Limitations of SARC-F as a Screening Tool for Sarcopenia in Patients on Hemodialysis

Diagnostic accuracy of a 'sarcopenia index' based on serum biomarkers creatinine and cystatin C in 458,702 UK Biobank participants

BACKGROUND & AIMS

There is an emerging and urgent need to identify biomarkers of sarcopenia. A novel sarcopenia index (SI), based on serum creatinine and cystatin C, has emerged as a potential biomarker for use. The SI can predict clinical outcomes and discriminate between the presence of sarcopenia in a range of chronic and acute conditions. However, the SI has not yet been tested in a large real-world general population dataset. This study aimed to investigate the accuracy of the SI in the identification of sarcopenia in a large prospective general population cohort.

METHODS

Data were taken from UK Biobank, a large prospective epidemiological study in the United Kingdom (UK). Serum creatinine and cystatin C values were used to calculate the SI [creatinine (mg/dl)/cystatin C (mg/dl) × 100]. Probable sarcopenia was defined by maximum handgrip strength (HGS). Muscle mass was assessed using bioelectrical impedance analysis. Low muscle mass was defined as an appendicular lean mass (ALM) index below prespecified thresholds. Confirmed sarcopenia was defined as both low HGS and low muscle mass. Pearson correlation coefficients and logistic regression were used to explore the association between various sarcopenia traits (probable sarcopenia, low ALM index, and confirmed sarcopenia) and the SI. The diagnostic value of the SI was investigated using the area under the receiver operating characteristic curve (area under the curve, AUC).

RESULTS

458,702 participants were included in the analysis (46.4% males, mean age, males: 68.7 (±8.2) years; females: 68.2 (±8.0) years)). Probable sarcopenia was observed in 4.5% of males and 6.1% of females; low ALM index in 2.8% of males and 0.7% of females; confirmed sarcopenia in 0.3% of males and 0.1% of females. SI was significantly lower in individuals with confirmed sarcopenia (males: 86.3 ± 16.6 vs. 99.5 ± 15.3, p < .01; females: 73.6 ± 13.7 vs. 84.6 ± 14.0, p < .01). For every 1-unit increase in the SI, the odds of confirmed sarcopenia were reduced by 5% in males (odds ratio (OR): 0.95, p < 0.001) and 7% in females (OR: 0.923, p < 0.001). The AUC showed acceptable discriminative ability of confirmed sarcopenia (males: AUC = 0.731; females: AUC = 0.711).

CONCLUSIONS

Using a large real-world dataset of almost half a million people, our study indicated the SI has acceptable diagnostic accuracy when identifying those with sarcopenia and may be a useful biomarker to aid the stratification of those at risk and in need of intervention.

Comparative evaluation of screening tools for sarcopenia in patients with axial spondyloarthritis

Sarcopenia is linked to chronic inflammation and muscle wasting. This research aims to compare the screening accuracy of tools for sarcopenia in axial spondyloarthritis (axSpA). A cross-sectional study involving 104 axSpA patients was conducted at Phramongkutklao Hospital between January 2020 and February 2021. Sarcopenia was diagnosed according to the AWGS 2019 criteria. Appendicular skeletal muscle mass was measured using DXA. SARC-F, SARC-CalF, and SARC-F+EBM, muscle strength, and physical performance were assessed. The screening tests were evaluated using ROC curves. The optimal cutoffs were identified with the Youden index. Most patients were male (74%), with a mean (SD) age and disease duration of 42.6 (12.22) and 8.3 (8.5), respectively. The prevalence of sarcopenia was 22.1%. The AUCs (95% CI) for calf circumference, SARC-F, SARC-CalF, SARC-F+EBM, handgrip strength, chair stand time, gait speed, and time and go test were 0.830 (0.734, 0.925), 0.509 (0.373-0.645), 0.782 (0.670-0.894), 0.856 (0.758-0.954), 0.710 (0.594-0.825), 0.640 (0.508-0.772), 0.689 (0.539-0.839), and 0.711 (0.576-0.846), respectively. The optimal cutoffs for SARC-F, SARC-CalF, and SARC-F+EBM were 1, 10, and 10, with sensitivity/specificity of 81.0%/29.7%, 90.5%/68.9%, and 77.3%/87.2%, respectively. Calf circumference, SARC-CalF, and SARC-F+EBM had the best performance to screen for sarcopenia in axSpA patients. Lowering the thresholds would potentially enhance the performances of SARC-CalF and SARC-F+EBM.

The 10-Item Physical Function Scale as a Sarcopenia Screening Tool for Patients on Hemodialysis

OBJECTIVE

We investigated the accuracy of the 10-item Physical Function (PF-10) questions of the SF-36 quality of life questionnaire as a sarcopenia screening tool among patients on hemodialysis.

METHODS

A cross-sectional, multicenter study that included adult patients on hemodialysis. The revised European Working Group on Sarcopenia in Older People was used to diagnose sarcopenia. The 10 questions about daily activities from the SF-36 quality of life questionnaire were used to appoint the PF-10, where the final score could range from 10 to 30, and the lower the worse the physical function. The PF-10 accuracy to identify confirmed sarcopenia (low muscle strength + low muscle mass) was assessed through a receiver operating characteristic curve and the cutoff was calculated using the Youden index.

RESULTS

One hundred eighty-five patients were included (median 59 years; 45% female). Prevalence of confirmed sarcopenia was 31.4%. The median PF-10 score was 23 (interquartile range: 17-27) and a significant association with all sarcopenia measurements was found (all P < .05). The best cutoff calculated from the receiver operating characteristic curve was ≤26 points (area under the curve = 0.69, 95% confidence interval 0.61-0.77) with sensitivity and specificity of 96.6% and 71.0%, respectively. Moreover, patients with ≤26 points (n = 133, 72%) had a higher prevalence of low muscle strength by handgrip (53 vs. 19%; P < .001) and 5-time sit-to-stand (41 vs. 10%; P < .001), low gait speed (44 vs. 19%; P = .002), confirmed sarcopenia (39 vs. 11%; P < .001), and severe sarcopenia (26 vs. 4%; P = .001), but not low muscle mass (49 vs. 35%; P = .08), in comparison with those >26 points (n = 52, 28%).

CONCLUSION

The PF-10 may be a useful physical dysfunction and sarcopenia screening tool in patients on hemodialysis. A PF-10 threshold of around 26 points appeared to display the fairest accuracy for diagnosing sarcopenia.

The significance of SARC-F scores in predicting postoperative outcomes of older adults undergoing elective major surgery for urologic cancer

BACKGROUND & AIMS

Recently, the strength, assistance with walking, rise from a chair, climb stairs, and falls (SARC-F) questionnaire has been developed to screen patients with signs of sarcopenia. However, its clinical benefit remains uncertain in elderly patients undergoing elective major surgeries. This study aimed to explore the role of the SARC-F questionnaire as a screening tool for patients who plan to undergo elective major surgery for urologic cancer and to also evaluate correlations of SARC-F scores with established indicators of sarcopenia.

METHODS

This retrospective observational study enrolled 815 patients over 40 years of age undergoing elective major surgery for urologic cancer and who were screened with the SARC-F questionnaire, preoperatively. The primary endpoint was an association between SARC-F scores and postoperative ambulation failure. Here we define postoperative ambulation failure as a condition where a patient is unable to walk independently within 2 days after surgery and required physical rehabilitation or was transferred to other hospitals in a bedridden state. The secondary endpoint was an association between SARC-F scores and overall survival (OS). Psoas muscle density (PMD) and psoas muscle index (PMI) were calculated from abdominal computed tomography images, and their correlations with SARC-F scores grouped by sex.

RESULTS

Of the 815 patients, 738 (91%) were male and the median age was 72 years. Although SARC-F scores weakly correlated with PMD in males and moderately correlated in females (ρ = -0.222 and ρ = -0.474, respectively), their correlation with PMI was negligible (ρ = -0.179 and ρ = -0.084, respectively). SARC-F scores successfully discriminate postoperative ambulation failure in both males and females with the respective area under the receiver operating characteristic curve of 0.856 and 0.813. Multivariate analysis also showed that SARC-F scores greater than 4 are an independent risk factor of postoperative ambulation failure along with older age, lower PMD, and poor performance status. SARC-F scores greater than 4 were significantly associated with a shorter OS in the whole cohort (P < 0.001) and a subgroup of patients undergoing radical cystectomy (P = 0.03; median follow-up of 515 days).

CONCLUSIONS

The SARC-F questionnaire might be applicable to identify elderly patients at a higher risk of unfavourable outcomes after major urologic cancer surgery. A randomised controlled trial is necessary to confirm this finding.

Design and methodology of the SARCopenia trajectories and associations with adverse clinical outcomes in patients on HemoDialysis: the SARC-HD study

BACKGROUND

Sarcopenia has been associated with adverse outcomes in patients with chronic kidney disease (CKD), particularly in those undergoing hemodialysis (HD). However, the trajectories across sarcopenia stages, their determinants, and associations with adverse clinical outcomes have yet to be comprehensively examined.

METHODS

The SARC-HD is a multicenter, observational prospective cohort study designed to comprehensively investigate sarcopenia in patients on HD. Eligibility criteria include adult patients undergoing HD for ≥ 3 months. The primary objective is to investigate the trajectories of sarcopenia stages and their potential determinants. Secondary objectives include evaluating the association between sarcopenia and adverse clinical outcomes (i.e., falls, hospitalization, and mortality). Sarcopenia risk will be assessed by the SARC-F and SARC-CalF questionnaire. Sarcopenia traits (i.e., low muscle strength, low muscle mass, and low physical performance) will be defined according to the revised European Working Group on Sarcopenia in Older People and will be assessed at baseline and after 12 follow-up months. Patients will be followed-up at 3 monthly intervals for adverse clinical outcomes during 24 months.

DISCUSSION

Collectively, we expect to provide relevant clinical findings for healthcare professionals from nephrology on the association between sarcopenia screening tools (i.e., SARC-F and SARC-CalF) with objective sarcopenia measurements, as well as to investigate predictors of trajectories across sarcopenia stages, and the impact of sarcopenia on adverse clinical outcomes. Hence, our ambition is that the data acquired from SARC-HD study will provide novel and valuable evidence to support an adequate screening and management of sarcopenia in patients on HD.

Validity of the SARC-F questionnaire in assessing sarcopenia in patients with chronic kidney disease: a cross-sectional study

Objective

To examine the validity of the 5-component SARC-F questionnaire for screening sarcopenia among patients with chronic kidney disease (CKD).

Methods

Eligible participants were enrolled from the Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine from March 2019 to November 2019. Evaluations were performed using the self-administered SARC-F questionnaire. Sarcopenia was diagnosed by grip strength, the chair stand test and appendicular skeletal muscle mass. The severity of sarcopenia was evaluated by gait speed. We calculated the sensitivity and specificity of the SARC-F to evaluate construct validity. Moreover, receiver operating characteristic (ROC) curve analysis was performed to identify the cutoff value for nondialysis-dependent (NDD) CKD patients' and maintenance hemodialysis (MHD) patients' scores.

Results

A total of 105 NDD-CKD patients and 125 MHD patients were included, and the prevalence of sarcopenia was 5.7 and 31.2%, respectively. Among them, there were 21 (16.8%) MHD patients with severe sarcopenia but no NDD-CKD patients with severe sarcopenia. The sensitivity and specificity of the SARC-F were 16.7 and 98.0% for NDD-CKD patients, and 48.7 and 89.5% for MHD patients, respectively. For NDD-CKD patients, the area under the receiver operating characteristic curve (AUROC) of the total SARC-F score was 0.978 (95% confidence interval (CI): 0.929-0.997, p < 0.001), and the cutoff value of 1 reached the highest Youden index of 0.950 and max ROC curve area of 0.974. For MHD patients, the AUROC of the total SARC-F score was 0.730 (95% CI: 0.644-0.806, p < 0.001), and the cutoff value of 4 reached the highest Youden index of 0.383 and max ROC curve area of 0.691.

Conclusion

CKD patients, especially MHD patients, were at high risk of suffering sarcopenia. The SARC-F had low-to-moderate sensitivity but high specificity for screening sarcopenia among patients with CKD. The best cutoff values of the SARC-F score were different for screening sarcopenia among NDD-CKD and MHD patients.

Simplified discriminant parameters for sarcopenia among patients undergoing haemodialysis

BACKGROUND

Patients with end-stage renal disease (ESRD) are at an increased risk of developing sarcopenia, which can lead to various adverse health outcomes. Although the diagnosis of sarcopenia is essential for clinical management, it is not feasible in routine clinical practice for populations undergoing haemodialysis because it is time-consuming and resources are limited. Serum creatinine levels in patients with ESRD have been gaining attention as a screening parameter for sarcopenia because serum creatinine is a routinely measured byproduct of skeletal muscle metabolism. This study aimed to evaluate the discriminative ability of the creatinine-derived index for sarcopenia in patients undergoing haemodialysis.

METHODS

We diagnosed sarcopenia according to the Asian Working Group for Sarcopenia (AWGS) 2 criteria in 356 clinically stable outpatients with ESRD enrolled from three dialysis facilities. We adopted the modified creatinine index as a simplified discriminant parameter for sarcopenia in addition to the calf circumference, SARC-F score, and combination of both (i.e. SARC-CalF score), which are recommended by the AWGS. Receiver operating characteristic analysis and logistic regression analysis were conducted to evaluate the discriminative ability of the modified creatinine index for sarcopenia.

RESULTS

Of the study participants, 142 (39.9%) were diagnosed with sarcopenia. The areas under the curve of the modified creatinine index against sarcopenia in the male and female participants were 0.77 (95% confidence interval [CI]: 0.71 to 0.83) and 0.77 (95% CI: 0.69 to 0.85), respectively. All simplified discriminant parameters were significantly associated with sarcopenia, even after adjusting for patient characteristics and centre. In the comparison of the odds ratios for sarcopenia for 1-standard deviation change in the simplified discriminant parameters, the odds ratio of the modified creatinine index was 1.92 (95% CI: 1.15 to 3.19), which was lower than that of the calf circumference (odds ratio: 6.58, 95% CI: 3.32 to 13.0) and similar to that of the SARC-F (odds ratio: 1.57, 95% CI: 1.14 to 2.16) and SARC-CalF scores (odds ratio: 2.36, 95% CI: 1.60 to 3.47).

CONCLUSIONS

This study revealed a strong association between the creatinine-derived index and sarcopenia in patients undergoing haemodialysis. The modified creatinine index was equal or superior to those of SARC-F and SARC-CalF score in discriminability for sarcopenia. However, the ability of the calf circumference to discriminate sarcopenia is extremely high, and further study is needed to determine whether it can be used to detect deterioration of muscle mass and function over time.

Comparison between magnetic resonance imaging and electrical impedance myography for evaluating lumbar skeletal muscle composition

Background

To compare electrical impedance myography (EIM) and MRI in assessing lumbar skeletal muscle composition.

Methods

One hundred forty-one patients (78 females, mean age 57 ± 19 years) were prospectively enrolled and underwent lumbar spine MRI, EIM with Skulpt®, and clinical evaluation including the questionnaire SARC-F. MRIs were reviewed to assess the Goutallier score of paravertebral muscles at L3 level and to calculate the cross sectional area (CSA) of both psoas, quadratus lumborum, erector spinae, and multifidus muscles on a single axial slice at L3 level, in order to calculate the skeletal muscle index (SMI=CSA/height2). We tested the correlation between EIM-derived parameters [body fat percentage (BF%) and muscle quality] and body mass index (BMI), Goutallier score (1–4), SMI, and SARC-F scores (0–10) using the Pearson correlation coefficient. The strength of association was considered large (0.5 to 1.0), medium (0.3 to 0.5), small (0.1 to 0.3).

Results

Pearson’s correlation coefficient showed small (0.26) but significant (p < 0.01) positive correlation between BF% obtained with EIM and Goutallier score. Small negative correlation (− 0.22, p < 0.01) was found between EIM muscle quality and Goutallier Score. Large negative correlation (− 0.56, p < 0.01) was found between SMI and Goutallier Score, while SMI showed small negative correlation with SARC-F (− 0.29, p < 0.01). Medium positive correlation was found between Goutallier Score and SARC-F (0.41, p < 0.01). BMI showed medium positive correlation with SMI (r = 0.369, p < 0.01) and small correlation with EIM muscle quality (r = − 0.291, p < 0.05) and BF% (r = 0.227, p < 0.05). We found a substantial increase of the strength of associations of BF% and muscle quality with Goutallier in the 18–40 years (r = 0.485 and r = − 0.401, respectively) and in the 41–70 years group (r = 0.448 and r = − 0.365, respectively).

Conclusions

Muscle quality and BF% measured by EIM device showed only small strength of correlation with other quantitative parameters for assessing muscle mass and fat infiltration. Interesting results have been found in younger patients, but Skulpt Chisel™ should be applied cautiously to assess lumbar skeletal muscle composition. This point deserves further investigation and other studies are warranted.

Trial registration

The registration number of this study is 107/INT/2019.

Knee Muscles Composition Using Electrical Impedance Myography and Magnetic Resonance Imaging

We evaluated the correlation of electrical impedance myography (EIM) measurements of knee muscles composition using Skulpt ChiselTM with MRI data retrieved from muscles segmentation. A total of 140 patients (71 females, 52 ± 21 years) underwent knee MRI, EIM with Skulpt®, and clinical evaluation (SARC-F questionnaire). MRIs were reviewed to assess the cross-sectional area (CSA) and skeletal muscle index (SMI = CSA/height2) of vastus medialis, vastus lateralis, biceps, semimembranosus, and sartorius. We tested the correlations of EIM-derived parameters [body fat-percentage (BF%) and muscle quality] with total CSA, CSA of each muscle, SMI, and SARC-F scores (0−10) using Pearson correlation coefficient. We found medium negative correlation of BF% with SMI (r = −0.430, p < 0.001) and total CSA (r = −0.445, p < 0.001), particularly with biceps (r = −0.479, p < 0.001), sartorius (r = −0.440, p < 0.001), and semimembranosus (r = −0.357, p < 0.001). EIM-derived muscle quality showed small-to-medium positive correlation with MRI measurements, ranging from r = 0.234 of biceps (p = 0.006) to r = 0.302 of total CSA (p < 0.001), except for vastus lateralis (r = 0.014, p = 0.873). SARC-F scores showed small correlations with EIM and MRI data, ranging from r = −0.132 (p = 0.121) with EIM muscle quality to r = −0.288 (p = 0.001) with CSA of vastus medialis. Hence, we observed small-to-medium correlations of muscle parameters derived from Skulpt ChiselTM with SARC-F scores and MRI parameters. We recommend using Skulpt ChiselTM with caution for assessing knee skeletal muscles composition.

Possible Sarcopenia and Its Association with Nutritional Status, Dietary Intakes, Physical Activity and Health-Related Quality of Life among Older Stroke Survivors

Background

Screening for sarcopenia in the stroke population is an emerging concept in research and clinical practice. Therefore, this cross-sectional study aimed to assess the prevalence of possible sarcopenia and its associated factors among older stroke survivors who visited the neurology and rehabilitation departments of three public hospitals in Malaysia.

Methods

We acquired data on sociodemographic characteristics, clinical profiles, malnutrition risk, dietary intake, physical activity level, and health-related quality of life. Possible sarcopenia was diagnosed in individuals with decreased calf circumference and low handgrip strength, as proposed by the Asia Working Group for Sarcopenia (2019). Finally, we performed descriptive analysis and binary logistic regression.

Results

Among 196 older adults with stroke (mean± standard deviation of age: 67.60 ± 5.70 years), 42.3% had possible sarcopenia, with a higher prevalence in the more advanced age group (≥70 years). In univariable analysis, possible sarcopenia was significantly associated with anthropometric indices, malnutrition risk, nutrient intake, physical activity level, and health-related quality of life. In multivariable analysis, body mass index (adjusted odds ratio [AOR]=0.57; 95% confidence interval [CI], 0.43–0.75) was the only factor associated with possible sarcopenia among individuals aged ≥70 years. Recurrent stroke (AOR=3.48; 95% CI, 1.02–11.92), body mass index (AOR=0.64; 95% CI, 0.54–0.76), and EQ-5D index (AOR=0.15; 95% CI, 0.03–0.78) were significantly associated with possible sarcopenia in the 60–69-year age group.

Conclusion

The prevalence of possible sarcopenia among community-dwelling older stroke survivors was high. Therefore, we recommend routine screening for possible sarcopenia to ensure early nutritional and exercise intervention.

The Effects of the 'Catabolic Crisis' on Patients' Prolonged Immobility after COVID-19 Infection

Background and Objectives: Quarantine, isolation and bed rest associated with COVID-19 infection favored the loss of muscle and bone mass, especially in elderly patients. The current study aims to compare the presence of sarcopenia and osteoporosis in patients with a recent (one month) history of SARS-CoV-2 infection versus the general population. Materials and Methods: A cross-sectional study was conducted in which 157 patients were enrolled, divided into two groups, comparable in structure. The COVID-19 group (group C) consisted of 86 patients who were diagnosed with SARS-CoV-2 respiratory infection within the last 30 days. The non-COVID-19 group (group NC) consists of 71 patients who had no clinical signs of respiratory infection and were not quarantined/hospitalized in the last 3 months. Muscle strength, incidence of sarcopenia (using SARC-F score) and osteoporosis (DEXA determination) and physical performance (SPPB score) in the two groups were assessed and compared. Results: No statistically significant differences were found between the SPPB scores of the C group versus the NC group. Statistically significant differences were found in the evaluation of three parameters included in the SARC-F score. Patients in the C group had difficulties in standing up from a chair (p = 0.009) and climbing stairs (p = 0.030) due to lower muscle strength (p = 0.002) compared with patients in the NC group. No correlation of the SARC F and SPPB scores with the T score values obtained by osteo-densitometry was found. Conclusions: The sudden and significant reduction in physical activity, through various measures taken in the general population during the pandemic, led to an increased incidence of sarcopenia, both in patients who did not have COVID-19 infection and among those quarantined/hospitalized for this condition.