Nicole Stobäus

Hand grip strength: Outcome predictor and marker of nutritional status

BACKGROUND & AIMS Among all muscle function tests, measurement of hand grip strength has gained attention as a simple, non-invasive marker of muscle strength of upper extremities, well suitable for clinical use. This review outlines the prognostic relevance of grip strength in various clinical and epidemiologic settings and investigates its suitability as marker of nutritional status in cross-sectional as well as intervention studies. METHODS Studies investigating grip strength as prognostic marker or nutritional parameter in cross-sectional or intervention studies were summarized. RESULTS AND CONCLUSIONS Numerous clinical and epidemiological studies have shown the predictive potential of hand grip strength regarding short and long-term mortality and morbidity. In patients, impaired grip strength is an indicator of increased postoperative complications, increased length of hospitalization, higher rehospitalisation rate and decreased physical status. In elderly in particular, loss of grip strength implies loss of independence. Epidemiological studies have moreover demonstrated that low grip strength in healthy adults predicts increased risk of functional limitations and disability in higher age as well as all-cause mortality. As muscle function reacts early to nutritional deprivation, hand grip strength has also become a popular marker of nutritional status and is increasingly being employed as outcome variable in nutritional intervention studies.

Bioelectrical phase angle and impedance vector analysis – Clinical relevance and applicability of impedance parameters

BACKGROUND & AIMS The use of phase angle (PhA) and raw parameters of bioelectrical impedance analysis (BIA) has gained attention as alternative to conventional error-prone calculation of body composition in disease. This review investigates the clinical relevance and applicability of PhA and Bioelectrical Impedance Vector Analysis (BIVA) which uses the plot of resistance and reactance normalized per height. METHODS A comprehensive literature search was conducted using Medline identifying studies relevant to this review until March 2011. We included studies on the use of PhA or BIVA derived from tetrapolar BIA in out- and in-patient settings or institutionalized elderly. RESULTS Numerous studies have proven the prognostic impact of PhA regarding mortality or postoperative complications in different clinical settings. BIVA has been shown to provide information about hydration and body cell mass and therefore allows assessment of patients in whom calculation of body composition fails due to altered hydration. Reference values exist for PhA and BIVA facilitating interpretation of data. CONCLUSION PhA, a superior prognostic marker, should be considered as a screening tool for the identification of risk patients with impaired nutritional and functional status, BIVA is recommended for further nutritional assessment and monitoring, in particular when calculation of body composition is not feasible.

Cutoff percentiles of bioelectrical phase angle predict functionality, quality of life, and mortality in patients with cancer

BACKGROUND The bioelectrical phase angle has shown predictive potential in various diseases, but general cutoffs are lacking in the clinical setting. OBJECTIVES This study evaluated the prognostic value of the fifth percentile of sex-, age-, and body mass index-stratified phase angle reference values in patients with cancer with respect to nutritional and functional status, quality of life, and 6-mo mortality. In a second step, we also studied the effect of the standardized phase angle (with a z score to determine individual deviations from the population average) on these variables. DESIGN A total of 399 patients with cancer were studied. Phase angle was obtained with bioelectrical impedance analysis; muscle function was assessed by handgrip strength and peak expiratory flow. Quality of life was determined by the European Organization for Research and Treatment of Cancer questionnaire. Nutritional status was assessed by using Subjective Global Assessment. Survival of patients was documented after 6 mo. RESULTS Patients with a phase angle of less than the fifth reference percentile had significantly lower nutritional and functional status, impaired quality of life (P lt 0.0001), and increased mortality (P lt 0.001). The standardized phase angle emerged as a significant predictor for malnutrition and impaired functional status in generalized linear model regression analyses. It was also a stronger indicator of 6-mo survival than were malnutrition and disease severity in the Cox regression model (P lt 0.0001) and according to the receiver operating characteristic curve. CONCLUSIONS The standardized phase angle is an independent predictor for impaired nutritional and functional status and survival. The fifth phase angle reference percentile is a simple and prognostically relevant cutoff for detection of patients with cancer at risk for these factors.

Determinants of hand grip strength, knee extension strength and functional status in cancer patients

BACKGROUND & AIMS Decreased functionality and muscle weakness are prominent features in cancer patients. We investigated determinants of muscle function assessed by hand grip and knee extension strength as well as functional status in cancer patients. METHODS 189 consecutively admitted cancer patients (age 60.8 ± 12.7 years, 96 male) were recruited. Muscle function was assessed by hand grip and knee extension strength, and percentage of anticipated peak expiratory flow (%PEF). Functional status was determined by the EORTC questionnaire of quality of life. Nutritional status was assessed with Subjective Global Assessment (SGA). Age, gender, SGA, body mass index, clinical variables such as cancer location, presence of distant metastases, tumour burden according to TNM stage, UICC stage, number of drugs per day, number of comorbidities, type of treatment and depression were investigated as potential risk factors for muscle weakness and impaired functional status in a multiple regression analysis. RESULTS 80 patients (39 male) were classified moderately or severely malnourished. Malnutrition also emerged as an independent determinant for hand grip (estimated effect size 11%, p < 0.01), knee extension strength (estimated effect size 12%, p < 0.001), and peak expiratory flow (estimated effect size 30%, p < 0.008) and functional status (estimated effect size 19.4%, p < 0.001) next to age and gender, which were the strongest predictors. Among the disease parameters, only amount of daily medication exhibited a significant influence on knee extension strength. CONCLUSIONS Malnutrition is a disease independent risk factor for reduced muscle strength and functional status in cancer patients. Treatment of malnutrition might therefore also restore muscle strength.

Determinants of bioelectrical phase angle in disease

Phase angle (PhA), a parameter of bioelectrical impedance analysis, is a well-known predictor of morbidity and mortality in various diseases. The causes of decreased PhA are, however, not yet completely understood. We therefore investigated determinants of PhA in 777 hospitalised patients in a retrospective analysis. PhA was assessed by bioelectrical impedance analysis at 50 KHz. Subjective global assessment (SGA) was used to evaluate nutritional status. Age, sex, BMI as well as nutritional status (SGA), benign or malignant disease and C-reactive protein (CRP) were investigated as potential determinants of PhA and standardised PhA (SPhA) = (observed PhA - mean PhA of reference values)/standard deviation of reference values in a general linear model regression analysis. Next to age (estimated effect size, 46·6%; P<0·0001), malnutrition (39·1%; P<0·0001) emerged as a major PhA determinant in our study population. Moreover, sex (6·4%; P<0·0001), CRP (4·4%; P<0·0001) and BMI (3·5%; P < 0·0001) exhibited a significant influence on PhA, whereas malignant disease showed no significant effect in this model. The only significant determinants of SPhA were malnutrition (85·4%; P<0·0001) and inflammation (9·6 %; P<0·0001). In conclusion, next to the established predictors, malnutrition and inflammation have a strong impact on PhA in sick individuals, which partly explains its prognostic power. When investigating the SPhA, only malnutrition and inflammation were found to be significant predictors, as a result of which the SPhA is considered a more suitable indicator of nutritional and health status.

The Bioimpedance Phase Angle Predicts Low Muscle Strength, Impaired Quality of Life, and Increased Mortality in Old Patients With Cancer

OBJECTIVES We investigated the impact of low phase angle (PhA) values on muscle strength, quality of life, symptom severity, and 1-year mortality in older cancer patients. DESIGN Prospective study with 1-year follow-up. PARTICIPANTS Cancer patients aged >60 years. METHODS PhA was derived from whole body impedance analysis. The fifth percentile of age-, sex-, and body mass index-stratified reference values were used as cut-off. Quality of life was determined with the European Organization of Research and Treatment in Cancer questionnaire, reflecting both several function scales and symptom severity. Muscle strength was assessed by hand grip strength, knee extension strength, and peak expiratory flow. RESULTS 433 cancer patients, aged 60-95 years, were recruited. Patients with low PhA (n = 197) exhibited decreased muscle strength compared with patients with normal PhA (hand grip strength: 22 ± 8.6 vs 28.9 ± 8.9 kg, knee extension strength: 20.8 ± 11.8 vs 28.1 ± 14.9 kg, and peak expiratory flow: 301.1 ± 118 vs 401.7 ± 142.6 L/min, P < .001). Physical function, global health status, and role function from the European Organization of Research and Treatment in Cancer questionnaire were reduced, and most symptoms (fatigue, anorexia, pain, and dyspnea) increased in patients with low PhA (P < .001). In a risk-factor adjusted regression analysis, PhA emerged as independent predictor of physical function (ß:-0.538, P = .023), hand grip strength (ß:-4.684, P < .0001), knee extension strength (ß:-4.548, P = .035), and peak expiratory flow (ß:-66.836, P < .0001). Low PhA moreover predicted 1-year mortality in the Cox proportional hazards regression model, whereas grip strength was no longer significant. CONCLUSIONS PhA below the fifth reference percentile is highly predictive of decreased muscle strength, impaired quality of life, and increased mortality in old patients with cancer and should be evaluated in routine assessment.

Effect of inflammation on handgrip strength in the non-critically ill is independent from age, gender and body composition

Background/Objectives:We investigated whether C-reactive protein (CRP) as indicator of acute inflammation is associated with maximal isometric handgrip strength in non-critically ill patients.Subjects/Methods:Handgrip strength was measured with Jamar dynamometer in 620 hospitalized patients (56.4±15.9 years old, 52.3% men). CRP was measured with immunoturbidimetric assay. Fat free mass (FFM) was assessed by bioelectrical impedance analysis. A general linear model regression analysis corrected for confounding variables such as age, sex, FFM, body mass index, comorbidity count and diagnosis category (malignant/benign disease) was performed to test the association between elevated levels of CRP and handgrip strength.Results:CRP was an independent predictor of grip strength (CRP: β-coefficient: −0.169, P=0.018) even after adjustment for relevant confounders. All groups with inflammation showed significant reduction in handgrip strength, corresponding to a loss of ∼1.6 kg in mild inflammation, 3.2 kg in moderate inflammation and 2.9 kg in severe inflammation compared with patients without inflammation.Discussion:Our data demonstrate the independent association between inflammation and handgrip strength in non-critically ill patients. If not corrected, reduced strength may have implications for the patients’ functional status and prognosis. Increasing physical activity and resistance training during convalescence are recommended.

Low Recent Protein Intake Predicts Cancer-Related Fatigue and Increased Mortality in Patients with Advanced Tumor Disease Undergoing Chemotherapy

Cancer patients, in general, suffer from anorexia hence diminished nutritional intake. In a prospective observational study, we investigated the impact of recent energy and protein intake on cancer-related fatigue and 6-month mortality in patients undergoing chemotherapy. Recent protein and energy intake was assessed by 24-h recall in 285 patients. Cancer-related fatigue was determined by Brief Fatigue Inventory, and fat free mass index (FFMI) was assessed with bioelectrical impedance analysis. Symptoms with the validated German version of European Organization for Research and Treatment of Cancer Quality of Life Core Questionnaire (30 questions) and 6-month mortality was documented. Risk factors of cancer-related fatigue and predictors of mortality were investigated with logistic regression analysis and stepwise Cox regression analysis, respectively. Low protein intake (<1 g/kg body weight) was found in 66% of patients, who were characterized by higher age, weight, and body mass index. Recent protein intake emerged as the strongest contributor to cancer-related fatigue followed by nausea/vomiting, insomnia, and age. Reduced protein intake, male sex, number of comorbidities, and FFMI were identified as significant predictors for increased 6-month mortality. In conclusion, a low recent protein intake assessed by 24-h recall is associated with a more than twofold higher risk of cancer-related fatigue and 6-month mortality. Every effort should be taken to assess and guarantee proper nutritional intake in patients undergoing chemotherapy.

Abdominal fat distribution differently affects muscle strength of the upper and lower extremities in women.

Background/Objectives:In obese subjects, reduced muscle mass and strength are associated with impaired functional and metabolic capacity. We therefore investigated the association between abdominal fat distribution, fat mass index and maximum muscle strength of upper and lower extremities in obese patients.Subjects/Methods:One hundred and fifty five outpatients with a body mass index (BMI)⩾30 kg/m2 (105 women; 45.1±14.6 years; BMI 43.5±8.2 kg/m2) were included in the study. Grip and knee extension strength were measured with dynamometers. Using bioelectric impedance analysis, fat-free mass and fat mass indices (FFMI, FMI) were calculated. The influence of age, weight, FFMI, FMI and waist-to-hip ratio (WHR) on grip and knee extension strength was investigated in a risk factor-adjusted regression analysis.Results:BMI did not correlate with hand grip or knee extension strength. The regression model confirmed a positive effect of higher weight on strength parameters; however, increased FMI was shown to have a negative effect on strength in both sexes (women, knee: β: −1.495, confidence interval (CI): −2.075 to −0.0914, P<0.0001; women, hand: β: −0.714, CI: −1.156 to −0.273, P=0.002; men, hand: β:−1.448, CI: −2.618 to −0.278, P=0.016). Although increased WHR positively influenced knee extension strength (β: 24.286, CI: 0.728–47.844, P<0.043), it did not affect grip strength in women. This association was not seen in men.Conclusions:Body fat distribution rather than BMI alone needs to be considered when evaluating strength parameters in obesity. As the relationship between obesity and strength of the upper versus lower extremities differs, grip strength cannot be considered an indicator of whole body strength in obese individuals.

Discrepancy Between Body Surface Area and Body Composition in Cancer

Calculation of cytostatic dose is typically based on body surface area (BSA) regardless of body composition. The aim of this study was to assess the discrepancy between BSA and low fat-free mass (FFM) by investigating the prevalence of low FFM with regard to BSA in 630 cancer patients. First, BSA was calculated according to DuBois and DuBois. Patients were divided into 6 categories with respect to their BSA. Each BSA category was further divided into 3 groups according to FFM: low (<−1 SD of mean FFM), normal (−0.99 and 0.99 SD of mean FFM) or high (>1 SD of mean FFM), which was derived through bioelectric impedance analysis. FFM was reduced in 15.7% of patients, 69% had normal and 15.2% had high FFM. In patients with low FFM (i.e., more than-1 SD lower than the mean FFM within their BSA group), body mass index and fatigue were higher whereas functional status was reduced. Moreover, in the subcohort of patients receiving chemotherapy, absolute FFM [Hazard ratio (HR) = 0.970, P = 0.026] as well as the allocation to the low FFM group (HR = 1.644, P = 0.025) emerged as predictors of increased 1-yr mortality. In conclusion, there was a large discrepancy between FFM and BSA. Particularly women were affected by low FFM.