The data used in this study are a nationally representative sample of pre-pandemic data from the National Health and Nutrition Examination Survey (NHANES) 2017 to March 2020, which is publicly available in the NHANES database.¹ The protocol for the NHANES study was authorized by the National Center for Health Statistics (NCHS) Research Institutional Review Board. Informed consent was obtained from all NHANES participants.

Blood pressure in NHANES was calculated as the average of systolic blood pressure (SBP) and diastolic blood pressure (DBP) calculated from three consecutive measurements, each taken 60 s apart. According to the 2017 American Heart Association/American College of Cardiology (AHA/ACC) guidelines for the classification of hypertension, individuals with SBP ≥130 mmHg and/or DBP ≥80 mmHg were defined as having hypertension (11). Liver stiffness was measured by FibroScan® which uses the vibration controlled transient elastography (VCTETM) to derive liver stiffness. The device also simultaneously measures the ultrasound attenuation related to the presence of hepatic steatosis and records the controlled attenuation parameter (CAPTM) as the indicator of the degree of hepatic steatosis. Liver stiffness measurements range from 1.6 to 75 kPa, with higher values indicating more severe fibrosis. CAP values range from 100 to 400 dB/m, with higher values indicating more liver fat content. The diagnostic criteria for MASLD are a median CAP score ≥ 285 dB/m, which has a sensitivity of 80% and a specificity of 77% for detecting hepatic steatosis (12), excluding other chronic liver diseases and excessive drinking. Significant fibrosis (SF) and advanced fibrosis (AF) were defined as liver stiffness ≥8.0 kPa and ≥ 13.1 kPa, respectively (13).

We collected information on demographic characteristics and lifestyle. Smoking status was categorized as current smokers, former smokers, and never smokers, based on whether participants had smoked fewer than 100 cigarettes in their lifetime or whether they were current smokers. BMI was calculated as weight (kg) / height (m²). Diabetes was defined as a previous history of diabetes, an HbA1c level ≥ 6.5%, or a fasting blood glucose level ≥ 126 mg/dL (7.0 mmol/L).

Baseline data were presented as weighted means with standard errors (continuous variables) and frequencies with weighted percentages (categorical variables), and the differences between the groups were compared using the Kruskal Wallis test for continuous variables and the Rao-Scott chi-square test for categorical variables to determine differences in demographic and clinical characteristics between the comparison groups. Multivariate logistic regression models were used to control for sociodemographic and metabolic factors to determine the associations between hypertension and MASLD and fibrosis. Model 1 did not include any covariate adjustments; Model 2 included adjustments for age, sex, race, education level, income, marital status, smoking, and physical activity; Model 3 included additional adjustments for Glycosylated hemoglobin, Body mass index (BMI), High-density lipoprotein (HbA1c), Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST), Albumin (ALB), Gamma-Glutamyl Transferase (GGT), total bilirubin, total cholesterol, and triglycerides based on Model 2. The results were presented as odds ratios (ORs) and 95% confidence intervals (CIs). Given the complex sampling of NHANES, we took weights into account in the statistical analyses. All analyses were performed using the “survey” package in R 4.2.2. Statistical significance was determined by two-sided p < 0.05.

Among the initial 15,560 participants, 9,232 were aged 20 years or older. A total of 2,025 participants were excluded due to a lack of ultrasound or transient elastography data or hypertension measurements data. An additional 1,073 participants were excluded for the following reasons: 35 tested positive for hepatitis B surface antigen, 167 tested positive for hepatitis C antibodies or HCV RNA, and 1,038 were heavy drinkers (average daily drinking of 1–2 drinks or more) or had missing information on alcohol consumption. The final study cohort consisted of 5,967 participants (Figure 1).

Among the study cohort, prevalence of MASLD was 38.80%, and among those with MASLD, 13.18% had SF, 7.38% had AF. Demographic and clinical characteristics of MASLD patients with and without MASLD are demonstrated in Table 1. Compared to individuals with non-MASLD, individuals with MASLD were more likely to have hypertension (64.24% vs. 44.80%) and diabetes (25.79% vs. 7.10%), as well as an older weighted mean age (50.48 vs. 45.82), a higher proportion of males (58.18% vs. 45.04%), a higher BMI (33.39 vs. 26.58), higher DBP (124.33 vs. 119.53) and SPB (76.88 vs. 72.18) levels (all p < 0.05) (Table 1).

In the study cohort, the prevalence of hypertension was 57.92%, the weighted mean age was 52.53 years, and 58% were male. Compared to individuals without hypertension, those with hypertension had higher levels of median stiffness (6.27 vs. 5.46) and median CAP (279.77 vs. 249.29), and higher prevalence of SF (8.95% vs. 4.32%), AF (4.13% vs. 2.38%), and MASLD (46.08% vs. 27.86%). In addition, compared to individuals with non-hypertension, individuals with hypertension had higher BMI (30.06 vs. 28.1) and higher rates of diabetes (18.05% vs. 9.77%) (Table 2). Further stratification by hypertension severity showed that the prevalence of SF was significantly different between groups (p < 0.05), increasing from 4.32% in the non-hypertension group to 10.70% in hypertension grade II. Median CAP increased from 249.29 dB/m in the non-hypertension group to 284.13 dB/m in hypertension grade II (p < 0.05) (Supplementary Table S1).

The results of the multivariate regression analysis indicated a significant association between stage I hypertension [OR: 1.70 (95% CI, 1.15–2.53, p = 0.05)] and stage II hypertension [OR: 1.98 (95% CI, 1.38–2.85, p < 0.01)] and an increased risk of SF when confounding factors were not adjusted. After adjusting for age, sex, race, income, education, marital status, smoking, and physical activity, a significant association remained between stage I hypertension [OR: 1.62 (95% CI, 1.1–2.4, p = 0.02)] and stage II [OR = 1.67, 95% CI (1.13–2.46), p = 0.01] in relation to the risk of SF when compared to patients without hypertension. In further adjustments that accounted for multiple confounding factors such as BMI, diabetes, and liver enzymes, stage I hypertension [OR = 1.59, 95% CI (1.09–2.24), p = 0.01)] and stage II hypertension [OR = 1.48, 95% CI, 1.06–2.06, p = 0.02] remained significantly associated with the risk of SF (Table 3). However, an increased risk for AF was not observed.

We assessed the impact of hypertension on fibrosis by stratifying the study population into four subgroups according to the presence of MASLD and hypertension. Approximately 25.88% of the study group had both MASLD and hypertension. Compared to individuals with MASLD alone or hypertension alone, those with both MASLD and hypertension had higher rates of SF at 14.83% and AF at 7.47%. In this context, while SF and AF were present 10.23 and 7.22% of patients with MASLD alone, and 3.92 and 1.27% in patients with hypertension alone (Supplementary Table S2).

Multivariate logistic regression analysis showed that after adjusting for multiple confounding factors such as age, sex, race, and education, marital status, smoking, and physical activity, compared to individuals with neither MASLD nor hypertension, individuals with MASLD alone had a 5.62-fold increased risk of SF [OR: 5.62 (95% CI, 3.15–10.02, p < 0.05)] and a 15.54-fold increased risk of AF [OR: 15.81 (95% CI, 7.72–31.29, p < 0.05)]. While patients with both MASLD and hypertension had an 8.02-fold increased risk of SF [OR: 8.02 (95% CI, 4.47–14.39, p < 0.05)] and a 15.13-fold increased risk of AF [OR: 15.13 (95% CI, 7.09–32.3, p < 0.05)]. Further adjustment for multiple metabolic factors such as BMI, diabetes, glucose, and liver enzymes, patients with both MASLD and hypertension still had a significantly higher risk of SF [OR: 3.07 (95% CI, 1.83–5.14, p < 0.05)] and AF [OR: 4.01 (95% CI, 1.48–10.89, p = 0.01)] (Table 4).