Administrative coding for non-alcoholic fatty liver disease is accurate in Swedish patients

Validating new coding algorithms to improve identification of alcohol-associated and nonalcohol-associated cirrhosis hospitalizations in administrative databases

BACKGROUND

Alcohol (AC) and nonalcohol-associated cirrhosis (NAC) epidemiology studies are limited by available case definitions. We compared the diagnostic accuracy of previous and newly developed case definitions to identify AC and NAC hospitalizations.

METHODS

We randomly selected 700 hospitalizations from the 2008 to 2022 Canadian Discharge Abstract Database with alcohol-associated and cirrhosis-related International Classification of Diseases 10th revision codes. We compared standard approaches for AC (ie, AC code alone and alcohol use disorder and nonspecific cirrhosis codes together) and NAC (ie, NAC codes alone) case identification to newly developed approaches that combine standard approaches with new code combinations. Using electronic medical record review as the reference standard, we calculated case definition positive and negative predictive values, sensitivity, specificity, and AUROC.

RESULTS

Electronic medical records were available for 671 admissions; 252 had confirmed AC and 195 NAC. Compared to previous AC definitions, the newly developed algorithm selecting for the AC code, alcohol-associated hepatic failure code, or alcohol use disorder code with a decompensated cirrhosis-related condition or NAC code provided the best overall positive predictive value (91%, 95% CI: 87-95), negative predictive value (89%, CI: 86-92), sensitivity (81%, CI: 76-86), specificity (96%, CI: 93-97), and AUROC (0.88, CI: 0.85-0.91). Comparing all evaluated NAC definitions, high sensitivity (92%, CI: 87-95), specificity (82%, CI: 79-86), negative predictive value (96%, CI: 94-98), AUROC (0.87, CI: 0.84-0.90), but relatively low positive predictive value (68%, CI: 62-74) were obtained by excluding alcohol use disorder codes and using either a NAC code in any diagnostic position or a primary diagnostic code for HCC, unspecified/chronic hepatic failure, esophageal varices without bleeding, or hepatorenal syndrome.

CONCLUSIONS

New case definitions show enhanced accuracy for identifying hospitalizations for AC and NAC compared to previously used approaches.

Substitutions of saturated fat intakes with other macronutrients and foods and risk of NAFLD cirrhosis and all-cause hepatocellular carcinoma: a prospective cohort study

BACKGROUND

Short-term trials have shown a reduction in liver fat when saturated fatty acids (SFAs) are substituted with polyunsaturated fatty acids (PUFA), or with low-glycemic carbohydrates. However, few cohort studies have been conducted to investigate the associations of replacing SFA and SFA-rich foods with different macronutrients and foods in more severe stages of liver disease; nonalcoholic fatty liver disease (NAFLD) cirrhosis and hepatocellular carcinoma (HCC).

OBJECTIVES

To investigate associations between the substitution of SFA and SFA-rich foods with other macronutrients and foods and NAFLD cirrhosis and HCC in a middle-aged to elderly Swedish population of n = 77,059 males and females.

METHODS

Time-to-event analyses were performed to investigate associations between the food and macronutrient substitutions and NAFLD cirrhosis and HCC. Multivariable Cox regression models were constructed to estimate hazard ratios (HRs) with corresponding 95% confidence intervals (CIs). Statistical isocaloric and equal-mass substitutions were performed using the leave-one-out method. Prespecified nutrient and food substitutions of interest were SFA with carbohydrates, SFA with fiber, SFA with PUFA, butter with margarine and vegetable oils, unprocessed red meat with fish, and milk with fermented milk.

RESULTS

Over a median follow-up of 24 y, 566 cases of NAFLD cirrhosis and 205 cases of HCC were registered. Overall, dietary substitutions showed no clear associations with either NAFLD cirrhosis or HCC. Substituting SFA with carbohydrates showed an HR of 0.87 (95% CI: 0.74, 1.02) for HCC and 1.00 (95% CI: 0.89, 1.11) for NAFLD cirrhosis. Substituting milk with fermented milk showed an HR of 0.93 (95% CI: 0.85, 1.01) for HCC and 0.97 (95% CI: 0.92, 1.03) for NAFLD cirrhosis.

CONCLUSIONS

No clear associations were observed between diet and NAFLD cirrhosis or HCC. Although accompanied by low precision, possible lowered risks of HCC by substituting SFA with carbohydrates or milk with fermented milk might be of interest, but needs replication in other cohorts.

Glucagon-like peptide-1 receptor agonists and risk of major adverse liver outcomes in patients with chronic liver disease and type 2 diabetes

OBJECTIVE

Phase II trials suggest glucagon-like peptide-1 receptor (GLP1) agonists resolve metabolic dysfunction-associated steatohepatitis but do not affect fibrosis regression. We aimed to determine the long-term causal effect of GLP1 agonists on the risk of major adverse liver outcomes (MALO) in patients with any chronic liver disease and type 2 diabetes.

DESIGN

We used observational data from Swedish healthcare registers 2010-2020 to emulate a target trial of GLP1 agonists in eligible patients with chronic liver disease and type 2 diabetes. We used an inverse-probability weighted marginal structural model to compare parametric estimates of 10-year MALO risk (decompensated cirrhosis, hepatocellular carcinoma, liver transplantation or MALO-related death) in initiators of GLP1 agonists with non-initiators. We randomly sampled 5% of the non-initiators to increase computational efficiency.

RESULTS

GLP1 agonist initiators had a 10-year risk of MALO at 13.3% (42/1026) vs 14.6% in non-initiators (1079/15 633) in intention-to-treat analysis (risk ratio (RR)=0.91, 95% CI=0.50 to 1.32). The corresponding 10-year per-protocol risk estimates were 7.4% (22/1026) and 14.4% (1079/15 633), respectively (RR=0.51, 95% CI=0.14 to 0.88). The per-protocol risk estimates at 6 years were 5.4% (21/1026) vs 9.0% (933/15 633) (RR=0.60, 95% CI=0.29 to 0.90) and at 8 years 7.2% (22/1026) vs 11.7% (1036/15 633) (RR=0.61, 95% CI=0.21 to 1.01).

CONCLUSION

In patients with chronic liver disease and type 2 diabetes who adhered to therapy over time, GLP1 agonists may result in lower risk of MALO. This suggests that GLP1 agonists are promising agents to reduce risk of chronic liver disease progression in patients with concurrent type 2 diabetes, although this needs to be corroborated in randomised trials.

Long-term major adverse liver outcomes in 1,260 patients with non-cirrhotic NAFLD

Background & Aims

Long-term studies of the prognosis of NAFLD are scarce. Here, we investigated the risk of major adverse liver outcomes (MALO) in a large cohort of patients with NAFLD.

Methods

We conducted a cohort study with data from Swedish university hospitals. Patients (n = 1,260) with NAFLD without cirrhosis were diagnosed through biopsy or radiology, and had fibrosis estimated through vibration-controlled transient elastography, biopsy, or FIB-4 score between 1974 and 2020 and followed up through 2020. Each patient was matched on age, sex, and municipality with up to 10 reference individuals from the general population (n = 12,529). MALO were ascertained from Swedish national registers. The rate of events was estimated by Cox regression.

Results

MALO occurred in 111 (8.8%, incidence rate = 5.9/1,000 person-years) patients with NAFLD and 197 (1.6%, incidence rate = 1.0/1,000 person-years) reference individuals during a median follow up of 13 years. The rate of MALO was higher in patients with NAFLD (hazard ratio = 6.6; 95% CI = 5.2-8.5). The risk of MALO was highly associated with the stage of fibrosis at diagnosis. In the biopsy subcohort (72% of total sample), there was no difference in risk between patients with and without non-alcoholic steatohepatitis. The 20-year cumulative incidences of MALO were 2% for the reference population, 3% for patients with F0, and 35% for F3. Prognostic information from biopsy was comparable to FIB-4 (C-indices around 0.73 vs. 0.72 at 10 years).

Conclusions

This study provides updated information on the natural history of NAFLD, showing a high rate of progression to cirrhosis in F3 and a similar prognostic capacity of non-invasive tests to liver biopsy.

Impact and implications

Several implications for clinical care and future research may be noted based on these results. First, the risk estimates for cirrhosis development are important when communicating risk to patients and deciding on clinical monitoring and treatment. Estimates can also be used in updated health-economic evaluations, and for regulatory agencies. Second, our results again highlight the low predictive information obtained from ascertaining NASHstatus by histology and call for more objective means by which to define NASH. Such methods may include artificial intelligence-supported digital pathology. We highlight that NASH is most likely the causal factor for fibrosis progression in NAFLD, but the subjective definition makes the prognostic value of a histological NASH diagnosis of limited value. Third, the finding that prognostic information from biopsy and the very simple Fibrosis-4 score were comparable is important as it may lead to fewer biopsies and further move the field towards non-invasive means by which to define fibrosis and, importantly, use non-invasive tests as outcomes in clinical trials. However, all modalities had modest discriminatory capacity and new risk stratification systems are needed in NAFLD. Repeated measures of non-invasive scores may be a potential solution.

Misclassified Alcohol-related Liver Disease is Common in Presumed Metabolic Dysfunction-associated Steatotic Liver Disease and Highly Increases Risk for Future Cirrhosis

BACKGROUND & AIMS

Alcohol overconsumption is a risk factor for disease progression in patients with presumed metabolic dysfunction-associated steatotic liver disease (MASLD). How commonly this occurs and how it affects progression to major adverse liver outcomes (MALOs) is not well known.

METHODS

We did a register-based cohort study, including all patients with a diagnosis of MASLD in Sweden between 1987 and 2020. Patients were stratified on co-occurrence of diagnoses of alcohol-related liver disease (ALD) or alcohol use disorder (AUD) prior to MASLD diagnosis. Incident MALOs were derived from national registers. Cox regression was used to calculate hazard ratios (HRs) for incident MALO.

RESULTS

A total of 15,107 patients with MASLD were identified. The median age was 55 years, and 52% were female. Of the patients, 1843 (12%) had a prior diagnosis of ALD or AUD. During follow-up, a further 787 patients (5.2%) received a diagnosis of ALD or AUD. Patients with previous ALD or AUD diagnoses at or before baseline had considerably higher rates of MALOs compared with patients without (19.5% vs 7.8%; adjusted HR, 3.12; 95% confidence interval, 2.74-3.55). Acquiring an ALD or AUD diagnosis after MASLD diagnosis was associated with higher rates of MALOs (adjusted HR, 5.81; 95% confidence interval, 4.90-6.88).

CONCLUSIONS

ALD or AUD is commonly diagnosed prior to or after MASLD diagnosis. Such patients have considerably higher rates of progression to MALOs. Correctly separating between MASLD and ALD is vital to assess prognosis.

Risk of infections in non-alcoholic fatty liver disease: A nationwide population-based cohort study

BACKGROUND AND AIMS

Previous literature suggests an association between non-alcoholic fatty liver disease (NAFLD) and infections. We aimed to determine the rate and risk of severe infections in NAFLD compared to the general population.

METHODS

In this population-based cohort study, we used national registers to identify all patients with a hospital-based diagnosis of NAFLD in Sweden 1987-2020 (n = 14 869). The patients were matched with ≤10 comparators from the general population for age, sex, municipality, and calendar year (n = 137 145). Cox regression was used to estimate hazard ratios (HR) for infections in patients with NAFLD compared to comparators. Cumulative incidences were calculated while accounting for competing risks (non-infection death and liver transplantation).

RESULTS

Severe infections leading to death or hospitalization occurred in 1990 (13.4%) patients with NAFLD and 9899 (7.2%) comparators during a median of 4.5 and 6.1 years of follow-up, respectively. The rate of severe infections per 1000 person-years was higher in patients with NAFLD (21.0) than comparators (9.1) independently of components related to the metabolic syndrome (adjusted HR 1.9, 95% CI = 1.8-2.0). Infection-related mortality was also higher in NAFLD compared to comparators (adjusted HR 1.8, 95% CI = 1.6-2.2). The 10-year cumulative incidence of severe infections was 16.6% (95% CI = 15.8-17.4) in NAFLD and 8.0% (95% CI = 7.8-8.2) in comparators.

CONCLUSION

NAFLD was associated with severe infections and infection-related mortality, independently of components associated with the metabolic syndrome. Increased clinical vigilance of severe infections in NAFLD may diminish the risk of premature death.