Reverse J-shaped relationship between body mass index and in-hospital mortality of patients hospitalized for heart failure in Japan

Association of waist circumference and BMI with premature death in young and middle-aged population

Introduction

Premature death is a global health indicator, significantly impacted by obesity, especially in young and middle-aged population. Both body mass index (BMI) and waist circumference (WC) assess obesity, with WC specifically indicating central obesity and showing a stronger relationship with mortality. However, despite known associations between BMI and premature death, as well as the well-recognized correlation between WC and adverse health outcomes, the specific relationship between WC and premature death remains unclear. Therefore, focusing on young and middle-aged individuals, this study aimed to reliably estimate independent and combined associations between WC, BMI and premature death, thereby providing causal evidence to support strategies for obesity management.

Methods

This study involved 49,217 subjects aged 18-50 years in the United States from 1999 to 2018 National Health and Nutrition Examination Survey (NHANES). Independent and combined associations between WC and BMI with premature death across sex and age stratum were examined by Cox regression. Survey weighting and inverse probability weighting (IPW) were further considered to control selection and confounding bias. Robustness assessment has been conducted on both NHANES and China Health and Retirement Longitudinal Study (CHARLS) data.

Results

A linear and positive relationship between WC and all-cause premature death was found in both males and females, with adjusted HRs of 1.019 (95%CI = 1.004-1.034) and 1.065 (95%CI = 1.039-1.091), respectively. Nonlinear relationships were found with respect to BMI and all-cause premature death. For females aged 36-50 with a BMI below 28.6 kg/m2, the risk of premature death decreased as BMI increased, indicated by adjusted HRs of 0.856 (95%CI = 0.790-0.927). Joint analysis showed among people living with obesity, a larger WC increased premature death risk (HR = 1.924, 95%CI = 1.444-2.564).

Discussion

WC and BMI exhibited prominent associations with premature death in young and middle-aged population. Maintaining an appropriate WC and BMI bears significant implications for preventing premature death.

A machine-learning-based prediction of non-home discharge among acute heart failure patients

BACKGROUND

Scarce data on factors related to discharge disposition in patients hospitalized for acute heart failure (AHF) were available, and we sought to develop a parsimonious and simple predictive model for non-home discharge via machine learning.

METHODS

This observational cohort study using a Japanese national database included 128,068 patients admitted from home for AHF between April 2014 and March 2018. The candidate predictors for non-home discharge were patient demographics, comorbidities, and treatment performed within 2 days after hospital admission. We used 80% of the population to develop a model using all 26 candidate variables and using the variable selected by 1 standard-error rule of Lasso regression, which enhances interpretability, and 20% to validate the predictive ability.

RESULTS

We analyzed 128,068 patients, and 22,330 patients were not discharged to home; 7,879 underwent in-hospital death and 14,451 were transferred to other facilities. The machine-learning-based model consisted of 11 predictors, showing a discrimination ability comparable to that using all the 26 variables (c-statistic: 0.760 [95% confidence interval, 0.752-0.767] vs. 0.761 [95% confidence interval, 0.753-0.769]). The common 1SE-selected variables identified throughout all analyses were low scores in activities of daily living, advanced age, absence of hypertension, impaired consciousness, failure to initiate enteral alimentation within 2 days and low body weight.

CONCLUSIONS

The developed machine learning model using 11 predictors had a good predictive ability to identify patients at high risk for non-home discharge. Our findings would contribute to the effective care coordination in this era when HF is rapidly increasing in prevalence.

The efficacy and safety of adaptive servo-ventilation therapy for heart failure with preserved ejection fraction

It is unclear whether adaptive servo-ventilation (ASV) therapy for heart failure with preserved ejection fraction (HFpEF) is effective. The aim of this study was to investigate the details of ASV use, and to evaluate the effectiveness and safety of ASV in real-world HFpEF patients. We retrospectively enrolled 36 HFpEF patients at nine cardiovascular centers who initiated ASV therapy during hospitalization or on outpatient basis and were able to continue using it at home from 2012 to 2017 and survived for at least one year thereafter. The number of hospitalizations for heart failure (HF) during the 12 months before and 12 months after introduction of ASV at home was compared. The median number of HF hospitalizations for each patient was significantly reduced from 1 [interquartile range: 1-2] in the 12 months before introduction of ASV to 0 [0-0] in the 12 months after introduction of ASV (p < 0.001). In subgroup analysis, reduction in heart failure hospitalization was significantly greater in female patients, patients with a body mass index < 25, and those with moderate or severe tricuspid valve regurgitation. In patients with HFpEF, the number of HF hospitalizations was significantly decreased after the introduction of ASV. HFpEF patients with female sex, BMI < 25, or moderate to severe tricuspid valve regurgitation are potential candidates who might benefit from ASV therapy.

Association Between Early Initiation of Cardiac Rehabilitation and Short-Term Outcomes of Patients With Acute Heart Failure Admitted to the Intensive Care Unit

Cardiac rehabilitation (CR) is a promising therapeutic option for chronic heart failure (HF). However, the extent to which early rehabilitation is beneficial for patients receiving critical care remains controversial. This study examined the association between the early initiation of CR and the short-term clinical outcomes of patients admitted to the intensive care unit (ICU) with acute HF. We used the Diagnosis Procedure Combination database, a nationwide inpatient database in Japan, and included patients with acute HF admitted to the ICU within 2 days after hospital admission. We defined the early initiation of CR as its initiation within 2 days of hospital admission. We performed an overlap weighting based on the propensity scores and inverse probability of treatment weighting analysis to compare the clinical outcomes between patients with and without early initiation of CR. Among 25,362 eligible patients, 3,582 (14.1%) received an early initiation of CR. Overlap weighting created well-balanced cohorts, which showed that the early initiation of CR was related to lower in-hospital mortality (odds ratio [OR] 0.81, 95% confidence interval [CI] 0.68 to 0.96) and shorter hospital stay. The inverse probability of treatment weighting analysis also showed that in-hospital mortality was lower in the patients with the early initiation of CR (OR 0.80, 95% CI 0.67 to 0.96). The instrumental variable analysis also demonstrated the association of the early initiation of CR with lower in-hospital mortality (OR 0.64, 95% CI 0.44 to 0.93). In conclusion, early initiation of CR after hospital admission was associated with better short-term outcomes in patients with acute HF admitted to the ICU, suggesting the potential of the early administration of CR for acute HF requiring intensive care.

Impact of elevated body mass index on burn injury-associated mortality in a representative US sample

BACKGROUND

The impact of obesity on burn-related mortality is inconsistent and incongruent; despite being a risk factor for numerous comorbidities that would be expected to increase complications and worsen outcomes, there is evidence of a survival advantage for patients with high body mass index-the so-called obesity paradox. We used a national data set to explore further the relationship between body mass index and burn-related mortality.

METHODS

Deidentified data from patients with second and third-degree burns between 2014 and 2018 were obtained from the Cerner Health Facts Database. Univariate and multivariate regression models were created to identify potential factors related to burn-related mortality. A restricted cubic spline model was built to assess the nonlinear association between body mass index and burn-related mortality. All statistical analyses were conducted using R (R Foundation for Statistical Computing).

RESULTS

The study included 9,405 adult burn patients. Univariate and multivariate analyses revealed that age (odds ratio = 2.189 [1.771, 2.706], P < .001), total burn surface area (odds ratio = 1.824 [1.605, 2.074], P < .001), full-thickness burns (odds ratio = 1.992 [1.322, 3.001], P < .001), and comorbidities (odds ratio = 2.03 [1.367, 3.014], P < .001) were associated with increased mortality. Sensitivity analysis showed similar results. However, a restricted cubic spline indicated a U-shaped relation between body mass index and burn-related mortality. The nadir of body mass index was 28.92 kg/m², with the lowest mortality. This association persisted even after controlling for age, total burn surface area, full-thickness burns, and comorbidities, which all remained significant.

CONCLUSION

This study confirms a U-shaped association between body mass index and burn-related mortality along with age, total burn surface area, full-thickness burns, and comorbidities as risk factors.

Association of weight change and in-hospital mortality in patients with repeated hospitalization for heart failure

BACKGROUND

Although weight loss in heart failure (HF) is a detrimental condition known as cachexia, weight gain caused by fluid retention should also be considered harmful. However, studies with sufficient number of patients examining the impact of weight change and its interval on in-hospital mortality in HF have not been conducted thus far. We sought to elucidate the association of weight change with in-hospital mortality in patients with HF.

METHODS

This retrospective observational study used data from the Diagnosis Procedure Combination database, a nationwide inpatient health claims database in Japan. In total, 48 234 patients repeatedly hospitalized for HF (median 82 [74-87] years; 46.4% men) between 2010 and 2018 were included. Weight change was derived from body weight at the first and second admissions.

RESULTS

The median weight change and interval between two hospitalizations were -3.1 [-8.3 to -1.8] % and 172 [67-420] days, with 66.9% of overall cohort experiencing any weight loss. As a result of multivariable-adjusted logistic regression analysis, weight loss <-5.0% and weight gain >+5.0% were associated with increased in-hospital mortality (adjusted odds ratio [OR] [95% confidence interval]: 1.46 [1.31-1.62], P < 0.001 and 1.23 [1.08-1.40], P = 0.002, respectively) whereas mild weight loss and gain of 2.0-5.0% were not (OR [95% confidence interval]: 0.96 [0.84-1.10], P = 0.57 and 1.07 [0.92-1.25], P = 0.37, respectively), in comparison with patients with a stable weight (fluctuating no more than -2.0% to +2.0%) used as a reference. Restrictive cubic spline models adjusted for multiple background factors illustrated that higher mortality in patients with weight loss was observed across all subgroups of the baseline body mass index (<18.5, 18.5-24.9 and ≥25.0 kg/m2 ). In patients with short (<90 days) and middle (<180 days) intervals between the two hospitalizations, both weight loss and weight gain were associated with high mortality, whereas the association between weight gain and high mortality was attenuated in those with longer intervals.

CONCLUSIONS

Both weight loss and weight gain in patients with repeated hospitalization for HF were associated with high in-hospital mortality, especially weight loss and short/middle-term weight gain. Such patients should be treated with caution in a setting of repeated hospitalization for HF.

Impact of body mass index on in-hospital mortality for six acute cardiovascular diseases in Japan

Body mass index (BMI) distribution and its impact on cardiovascular disease (CVD) vary between Asian and western populations. The study aimed to reveal time-related trends in the prevalence of obesity and underweight and safe ranges of BMI in Japanese patients with CVD. We analyzed 5,020,464 records from the national Japanese Registry of All Cardiac and Vascular Diseases-Diagnosis Procedure Combination dataset over time (2012-2019) and evaluated BMI trends and the impact on in-hospital mortality for six acute CVDs: acute heart failure (AHF), acute myocardial infarction (AMI), acute aortic dissection (AAD), ischemic stroke (IS), intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH). Patients were categorized into five groups using the WHO Asian-BMI criteria: underweight (< 18.5 kg/m²), normal (18.5-22.9 kg/m²), overweight at risk (23.0-24.9 kg/m²), obese I (25.0-29.9 kg/m²), and obese II (≥ 30.0 kg/m²). Age was significantly and inversely related to high BMI for all diseases (P < 0.001). The proportion of BMI categories significantly altered over time; annual BMI trends showed a significant and gradual increase, except AAD. In adjusted mixed models, underweight was significantly associated with a high risk of in-hospital mortality in all CVD patients (AHF, OR 1.41, 95% CI 1.35-1.48, P < 0.001; AMI, OR 1.27, 95% CI 1.20-1.35, P < 0.001; AAD, OR 1.23, 95% CI 1.16-1.32, P < 0.001; IS, OR 1.45, 95% CI 1.41-1.50, P < 0.001; ICH, OR 1.18, 95% CI 1.13-1.22, P < 0.001; SAH, OR 1.17, 95% CI 1.10-1.26, P < 0.001). Moreover, obese I and II groups were significantly associated with a higher incidence of in-hospital mortality, except AHF and IS. Age was associated with in-hospital mortality for all BMI categories in six CVD patients. BMI increased annually in patients with six types of CVDs. Although underweight BMI was associated with high mortality rates, the impact of obesity on in-hospital mortality differs among CVD types.

[Heart failure and obesity]

Obesity is an independent predictor of cardiovascular diseases (CVD), including heart failure (HF). Nevertheless, numerous studies have shown that patients with CVD who are overweight and slightly obese have a better short-term and moderate prognosis than thinner patients with CVD. This phenomenon has been called the obesity paradox. Understanding the obesity paradox is important in patients with HF, given the high prevalence of obesity in patients with HF. The article presents an overview of clinical studies devoted to the study of obesity as a risk factor for HF, the pathogenesis of HF in obesity, and highlights the issues of the obesity paradox and the treatment of obesity in this category of patients.

Hospital-associated disability and hospitalization costs for acute heart failure stratified by body mass index- insight from the JROAD/JROAD-DPC database

BACKGROUND

The impact of body mass index (BMI) on hospital mortality in patients with acute heart failure has been well documented in Asian populations. However, the relationship between BMI, hospital-associated disability (HAD), and hospitalization costs in patients with heart failure is poorly understood. This study aimed to explore the impact of BMI on HAD and hospitalization costs for acute heart failure in Japan.

METHODS

From April 2012 to March 2020, the Japanese Registry of All Cardiac and Vascular Disease Diagnosis Procedure Combination (JROAD-DPC) database was used to identify patients with acute heart failure. All patients were categorized into five groups according to the World Health Organization Asian BMI criteria. The hospitalization costs and HAD were evaluated.

RESULTS

Among the 238,160 eligible patients, 15.7% were underweight, 42.2% were normal, 16.7% were overweight, 19.3% were obese I, and 6.0% were obese II, according to BMI. The prevalence of HAD was 7.43% in the total cohort, and the risk of HAD increased with a lower BMI. Restricted cubic spline analysis showed a U-shaped relationship between BMI and hospitalization costs for all ages. Furthermore, developing HAD was associated with greater costs compared with non-HAD, regardless of BMI category.

CONCLUSIONS

We found that the lower the BMI, the higher the incidence of HAD. A U-shaped association was confirmed between BMI and hospitalization costs, indicating that hospitalization costs increased for both lower and higher BMI regardless of age. BMI could be an important and informative risk stratification tool for functional outcomes and economic burdens.

Acute-Phase Initiation of Cardiac Rehabilitation for Short-Term Improvement in Activities of Daily Living in Patients Hospitalized for Acute Heart Failure

BACKGROUND

Whether acute-phase cardiac rehabilitation (CR) is beneficial for short-term improvement in activities of daily living (ADL) in patients hospitalized for acute heart failure (AHF) remains unclear.

AIM

To investigate the association of acute-phase initiation of CR with short-term improvement in ADL in patients hospitalized for AHF.

METHODS

We retrospectively analyze data from the Diagnosis Procedure Combination Database, a nationwide inpatient database. Patients hospitalized for HF between January 2010 and March 2018 are included. Propensity score matching and generalized linear models are built to examine the association between improvement in ADL and acute-phase CR initiation, defined as the initiation of CR within two days of admission.

RESULTS

Among 306,826 eligible patients, CR is initiated in 45,428 patients (14.8%) within two days of hospital admission. Propensity score matching creates 45,427 pairs. CR initiation within two days of hospital admission is associated with ADL improvement (risk ratio: 1.018; 95% confidence interval: 1.004-1.032), particularly in elderly patients, females, and individuals with low ADL at admission, body mass index of 18.5-24.9 kg/m2, and New York Heart Association class IV.

CONCLUSIONS

Our analyses highlight the possibility that acute-phase CR initiation may result in short-term improvement in ADL in patients hospitalized for AHF.

Obesity paradox and aging: Visceral Adiposity Index and all-cause mortality in older individuals: A prospective cohort study

BACKGROUND

The relationship between body mass index (BMI) and mortality in older adults diminished. It is necessary to examine other factors that may accurately predict mortality in older adults. The visceral adiposity index (VAI) is an uncomplicated marker specific to the gender that incorporates anthropometric data and lipid profiles. VAI has been proposed as a marker of visceral adipose tissue dysfunction and of the related cardiometabolic risk. The aim of this study was to evaluate the link of VAI with all-cause mortality among the elderly.

METHODS

The present prospective cohort study included data from 1999 to 2014 provided by the National Health and Nutrition Examination Survey (NHANES) in the United States. NHANES participants at or above the age of 65 were included. Data collection was carried out by taking face-to-face interviews, mobile-physical examinations, and lab tests. From the start of the survey to the end of December 2015, mortality-related follow-up statistics are available. The shape of the link between VAI and all-cause mortality was investigated using a restricted cubic spline model. Univariate- and multivariate-adjusted Cox proportional hazard models were estimated for VAI, and the results were presented as regression coefficients and 95% confidence intervals (CI).

RESULTS

The 82,091 NHANES participants represented 442.2 million non-institutionalized residents of the United States. A total of 11,173 older individuals (representing 23.3 million; aged 73.4 ± 5.8 years; 56.3% women, 82.7% non-Hispanic Whites, 6.8% non-Hispanic Blacks, and 3.3% Mexican Americans) were included in the study. During the 80-month follow-up period, 4466 fatalities were reported, including 825 deaths from cancer, 867 from heart disease, and 211 from cerebrovascular disease. The restricted cubic spline model demonstrated a robust J-shaped link between VAI and all-cause mortality, revealing a significant decrease in risk within the lower range of VAI, which attained the lowest risk close to 1.7. With VAI greater than 1.7, the risk of mortality increased with the increase of VAI (P for non-linearity = 0.025). In the multivariate-adjusted model, the risk of all-cause mortality was 0.73 (0.56-0.97) and 1.05 (1.01-1.09) in participants with VAI less than 1.7 and VAI greater than or equal to 1.7, respectively.

CONCLUSION

This investigation is a population-based cohort study with high sample sizes and a long-term in older individuals follow-up that showed a J-shaped link between VAI levels and all-cause mortality. Understanding the independent roles of VAI in the relationship between BMI and mortality is crucial to understanding the obesity paradox phenomenon.

Acute-phase initiation of cardiac rehabilitation and clinical outcomes in hospitalized patients for acute heart failure

BACKGROUND

Extensive data support the clinical benefit of cardiac rehabilitation (CR) for patients with chronic heart failure (HF). However, whether CR could be beneficial for patients hospitalized for acute heart failure remains unclear.

METHODS

We retrospectively analyzed data from the Diagnosis Procedure Combination database, a nationwide inpatient database. We included patients hospitalized for HF, who were aged ≥20 years and with New York Heart Association class ≥II, between January 2010 and March 2018. We excluded patients with length of hospital stay ≤2 days, those undergoing major procedures under general anesthesia, those requiring advanced mechanical supports within 2 days after admission, and those with disturbance of consciousness. Propensity score matching and instrumental variable analyses were conducted to compare clinical outcomes between the patients with and without acute-phase initiation of CR defined as initiation of CR within two days after hospital admission.

RESULTS

Among 430,216 eligible patients, 63,470 patients (14.8%) received the acute-phase initiation of CR. Propensity score matching created 63,470 pairs and found that the acute-phase initiation of CR was associated with lower in-hospital mortality (odds ratio [OR] 0.76, 95% confidence interval [CI] 0.73-0.80), shorter hospital stay and lower incidence of 30-day readmission due to HF. The instrumental variable analysis also showed patients with acute-phase initiation of CR was associated with lower in-hospital mortality than those without (OR, 0.73; 95% CI, 0.68-0.79).

CONCLUSION

Our analysis suggested a potential benefit of acute-phase initiation of CR for short-term clinical outcomes in hospitalized patients with acute HF.

Association of Body Mass Index with Ischemic and Hemorrhagic Stroke

Data on the association between body mass index (BMI) and stroke are scarce. We aimed to examine the association between BMI and incident stroke (ischemic or hemorrhagic) and to clarify the relationship between underweight, overweight, and obesity and stroke risk stratified by sex. We analyzed the JMDC Claims Database between January 2005 and April 2020 including 2,740,778 healthy individuals (Median (interquartile) age, 45 (38-53) years; 56.2% men; median (interquartile) BMI, 22.3 (20.2-24.8) kg/m²). None of the participants had a history of cardiovascular disease. Each participant was categorized as underweight (BMI <18.5 kg/m²), normal weight (BMI 18.5-24.9 kg/m²), overweight (BMI 25.0-29.9 kg/m²), or obese (BMI ≥ 30 kg/m²). We investigated the association of BMI with incidence stroke in men and women using the Cox regression model. We used restricted cubic spline (RCS) functions to identify the association of BMI as a continuous parameter with incident stroke. The incidence (95% confidence interval) of total stroke, ischemic stroke, and hemorrhagic stroke was 32.5 (32.0-32.9), 28.1 (27.6-28.5), and 5.5 (5.3-5.7) per 10,000 person-years in men, whereas 25.7 (25.1-26.2), 22.5 (22.0-23.0), and 4.0 (3.8-4.2) per 10,000 person-years in women, respectively. Multivariable Cox regression analysis showed that overweight and obesity were associated with a higher incidence of total and ischemic stroke in both men and women. Underweight, overweight, and obesity were associated with a higher hemorrhagic stroke incidence in men, but not in women. Restricted cubic spline showed that the risk of ischemic stroke increased in a BMI dose-dependent manner in both men and women, whereas there was a U-shaped relationship between BMI and the hemorrhagic stroke risk in men. In conclusion, overweight and obesity were associated with a greater incidence of stroke and ischemic stroke in both men and women. Furthermore, underweight, overweight, and obesity were associated with a higher hemorrhagic stroke risk in men. Our results would help in the risk stratification of future stroke based on BMI.

Impact of hospital volume on clinical outcomes of hospitalized heart failure patients: analysis of a nationwide database including 447,818 patients with heart failure

BACKGROUND

Hospital volume is known to be associated with outcomes of patients requiring complicated medical care. However, the relationship between hospital volume and prognosis of hospitalized patients with heart failure (HF) remains not fully understood. We aimed to clarify the impact of hospital volume on clinical outcomes of hospitalized HF patients using a nationwide inpatient database.

METHODS AND RESULTS

We studied 447,818 hospitalized HF patients who were admitted from January 2010 and discharged until March 2018 included in the Japanese Diagnosis Procedure Combination database. According to the number of patients, patients were categorized into three groups; those treated in low-, medium-, and high-volume centers. The median age was 81 years and 238,192 patients (53%) were men. Patients who had New York Heart Association class IV symptom and requiring inotropic agent within two days were more common in high volume centers than in low volume centers. Respiratory support, hemodialysis, and intra-aortic balloon pumping were more frequently performed in high volume centers. As a result, length of hospital stay was shorter, and in-hospital mortality was lower in high volume centers. Lower in-hospital mortality was associated with higher hospital volume. Multivariable logistic regression analysis fitted with generalized estimating equation indicated that medium-volume group (Odds ratio 0.91, p = 0.035) and high-volume group (Odds ratio 0.86, p = 0.004) had lower in-hospital mortality compared to the low-volume group. Subgroup analysis showed that this association between hospital volume and in-hospital mortality among overall population was seen in all subgroups according to age, presence of chronic renal failure, and New York Heart Association class.

CONCLUSION

Hospital volume was independently associated with ameliorated clinical outcomes of hospitalized patients with HF.