論文ID: CJ-17-1202
Background: Whether the short-term effect of cardiac rehabilitation (CR) in elderly patients with heart failure (HF) is influenced by nutritional status is uncertain, so the present study investigated the effect of nutritional status on functional recovery after CR in elderly HF inpatients.
Methods and Results: We enrolled 145 patients admitted for treatment of HF who were aged ≥65 years and had a low functional status defined as a Barthel index (BI) score ≤85 points at the commencement of CR. Nutritional status was assessed by the Mini Nutritional Assessment Short Form (MNA-SF) and total energy intake per day. The primary endpoint was functional status determined by the BI score at discharge. The median CR period was 20 days (interquartile range: 14–34 days), and 87 patients (60%) were functionally dependent (BI score ≤85) at discharge. Multivariate logistic regression analysis showed that MNA-SF score (odds ratio [OR]: 0.76, P=0.02) and total energy intake at the commencement of CR (OR: 0.91, P=0.02) were independent predictors of functional dependence after CR. MNA-SF score ≤7 and total energy intake ≤24.5 kcal/kg/day predicted functional dependence at discharge with moderate sensitivity and specificity.
Conclusions: MNA-SF score and total energy intake at the commencement of CR are novel predictors of the extent of functional recovery of elderly HF inpatients after in-hospital CR.
Heart failure (HF) is one of the important causes of functional decline in elderly people,1,2 and hospitalization for an acute cardiovascular event potentially leads to a decline in physical function despite treatment during both hospitalization and after discharge.2,3 Functional decline in elderly HF patients often requires social healthcare support and is causally related to adverse outcomes such as hospitalization and death.4–6 Thus, prevention and management of functional decline associated with HF is particularly important in the elderly.
Malnutrition is common in HF patients,7–9 and leads to fluid retention, inflammation, neuroendocrine activation and, ultimately, to exacerbation of both HF and malnutrition.10 In addition to advanced age, female sex, anemia and diabetes,5 poor nutritional status is shown to be associated with poor rehabilitation outcome in patients with stroke or chronic illness.11–13 However, the influence of malnutrition on the outcome of cardiac rehabilitation (CR) remains unclear. In the present study, we hypothesized that nutritional status was an independent determinant of the short-term effect of CR in elderly inpatients with HF. To examine this hypothesis, we retrospectively enrolled 407 elderly patients admitted for HF therapy and analyzed the relationships between indices of nutritional status at the commencement of CR and functional status assessed by the Barthel index (BI)14 after CR.
The protocol of this study was approved by the Institutional Review Board for Human Investigation at Sapporo Medical University Hospital (approval no. 282-247). We retrospectively retrieved data for 407 consecutive HF patients aged ≥65 years who were admitted to Sapporo Medical University Hospital between August 1, 2010 and January 31, 2016 for exacerbation of HF. All of the patients were able to walk independently before hospitalization for HF treatment, though frailty and cachexia were not quantitatively assessed during the study period. The patients underwent comprehensive CR during hospitalization. Exclusion criteria were as follows: a CR period of ≤7 days; musculoskeletal disorder; hemiplegia caused by stroke; cancer; liver cirrhosis; endstage renal failure requiring hemodialysis; transfer to another hospital; and death during hospitalization. Diet therapy was ordered by a physician in charge of each patient.
The institution’s comprehensive CR program consisted of blood pressure control, lipid management, diabetes management, antismoking education, physical therapy and counseling for specific problems in individual patients. All of the patients underwent physical therapy 5 times per week, including stretching, massage, resistance training, balance training, functional training in self-care, and aerobic exercise such as ambulation and bicycle ergometer exercise. The exercise menu and its step-up protocol were individualized for each patient according to clinical condition and physical function.
Data CollectionMedical records were retrospectively reviewed with regard to demography, medical history, comorbidity, medications, laboratory data, echocardiograms, CR settings, functional status, nutritional status and total energy intake.
Primary EndpointThe primary endpoint in this study was functional status evaluated by use of BI at the time of discharge. BI is a scoring system that assesses performance in basic activities of daily living, ranging from 0 (total dependence) to 100 points (independence). We determined the BI score just before the commencement of CR and at discharge. In this study, functional dependence was defined as a BI score ≤85 points.
Laboratory Data and EchocardiographyData for serum albumin, hemoglobin, total lymphocyte count and C-reactive protein within 7 days before the commencement of CR were retrieved from the patients’ medical records. Data for B-type natriuretic peptide (BNP) within 14 days before the commencement of CR were also retrieved from the medical records. Echocardiography was performed by the standard protocol, and the left ventricular ejection fraction (LVEF) was measured by the modified Simpson method.
Nutritional StatusNutritional status was assessed using the Mini Nutritional Assessment Short Form (MNA-SF) immediately before the commencement of CR. The MNA-SF consists of 6 questions about reduction in food intake over the past 3 months, weight loss during the past 3 months, mobility, psychological stress or acute disease in the past 3 months, neuropsychological problems, and body mass index (BMI).15 It has been shown that the MNA-SF is a reliable tool for malnutrition screening in the elderly.15
The type of malnutrition was assessed according to a previous study.11 Starvation-related malnutrition was defined as an inadequate total energy intake to meet basal energy expenditure. Total energy intake was calculated by the amount of oral intake and enteral and/or parenteral nutrition at the commencement of CR. Basal energy expenditure was calculated by the Harris-Benedict equation.16 Chronic disease-related malnutrition was assessed as pre-cachexia, defined by consensus criteria of the European Society for Clinical Nutrition and Metabolism.17 According to the criteria, all of the following must be present to diagnose pre-cachexia: underlying chronic disease, unintentional weight loss <5% of usual body weight during the past 6 months, chronic or recurrent systemic inflammatory response and anorexia or anorexia-related symptoms. Acute disease-related or injury-related malnutrition was diagnosed by the presence of acute disease or injury at or following admission.
Statistical AnalysisNormal distribution was assessed by the Shapiro-Wilk test. Continuous variables are expressed as means and standard deviation (SD) or median and interquartile range (IQR: 25–75th percentile) depending on the results of the Shapiro-Wilk test. Categorical variables are expressed as frequency and percentage. Because the BI scores were not normally distributed, comparison within a group was made using the Wilcoxon signed-rank test, and comparisons between groups of the BI scores at discharge were made using the Mann-Whitney U test. Correlations between the clinical characteristics of patients and CR protocols were examined by calculation of Spearman’s rank correlation coefficient. Univariate logistic regression analyses were used for examining associations between variables and functional dependence at discharge. Variables that significantly differed between patients with functional dependence and those with functional independence at discharge were used as explanatory variables in the univariate analyses together with age, sex, BMI, ischemic etiology, logarithmic BNP, serum albumin, hemoglobin, total lymphocyte count and LVEF. All variables used in univariate analyses were entered into the multivariate logistic regression analysis. A model was constructed by the stepwise forward selection procedure based on Akaike’s Information Criterion. Next, the odds ratio (OR) with the 95% confidence interval (CI) was calculated. Moreover, receiver-operating characteristic (ROC) curve analysis was used to construct areas under the curve (AUC) and calculate the optimal cutoff values of MNA-SF score and total energy intake for prediction of a BI score at discharge ≤85. A P-value <0.05 was considered statistically significant. JMP® version 12.2.0 (SAS Institute Inc., Cary, NC, USA) was used for statistical analyses in this study.
Of the 407 patients initially enrolled, 262 were excluded by the exclusion criteria, and data for 145 patients contributed to the present analyses. Clinical characteristics of the patients are shown in Table 1. The median age of the patients was 75 years (IQR: 70–81 years) and 51% of the patients were female. Before CR, 34% and 65% of the patients were classified as NYHA functional class II and class III, respectively. The most frequent heart disease was dilated cardiomyopathy (31%) followed by ischemic cardiomyopathy (21%) and valvular heart disease (15%). The median LVEF was 34% and 82 patients (59%) had LVEF <40%. The median interval between admission and commencement of CR was 9 days. The median CR period was 20 days and the median number of physical therapy sessions was 11.
| Parameters | Overall | Functional dependence (BI score at discharge ≤85) |
Functional independence (BI score at discharge >85) |
P value |
|---|---|---|---|---|
| n=145 | n=87 (60%) | n=58 (40%) | ||
| Age, years | 75 (70–81) | 76 (69–81) | 74 (70–79) | 0.77 |
| ≥75 years, n (%) | 73 (50) | 46 (53) | 27 (47) | 0.50 |
| Female, n (%) | 74 (51) | 47 (54) | 27 (47) | 0.40 |
| Height, cm | 157±9 | 157±8 | 158±9 | 0.48 |
| Body weight, kg | 52±10 | 51±10 | 53±10 | 0.22 |
| Systolic BP, mmHg | 109±19 | 108±19 | 110±18 | 0.61 |
| Diastolic BP, mmHg | 62±11 | 61±11 | 63±10 | 0.13 |
| NYHA-FC III, n (%) | 94 (65) | 65 (75) | 29 (50) | <0.01 |
| LVEF, % | 34 (27–51) | 26 (27–50) | 31 (26–51) | 0.62 |
| <40%, n (%) | 82 (57) | 49 (56) | 33 (57) | 0.86 |
| Etiology of HF, n (%) | ||||
| ICM | 30 (21) | 21 (24) | 9 (16) | 0.30 |
| DCM | 45 (31) | 28 (32) | 17 (29) | 0.85 |
| VHD | 22 (15) | 12 (14) | 10 (17) | 0.64 |
| Comorbidity, n (%) | ||||
| Hypertension | 71 (49) | 39 (45) | 32 (55) | 0.24 |
| Diabetes mellitus | 38 (26) | 24 (28) | 14 (24) | 0.70 |
| Dyslipidemia | 63 (43) | 36 (41) | 27 (47) | 0.61 |
| Atrial fibrillation | 55 (38) | 35 (40) | 20 (34) | 0.60 |
| Chronic kidney disease | 78 (54) | 45 (52) | 33 (57) | 0.61 |
| History of HF hospitalization, n (%) | 82 (57) | 50 (57) | 32 (55) | 0.86 |
| BI score at the commencement of CR, points | 70 (50–80) | 60 (45–75) | 80 (65–81) | <0.01 |
| Duration of hospital stay, days | 32 (23–49) | 36 (24–48) | 29 (23–49) | 0.46 |
| Duration of CR, days | 20 (14–34) | 22 (14–35) | 19 (15–33) | 0.45 |
| No. of physical therapy sessions | 11 (8–17) | 13 (8–17) | 10 (7–16) | 0.24 |
| Total time of physical therapy, min | 460 (330–740) | 520 (340–740) | 400 (320–760) | 0.24 |
| Duration between admission and commencement of CR, days |
9 (6–15) | 9 (6–17) | 9 (5–14) | 0.85 |
| Laboratory data | ||||
| BNP level, pg/mL | 504 (223–876) | 528 (238–882) | 438 (208–890) | 0.31 |
| Creatinine, mg/mL | 1.2 (0.8–1.8) | 1.1 (0.8–1.6) | 1.4 (1.0–2.1) | 0.02 |
| BUN, mg/dL | 28 (21–45) | 26 (21–37) | 31 (19–47) | 0.15 |
| Medications, n (%) | ||||
| β-blocker | 106 (73) | 60 (69) | 46 (79) | 0.19 |
| ACEI or ARB | 61 (42) | 35 (40) | 26 (45) | 0.61 |
| Loop diuretics | 121 (83) | 73 (84) | 48 (83) | 1.00 |
| Mineralocorticoid receptor antagonists | 85 (59) | 51 (59) | 34 (59) | 1.00 |
| Thiazide | 19 (13) | 13 (15) | 6 (10) | 0.46 |
| Tolvaptan | 36 (25) | 23 (26) | 13 (22) | 0.70 |
| Concurrent use of intravenous inotropic agents | 12 (8) | 10 (11) | 2 (3) | 0.12 |
All measurements are represented as number (%), mean±standard deviation or median (interquartile range). P<0.05 was considered statistically significant. ACEI, angiotensin-converting enzyme inhibitor; ARB, angiotensin II receptor blocker; BI, Barthel index; BNP, B-type natriuretic peptide; BP, blood pressure; BUN, blood urea nitrogen; CR, cardiac rehabilitation; DCM, dilated cardiomyopathy; HF, heart failure; ICM, ischemic cardiomyopathy; LVEF, left ventricular ejection fraction; NYHA-FC, New York Heart Association functional class; VHD, valvular heart disease.
A total of 60% of the patients (87/145) had functional dependence at discharge. At discharge, functionally dependent patients had a higher rate of NYHA functional class III, lower BI score, and lower serum creatinine level at baseline (i.e., before CR) than did functionally independent patients (Table 1), though CR duration and the number of physical therapy sessions were comparable in the 2 groups.
Nutritional StatusIndices of nutritional status in patients before CR are shown in Table 2. The median MNA-SF score was 7 points (IQR: 6–8.5 points), and 81 patients (56%) were malnourished (MNA-SF score ≤7), 58 patients (40%) were at risk of malnutrition (MNA-SF score ≥8 and ≤11) and 6 patients (4%) were sufficiently nourished (MNA-SF score ≥12). Median total energy intake was 22.8 kcal/kg/day. Acute disease-related or injury-related malnutrition was the most frequent type of malnutrition (52%), followed by starvation-related malnutrition (41%) and chronic disease-related malnutrition (6%). Only 3% of the study population (4/145) received intervention by the nutritional support team during admission. In patients with functional dependence at discharge, the MNA-SF score before CR was lower, the prevalence of malnutrition was higher, and total energy intake was lower than in patients with functional independence at discharge. The rate of starvation-related malnutrition before CR was also higher in functionally dependent patients at discharge.
| Parameters | Overall | Functional dependence (BI score at discharge ≤85) |
Functional independence (BI score at discharge >85) |
P value |
|---|---|---|---|---|
| n=145 | n=87 (60%) | n=58 (40%) | ||
| BMI, kg/m2 | 21±3 | 21±4 | 21±3 | 0.37 |
| MNA-SF score, points | 7 (6–8.5) | 7 (5–8) | 8 (7–10) | <0.01 |
| MNA-SF classification, n (%) | <0.01 | |||
| Well-nourished | 6 (4) | 1 (1) | 5 (9) | |
| At risk of malnutrition | 58 (40) | 27 (31) | 31 (53) | |
| Malnourished | 81 (56) | 59 (68) | 22 (38) | |
| Total energy intake at the commencement of CR, kcal/kg/day |
22.8 (18.5–27.5) | 21.4 (16.6–25.6) | 25.3 (20.7–30.0) | <0.01 |
| Type of malnutrition, n (%) | ||||
| Starvation-related malnutrition | 59 (41) | 44 (51) | 15 (26) | <0.01 |
| Acute disease or injury-related malnutrition | 75 (52) | 49 (56) | 26 (45) | 0.18 |
| Chronic disease-related malnutrition | 8 (6) | 6 (7) | 2 (3) | 0.48 |
| Laboratory data | ||||
| Albumin, g/dL | 3.6 (3.2–3.8) | 3.6 (3.2–3.8) | 3.7 (3.4–3.9) | 0.22 |
| Hemoglobin, g/dL | 11.2 (10.1–12.6) | 11.1 (9.9–12.5) | 11.3 (10.3–12.8) | 0.37 |
| Total lymphocyte count, cells/mm3 | 1,258 (942–1,600) | 1,208 (888–1,605) | 1,264 (1000–1,596) | 0.65 |
| C-reactive protein, mg/dL | 0.51 (0.10–1.44) | 0.60 (0.10–1.46) | 0.35 (0.10–0.95) | 0.32 |
All measurements are represented as number (%), mean±standard deviation or median (interquartile range). P<0.05 was considered statistically significant. BMI, body mass index; MNA-SF, Mini Nutritional Assessment Short Form. Other abbreviations as in Table 1.
Differences in BI score at discharge between subgroups of patients according to clinical parameters before CR are shown in Table 3. There were no significant differences in BI scores at discharge between age or sex subgroups. NYHA functional class III, concurrent use of intravenous inotropic agents, starvation-related malnutrition, acute disease or injury-related malnutrition, and chronic disease-related malnutrition before CR were associated with lower BI score at discharge. To examine the possible effect of cardio-renal anemic syndrome on the outcome of CR, we defined it as estimated glomerular filtration rate <60 mL/min/1.73 m2 and hemoglobin <13 g/dL in males or <11.4 g/dL in females. BI scores at discharge were comparable in patients with and without cardio-renal anemic syndrome (85 points [IQR: 80–90] vs. 85 points [IQR: 85–90], P=0.68). Prevalence of cardio-renal anemic syndrome at the commencement of CR was not significantly different between patients with functional dependence at discharge and those with functional independence at discharge (53% vs. 57%, P=0.61).
| Categorical variables | n (%) | Median (IQR) | P value |
|---|---|---|---|
| Age | |||
| ≥75 years | 73 (50) | 85 (75–90) | 0.12 |
| <75 years | 72 (50) | 85 (85–90) | |
| Sex | |||
| Male | 71 (49) | 85 (80–90) | 0.79 |
| Female | 74 (51) | 85 (80–90) | |
| NYHA-FC III | |||
| Yes | 94 (65) | 85 (80–90) | 0.01 |
| No | 51 (35) | 90 (85–95) | |
| Concurrent use of intravenous inotropic agents | |||
| Yes | 12 (8) | 78 (71–84) | <0.01 |
| No | 133 (92) | 85 (83–90) | |
| Starvation-related malnutrition | |||
| Yes | 59 (41) | 85 (75–90) | <0.01 |
| No | 86 (59) | 88 (85–95) | |
| Acute disease or injury-related malnutrition | |||
| Yes | 75 (52) | 85 (80–90) | 0.03 |
| No | 70 (48) | 85 (85–90) | |
| Chronic disease-related malnutrition | |||
| Yes | 8 (6) | 78 (55–80) | 0.02 |
| No | 137 (94) | 85 (80–90) | |
P<0.05 was considered statistically significant. Abbreviations as in Tables 1,2.
Univariate and multivariate analyses were performed to identify clinical parameters that predict functional dependence (i.e., BI score ≤85) at discharge. In the univariate analysis, NYHA functional class III, low BI score, low MNA-SF score, starvation-related malnutrition and low total energy intake were associated with functional dependence at discharge (Table 4). Multivariate analysis showed that BI score, low MNA-SF score, low total energy intake, and low serum creatinine level before CR were independently associated with functional dependence at discharge (Table 4). In the ROC curve analysis, the AUC for MNA-SF score and that for total energy intake per day as predictors of functional dependence at discharge were 0.690 (95% CI: 0.597–0.770) and 0.669 (95% CI: 0.575–0.751), respectively. The optimal cutoff points of MNA-SF score and total energy intake were 7.0 and 24.5 kcal/kg/day, respectively; sensitivity and specificity for prediction of functional dependence of MNA-SF score ≤7 were 68% and 62%, and those of total energy intake ≤24.5 kcal/kg/day were 72% and 59%, respectively.
| Independent variables | Univariate model | Multivariate model | ||
|---|---|---|---|---|
| OR (95% CI) | P value | OR (95% CI) | P value | |
| Age, years | 1.01 (0.96–1.06) | 0.74 | ||
| Sex: female | 1.35 (0.69–2.34) | 0.38 | ||
| NYHA-FC III: yes | 2.96 (1.47–6.05) | <0.01 | 2.12 (0.93–4.90) | 0.07 |
| Etiology of HF: ICM | 1.73 (0.75–4.29) | 0.20 | ||
| BMI, kg/m2 | 0.96 (0.87–1.05) | 0.37 | ||
| BI score at the commencement of CR, points | 0.94 (0.91–0.96) | <0.01 | 0.95 (0.92–0.98) | <0.01 |
| MNA-SF score, points | 0.70 (0.58–0.83) | <0.01 | 0.76 (0.59–0.96) | 0.02 |
| Starvation-related malnutrition: yes | 2.93 (1.45–6.18) | <0.01 | 0.45 (0.11–1.72) | 0.25 |
| Acute disease or injury-related malnutrition: yes | 1.59 (0.82–3.12) | 0.17 | ||
| Chronic disease-related malnutrition: yes | 2.07 (0.46–14.50) | 0.36 | ||
| Total energy intake, kcal/kg/day | 0.92 (0.88–0.96) | <0.01 | 0.91 (0.83–0.99) | 0.02 |
| Log BNP level | 1.25 (0.87–1.82) | 0.23 | ||
| Albumin, g/dL | 0.59 (0.23–1.19) | 0.14 | ||
| Hemoglobin, g/dL | 0.96 (0.79–1.15) | 0.63 | ||
| Creatinine, mg/dL | 0.78 (0.55–1.12) | 0.19 | 0.63 (0.41–0.95) | 0.03 |
| Total lymphocyte count, cells/mm3 | 0.82 (0.35–1.88) | 0.64 | ||
| LVEF, % | 1.00 (0.98–1.03) | 0.91 | ||
| History of HF hospitalization: yes | 1.10 (0.56–2.15) | 0.78 | ||
| Concurrent use of intravenous inotropic agents: yes | 3.64 (0.91–24.26) | 0.07 | ||
P<0.05 was considered statistically significant. CI, confidence interval; OR, odds ratio. Other abbreviations as in Tables 1,2.
Figure shows a comparison of the change in BI score after CR during hospitalization in 2 groups of patients with different baseline MNA-SF scores: ≤7 and ≥8. Although the BI score significantly increased in both groups (Figure A), the change in BI score after comprehensive CR was significantly greater in the group with a low baseline MNA-SF score (Figure B). However, the proportion of functionally independent patients at discharge was significantly lower in patients with a low MNA-SF score than in those with a high MNA-SF score (27% vs. 56%, P<0.01).
Baseline MNA-SF scores and change in BI scores. BI scores before and after CR (A) and change in BI score after CR (B) in a group with MNA-SF score ≤7 and a group with MNA-SF score ≥8. P<0.05 was considered statistically significant. BI, Barthel index; CR, cardiac rehabilitation; MNA-SF, Mini Nutritional Assessment Short Form.
To exclude the possibility that insufficient improvement of functional status by CR in malnourished patients was related to insufficient CR, additional analyses were performed. In the Spearman’s rank correlation analysis, neither MNA-SF score nor total energy intake at the commencement of CR correlated with the number of physical therapy sessions or total time of physical therapy. In addition, the number of physical therapy sessions (10 sessions [IQR: 7–16] vs. 12 sessions [IQR: 8–18], P=0.40) and total time of physical therapy (480 min [IQR: 330–750] vs. 430 min [IQR: 325–735], P=0.33) were comparable in the both groups.
In the present study, we consecutively enrolled elderly HF patients with a BI score ≤85 and showed that BI score, MNA-SF score, total energy intake and serum creatinine level at the commencement of CR are independent predictors of functional dependence at discharge. CR during hospitalization failed to improve physical status at discharge to a level of functional independence (i.e., BI score to >85) in 60% of the patients, though significant improvement in functional status was observed in patients with poorer nutritional status (i.e., MNA-SF score ≤7) as well (Figure). To our knowledge, this is the first study suggesting that nutritional status is a major determinant of the effect of CR on functional status in elderly HF patients.
An implication of the present study for clinical practice is the possible merit of the MNA-SF score and a total energy intake assessment in patients with HF for prediction of functional outcome of CR during hospitalization. Cutoff values of MNA-SF score (7.0) and total energy intake per day (24.5 kcal/kg/day) at the commencement of CR predicted functional dependence at discharge with moderate sensitivity and specificity (≈70% and 60%, respectively), and significant improvement in functional status by CR is also expected in patients with an MNA-SF score below the cutoff level (Figure). Early prediction of physical function at discharge in hospitalized HF patients would be helpful for early predischarge planning of post-discharge patient care by family and healthcare providers. In addition, prediction of functional dependence in an HF patient at the commencement of CR would enable comprehensive evaluation of modifiable factors to improve the physical status of that patient.
Malnutrition identified by a low MNA-SF score was independently related to failure of CR to improve functional status to an independent level (Table 4). The results of a number studies have suggested that nutritional status is a relevant factor for the outcome of rehabilitation in patients with disuse syndrome caused by being bedridden, including patients with cerebrovascular disorders.11–13,18 In contrast, there are limited data regarding any association between nutritional status and the effect of CR on functional status in elderly patients with cardiovascular disease. Using bivariate analysis, Kinugasa et al showed that functional status at discharge was poorer in HF patients with a lower nutritional level at admission (geriatric nutritional risk index [GNRI] score <92) than in those with a higher nutritional level at admission (GNRI score ≥92).19 However, because of the nature of bivariate analysis in their study, it was unknown whether the influence of nutritional status on functional status after CR was independent of other clinical variables.19 Using a cross-sectional analysis of the population of the KORINNA study, Quinones et al showed that nutritional deficiency in home-dwelling elderly survivors of acute myocardial infarction was an independent determinant of functional disability (OR: 3.38, 95% CI: 1.60–7.15) even after adjustment of clinical variables.1 The present study extended the previous findings and indicated that low energy intake before CR was independently related to functional dependence after CR in elderly HF inpatients (Table 4).
Inadequate total energy intake to meet energy needs in HF patients has been reported not only for inpatients,20 but also clinically stable outpatients.21–23 It was shown in recent studies that inadequate energy intake reduces the effect of rehabilitation on disuse condition in patients with non-cardiac disease (e.g., stroke and cachexia).13,18,24,25 The clinical characteristics of the study populations and therapies are different between the earlier studies13,18,24,25 and the present study. However, the findings of the present study indicated that CR for HF in the elderly shares an important predictor of clinical outcome (i.e., total energy intake) with rehabilitation for stroke and other non-cardiac disorders.
Previous studies have demonstrated that loss of skeletal muscle mass in HF patients, called “sarcopenia” or “muscle wasting”, is closely associated with malnutrition, muscle strength, decline in physical function, and poor improvement in exercise capacity after exercise training.26–28 Besides its effect on muscle mass, prolonged insufficient total energy intake has detrimental effects on skeletal muscle function.21,22,29,30 Thus, a plausible explanation for the association of nutritional status and total energy intake at the commencement of CR with functional status after CR in elderly HF inpatients is preexisting muscle loss and reduced function of skeletal muscle. However, the possibility of involvement of other factors, such as a depressive state, influencing both total energy intake and outcome of CR cannot be excluded.
Because both nutritional status and total energy intake are modifiable, nutrition might be an important therapeutic target for enhancing the effect of CR on functional status in elderly HF inpatients. In fact, recent studies have shown that nutritional interventions such as nutritional supplement or individualized nutritional therapy have favorable effects on body composition,31 metabolic function,32 exercise capacity31–33 and prognosis34 in patients with acute or chronic HF. The combination of nutritional intervention and CR was shown to improve outcome in disabled elderly patients with malnutrition and sarcopenia,35 and the beneficial effects of physical therapy combined with nutritional therapy on malnutrition, sarcopenia, and cachexia in patients with acute HF were recently reported.36 However, the addition of nutritional intervention alone to CR is unlikely to be sufficient to reverse the clinical condition of some HF patients. In addition to malnutrition, depressive symptoms are common in HF patients,37 and elderly patients frequently have orthopedic problems, such as degenerative arthritis, that limit physical activity. Taken together, the results suggest that comprehensive assessment and management of comorbidities and nutritional status are necessary for CR to restore physical activity in HF patients.
Study LimitationsFirst, subjects were retrospectively enrolled in a single center, so the possibility of selection bias on the results cannot be excluded. Second, because we did not enroll HF patients aged less than 65 years of age, it is unclear whether the findings in this study are directly applicable to relatively young HF patients. However, in the light of the association between nutritional and physical status in patients with stroke and non-cardiac diseases,11–13,18 we speculate that attenuation of the effect of CR by malnutrition in HF patients is not specific to elderly HF patients. Third, the menu of exercises in each session and the step-up protocol in the CR for HF patients are not strictly standardized among institutes, and we cannot exclude the possibility that the importance of malnutrition and energy intake level before CR as determinants of functional dependence after CR may differ depending on the CR program. Finally, we did not directly assess muscle wasting, cachexia and frailty, which could have been determinants of functional recovery by CR. However, we excluded elderly patients with functional independence before CR from the analysis. The majority of our study population had starvation-related malnutrition and/or acute disease or injury-related malnutrition (Table 2), and these types of malnutrition induce sarcopenia. Nutritional status is closely associated with muscle wasting and frailty in the elderly.27,38,39 Thus, it is unlikely that the lack of data for the levels of muscle wasting and frailty greatly misled the interpretation of data for determinants of functional recovery after CR.
The present retrospective study indicated that not only nutritional status determined by MNA-SF score but also total energy intake at the commencement of CR are independent predictors of restoration and/or improvement of functional status attained in elderly HF inpatients after CR.
The authors received no specific grants for this work.
The authors have no relationships relevant to the contents of this paper to disclose.
The authors gratefully acknowledge all the patients for their participation in this study and thank all colleagues at our institution for their contribution to the medical care of the patients.
