Claudication. Peripheral Vascular Diseases.ResumoA doença arterial obstrutiva periférica (DAOP) é uma doença crônica que tem como sintoma principal a claudicação intermitente e causa um progressivo comprometimento funcional do paciente. A literatura ainda é inconclusiva quando aborda a relação entre a capacidade funcional, endurance, velocidade de contração muscular e grau de comprometimento de fluxo sanguíneo em pacientes com DAOP. O objetivo deste estudo foi avaliar a aptidão física de indivíduos com DAOP bilateral, claudicantes e Índice tornozelo-braço entre 0,8 e 0,9, verificar o impacto da doença neste desfecho e analisar a associação entre os testes. Quarenta indivíduos, com faixa etária média de 56 anos, divididos em grupo DAOP (n=20) e grupo controle (n=20), foram submetidos aos testes: Teste senta-levanta (TSL), teste ponta de pé (TPP), testes de velocidade usual (VU) e máxima (VM), teste de deslocamento bidirecional progressivo (TDBP). Houve diferença significativa entre as variáveis do TPP, VU, VM e TDBP, mostrando pior performance do grupo com DAOP comparado ao controle. O teste TSL não apresentou diferença entre os grupos. Analisando os grupos em conjunto a presença de DAOP foi indicadora de pior desempenho no TDBP. Este estudo sugere que pacientes com DAOP leve apresentam redução da performance nos testes funcionais de endurance dos membros inferiores e que existe uma relação direta entre a velocidade da marcha e a patência do fluxo arterial local, demonstrando de forma inédita, a necessidade de avaliação deste público, considerando a possibilidade de identificação inicial dos sintomas e conferindo maior eficiência no planejamento terapêutico de manutenção da funcionalidade.Palavras-chave: Aptidão Física. Claudicação Intermitente. Doenças Vasculares Periféricas.

Associations of Weight Change With Changes in Calf Muscle Characteristics and Functional Decline in Peripheral Artery Disease

Background

Among people with lower extremity peripheral artery disease, obesity is associated with faster functional decline than normal weight. The association of weight loss with functional decline in peripheral artery disease is unknown.

Methods and Results

Adults with an ankle‐brachial index <0.90 were identified from Chicago‐area hospitals in 2002–2004. Weight and 6‐minute walk distance were measured annually. Weight change categories were weight loss or gain (≥5 pounds/year at ≥1 visit) or stable (weight change <5 pounds at each visit). Participants reported whether weight loss was “intentional” or “unintentional.” Calf muscle area was measured with computed tomography every 2 years. Associations of weight change with changes in calf muscle area and 6‐minute walk distance were analyzed using mixed‐effects models and adjusted for age, body mass index, ankle‐brachial index, physical activity, and other confounders. Among 389 participants, mean ankle‐brachial index was 0.63±0.16, mean age was 74.5±7.8, and mean body mass index was 28.1±5.1 kg/m². Over 3.23±1.37 years, muscle area declined more in adults with intentional weight loss versus stable or gain (pair‐wise comparisons, P<0.001). Intentional weight loss was associated with less annual decline in 6‐minute walk distance than weight gain (intentional loss, 3.7 m; stable, –14.0 m; gain, −28.5 m; unintentional loss, −20.8 m; pair‐wise comparison intentional loss versus gain, P=0.003).

Conclusions

Despite a greater loss of calf muscle area, adults with peripheral artery disease who intentionally lost ≥5 pounds experienced less functional decline than those who gained weight. A randomized trial is needed to establish whether benefits of weight loss in peripheral artery disease outweigh potential adverse effects.

See Editorial Kokkinidis et al

Associations of pre-existing co-morbidities with skeletal muscle mass and radiodensity in patients with non-metastatic colorectal cancer

BACKGROUND AND AIM

Co-morbidities and computerized tomography-measured muscle abnormalities are both common in cancer patients and independently adversely influence clinical outcomes. Muscle abnormalities are also evident in other diseases, such as diabetes and obesity. This study examined for the first time the association between co-morbidities and muscle abnormalities in patients diagnosed with colorectal cancer (CRC).

METHODS

This cross-sectional study included 3051 non-metastatic patients with Stages I-III CRC. Muscle abnormalities, measured at diagnosis, were defined as low skeletal muscle mass index (SMI) or low skeletal muscle radiodensity (SMD) quantified using computerized tomography images using optimal stratification. Co-morbidities included in the Charlson index were ascertained. χ2 tests were used to compare the prevalence of co-morbidities by the presence or absence of each muscle abnormality. Logistic regressions were performed to evaluate which co-morbidities predicted muscle abnormalities adjusting for age, sex, body mass index, weight change, cancer stage, cancer site, race/ethnicity, and smoking.

RESULTS

Mean age was 63 years; 50% of patients were male. The prevalence of low SMI and low SMD were 43.1% and 30.2%, respectively. Co-morbidities examined were more prevalent in patients with low SMD than in those with normal SMD, and most remained independent predictors of low SMD after adjustment for covariates. Co-morbidities associated with higher odds of low SMD included myocardial infarction [odds ratio (OR) = 1.77, P = 0.023], congestive heart failure (OR = 3.27, P < 0.001), peripheral vascular disease (OR = 2.15, P = 0.002), diabetes with or without complications (OR = 1.61, P = 0.008; OR = 1.46, P = 0.003, respectively), and renal disease (OR = 2.21, P < 0.001). By contrast, only diabetes with complications was associated with lower odds of low SMI (OR = 0.64, P = 0.007).

CONCLUSIONS

Prevalence of muscle abnormalities was high in patients with non-metastatic CRC. Pre-existing co-morbidities were associated with low SMD, suggestive of a potential shared mechanism between fat infiltration into muscle and each of these co-morbidities.

Gait Mechanics Differences Between Healthy Controls and Patients With Peripheral Artery Disease After Adjusting for Gait Velocity Stride Length and Step Width

Patients with peripheral artery disease (PAD) experience significant leg dysfunction. The effects of PAD on gait include shortened steps, slower walking velocity, and altered gait kinematics and kinetics, which may confound joint torques and power measurements.

Spatiotemporal parameters, joint torques and powers were calculated and compared between 20 patients with PAD and 20 healthy controls using independent t-tests. Separate ANCOVA models were used to evaluate group differences after independently adjusting for gait velocity, stride length and step width. Compared to healthy controls, patients with PAD exhibited reduced peak extensor and flexor torques at the knee, and hip. After adjusting for all covariates combined, differences between groups remained for ankle power generation in late stance, and knee flexor torque. Reduced walking velocity observed in subjects affected by PAD was closely connected with reductions in joint torques and powers during gait. Gait differences remained, at the knee and ankle, after adjusting for the combined effect of spatiotemporal parameters. Improving muscle function through exercise or with the use of assistive devices needs to be a key tool in the development of interventions that aim to enhance the ability of PAD patients to restore spatiotemporal gait parameters.

A systematic review of muscle morphology and function in intermittent claudication

OBJECTIVE

Intermittent claudication (IC) is frequently associated with deterioration in walking capacity and physical function, and it can often result in an impairment in balance. Whereas supervised exercise is recommended by the National Institute for Health and Care Excellence as the first-line treatment, the mechanism behind walking improvement is poorly understood. The existing literature suggests that there may be some physiologic change to the skeletal muscle contributing to the functional impairment, but these data are conflicting. We therefore sought to undertake a systematic review to clarify the muscle properties of patients with IC.

METHODS

A systematic review of randomized and nonrandomized trials that investigated the role of muscle function in patients diagnosed with IC was undertaken using MEDLINE, Cochrane Central Register of Controlled Trials, and Embase databases. The searches were limited from 1947 to June 2016 in the English language.

RESULTS

The search yielded a total of 506 articles, of which 206 were duplicate articles. Of the remaining 300, a total of 201 were excluded from full-text analysis; 99 full-text articles were assessed for eligibility, with 30 articles deemed appropriate for inclusion in the review. There were four main categories of functional outcome measures: muscle strength, muscle size, muscle fiber type, and muscle metabolism. A total of 2837 patients were included in the study. Nine studies reported on muscle strength, incorporating isometric, concentric, eccentric, and endurance measures. Eight studies reported on muscle size, incorporating circumference, computed tomography scans, and ultrasound imaging techniques. Eleven studies reported on muscle fibers, incorporating fiber type proportions, fiber size, and capillarity measures. Seven papers reported on muscle metabolism, incorporating adenosine diphosphate recovery and phosphocreatine recovery measures.

CONCLUSIONS

Previous literature has found clear evidence that strength (of the calf and thigh musculature) and calf characteristics are related to mortality and functional declines. However, this review has demonstrated the vast array of muscle groups assessed and multiple methods employed to determine strength; therefore, it is unclear exactly what measure of "strength" is impaired. Furthermore, the underlying morphologic causes of potential changes in strength are unclear. This information is essential for designing optimal exercise interventions. The data acquired during this systematic review are heterogeneous, with a substantial lack of high-quality intervention-based studies. Future research should endeavor to establish standardized testing procedures and to implement randomized controlled trials for targeted therapeutic interventions.

Relationship between sensorimotor peripheral nerve function and indicators of cardiovascular autonomic function in older adults from the Health, Aging and Body Composition Study

BACKGROUND

Age-related peripheral nervous system (PNS) impairments are highly prevalent in older adults. Although sensorimotor and cardiovascular autonomic function have been shown to be related in persons with diabetes, the nature of the relationship in general community-dwelling older adult populations is unknown.

METHODS

Health, Aging and Body Composition participants (n=2399, age=76.5±2.9years, 52% women, 38% black) underwent peripheral nerve testing at the 2000/01 clinic visit. Nerve conduction amplitude and velocity were measured at the peroneal motor nerve. Sensory nerve function was assessed with vibration detection threshold and monofilament (1.4-g/10-g) testing at the big toe. Symptoms of lower-extremity peripheral neuropathy were collected by self-report. Cardiovascular autonomic function indicators included postural hypotension, resting heart rate (HR), as well as HR response to and recovery from submaximal exercise testing (400m walk). Multivariable modeling adjusted for demographic/lifestyle factors, medication use and comorbid conditions.

RESULTS

In fully adjusted models, poor motor nerve conduction velocity (<40m/s) was associated with greater odds of postural hypotension, (OR=1.6, 95% CI: 1.0-2.5), while poor motor amplitude (<1mV) was associated with 2.3beats/min (p=0.003) higher resting HR. No associations were observed between sensory nerve function or symptoms of peripheral neuropathy and indicators of cardiovascular autonomic function.

CONCLUSIONS

Motor nerve function and indicators of cardiovascular autonomic function remained significantly related even after considering many potentially shared risk factors. Future studies should investigate common underlying processes for developing multiple PNS impairments in older adults.

Characteristics of physical activity in patients with critical limb ischemia

[Purpose] The purpose of this study was to evaluate the amount of physical activity of the patients with critical limb ischemia consecutively in order to clarify the characteristics of physical activity of critical limb ischemia. [Subjects and Methods] Twelve patients who were eligible for the 2 months of consecutive evaluation of the amount of physical activity were enrolled in the study (men: 11; woman: 1; mean age: 64.4 [range: 44-80]). A pedometer with an accelerometer was used for the measurement of the number of steps walked as an index of the amount of physical activity. Participants were asked to lead a regular life and no instruction was given as to the number of steps. [Results] The average number of daily steps walked was 2,323 steps (range: 404-6,505). There was no clear tendency in the number of amputation site-specific steps walked. There was also no correlation between the number of steps walked and age as well as the maximum strength of the knee-extension muscle, skin perfusion pressure of the sole and the dorsum, and QOL scores. [Conclusion] The number of steps walked of the patients with critical limb ischemia was remarkably low and no significant association with health-related QOL.

Muscle dysfunction in type 2 diabetes: a major threat to patient's mobility and independence

Type 2 diabetes, a common metabolic disease in older people, is a major risk factor for functional limitation, impaired mobility, and loss of independence. In older people, the pathogenesis of functional limitation and disability is complex and multifactorial. A number of potential pathways are involved including cardiovascular disease, peripheral neuropathy, overweight, osteoarthritis, visual deficit, and cognitive impairment, conditions that are all more prevalent among patients with diabetes. Sarcopenia, a geriatric condition characterized by a progressive and generalized loss of skeletal muscle mass and strength, is also involved in the pathogenesis of functional limitations and disability. Recent research has shown that older patients with type 2 diabetes are often affected by skeletal muscle impairment, leading to reduced muscle strength and physical function. Insulin resistance, hyperglycemia, muscle fat infiltration, and peripheral neuropathies are hypothesized as the fundamental biological mechanisms leading to muscle impairment in people with diabetes. This review summarizes the current literature on the biological pathways responsible for skeletal muscle dysfunction in type 2 diabetes and analyzes the role of decline in muscle strength and quality on the association between diabetes and mobility disability.

Alterations in gait parameters with peripheral artery disease: The importance of pre-frailty as a confounding variable

Although poor walking is the most common symptom of peripheral artery disease (PAD), reported results are inconsistent when comparing gait parameters between PAD patients and healthy controls. This inconsistency may be due to frailty, which is highly prevalent among PAD patients. To address this hypothesis, 41 participants, 17 PAD (74±8 years) and 24 aged-matched controls (76±7 years), were recruited. Gait was objectively assessed using validated wearable sensors. Analysis of covariate (ANCOVA) tests were used to compare gait parameters between PAD and non-PAD groups, considering age, gender, and body mass index as covariates, while stratified based on frailty status. According to the Fried frailty index, 47% of PAD and 50% of control participants were non-frail and the rest were classified as pre-frail. Within non-frail participants, gait speed, body sway during walking, stride length, gait cycle time, double-support, knee range of motion, speed variability, mid-swing speed, and gait initiation were significantly different between PAD and control groups (effect size d = 0.75±0.43). In the pre-frail group, however, most of the gait differences were diminished except for gait initiation and gait variability. Results suggest that gait initiation is the most sensitive parameter for detecting gait impairment in PAD participants when compared to controls, regardless of frailty status (d = 1.30-1.41; p<0.050). The observed interaction effect between frailty and PAD on gait parameters confirms the importance of assessing functionality in addition to age to provide more consistency in detecting motor performance impairments due to PAD.

Sensorimotor Peripheral Nerve Function and Physical Activity in Older Men

We determined whether sensorimotor peripheral nerve (PN) function was associated with physical activity (PA) in older men. The Osteoporotic Fractures in Men Study Pittsburgh, PA, site (n = 328, age 78.8 ± 4.7 years) conducted PN testing, including: peroneal motor and sural sensory nerve conduction (latencies, amplitudes: CMAP and SNAP for motor and sensory amplitude, respectively), 1.4g/10g monofilament (dorsum of the great toe), and neuropathy symptoms. ANOVA and multivariate linear regression modeled PN associations with PA (Physical Activity Scale for the Elderly [PASE] and SenseWear Armband). After multivariable adjustment, better motor latency was associated with higher PASE scores (160.5 ± 4.8 vs. 135.6 ± 6.7, p < .01). Those without versus with neuropathy symptoms had higher PASE scores (157.6 ± 5.3 vs. 132.9 ± 7.1, p < .01). Better versus worse SNAP was associated with slightly more daily vigorous activity (9.5 ± 0.8 vs. 7.3 ± 0.7, p = .05). Other PN measures were not associated with PA. Certain PN measures were associated with lower PA, suggesting a potential pathway for disability.

Sensorimotor Peripheral Nerve Function and the Longitudinal Relationship With Endurance Walking in the Health, Aging and Body Composition Study

OBJECTIVES

To determine whether lower extremity sensorimotor peripheral nerve deficits are associated with reduced walking endurance in older adults.

DESIGN

Prospective cohort study with 6 years of follow-up.

SETTING

Two university research clinics.

PARTICIPANTS

Community-dwelling older adults enrolled in the Health, Aging and Body Composition Study from the 2000-2001 annual clinical examination (N=2393; mean age ± SD, 76.5±2.9y; 48.2% men; 38.2% black) and a subset with longitudinal data (n=1178).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Participants underwent peripheral nerve function examination in 2000-2001, including peroneal motor nerve conduction amplitude and velocity, vibration perception threshold, and monofilament testing. Symptoms of lower extremity peripheral neuropathy included numbness or tingling and sudden stabbing, burning, pain, or aches in the feet or legs. The Long Distance Corridor Walk (LDCW) (400 m) was administered in 2000-2001 and every 2 years afterward for 6 years to assess endurance walking performance over time.

RESULTS

In separate, fully adjusted linear mixed models, poor vibration threshold (>130 μm), 10-g and 1.4-g monofilament insensitivity were each associated with a slower 400-m walk completion time (16.0 s, 14.4s, and 6.9 s slower, respectively; P<.05 for each). Poor motor amplitude (<1 mV), poor vibration perception threshold, and 10-g monofilament insensitivity were related to greater slowing per year (4.7, 4.2, and 3.8 additional seconds per year, respectively; P<.05), although poor motor amplitude was not associated with initial completion time.

CONCLUSIONS

Poorer sensorimotor peripheral nerve function is related to slower endurance walking and greater slowing longitudinally. Interventions to reduce the burden of sensorimotor peripheral nerve function impairments should be considered to help older adults maintain walking endurance-a critical component for remaining independent in the community.

Avaliação da saturação tecidual de oxigênio durante o sintoma claudicante em pacientes com doença arterial periférica

Resumo Contexto O relato de sintoma claudicante em pacientes com doença arterial periférica é utilizado como modulador da intensidade de exercício físico para o tratamento clínico, entretanto os valores de oxigenação tecidual nesse momento são desconhecidos. Objetivo Descrever o suprimento tecidual de oxigênio por meio da espectroscopia de luz próxima ao infravermelho ou Near-Infrared Spectroscopy (NIRS) nos momentos em que o paciente relata sintoma claudicante inicial e máximo em testes de exercício. Métodos Nove pacientes, oito homens com 65,63 ± 6,02 anos de idade, previamente diagnosticados com doença arterial periférica, realizaram teste de exercício de carga constante e de carga incremental com monitorização do nível de oxigenação tecidual através da NIRS. As saturações de oxigênio obtidas no momento em que o paciente relata sintoma claudicante inicial e no momento em que relata sintoma claudicante máximo foram comparadas com os valores de saturação da manobra de oclusão arterial por meio do intervalo de confiança de 95% da diferença. Resultados Verificou-se que os valores de saturação nos momentos de sintoma claudicante inicial e máximo são estatisticamente distintos quando comparados àqueles obtidos na manobra de oclusão arterial, entretanto, através da análise percentual do quão distante esses valores encontram-se é possível observar que, do ponto de vista clínico, eles estão próximos. Conclusões A saturação no momento em que o paciente relata sintomas claudicantes inicial e máximo é bastante próxima do valor de saturação no momento de oclusão e do ponto de vista clínico o relato subjetivo de sintoma do paciente é adequado como parâmetro para a prescrição do exercício físico.

Spectral improvement by fourier thresholding of in vivo dynamic spectroscopy data

PURPOSE

MR spectroscopy (MRS) typically requires averaging of multiple acquisitions to achieve adequate signal-to-noise ratio (SNR). In systems undergoing dynamic changes this can compromise the temporal resolution of the measurement. One such example is (31) P MRS of exercising skeletal muscle. Spectral improvement by Fourier thresholding (SIFT) offers a way of suppressing noise without averaging. In this study, we evaluate the performance of SIFT in healthy subjects and clinical cases.

METHODS

(31) P MRS of the calf or thigh muscle of subjects (n = 12) was measured continuously before, during, and after exercise. The data were processed conventionally and with the addition of SIFT before quantifying peak amplitudes and frequencies. The postexercise increase in the amplitude of phosphocreatine was also characterized by fitting with an exponential function to obtain the recovery time constant.

RESULTS

Substantial reductions in the uncertainty of peak fitting for phosphocreatine (73%) and inorganic phosphate (60%) were observed when using SIFT relative to conventional processing alone. SIFT also reduced the phosphocreatine recovery time constant uncertainty by 38%.

CONCLUSION

SIFT considerably improves SNR, which improved quantification and parameter estimation. It is suitable for any type of time varying MRS and is both straightforward and fast to apply. Magn Reson Med 76:978-985, 2016. © 2015 Wiley Periodicals, Inc.

A review of the relationship between leg power and selected chronic disease in older adults

OBJECTIVE

This review investigates the relationship between leg muscle power and the chronic conditions of osteoarthritis, diabetes mellitus, and cardiovascular disease among older adults. Current literature assessing the impact of chronic disease on leg power has not yet been comprehensively characterized. Importantly, individuals with these conditions have shown improved leg power with training.

METHODS

A search was performed using PubMed to identify original studies published in English from January 1998 to August 2013. Leg power studies, among older adults ≥ 50 years of age, which assessed associations with osteoarthritis, diabetes mellitus, and/or cardiovascular disease were selected. Studies concerning post-surgery rehabilitation, case studies, and articles that did not measure primary results were excluded.

RESULTS

Sixteen studies met inclusion criteria, addressing osteoarthritis (n=5), diabetes mellitus (n=5), and cardiovascular disease (n=6). Studies generally supported associations of lower leg power among older adults with chronic disease, although small sample sizes, cross-sectional data, homogenous populations, varied disease definitions, and inconsistent leg power methods limited conclusions.

CONCLUSIONS

Studies suggest that osteoarthritis, diabetes mellitus, and cardiovascular disease are associated with lower leg power compared to older adults without these conditions. These studies are limited, however, by the heterogeneity in study populations and a lack of standardized measurements of leg power. Future larger studies of more diverse older adults with well-defined chronic disease using standard measures of leg power and interventions to improve leg power in these older adults with chronic disease are needed.

Poor lower extremity function was associated with pre-diabetes and diabetes in older chinese people

OBJECTIVE

To determine whether a relationship exists between performance-based physical assessments and pre-diabetes/diabetes in an older Chinese population.

METHODS

Our study population comprised 976 subjects (mean ± SD age: 67.6±6.0 years; 44.5% men) from the Hangu area of Tianjin, China. Diabetes was defined by self-reporting of a physician's diagnosis, or a fasting plasma glucose level ≥126 mg/dL; and pre-diabetes was defined as a fasting plasma glucose level ≥100 mg/dL and <126 mg/dL.

RESULTS

When all other variables were adjusted for, men needing longer to finish a Timed Up and Go Test and a decreased usual walking speed had higher odds of pre-diabetes (P for trend = 0.007 and 0.008, respectively) and diabetes (P for trend = 0.012 and 0.014, respectively). However, women needing longer to finish the test and a decreased usual walking speed had a higher odds of diabetes (P for trend = 0.020 and 0.034, respectively) but not of pre-diabetes. There was no apparent association between grip strength and pre-diabetes/diabetes in both sexes.

CONCLUSIONS

In this study, poor lower extremity function was associated with pre-diabetes/diabetes in older people.

Age-related and disease-related muscle loss: the effect of diabetes, obesity, and other diseases

The term sarcopenia refers to the loss of muscle mass that occurs with ageing. On the basis of study results showing that muscle mass is only moderately related to functional outcomes, international working groups have proposed that loss of muscle strength or physical function should also be included in the definition. Irrespective of how sarcopenia is defined, both low muscle mass and poor muscle strength are clearly highly prevalent and important risk factors for disability and potentially mortality in individuals as they age. Many chronic diseases, in addition to ageing, could also accelerate decrease of muscle mass and strength, and this effect could be a main underlying mechanism by which chronic diseases cause physical disability. In this Review, we address both age-related and disease-related muscle loss, with a focus on diabetes and obesity but including other disease states, and potential common mechanisms and treatments. Development of treatments for age-related and disease-related muscle loss might improve active life expectancy in older people, and lead to substantial health-care savings and improved quality of life.

Neurological and electrophysiological parameters as outcome measurements for peripheral arterial occlusive disease

BACKGROUND

Ischemic monomelic neuropathy is not an uncommon complication of peripheral arterial occlusive disease (PAOD). However, many investigators have used revascularization, limb salvage, and complete wound healing rates instead of neurologic and electrophysiological parameters as outcome measurements of PAOD. The aim of the study is to investigate the neurologic and electrophysiological parameters associated with PAOD and to find the ideal tools for assessing PAOD.

METHODS

A total of 38 PAOD patients (68.5 ± 8.1 years old, male:female = 32:6) with a total of 76 lower limbs were enrolled in the study. Primary outcomes were neurological symptoms scores (NSSs) and neurological impairment scores (NISs) for the lower extremities. Secondary outcomes were taken from nerve conduction studies (NCSs) and included the following: sensory nerve action potential (SNAP) amplitudes of the sural, superficial peroneal, and medial plantar nerves and the compound muscle action potential (CMAP) amplitudes of the posterior tibial and common peroneal nerves.

RESULTS

Female patients with old age, hypertension, low body weights, low body mass indices (BMIs), decreased ankle-brachial indices (ABIs), and poorer Fontaine classifications exhibited worse NSSs and NISs indices. Patients with old age, diabetes mellitus, hypertension, histories of social alcohol consumption, low body weights, low BMIs, and poorer Fontaine classifications exhibited decreased SNAP and CMAP amplitudes in the sensory and motor NCSs. Decreased ABI was associated with decreased SNAP amplitudes in the sensory NCSs.

CONCLUSIONS

Neurologic and electrophysiological parameters can be good tools for the assessment of PAOD. NSSs and NISs are particularly good candidates for outcome measures of PAOD.

Peripheral vascular insufficiency impairs functional capacity in patients with heart failure

INTRODUCTION: Heart failure (HF) is a complex syndrome in which effort limitation is associated with deterioration of peripheral musculature. Improving survival rates among these patients have led to the appearance of cases in which other pathologies are associated with HF, such as peripheral vascular insufficiency (PVI). The combination of these two pathologies is common, with significant repercussions for affected patients. OBJECTIVE: To compare functional limitations and quality of life between patients with HF in isolation or HF + PVI. METHOD: Twelve patients with HF+PVI were paired to 12 patients with HF in isolation. All had ejection fraction <40%. The following were conducted: 6 minute walk test (6MWT), chair test (CT), step test (ST), one repetition maximum test (1RM) and quality of life questionnaire. RESULTS: The results for the 6MWT (311±27 vs. 447±29), ST (49±3 vs. 81±10) and CT (17±1 vs. 21±1) were lower in the HF+PVI group than in the HF group (p<0.05). The HF+PVI group exhibited a reduction in the number of steps taken from the first to the second minute of the ST, in relation to the HF group. The HF group exhibited better HR recovery than the HF+PVI group (50±4 vs. 26±3; p<0.05). No differences were found in results for the Borg scale, the peripheral muscle strength test (1RM) or the questionnaires (p>0.05). CONCLUSIONS: The study participants who had mixed disease exhibited a greater degree of functional impairment than the group with HF, without reporting worsened quality of life.

A group-mediated, home-based physical activity intervention for patients with peripheral artery disease: effects on social and psychological function

BACKGROUND

PAD is a disabling, chronic condition of the lower extremities that affects approximately 8 million people in the United States. The purpose of this study was to determine whether an innovative home-based walking exercise program for patients with peripheral artery disease (PAD) improves self-efficacy for walking, desire for physical competence, satisfaction for physical functioning, social functioning, and acceptance of PAD related pain and discomfort.

METHODS

The design was a 6-month randomized controlled clinical trial of 194 patients with PAD. Participants were randomized to 1 of 2 parallel groups: a home-based group-mediated cognitive behavioral walking intervention or an attention control condition.

RESULTS

Of the 194 participants randomized, 178 completed the baseline and 6-month follow-up visit. The mean age was 70.66 (±9.44) and was equally represented by men and women. Close to half of the cohort was African American. Following 6-months of treatment, the intervention group experienced greater improvement on self-efficacy (p = .0008), satisfaction with functioning (p = .0003), pain acceptance (p = .0002), and social functioning (p = .0008) than the control group; the effects were consistent across a number of potential moderating variables. Change in these outcomes was essentially independent of change in 6-minute walk performance.

TRIAL REGISTRATION

[ClinicalTrials.gov Identifier: NCT00693940].

Sarcopenia and nutrition

Preserving or restoring adequate nutritional status is a key factor to delay the onset of chronic diseases and to accelerate recovery from acute illnesses. In particular, consistent and robust data show the loss of muscle mass, that is, sarcopenia, is clinically relevant since it is closely related to increased morbidity and mortality in healthy individuals and patients. Sarcopenia is defined as the age-related loss of muscle mass and function. International study groups have recently proposed separate definitions and diagnostic criteria for sarcopenia. Unfortunately, the rate of agreement in assessing the prevalence of sarcopenia is just fair, which highlights the need for a common effort to harmonize definitions and diagnostic criteria. Sarcopenia should be distinct from myopenia, which is the disease-associated loss of muscle mass, although in clinical practice it may be impossible to separate them (i.e., in old cancer patients). The pathogenesis of sarcopenia is complex and multifactorial. Consequently, its treatment should target the different factors involved, including quantitatively and qualitatively inappropriate food intake and reduced physical activity.

Development and validation of an ankle brachial index risk model for the prediction of cardiovascular events

BACKGROUND

The ankle brachial index (ABI) is related to risk of cardiovascular events independent of the Framingham risk score (FRS). The aim of this study was to develop and evaluate a risk model for cardiovascular events incorporating the ABI and FRS.

DESIGN

An analysis of participant data from 18 cohorts in which 24,375 men and 20,377 women free of coronary heart disease had ABI measured and were followed up for events.

METHODS

Subjects were divided into a development and internal validation dataset and an external validation dataset. Two models, comprising FRS and FRS + ABI, were fitted for the primary outcome of major coronary events.

RESULTS

In predicting events in the external validation dataset, C-index for the FRS was 0.672 (95% CI 0.599 to 0.737) in men and 0.578 (95% CI 0.492 to 0.661) in women. The FRS + ABI led to a small increase in C-index in men to 0.685 (95% CI 0.612 to 0.749) and large increase in women to 0.690 (95% CI 0.605 to 0.764) with net reclassification improvement (NRI) of 4.3% (95% CI 0.0 to 7.6%, p = 0.050) and 9.6% (95% CI 6.1 to 16.4%, p < 0.001), respectively. Restricting the FRS + ABI model to those with FRS intermediate 10-year risk of 10 to 19% resulted in higher NRI of 15.9% (95% CI 6.1 to 20.6%, p < 0.001) in men and 23.3% (95% CI 13.8 to 62.5%, p = 0.002) in women. However, incorporating ABI in an improved newly fitted risk factor model had a nonsignificant effect: NRI 2.0% (95% CI 2.3 to 4.2%, p = 0.567) in men and 1.1% (95% CI 1.9 to 4.0%, p = 0.483) in women.

CONCLUSIONS

An ABI risk model may improve prediction especially in individuals at intermediate risk and when performance of the base risk factor model is modest.

Physical disability in the elderly with diabetes: epidemiology and mechanisms

Diabetes mellitus is a common chronic condition worldwide, especially in the elderly population. Several epidemiologic studies in the last 2 years have consistently associated diabetes with physical disability, a condition that may profoundly affect the quality of life of older people. Although in older people with diabetes, the pathogenesis of functional limitation and disability has not been completely elucidated, it is certainly complex and involves multiple potential pathways. In this narrative review, we described the most recent epidemiologic and clinical evidence supporting the association between diabetes and impaired physical function in older persons focusing on emerging biological mechanisms explaining the excess risk of disability associated with diabetes.

Null association between abdominal muscle and calcified atherosclerosis in community-living persons without clinical cardiovascular disease: the multi-ethnic study of atherosclerosis

OBJECTIVE

Lean muscle loss has been hypothesized to explain J-shaped relationships of body mass index (BMI) with cardiovascular disease (CVD), yet associations of muscle mass with CVD are largely unknown. We hypothesized that low abdominal lean muscle area would be associated with greater calcified atherosclerosis, independent of other CVD risk factors.

MATERIALS/METHODS

We investigated 1020 participants from the Multi-Ethnic Study of Atherosclerosis who were free of clinical CVD. Computed tomography (CT) scans at the 4th and 5th lumbar disk space were used to estimate abdominal lean muscle area. Chest and abdominal CT scans were used to assess coronary artery calcification(CAC), thoracic aortic calcification (TAC), and abdominal aortic calcification (AAC).

RESULTS

The mean age was 64±10 years, 48% were female, and mean BMI was 28±5 kg/m2. In models adjusted for demographics, physical activity, caloric intake, and traditional CVD risk factors, there was no inverse association of abdominal muscle mass with CAC (prevalence ratio [PR] 1.02 [95% CI 0.95,1.10]), TAC (PR 1.13 [95% CI 0.92, 1.39]) or AAC (PR 0.99 [95% CI 0.94, 1.04]) prevalence. Similarly, there was no significant inverse relationship between abdominal lean muscle area and CAC, TAC, and AAC severity.

CONCLUSION

In community-living individuals without clinical CVD, greater abdominal lean muscle area is not associated with less calcified atherosclerosis.

Preliminary evidence that low ankle-brachial index is associated with reduced bilateral hip extensor strength and functional mobility in peripheral arterial disease

OBJECTIVE

Peripheral arterial disease (PAD) has been associated with skeletal muscle pathology, including atrophy of the affected muscles. In addition, oxidative metabolism is impaired, muscle function is reduced, and gait and mobility are restricted. We hypothesized that greater severity of symptomatic PAD would be associated with lower levels of muscle mass, strength, and endurance, and that these musculoskeletal abnormalities in turn would impair functional performance and walking ability in patients with PAD.

METHODS

We assessed 22 persons with intermittent claudication from PAD in this cross-sectional pilot study. Outcome assessments included initial claudication distance and absolute claudication distance via treadmill protocols and outcomes from the 6-minute walk (6MW). Secondary outcomes included one repetition maximum strength/endurance testing of hip extensors, hip abductors, quadriceps, hamstrings, plantar flexors, pectoral, and upper back muscle groups, as well as performance-based tests of function. Univariate and stepwise multiple regression models were constructed to evaluate relationships and are presented.

RESULTS

Twenty-two participants (63.6% male; mean [standard deviation] age, 73.6 [8.2] years; range, 55-85 years) were studied. Mean (standard deviation) resting ankle-brachial index (ABI) was 0.54 ([0.13]; range, 0.28-0.82), and participants ranged from having mild claudication to rest pain. Lower resting ABI was significantly associated with reduced bilateral hip extensor strength (r = 0.54; P = .007) and reduced whole body strength (r = 0.32; P = .05). In addition, lower ABI was associated with a shorter distance to first stop during the 6MW (r = 0.38; P = .05) and poorer single leg balance (r = 0.44; P = .03). Reduced bilateral hip extensor strength was also significantly associated with functional outcomes, including reduced 6MW distance to first stop (r = 0.74; P = .001), reduced 6MW distance (r = 0.75; P < .001), and reduced total short physical performance battery score (worse function; r = 0.75; P = .003).

CONCLUSIONS

Our results suggest the existence of a causal pathway from a reduction in ABI to muscle atrophy and weakness, to whole body disability represented by claudication outcomes and performance-based tests of functional mobility in an older cohort with symptomatic PAD. Longitudinal outcomes from this study and future trials are required to investigate the effects of an anabolic intervention targeting the muscles involved in mobility and activities of daily living and whether an increase in muscle strength will improve symptoms of claudication and lead to improvements in other functional outcomes in patients with PAD.

Fibular motor nerve conduction studies and ankle sensorimotor capacities

INTRODUCTION

Nerve conduction studies provide information regarding the status of peripheral nerves, but relationships with sensorimotor capacities that influence mobility have not been defined.

METHODS

A secondary analysis was conducted on data from 41 older subjects (20 women and 21 men, age 69.1 ± 8.3 years), including 25 with diabetic neuropathy of varying severity and 16 without diabetes or neuropathy. Measurements included routine fibular motor nerve conduction studies and laboratory-based determination of ankle inversion/eversion proprioceptive thresholds and ankle inversion/eversion motor function.

RESULTS

Independent of age, fibular amplitude correlated robustly with ankle inversion/eversion proprioceptive thresholds (R(2) = 0.591, P < 0.001), moderately with ankle inversion and eversion rates of torque generation (R(2) = 0.216; P = 0.004 and R(2) = 0.200; P = 0.006, respectively), and more strongly when fibular motor amplitude was normalized for body mass index (R(2) = 0.350; P < 0.001 and R(2) = 0.275; P = 0.001).

CONCLUSIONS

Fibular motor amplitude was strongly associated with ankle sensorimotor capacities that influence lateral balance and recovery from perturbations during gait. The results suggest that nerve conduction study measures have potential for an expanded clinical role in evaluating mobility function in the population studied.

Predicting 3-year incident mobility disability in middle-aged and older adults using physical performance tests

OBJECTIVE

To identify a standard physical performance test, which can predict 3-year incident mobility disability independent of demographics.

DESIGN

Longitudinal cohort study.

SETTING

Population-based middle-aged and older adult cohort assessment performed at a local geriatric clinical center.

PARTICIPANTS

Community-living middle-aged and older persons (age, 50-85y) without baseline mobility disability (N=622).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Mobility disability was ascertained at baseline and at 3-year follow-up using an established self-report method: self-reported inability to walk a quarter mile without resting or inability to walk up a flight of stairs unsupported. Physical performance tests included self-selected usual gait speed, time required to complete 5 times sit-to-stand (5TSTS), and 400-m brisk walking. Demographic variables age, sex, height, and weight were recorded.

RESULTS

Overall, 13.5% participants reported 3-year incident mobility disability. Usual gait speed <1.2m/s, requiring >13.6 seconds to complete 5TSTS, and completing 400m at <1.19m/s walking speed were highly predictive of future mobility disability independent of demographics.

CONCLUSIONS

Inability to complete 5TSTS in <13.7 seconds can be a clinically convenient guideline for monitoring and for further assessment of middle-aged and older persons, in order to prevent or delay future mobility disability.

Vascular factors predict polyneuropathy in a non-diabetic elderly population

We prospectively examined whether vascular factors are related to an increased incidence of Chronic Idiopathic Distal Symmetric Neuropathy (CI-DSN) in a non-diabetic elderly population. In 8 Italian municipalities, 2,512 men and women without both diabetes and CI-DSN at baseline are examined. Potential effect of vascular factors was estimated by regressing new onset CI-DSN on the occurrence of several vascular diseases and risk factors. Multivariate relative risks of CI-DSN were estimated by Cox proportional hazards models. After 3.8 (±2.4) years of follow-up, we documented 51 incident CI-DSN cases. At univariate analysis, age, comorbidity, waist circumference, leg length, peripheral artery disease, and coronary heart disease proved to increase the risk of developing CI-DSN. By multivariate analyses, only age (RR = 1.08; 95 % CI, 1.02-1.14), leg length (RR = 1.05; 95 % CI, 1.01-1.1) and peripheral artery disease (RR = 2.75; 95 % CI, 1.15-6.56) proved significant predictors of CI-DSN. Separate analyses by gender show that age is an independent predictor of CI-DSN both in men and in women, while PAD predicts the disease only in men, together with body height. Incidence of CI-DSN is higher in individuals carrying vascular conditions. In men, the presence at baseline of peripheral artery disease is associated with a threefold increase in the risk of developing CI-DSN. The incidence of neuropathy in non-diabetic individuals is associated with potentially modifiable vascular factors.

Role of muscle mass and muscle quality in the association between diabetes and gait speed

OBJECTIVE

Older people with type 2 diabetes are at high risk of mobility disability. We investigated the association of diabetes with lower-limb muscle mass and muscle quality to verify whether diabetes-related muscle impairments mediate the association between diabetes and low walking speed.

RESEARCH DESIGN AND METHODS

We performed a cross-sectional analysis of 835 participants (65 years old and older) enrolled in the InCHIANTI (Invecchiare in Chianti, aging in the Chianti area) population-based study. Total, muscular, and fat cross-sectional areas of the calf and relative muscle density were measured using peripheral quantitative computerized tomography. Indicators of muscle performance included knee-extension torque, ankle plantar flexion and dorsiflexion strength, lower-extremity muscle power, and ankle muscle quality (ratio of ankle strength to the muscle area [kilograms per centimeters squared]). Gait performance was assessed by 4- and 400-m walking speed. Diabetes was ascertained by standard American Diabetes Association criteria.

RESULTS

Prevalence of diabetes was 11.4%. After adjustment for age and sex, participants with diabetes had lower muscle density, knee and ankle strength, and muscle power and worse muscle quality (all P < 0.05). Diabetic participants were also slower on both 4-m (β: -0.115 ± 0.024 m/s, P < 0.001) and 400-m (β:-0.053 ± 0.023 m/s, P < 0.05) walking tests. In multivariable linear regression models, lower-limb muscle characteristics accounted for 24.3 and 15.1% of walking speed difference comparing diabetic and nondiabetic subjects in the 4- and 400-m walks, respectively.

CONCLUSIONS

In older persons, diabetes is associated with reduced muscle strength and worse muscle quality. These impairments are important contributors of walking limitations related to diabetes.

Vitamin D status and functional performance in peripheral artery disease

The clinical implications of low vitamin D in peripheral artery disease (PAD) are unknown. We hypothesized that among individuals with PAD, lower levels of 25-hydroxyvitamin D would be associated with poorer functional performance, more adverse calf muscle characteristics, and poorer peripheral nerve function. Participants were 402 men and women with PAD who underwent measurement of 25-hydroxyvitamin D (DiaSorin radioimmunoassay) along with 6-minute walk testing, measurement of walking velocity at usual and fastest pace, computed tomography-measured calf muscle density, and peripheral nerve conduction velocity (NCV). Among PAD participants, 20.4% had 25-hydroxyvitamin D levels < 30 nmol/L, consistent with deficient vitamin D status. Adjusting for age, sex, and race, lower 25-hydroxyvitamin D levels were associated with poorer 6-minute walk performance (p trend = 0.002), slower usual-paced 4-meter walking velocity (p trend = 0.031), slower fast-paced 4-meter walking velocity (p trend = 0.043), and lower calf muscle density (p trend = 0.031). After additional adjustment for body mass index (BMI) and diabetes, none of these associations remained statistically significant. However, lower levels of 25-hydroxyvitamin D were associated with poorer peroneal NCV (p trend = 0.013) and poorer sural NCV (p trend = 0.039), even after adjusting for age, sex, race, BMI, comorbidities, smoking, physical activity, and other confounders. In conclusion, vitamin D deficiency is common among people with PAD encountered in clinical settings. After adjusting for BMI and diabetes mellitus, we found no significant associations of lower levels of 25-hydroxyvitamin D with poorer functional performance or calf muscle characteristics. Associations of low vitamin D levels with poorer peripheral nerve function require further study.