Obesity paradox in cirrhosis: is it real or just an illusion?

Long-term exposure to air pollution and incident non-alcoholic fatty liver disease and cirrhosis: A cohort study

BACKGROUND AND AIMS

Epidemiological evidence regarding the association of air pollution with the risk of non-alcoholic fatty liver disease (NAFLD) is limited. This study was to examine the associations of long-term exposure to various air pollutants and overall air pollution with risk of incident NAFLD as well as cirrhosis, a major liver-related morbidity for NAFLD.

METHODS

Included were 456 687 UK residents. Air pollution data included PM_2.5 , PM_2.5-10 , PM₁₀ , NO₂ and NO_x . A weighted air pollution score was also generated from PM₁₀ and NO_x . Cox proportional hazard models were employed to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

We identified 4978 cases of NAFLD and 1575 cases of incident cirrhosis, over a median follow-up of 11.9 years. PM_2.5 , PM₁₀ , NO₂ and NO_x exposures contributed to the excess risk of NAFLD associated with air pollution score; and the corresponding adjusted HRs (95% CI) were 1.10 (1.05, 1.14), 1.14 (1.09, 1.20), 1.19 (1.13, 1.24) and 1.11 (1.07, 1.15), respectively, for each interquartile range increase in the above specific air pollutants. Similar patterns were also indicated for cirrhosis risk. Alcohol consumption was an effect modifier for the association between air pollution score and NAFLD risk, whereas body mass index modified the association for cirrhosis risk.

CONCLUSION

Long-term exposure to air pollution was associated with risks of NAFLD and cirrhosis among the UK population.

Pre-operative TIPS may reduce post-operative ACLF occurrence

Background & Aims

Acute-on-chronic liver failure (ACLF) is a syndrome associated with organ failure and high short-term mortality. Recently, the role of surgery as a precipitating event for ACLF has been characterised. However, the impact of preoperative transjugular intrahepatic portosystemic shunt (TIPS) placement on ACLF development in patients with cirrhosis undergoing surgery has not been investigated yet.

Methods

A total of 926 patients (363 with cirrhosis undergoing surgery and 563 patients with TIPS) were screened. Forty-five patients with preoperative TIPS (TIPS group) were 1:1 propensity matched to patients without preoperative TIPS (no-TIPS group). The primary endpoint was the development of ACLF within 28 and 90 days after surgery. The secondary endpoint was 1-year mortality. Results were confirmed by a differently 1:2 matched cohort (n = 176).

Results

Patients in the no-TIPS group had significantly higher rates of ACLF within 28 days (29 vs. 9%; p = 0.016) and 90 days (33 vs. 13%; p = 0.020) after surgery as well as significantly higher 1-year mortality (38 vs. 18%; p = 0.023) compared with those in the TIPS group. Surgery without preoperative TIPS and Chronic Liver Failure Consortium–Acute Decompensation (CLIF-C AD) score were independent predictors for 28- and 90-day ACLF development and 1-year mortality after surgery, especially in patients undergoing visceral surgery. In the no-TIPS group, a CLIF-C AD score of >45 could be identified as cut-off for patients at risk for postoperative ACLF development benefiting from TIPS.

Conclusions

This study suggests that preoperative TIPS may result in lower rates of postoperative ACLF development especially in patients undergoing visceral surgery and with a CLIF-C AD score above 45.

Lay summary

Acute-on-chronic liver failure (ACLF) is a syndrome that is associated with high short-term mortality. Surgical procedures are a known precipitating event for ACLF. This study investigates the role of preoperative insertion of a transjugular intrahepatic portosystemic shunt (TIPS) on postoperative mortality and ACLF development. Patients with TIPS insertion before a surgical procedure exhibit improved postoperative survival and lower rates of postoperative ACLF, especially in patients undergoing visceral surgery and with a high CLIF-C AD prognostic score. Thus, this study suggests preoperative TIPS insertion in those high-risk patients.

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This study investigates the impact of preoperative TIPS on postsurgical ACLF.

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Patients with preoperative TIPS, especially before visceral surgery, develop significantly lower rates of ACLF.

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Preoperative TIPS is associated with improved postsurgical survival.

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CLIF-C AD score >45 can be used as cut-off for patients at risk for postsurgical ACLF.

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Selected patients might benefit from preoperative TIPS insertion.

Relationship Between Body Mass Index and Survival Among Critically Ill Patients With Cirrhosis

BACKGROUND

Obesity paradox is a phenomenon in which obesity increases the risk of obesity-related chronic diseases but paradoxically is associated with improved survival among obese patients with these diagnoses.

OBJECTIVES

The aim of this study was to explore the obesity paradox among critically ill patients with cirrhosis admitted to the Intensive Care Unit.

METHODS

A retrospective cohort of 1,143 consecutive patients with cirrhosis admitted to the ICU between January of 2006 and December of 2015 was analyzed. Primary outcome of interest was in-hospital mortality with secondary end points including ICU and short-term mortality at 30 days post ICU admission.

RESULTS

Logistic regression with generalized additive models was used, controlling for clinically relevant and statistically significant factors to determine the adjusted relationship between body mass index (BMI) and ICU, post-ICU in-hospital, and 30 day mortality following ICU discharge. ICU and hospital length of stay was similar across all BMI classes. Adjusted ICU mortality was also similar when stratified by BMI. However, a significant reduction in post-ICU hospital mortality was observed in class I and II obese patients with cirrhosis (BMI 30-39.9 kg/m²) compared to normal BMI (OR = 0.41; 95% CI, 0.20 to 0.83; P = 0.014). Similarly, overweight (BMI 25-29.9 kg/m²) and class I and II obese patients with cirrhosis had significantly lower 30-day mortality following ICU discharge (OR = 0.52, 95% CI 0.31 to 0.87; P = 0.014; OR = 0.50, 95% CI 0.29 to 0.86; P = 0.012, respectively) compared to those with normal BMI.

CONCLUSION

The signal of obesity paradox is suggested among critically ill patients with cirrhosis.

Effect of Body Mass Index on the Prognosis of Liver Cirrhosis

Objective: At present, the association of body mass index (BMI) with the prognosis of liver cirrhosis is controversial. Our retrospective study aimed to evaluate the impact of BMI on the outcome of liver cirrhosis. Methods: In the first part, long-term death was evaluated in 436 patients with cirrhosis and without malignancy from our prospectively established single-center database. In the second part, in-hospital death was evaluated in 379 patients with cirrhosis and with acute gastrointestinal bleeding (AGIB) from our retrospective multicenter study. BMI was calculated and categorized as underweight (BMI <18.5 kg/m²), normal weight (18.5 ≤ BMI < 23.0 kg/m²), and overweight/obese (BMI ≥ 23.0 kg/m²). Results: In the first part, Kaplan-Meier curve analyses demonstrated a significantly higher cumulative survival rate in the overweight/obese group than the normal weight group (p = 0.047). Cox regression analyses demonstrated that overweight/obesity was significantly associated with decreased long-term mortality compared with the normal weight group [hazard ratio (HR) = 0.635; 95% CI: 0.405-0.998; p = 0.049] but not an independent predictor after adjusting for age, gender, and Child-Pugh score (HR = 0.758; 95%CI: 0.479-1.199; p = 0.236). In the second part, Kaplan-Meier curve analyses demonstrated no significant difference in the cumulative survival rate between the overweight/obese and the normal weight groups (p = 0.094). Cox regression analyses also demonstrated that overweight/obesity was not significantly associated with in-hospital mortality compared with normal weight group (HR = 0.349; 95%CI: 0.096-1.269; p = 0.110). In both of the two parts, the Kaplan-Meier curve analyses demonstrated no significant difference in the cumulative survival rate between underweight and normal weight groups. Conclusion: Overweight/obesity is modestly associated with long-term survival in patients with cirrhosis but not an independent prognostic predictor. There is little effect of overweight/obesity on the short-term survival of patients with cirrhosis and with AGIB.

Alcoholic and Nonalcoholic Fatty Liver Disease and Incident Hospitalization for Liver and Cardiovascular Diseases

BACKGROUND & AIMS

We compared the associations of nonalcoholic fatty liver disease (NAFLD) and alcohol-associated fatty liver disease (AFLD) with risk of incident hospitalization for liver and cardiovascular diseases.

METHODS

We collected data from the Kangbuk Samsung Health Study on 218,030 men and women in Korea who underwent a health examination from 2011 through 2016. Fatty liver disease (FLD) was detected by ultrasound during the initial examination. The Fibrosis-4 index was used to identify individuals with liver fibrosis. Participants were followed up for as long as 5.9 years and data on hospitalizations for liver and cardiovascular diseases were collected.

RESULTS

The prevalence of NAFLD was 22.0% and the prevalence of AFLD was 6.4%. Over a median follow-up period of 4.2 years, we observed 51 and 1097 incident cases of liver disease- or cardiovascular disease-related hospitalizations, respectively. After adjustment for potential confounders, the multivariable-adjusted hazard ratios for liver disease-related hospitalization, comparing NAFLD and AFLD with the reference category (no excessive alcohol intake and no FLD), were 1.73 (95% CI, 0.76-3.96) and 5.00 (95% CI, 2.12-11.83), respectively. The corresponding hazard ratios for cardiovascular disease hospitalization were 1.20 (95% CI, 1.02-1.40) and 1.08 (95% CI, 0.86-1.34), respectively. Among participants with FLD, the risk of liver disease-related hospitalization increased with high Fibrosis-4 index scores, whereas the risk of incident cardiovascular disease did not.

CONCLUSIONS

In a large cohort study, we found an increased risk of liver disease-related hospitalizations for patients with NAFLD or AFLD, especially among those with Fibrosis-4 index scores. An increased risk of cardiovascular disease-associated hospitalization was observed in patients with NAFLD but not AFLD.

Alcoholic and Nonalcoholic Fatty Liver Disease and Liver-Related Mortality: A Cohort Study

OBJECTIVES

We compared liver-related mortality by fibrosis severity between 2 types of fatty liver disease (FLD), nonalcoholic FLD (NAFLD) and alcoholic FLD (AFLD), in a large cohort of nonobese and obese individuals.

METHODS

A cohort study was performed with 437,828 Korean adults who were followed up for up to 14 years. Steatosis was diagnosed based on ultrasonography; fibrosis severity was determined by the fibrosis 4 (FIB-4) score. Vital status and liver-related deaths were ascertained through linkage to national death records.

RESULTS

The prevalence of NAFLD and AFLD was 20.9% and 4.0%, respectively. During 3,145,541.1 person-years of follow-up, 109 liver-related deaths were identified (incidence rate of 3.5 per 10 person-years). When changes in fatty liver status, FIB-4 scores, and confounders during follow-up were updated as time-varying covariates, compared with the reference (absence of both excessive alcohol use and FLD), the multivariable-adjusted hazard ratios with 95% confidence intervals for liver-related mortality among those with low, intermediate, and high FIB-4 scores were 0.43 (0.19-0.94), 2.74 (1.23-6.06), and 84.66 (39.05-183.54), respectively, among patients with NAFLD, whereas among patients with AFLD, the corresponding hazard ratios (95% confidence intervals) were 0.67 (0.20-2.25), 5.44 (2.19-13.49), and 59.73 (27.99-127.46), respectively. The associations were more evident in nonobese individuals than in obese individuals (P for interaction = 0.004).

DISCUSSION

In this large cohort of young and middle-aged individuals, NAFLD and AFLD with intermediate to high fibrosis scores were associated with an increased risk of liver-related mortality in a dose-dependent manner, especially among nonobese individuals.