Reduced calf circumference is an independent predictor of worse quality of life, severity of disease, frequent exacerbation, and death in patients with chronic obstructive pulmonary disease admitted to a pulmonary rehabilitation program: A historic cohort study

Prevalence of low calf circumference in hospitalized patients classified by raw or body mass index-adjusted values

BACKGROUND

Adiposity can influence the estimation of muscle mass using calf circumference (CC) and underestimate the frequency of low CC. An adjustment for CC using body mass index (BMI) was proposed to reduce this effect. We aimed to compare the low CC frequency in hospitalized patients when considering raw and BMI-adjusted values and explore data by sex, age, and race (white and non-white).

METHODS

Secondary analysis from two cohort studies conducted with adult hospitalized patients using BMI and CC data collected in the first 72 h after hospital admission. We classified low CC by two approaches: (1) raw CC; (2) BMI-adjusted CC for patients with BMI ≥ 25. Cutoff values for low CC were ≤34 cm (men) and ≤33 cm (women).

RESULTS

Among 1272 patients (54.1 ± 15.3 years old; 51.7% women; 82.1% White race), low CC frequency was 30.6% and low BMI-adjusted CC was 68.9%. For all elevated BMI categories, the low CC frequency was higher when considering BMI-adjusted values (P < 0.001). Low CC was more frequent (P < 0.001) in older adults (38.7% by raw; 79.1% by BMI-adjusted value) than in younger adults (27.6% by raw; 65.2% by BMI-adjusted value) and it was not associated with race. Low CC by raw values was more frequent in men than in women (35.0% versus 26.4%; P = 0.001), but did not differ between sexes when classified by BMI-adjusted values (70.7% versus 67.1%; P = 0.184).

CONCLUSION

Low CC BMI adjusted was 2.2 times more frequent in comparison with raw CC values, and it was identified in >60% of patients with BMI ≥ 25.

Absence of association between low calf circumference, adjusted or not for adiposity, and ICU mortality in critically ill adults: A secondary analysis of a cohort study

BACKGROUND

Despite its correlation with skeletal muscle mass and its predictive value for adverse outcomes in clinical settings, calf circumference is a metric underexplored in intensive care. We aimed to determine whether adjusting low calf circumference for adiposity provides prognostic value superior to its unadjusted measurement for intensive care unit (ICU) mortality and other clinical outcomes in critically ill patients.

METHODS

In a secondary analysis of a cohort study across five ICUs, we assessed critically ill patients within 24 h of ICU admission. We adjusted calf circumference for body mass index (BMI) (25-29.9, 30-39.9, and ≥40) by subtracting 3, 7, or 12 cm from it, respectively. Values ≤34 cm for men and ≤33 cm for women identified low calf circumference.

RESULTS

We analyzed 325 patients. In the primary risk-adjusted analysis, the ICU death risk was similar between the low and preserved calf circumference (BMI-adjusted) groups (hazard ratio, 0.90; 95% CI, 0.47-1.73). Low calf circumference (unadjusted) increased the odds of ICU readmission 2.91 times (95% CI, 1.40-6.05). Every 1-cm increase in calf circumference as a continuous variable reduced ICU readmission odds by 12%. Calf circumference showed no significant association with other clinical outcomes.

CONCLUSION

BMI-adjusted calf circumference did not exhibit independent associations with ICU and in-hospital death, nor with ICU and in-hospital length of stay, compared with its unadjusted measurement. However, low calf circumference (unadjusted and BMI-adjusted) was independently associated with ICU readmission, mainly when analyzed as a continuous variable.

Evaluating the association between anthropometric parameters and successful aging in older adults

This study aimed to determine the relationship between successful aging (SA) and anthropometric parameters in older adults. We used body mass index (BMI), waist circumference, hip circumference, and calf circumference to reflect anthropometric parameters. SA was assessed by the following five aspects: self-rated health, self-rated psychological status or mood, cognitive function, activities of daily life, and physical activity. Logistic regression analyses were employed to examine the relationship between anthropometric parameters and SA. Results showed that larger BMI, waist circumference, and calf circumference are related to a higher prevalence of SA in older women; greater waist circumference and calf circumference are associated with a higher rate of SA in old-old adults. These findings suggest that the greater BMI, waist circumference, hip circumference, and calf circumference are associated with a higher rate of SA in older adults, and the associations are influenced to some extent by the sex and age.

Low calf circumference adjusted for body mass index is associated with prolonged hospital stay

BACKGROUND

Calf circumference (CC) is of emerging importance because of its practicality, high correlation with skeletal muscle, and potential predictive value for adverse outcomes. However, the accuracy of CC is influenced by adiposity. CC adjusted for BMI (BMI-adjusted CC) has been proposed to counteract this problem. However, its accuracy to predict outcomes is unknown.

OBJECTIVES

To evaluate the predictive validity of BMI-adjusted CC in hospital settings.

METHODS

A secondary analysis of a prospective cohort study in hospitalized adult patients was conducted. The CC was adjusted for BMI by reducing 3, 7, or 12 cm for BMI (in kg/m²) of 25-29.9, 30-39.9, and ≥40, respectively. Low CC was defined as ≤34 cm for males and ≤33 cm for females. Primary outcomes included length of hospital stay (LOS) and in-hospital death, and secondary outcomes were hospital readmissions and mortality within 6 mo after discharge.

RESULTS

We included 554 patients (55.2 ± 14.9 y, 52.9% men). Among them, 25.3% presented with low CC, whereas 60.6% had BMI-adjusted low CC. In-hospital death occurred in 13 patients (2.3%), and median LOS was 10.0 (5.0-18.0) d. Within 6 mo from discharge, 43 patients (8.2%) died, and 178 (34.0%) were readmitted to the hospital. BMI-adjusted low CC was an independent predictor of LOS ≥ 10 d (odds ratio = 1.70; 95% confidence interval: 1.18, 2.43], but it was not associated with the other outcomes.

CONCLUSIONS

BMI-adjusted low CC was identified in more than 60% of hospitalized patients and was an independent predictor of longer LOS.

The Association between Fat-Free Mass and Exercise Test Outcomes in People with Chronic Obstructive Pulmonary Disease: A Systematic Review

People with chronic obstructive pulmonary disease (COPD) tend to have abnormally low levels of fat-free mass (FFM), which includes skeletal muscle mass as a central component. The purpose of this systematic review was to synthesise available evidence on the association between FFM and exercise test outcomes in COPD. MEDLINE, Cochrane Library, EMBASE, Web of Science, and Scopus were searched. Studies that evaluated exercise-related outcomes in relation to measures of FFM in COPD were included. Eighty-three studies, containing 18,770 (39% female) COPD participants, were included. Considerable heterogeneity was identified in the ways that FFM and exercise test outcomes were assessed; however, higher levels of FFM were generally associated with greater peak exercise capacity. This association was stronger for some exercise test outcomes (e.g. peak rate of oxygen consumption during incremental cycle exercise testing) than others (e.g. six-minute walking distance). This review identified heterogeneity in the methods used for measuring FFM and exercise capacity. There was, in general, a positive association between FFM and exercise capacity in COPD. There was also an identified lack of studies investigating associations between FFM and temporal physiological and perceptual responses to exercise. This review highlights the significance of FFM as a determinant of exercise capacity in COPD.

The association between low calf circumference and mortality: a systematic review and meta-analysis

PURPOSE

Low calf circumference is an important indicator of malnutrition and has been widely studied, especially among older adults. However, data on the association between low calf circumference and mortality have been inconsistent. This systematic review was aimed to quantify this association.

METHODS

The internet databases (PubMed, Embase, ScienceDirect and Cochrane Library databases) were systematically searched from inception to November 01, 2021 for studies investigating the association between low calf circumference and mortality. A random effects model was adopted to pool the relevant data.

RESULTS

Low calf circumference was associated with a higher risk of mortality than normal calf circumference, with a pooled HR of 2.42 (95% CI 1.97-2.97, I² = 74.3%). In addition, this association between low calf circumference and morality was still statistically significant in the subgroup analysis across different settings, including hospitals (pooled HR = 2.63, 95% CI 1.93-3.58), nursing homes (pooled HR = 2.49, 95% CI 1.76-3.54), and communities (pooled HR = 2.22, 95% CI 1.60-3.07). Other subgroup analyses based on different cutoffs of calf circumference showed that, compared to individual with normal calf circumference, participants with low calf circumference had an increased risk of mortality (pooled HR = 2.66, 95% CI 2.06-3.43) when using the Asian Working Group for Sarcopenia (AWGS) criterion (≤ 34 cm for males and ≤ 33 cm for females). Similar results were found when the Mini Nutritional Assessment (MNA) criterion (≤ 31 cm) was used, with a pooled HR of 2.11 (95% CI 1.59-2.81).

CONCLUSION

Calf circumference, which is simple and convenient to measure, could be used to stratify the high-risk group, as low calf circumference was significantly associated with mortality among patients. Interventions, including exercise and nutrition programs, could be conducted promptly once low calf circumference is detected.

Calf Circumference and All-Cause Mortality: A Systematic Review and Meta-Analysis Based on Trend Estimation Approaches

OBJECTIVES

To perform a systematic review and meta-analysis and quantify the associations of total mortality with calf circumference (CC) in adults 18 years and older via combining various analyses based on empirical dichotomic CC, continuous CC, and dose-response CC.

METHODS

We conducted a systematic search of relevant studies in PubMed, EMBASE, Cochrane Library, and Web of Science published through April 12, 2022. This systematic review includes longitudinal observational studies reporting the relationships of total mortality with CC. We calculated the pooled relative risk (RR) and 95% confidence interval (CI) of total mortality with CC per 1 cm for each study and combined the values using standard meta-analysis approaches. Newcastle-Ottawa scale (NOS), Grading of Recommendations, Assessment, Development and Evaluations approach (GRADE), and the Instrument for assessing the Credibility of Effect Modification Analyses (ICEMAN) were assessed for meta-analyses.

RESULTS

Our analysis included a total of 37 cohort studies involving 62,736 participants, across which moderate heterogeneity was observed (I2=75.7%, P<0.001), but no publication bias was found. Study quality scores ranged from 6 to 9 (mean 7.7), with only three studies awarded a score of 6 (fair quality). We observed an inverse trend between total death risk and CC per 1 cm increase (RR, 0.95, 95% CI, 0.94-0.96; P<0.001; GRADE quality=high). Only a very slight difference was found among residents of nursing homes (6.9% mortality risk reduction per one cm CC increase), community-dwellers (5.4%), and those living in hospitals (4.8%), respectively (P for meta-regression=0.617). Low credible subgroup difference was found based on the ICEMAN tool.

CONCLUSIONS

Calf circumference is a valid anthropometric measure for mortality risk prediction in a community, nursing home, or hospital.