Prevalence, trends, outcomes, and disparities in hospitalizations for nonalcoholic fatty liver disease in the United States

Sex and racial disparities in non-alcoholic fatty liver disease-related cardiovascular events: National inpatient sample analysis (2019)

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) increases cardiovascular disease (CVD) risk irrespective of other risk factors. However, large-scale cardiovascular sex and race differences are poorly understood.

AIM

To investigate the relationship between NAFLD and major cardiovascular and cerebrovascular events (MACCE) in subgroups using a nationally representative United States inpatient sample.

METHODS

We examined National Inpatient Sample (2019) to identify adult hospitalizations with NAFLD by age, sex, and race using ICD-10-CM codes. Clinical and demographic characteristics, comorbidities, and MACCE-related mortality, acute myocardial infarction (AMI), cardiac arrest, and stroke were compared in NAFLD cohorts by sex and race. Multivariable regression analyses were adjusted for sociodemographic characteristics, hospitalization features, and comorbidities.

RESULTS

We examined 409130 hospitalizations [median 55 (IQR 43-66) years] with NFALD. NAFLD was more common in females (1.2%), Hispanics (2%), and Native Americans (1.9%) than whites. Females often reported non-elective admissions, Medicare enrolment, the median age of 55 (IQR 42-67), and poor income. Females had higher obesity and uncomplicated diabetes but lower hypertension, hyperlipidemia, and complicated diabetes than males. Hispanics had a median age of 48 (IQR 37-60), were Medicaid enrollees, and had non-elective admissions. Hispanics had greater diabetes and obesity rates than whites but lower hypertension and hyperlipidemia. MACCE, all-cause mortality, AMI, cardiac arrest, and stroke were all greater in elderly individuals (P < 0.001). MACCE, AMI, and cardiac arrest were more common in men (P < 0.001). Native Americans (aOR 1.64) and Asian Pacific Islanders (aOR 1.18) had higher all-cause death risks than whites.

CONCLUSION

Increasing age and male sex link NAFLD with adverse MACCE outcomes; Native Americans and Asian Pacific Islanders face higher mortality, highlighting a need for tailored interventions and care.

Impact of metabolic dysfunction-associated steatotic liver disease on COVID-19 hospitalizations: A propensity-matched analysis of the United States

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD), formally known as nonalcoholic fatty liver disease, is the most common chronic liver disease in the United States. Patients with MASLD have been reported to be at a higher risk of developing severe coronavirus disease 2019 (COVID-19) and death. However, most studies are single-center studies, and nationwide data in the United States is lacking.

AIM

To study the influence of MASLD on COVID-19 hospitalizations during the initial phase of the pandemic.

METHODS

We retrospectively analyzed the 2020 National Inpatient Sample (NIS) database to identify primary COVID-19 hospitalizations based on an underlying diagnosis of MASLD. A matched comparison cohort of COVID-19 hospitalizations without MASLD was identified from NIS after 1: N propensity score matching based on gender, race, and comorbidities, including hypertension, heart failure, diabetes, and cirrhosis. The primary outcomes included inpatient mortality, length of stay, and hospitalization costs. Secondary outcomes included the prevalence of systemic complications.

RESULTS

A total of 2210 hospitalizations with MASLD were matched to 2210 hospitalizations without MASLD, with a good comorbidity balance. Overall, there was a higher prevalence of severe disease with more intensive care unit admissions (9.5% vs 7.2%, P = 0.007), mechanical ventilation (7.2% vs 5.7%, P = 0.03), and septic shock (5.2% vs 2.7%, P <0.001) in the MASLD cohort than in the non-MASLD cohort. However, there was no difference in mortality (8.6% vs 10%, P = 0.49), length of stay (5 d vs 5 d, P = 0.25), and hospitalization costs (42081.5 $ vs 38614$, P = 0.15) between the MASLD and non-MASLD cohorts.

CONCLUSION

The presence of MAFLD with or without liver cirrhosis was not associated with increased mortality in COVID-19 hospitalizations; however, there was an increased incidence of severe COVID-19 infection. This data (2020) predates the availability of COVID-19 vaccines, and many MASLD patients have since been vaccinated. It will be interesting to see if these trends are present in the subsequent years of the pandemic.

Dietary patterns and metabolic dysfunction-associated fatty liver disease in China's multi-ethnic regions

BACKGROUND

The prevalence of metabolic dysfunction-associated fatty liver disease (MAFLD) has been rising rapidly in western China. Diet acts as an effective therapy for MAFLD. However, there has been scarce research on the association between a posteriori diet patterns (DPs) and MAFLD in this region.

METHOD

We identified three a posteriori DPs which were "Sichuan Basin pattern" characterized by a high intake of fish/seafood, poultry, fresh fruit and vegetables, indicating a balanced and modern DP; the "Yunnan-Guizhou Plateau dietary pattern" characterized mainly by a high intake of animal oil and salt, indicating an agricultural and poor DP; and the "Qinghai-Tibet Plateau dietary pattern" characterized by a high intake of coarse grains, wheat products, tubers and tea, respectively, indicating a high-altitude DP. Then, we performed marginal structural models that combined logistic regression and inverse probability exposure weighting (IPEW) to examine the associations between MAFLD and these a posteriori DPs.

RESULT

We found the "Yunnan-Guizhou Plateau dietary pattern" revealed stronger positive association (OR = 1.50, 95% CI 1.40-1.60) with MAFLD than that of the "Qinghai-Tibet Plateau dietary pattern" (OR = 1.21, 95% CI 1.14-1.30). In contrast, the "Sichuan Basin dietary pattern" showed no significant association with MAFLD. In the further stratified analysis, we found those above associations were stronger in ethnic minorities and rural residents than their counterparts.

CONCLUSION

Our study implied the unfavourable effects of "Yunnan-Guizhou Plateau dietary pattern" on MAFLD and provided evidence that reducing the intake of oil and sodium may be optimal for MAFLD control in the multi-ethnic region in western China.

Role of fatty liver index in risk-stratifying comorbid disease outcomes in non-alcoholic fatty liver disease

Background & Aims

Population screening for non-alcoholic fatty liver disease (NAFLD) and associated comorbidities remains an unaddressed clinical need. We aimed to assess the utility of the fatty liver index (FLI) for risk stratification of NAFLD and related comorbidities using the UK Biobank.

Methods

Electronic health records and liver MRI-proton density fat fraction (PDFF) were used to define NAFLD cases. FLI was calculated and individuals with high alcohol intake and other liver diseases were excluded. Using listwise deletion analysis, the area under receiver-operating characteristic curve (AUROC) of FLI for NAFLD risk was determined. Thereafter, time-dependent covariate-adjusted Cox regression models were used to estimate FLI's risk stratification potential for comorbidities of interest.

Results

FLI was derived for 327,800 individuals with a median age of 58 (IQR 51.5-64.5), of whom 59.8% were females. Using Perspectum Diagnostics and AMRA protocols as references, FLI identified the risk of NAFLD with AUROCs (95% CI, n) of 0.858 (0.848-0.867, n = 7,566) and 0.851 (0.844-0.856, n = 10,777), respectively. Intermediate and high-risk FLI was associated with increased cardiometabolic and malignant disease. In the first 3 years, high-risk FLI conferred an increased risk (adjusted hazard ratio, 95% CI) of ischaemic heart disease (2.14, 1.94-2.36), hypertension (2.84, 2.70-2.98), type 2 diabetes mellitus (4.55, 4.04-5.12), dyslipidaemia (2.48, 2.32-2.64), ischaemic stroke (1.31, 1.20-1.42) and hepatic malignancy (1.69, 1.23-2.30). FLI was not associated with risk of extrahepatic malignancy but was associated with a higher risk of specific cancers (colon, upper gastrointestinal and breast). All-cause mortality was similarly stratified by FLI, independently of non-invasive fibrosis scores.

Conclusions

FLI identifies NAFLD and holds potential for the risk stratification of cardiometabolic and malignant disease outcomes (including some extrahepatic malignancies), as well as all-cause mortality. Its use in population screening for primary and secondary prevention of NAFLD should be considered.

Impact and implications

Our analysis using the UK Biobank study shows the potential of the fatty liver index as a risk stratification tool for identifying the risk of developing NAFLD, ischaemic heart disease, ischaemic stroke, type 2 diabetes mellitus, hypertension, hyperlipidaemia, hepatic malignancy, specific metabolism-related malignancies and all-cause mortality. These results suggest that the fatty liver index should be considered as a non-invasive steatosis score that may help guide primary prevention strategies for NAFLD and related outcomes.

Peptic ulcer disease in non-alcoholic fatty liver disease hospitalizations: A new challenge on the horizon in the United States

BACKGROUND

Peptic ulcer disease (PUD) is frequently seen in patients with liver cirrhosis. However, current literature lacks data on PUD in non-alcoholic fatty liver disease (NAFLD) hospitalizations.

AIM

To identify trends and clinical outcomes of PUD in NAFLD hospitalizations in the United States.

METHODS

The National Inpatient Sample was utilized to identify all adult (≥ 18 years old) NAFLD hospitalizations with PUD in the United States from 2009-2019. Hospitalization trends and outcomes were highlighted. Furthermore, a control group of adult PUD hospitalizations without NAFLD was also identified for a comparative analysis to assess the influence of NAFLD on PUD.

RESULTS

The total number of NAFLD hospitalizations with PUD increased from 3745 in 2009 to 3805 in 2019. We noted an increase in the mean age for the study population from 56 years in 2009 to 63 years in 2019 (P < 0.001). Racial differences were also prevalent as NAFLD hospitalizations with PUD increased for Whites and Hispanics, while a decline was observed for Blacks and Asians. The all-cause inpatient mortality for NAFLD hospitalizations with PUD increased from 2% in 2009 to 5% in 2019 (P < 0.001). However, rates of Helicobacter pylori (H. pylori) infection and upper endoscopy decreased from 5% in 2009 to 1% in 2019 (P < 0.001) and from 60% in 2009 to 19% in 2019 (P < 0.001), respectively. Interestingly, despite a significantly higher comorbidity burden, we observed lower inpatient mortality (2% vs 3%, P = 0.0004), mean length of stay (LOS) (11.6 vs 12.1 d, P < 0.001), and mean total healthcare cost (THC) ($178598 vs $184727, P < 0.001) for NAFLD hospitalizations with PUD compared to non-NAFLD PUD hospitalizations. Perforation of the gastrointestinal tract, coagulopathy, alcohol abuse, malnutrition, and fluid and electrolyte disorders were identified to be independent predictors of inpatient mortality for NAFLD hospitalizations with PUD.

CONCLUSION

Inpatient mortality for NAFLD hospitalizations with PUD increased for the study period. However, there was a significant decline in the rates of H. pylori infection and upper endoscopy for NAFLD hospitalizations with PUD. After a comparative analysis, NAFLD hospitalizations with PUD had lower inpatient mortality, mean LOS, and mean THC compared to the non-NAFLD cohort.

Influence of non-alcoholic fatty liver disease on non-variceal upper gastrointestinal bleeding: A nationwide analysis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of liver disease globally with an estimated prevalence of 25%, with the clinical and economic burden expected to continue to increase. In the United States, non-variceal upper gastrointestinal bleeding (NVUGIB) has an estimated incidence of 61-78 cases per 100000 people with a mortality rate of 2%-15% based on co-morbidity burden.

AIM

To identify the outcomes of NVUGIB in NAFLD hospitalizations in the United States.

METHODS

We utilized the National Inpatient Sample from 2016-2019 to identify all NVUGIB hospitalizations in the United States. This population was divided based on the presence and absence of NAFLD. Hospitalization characteristics, outcomes and complications were compared.

RESULTS

The total number of hospitalizations for NVUGIB was 799785, of which 6% were found to have NAFLD. NAFLD and GIB was, on average, more common in younger patients, females, and Hispanics than GIB without NAFLD. Interestingly, GIB was less common amongst blacks with NAFLD. Multivariate logistic regression analysis was conducted, controlling for the multiple covariates. The primary outcome of interest, mortality, was found to be significantly higher in patients with NAFLD and GIB [adjusted odds ratio (aOR) = 1.018 (1.013-1.022)]. Secondary outcomes of interest, shock [aOR = 1.015 (1.008-1.022)], acute respiratory failure [aOR = 1.01 (1.005-1.015)] and acute liver failure [aOR = 1.016 (1.013-1.019)] were all more likely to occur in this cohort. Patients with NAFLD were also more likely to incur higher total hospital charges (THC) [$2148 ($1677-$2618)]; however, were less likely to have a longer length of stay [0.27 d (0.17-0.38)]. Interestingly, in our study, the patients with NAFLD were less likely to suffer from acute myocardial infarction [aOR = 0.992 (0.989-0.995)]. Patients with NAFLD were not more likely to suffer acute kidney injury, sepsis, blood transfusion, intubation, or dialysis.

CONCLUSION

NVUGIB in NAFLD hospitalizations had higher inpatient mortality, THC, and complications such as shock, acute respiratory failure, and acute liver failure compared to those without NAFLD.

PM2.5 air pollution exposure and nonalcoholic fatty liver disease in the Nationwide Inpatient Sample

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease. Particulate matter air pollution <2.5 μm in diameter (PM_2.5) is a ubiquitous exposure primarily produced from fossil fuel combustion. Previous epidemiologic studies have been mixed. The objective of this study was to examine the association between ambient PM_2.5 exposure and NAFLD among hospitalized patients in the Nationwide Inpatient Sample (NIS).

METHODS

We conducted a cross-sectional analysis of hospitalizations from 2001 to 2011 using the NIS, the largest nationally representative all-payer inpatient care administrative database in the United States. Average annual PM_2.5 exposure was estimated by linking census tracts (based on NIS-provided hospital ZIP Codes) with a spatiotemporal exposure model. Clinical conditions were identified using hospital discharge diagnosis codes. Multivariable logistic regression incorporating discharge weights was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between PM_2.5 exposure and odds of NAFLD among hospitalized patients adjusting for age, sex, race/ethnicity, year, individual- and area-level socioeconomic status, urbanicity, region, obesity, diabetes, metabolic syndrome, impaired fasting glucose, dyslipidemia, hypertension, obstructive sleep apnea, and smoking.

RESULTS

There were 269,705 hospitalized patients with NAFLD from 2001 to 2011 (total unweighted n = 45,433,392 hospitalizations). Higher ambient PM_2.5 exposure was associated with increased odds of NAFLD among hospitalized patients (adjusted OR: 1.24 per 10 μg/m³ increase, 95% CI 1.15-1.33, p < 0.01). There were statistically significant interactions between PM_2.5 exposure and age, race/ethnicity, diabetes, smoking, and region, with stronger positive associations among patients who were aged ≥45 years, non-Hispanic White or Asian/Pacific Islander, non-diabetics, non-smokers, or in the Midwest and West regions, respectively.

CONCLUSIONS

In this nationwide cross-sectional analysis of the NIS database, there was a positive association between ambient PM_2.5 exposure and odds of NAFLD among hospitalized patients. Future research should examine the effects of long-term historical PM_2.5 exposure and incident NAFLD cases.

What Do We Know about Inequalities in NAFLD Distribution and Outcomes? A Scoping Review

With prevalence high and rising given the close relationship with obesity and diabetes mellitus, non-alcoholic fatty liver disease (NAFLD) is progressively becoming the most common chronic liver condition worldwide. However, little is known about the health inequalities in NAFLD distribution and outcomes. This review aims to analyze health inequalities in NAFLD distribution globally and to assess the health disparities in NAFLD-related outcomes. We conducted a scoping review of global health inequalities in NAFLD distribution and outcomes according to gender/sex, ethnicity/race, and socioeconomic position from PubMed's inception to May 2021. Ultimately, 20 articles were included in the review, most (75%) of them carried out in the United States. Males were found to have a higher NAFLD prevalence (three articles), while available evidence suggests that women have an overall higher burden of advanced liver disease and complications (four articles), whereas they are less likely to be liver-transplanted once cirrhosis develops (one article). In the US, the Hispanic population had the highest NAFLD prevalence and poorer outcomes (seven articles), whereas Whites had fewer complications than other ethnicities (two articles). Patients with low socioeconomic status had higher NAFLD prevalence (four articles) and a higher likelihood of progression and complications (five articles). In conclusion, globally there is a lack of studies analyzing NAFLD prevalence and outcomes according to various axes of inequality through joint intersectional appraisals, and most studies included in our review were based on the US population. Available evidence suggests that NAFLD distribution and outcomes show large inequalities by social group. Further research on this issue is warranted.

A Retrospective Study of Hospitalizations in the USA: Proportion of Hospitalizations With Non-Alcoholic Fatty Liver Disease in Non-Obese Population

Background Non-alcoholic fatty liver disease (NAFLD), one of the leading causes of end-stage liver disease, is known to be associated with obesity. However, only a few studies in the United States (US) have described non-obese NAFLD, most of which were on the outpatient population. Aim We aimed to investigate the proportion of hospitalizations in the US with a diagnosis code that included NAFLD in the non-obese population. Methods We analyzed adult discharges from the Nationwide Inpatient Sample with a diagnosis of NAFLD from January 2010 to December 2014. We created two groups: obese (overweight or obese) and non-obese (normal or underweight) groups. Basic demographic and clinical characteristics were compared using the chi-square test and Student's t-test. Results A total of 194,787 hospitalizations with NAFLD were identified over the five-year period. It was observed that the prevalence of non-obese NAFLD hospitalizations increased yearly. Non-obese NAFLD hospitalizations had a higher mean age (57.5 vs 51.5 years, p < 0.0001) and a higher proportion of males (43.3% vs 36.1%, p < 0.0001) than obese NAFLD hospitalizations. With univariate analysis, non-obese NAFLD hospitalizations had lower odds of hypertension (OR 0.74, p < 0.0001), diabetes mellitus (OR 0.65, p < 0.0001). Non-obese hospitalizations had higher odds of cirrhosis (OR 1.30, p < 0.001) and decompensated cirrhosis (OR 1.30, p < 0.001) after adjusting for age, sex, race, diabetes mellitus, and dyslipidemia. Hospitalizations with non-obese NAFLD had higher odds of death (OR 1.49, p < 0.001) after adjusting for age, gender, race, co-morbidities, cirrhosis, and liver decompensation. Conclusion There is a continued rise in the proportion of non-obese NAFLD among hospitalizations in the US. Non-obese NAFLD hospitalizations were less likely to have hypertension and diabetes, but more likely to have decompensated liver disease. Further studies are needed to better characterize these patients to enable early detection, treatment, and reduction in complications of liver disease.

Racial differences in prevalence and severity of non-alcoholic fatty liver disease

The aim of this review is to assess the evidence regarding racial differences in the prevalence and severity of nonalcoholic fatty liver disease (NAFLD). We reviewed the published literature that reported prevalence, severity, and genetic associations of NAFLD in different ethnic groups. The metabolic syndrome (MetS) has been associated with NAFLD, but each component of the MetS is present in various races in different percentages and their effect on NAFLD appears to be dissimilar. An elevated triglyceride (TG) level seems to have the strongest association with NAFLD. The latter is more prevalent in Hispanic patients; Blacks have lower TG levels and a lower NAFLD prevalence, compared to Caucasians or Hispanics. The severity of liver fibrosis is lower in some, but not all biopsy-based studies of Black patients. No study has evaluated the severity of liver disease controlling for the individual components of MetS, especially TG. Important racial differences in the prevalence of selected genetic polymorphisms, particularly PNPLA-3 and MBOAT7 have been documented, together with their effects on the prevalence of liver steatosis and fibrosis. Data on overall and liver mortality have found no significant differences according to race/ethnicity, with the possible exception of one paper reporting lower cirrhosis mortality in Black patients. We conclude that NAFLD is more prevalent in Hispanics and less in Blacks. This is supported by differences in key genetic polymorphisms associated with hepatic fat storage. However, there is presently insufficient evidence to firmly conclude that race, per se, plays a role in the development of liver fibrosis and its complications. Further studies, appropriately controlled for diet, exercise, and individual MetS parameters are needed.

Gender and Racial Differences in Hospitalizations for Primary Biliary Cholangitis in the USA

BACKGROUND/AIM

The prevalence, characteristics, burden and trends of primary biliary cholangitis (PBC) hospitalizations in the USA remain unclear.

METHOD

We identified primary PBC hospitalizations from the National Inpatient Sample (NIS) 2007 through 2014 using ICD-9-CM codes. We calculated the rates and trends of hospitalization for PBC per 100,000 US population among each gender (males and females) and racial categories (Whites, Blacks, Hispanics and other racial minorities), and measured the predictors of hospitalization, and of mortality, charges and length of stay (LOS) among PBC hospitalizations.

RESULT

There were 8460 (weighted: 41,191) PBC hospitalizations between 2007 and 2014. The mean national PBC hospitalization rate was 2.2 cases per 100,000 population (2.2/100,000), increasing from 1.7/100,000 (2007) to 2.5/100,000 (2014). From 2007 to 2014, the in-hospital mortality and LOS were unchanged while the charges increased from $65,993 to $73,093 ($225 million to $447 million overall expenses). Compared to Whites, the PBC hospitalization rate was 12% higher among Hispanics (RR: 1.12 [1.09-1.16]), 53% lower in Blacks (RR: 0.47 [0.45-0.49]) and 5% lower among other racial minorities (0.95 [0.91-0.99]). The rate was higher among females (RR:4.02 [3.93-4.12]) compared to males. On multivariate analysis, Blacks and other racial minorities, respectively, had higher odds of mortality (AOR: 1.47 [1.03-2.10] and 1.33 [0.96-1.84]), while other racial minorities had longer LOS (7.0 vs. 5.6 days) and higher hospital charges ($48,984 vs. $41,495) when compared to Whites.

CONCLUSION

The hospitalization rate and burden of PBC in the USA have increased disproportionately among females and Hispanics with higher mortality in Blacks.

Diversity in NAFLD: A Review of Manifestations of Nonalcoholic Fatty Liver Disease in Different Ethnicities Globally

Globally, the rise in prevalence of obesity and metabolic syndrome as a whole has been linked to increased access to processed foods, such as refined sugars and saturated fats. Consequently, nonalcoholic fatty liver disease (NAFLD) is on the rise in both developed and developing nations. However, much is still unknown on the NAFLD phenotype with regards to the effect of ethnic diversity. Despite similarities in dietary habits, it appears that certain ethnicities are more protected against NAFLD than others. However, manifestations of the same genetic polymorphisms in different groups of people increase those individuals' predisposition to NAFLD. Diets from different regions have been associated with a lower prevalence of NAFLD and have even been linked to regression of hepatic steatosis. Socioeconomic variations amongst different regions of the world also contribute to NAFLD prevalence and associated complications. Thus, a thorough understanding of ethnic variability in NAFLD is essential to tailoring treatment recommendations to patients of different backgrounds.

Burden of nonalcoholic fatty liver disease in Canada, 2019-2030: a modelling study

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) account for a growing proportion of liver disease cases, and there is a need to better understand future disease burden. We used a modelling framework to forecast the burden of disease of NAFLD and NASH for Canada.

METHODS

We used a Markov model to forecast fibrosis progression from stage F0 (no fibrosis) to stage F4 (compensated cirrhosis) and subsequent progression to decompensated cirrhosis, hepatocellular carcinoma, liver transplantation and liver-related death among Canadians with NAFLD from 2019 to 2030. We used historical trends for obesity prevalence among adults to estimate longitudinal changes in the number of incident NAFLD cases.

RESULTS

The model projected that the number of NAFLD cases would increase by 20% between 2019 and 2030, from an estimated 7 757 000 cases to 9 305 000 cases. Increases in advanced fibrosis cases were relatively greater, as the number of model-estimated prevalent stage F3 cases would increase by 65%, to 357 000, and that of prevalent stage F4 cases would increase by 95%, to 195 000. Estimated incident cases of hepatocellular carcinoma and decompensated cirrhosis would increase by up to 95%, and the number of annual NAFLD-related deaths would double, to 5600.

INTERPRETATION

Increasing rates of obesity translate into increasing NAFLD-related cases of cirrhosis and hepatocellular carcinoma and related mortality. Prevention efforts should be aimed at reducing the incidence of NAFLD and slowing fibrosis progression among those already affected.