Background
The relationship between body mass index (BMI) and outcomes in patients with nonalcoholic fatty liver disease (NAFLD) is not well defined. This study aimed to evaluate the presentations, outcomes, and development of liver-related events (LRE) and non-LRE in patients with NAFLD stratified by BMI.
Methods
Records of patients with NAFLD were reviewed from 2000 to 2022. Patients were classified as lean (18.5–22.9 kg/m 2), overweight (23–24.9 kg/m 2), and obese (> 25 kg/m 2) according to BMI. Steatosis stage, fibrosis, and NAFLD activity score were observed in patients undergoing liver biopsy in each group.
Results
Of 1051 patients with NAFLD, 127 (12.1%) had normal BMI, 177 (16.8%) and 747 (71.1%) were overweight and obese, respectively. Median [interquartile range] BMI was 21.9 [20.6–22.5], 24.2 [23.7–24.6], and 28.3 [26.6–30.6] kg/m 2in each group, respectively.
The prevalence of metabolic syndrome and dyslipidemia was significantly higher in the obese.
Obese patients had significantly higher mean [interquartile range] liver stiffness (6.4 [4.9–9.4] kPa) than overweight and lean subjects.
A higher proportion of obese patients had significant and advanced liver fibrosis .
At follow-up, there were no significant differences in liver disease progression, new LRE, coronary artery disease, or hypertension between the BMI groups.
Overweight and obese patients were more likely to develop new-onset diabetes during follow-up.
Mortality rates in the three groups were comparable (0.47, 0.68, and 0.49 per 100 person-years, respectively), with similar causes of death (liver-related and non-liver-related).
Conclusions
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Key messages
What is already known about this topic?
- Nonalcoholic fatty liver disease (NAFLD) can occur in both obese and lean subjects .
- The nature of disease progression in lean compared to obese individuals is not well understood.
- There are limited therapeutic goals in patients with NAFLD, with weight loss being the cornerstone of therapy.
What this study adds
- There are no differences in fibrosis and inflammation scores in liver biopsies from lean patients compared to obese patients.
- Rates of new-onset comorbidities and disease progression are similar in both lean and obese patients.
- Obese patients with NAFLD do not have worse outcomes than those who are lean and have NAFLD.
How this study might impact health research, practice, or policy
- Development of newer therapeutic targets for patients with lean NAFLD for use in future trials.
- Further prospective studies to evaluate changes in histology and transient elastography with changes in body mass index in patients with NAFLD.
- Studies delineating the natural history of lean patients with NAFLD and the change in clinical outcomes when a patient changes body mass index class from obese to lean or vice versa.
