Risk factors analysis for poor prognosis after percutaneous drainage in liver abscess patients with fatty liver

Abstract

BACKGROUND

Liver abscess is a serious hepatic infectious disease for which percutaneous drainage has become the preferred treatment method due to its minimally invasive advantages. With the rising prevalence of non-alcoholic fatty liver disease reaching 29.2% in Chinese adults, the number of patients with liver abscess combined with fatty liver has shown a significant increasing trend clinically.

AIM

To analyze risk factors affecting prognosis after percutaneous drainage in liver abscess patients with fatty liver.

METHODS

A retrospective analysis of 165 liver abscess patients with fatty liver who underwent percutaneous drainage from January 2020 to April 2024. Patients were divided into good prognosis (n = 121, 73.3%) and poor prognosis groups (n = 44, 26.7%) based on 30-day outcomes. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors.

RESULTS

The poor prognosis group had older age (65.2 ± 11.8 years vs 56.1 ± 11.9 years, P < 0.001), higher diabetes prevalence (70.5% vs 47.2%, P = 0.008), elevated inflammatory markers, and lower serum albumin (26.8 ± 4.2 g/L vs 32.1 ± 5.6 g/L, P < 0.001). Moderate-to-severe fatty liver was more prevalent in the poor prognosis group (68.2% vs 38.0%, P = 0.001). Multivariate analysis identified five independent risk factors: Age ≥ 65 years (OR = 2.847, P = 0.007), diabetes history (OR = 3.124, P = 0.003), abscess diameter ≥ 8 cm (OR = 2.591, P = 0.015), serum albumin < 30 g/L (OR = 3.456, P = 0.001), and moderate-to-severe fatty liver (OR = 2.213, P = 0.035).

CONCLUSION

Advanced age, diabetes history, large abscess, hypoalbuminemia, and moderate-to-severe fatty liver are independent risk factors for poor prognosis after percutaneous drainage in liver abscess patients with fatty liver.

Key Words: Liver abscess; Fatty liver; Percutaneous drainage; Prognosis; Risk factors

Core Tip: This retrospective study of 165 liver abscess patients with fatty liver undergoing percutaneous drainage identified five independent risk factors for poor prognosis: Advanced age (≥ 65 years), diabetes history, large abscess diameter (≥ 8 cm), hypoalbuminemia (< 30 g/L), and moderate-to-severe fatty liver disease.

INTRODUCTION

Liver abscess is a serious infectious disease of the liver, classified etiologically into bacterial liver abscess and amoebic liver abscess. Bacterial liver abscess is more common in China, mostly caused by biliary tract infection, portal vein bacteremia, or hematogenous dissemination, with pathogens mainly including Escherichia coli, Klebsiella species, and Streptococcus. In recent years, with the acceleration of population aging, rising incidence of metabolic diseases such as diabetes, and continuous development of medical technology, the characteristics and treatment patterns of liver abscess have been changing. Traditional surgical treatment has gradually been replaced by minimally invasive percutaneous drainage, which has become the preferred treatment method for liver abscess due to its advantages of minimal trauma, rapid recovery, and fewer complications[1,2].

Meanwhile, non-alcoholic fatty liver disease (NAFLD) has become one of the most common chronic liver diseases globally, with its prevalence showing a rapid upward trend worldwide. According to epidemiological surveys, the prevalence of NAFLD in Chinese adults has reached 29.2%, and this proportion continues to grow with lifestyle changes and westernization of dietary patterns. The pathogenesis of fatty liver is complex, mainly related to various factors including insulin resistance, lipid metabolism disorders, oxidative stress, and inflammatory responses. Abnormal fat deposition in hepatocytes not only affects normal liver metabolic function but may also lead to decreased liver immune function and fibrosis progression, thereby increasing the risk of various liver diseases[3-5].

With the continuous rise in fatty liver prevalence, the number of patients with liver abscess combined with fatty liver has also shown a significant increasing trend clinically. This phenomenon is not accidental but results from the combined action of multiple factors. First, fatty liver patients often have comorbidities such as diabetes, obesity, and metabolic syndrome, which are themselves risk factors for liver abscess development. Diabetic patients, due to poor blood glucose control, have impaired immune function and are more susceptible to various infectious diseases, including liver abscess. Second, fatty liver may affect the liver's anti-infection ability through multiple mechanisms: Fat deposition leads to hepatocyte dysfunction, affecting the liver's detoxification and immune functions; chronic inflammatory states associated with fatty liver may weaken local immune responses; fatty liver patients often have intestinal flora imbalance, increasing the risk of bacterial translocation and bloodstream infection[6,7].

More importantly, the presence of fatty liver may significantly affect the treatment outcomes and prognosis of liver abscess patients. The liver tissue structure of fatty liver patients undergoes changes, with hepatocyte swelling and fiber proliferation, which may affect drainage effectiveness; metabolic abnormalities and inflammatory responses associated with fatty liver may delay wound healing and prolong treatment time. Additionally, fatty liver patients often have poor nutritional status and decreased protein synthesis function, with weakened body repair capacity. These factors may all lead to slow recovery after percutaneous drainage and increase the risk of complications[8-10].

Currently, there have been numerous reports on factors affecting prognosis after percutaneous drainage in patients with simple liver abscess, generally considering patient age, underlying diseases, abscess size and number, pathogen type, and laboratory indicators as important prognostic factors. However, prognostic studies specifically targeting the special patient population of liver abscess combined with fatty liver are relatively limited, with existing studies mostly being small-sample, single-center studies lacking systematic risk factor analysis. Particularly, the specific impact of fatty liver severity on liver abscess prognosis and its independent predictive value in multivariate analysis still require more clinical evidence support[11-13].

In clinical practice, physicians often formulate treatment plans based on experience and traditional prognostic assessment indicators, but for liver abscess patients with concurrent fatty liver, targeted prognostic assessment tools and treatment strategies are lacking. In this situation, some patients may receive inappropriate treatment plans due to inaccurate prognostic assessment, leading to poor treatment outcomes or increased complications. Therefore, in-depth research on risk factors affecting prognosis after percutaneous drainage in liver abscess patients with fatty liver, and establishing targeted prognostic assessment models, is of great significance for guiding clinical decision-making, optimizing treatment plans, and improving patient prognosis[14].

In summary, with the continuous rise in fatty liver incidence and changes in population structure, liver abscess combined with fatty liver has become an important clinical issue that cannot be ignored. In-depth understanding of prognostic factors in this special patient population not only helps improve clinicians' understanding of disease complexity but also provides scientific evidence for formulating individualized treatment strategies, ultimately improving patients' clinical outcomes and quality of life.

MATERIALS AND METHODS

Study design and subjects

This study adopted a retrospective cohort study design, collecting and analyzing clinical data of liver abscess patients with fatty liver who were hospitalized in the Department of Infectious Diseases, Hepatobiliary Surgery, and Interventional Radiology at our hospital from January 2020 to April 2024. The study was approved by the Ethics Committee of Tongde Hospital of Zhejiang Province (approval number: 2024094-JY). Due to the retrospective design and anonymization of patient data, the ethics committee waived the requirement for informed consent. All patients meeting the criteria and screened through the Hospital Information System and Picture Archiving and Communication System during the study period were consecutively included.

Inclusion criteria included: Age ≥ 18 years, regardless of gender; clinically confirmed liver abscess with typical symptoms (fever, right upper quadrant pain, etc.) and abnormal laboratory tests (elevated white blood cells, abnormal inflammatory markers), imaging examination confirming intrahepatic space-occupying lesions consistent with abscess characteristics; imaging-confirmed fatty liver with liver computed tomography (CT) plain scan density 10 HU lower than spleen density, or magnetic resonance imaging examination indicating liver fat fraction ≥ 5%; all received percutaneous drainage treatment; complete clinical data and follow-up information; hospitalization time ≥ 7 days.

Exclusion criteria included patients with other serious liver diseases (viral hepatitis, cirrhosis, liver cancer, autoimmune liver disease, etc.), other serious infectious diseases (sepsis, infectious endocarditis, severe pulmonary infection, etc.), pregnant women, severe cardiopulmonary and renal dysfunction, malignant tumors, immune deficiency or long-term use of immunosuppressants, psychiatric diseases or cognitive dysfunction, incomplete clinical data or loss to follow-up, and patients with pre-existing serious complications or multiple organ failure.

Patients were grouped according to clinical outcomes within 30 days post-procedure: The good prognosis group was defined as patients whose clinical symptoms completely resolved within 30 days after percutaneous drainage, laboratory indicators returned to normal or significantly improved, imaging examination showed abscess cavity disappearance or significant reduction, no serious complications occurred, successful discharge and completed follow-up; the poor prognosis group was defined as patients who experienced serious complications (major bleeding, bile leak, abdominal infection, septic shock, etc.), treatment failure requiring repeat percutaneous drainage, conservative treatment failure requiring surgical conversion, in-hospital death, or prolonged hospitalization ≥ 30 days without significant improvement within 30 days post-procedure.

Follow-up protocol

Our follow-up protocol included structured outpatient visits at 1 week, 2 weeks, and 1 month post-discharge, primarily assessed through clinical visits, laboratory examinations, and patient interviews. Imaging follow-up was conducted 2-4 weeks post-discharge using abdominal CT or ultrasound to assess abscess cavity changes and treatment response. For high-risk patients or those with concerning clinical findings, follow-up frequency was increased to weekly intervals until complete symptom resolution. Follow-up assessments included clinical symptom evaluation, vital signs monitoring, laboratory tests (complete blood count, inflammatory markers, liver function), and imaging studies as clinically indicated.

Observation indicators, primary and secondary endpoints

The observation indicators collected included patient demographics, laboratory examination indicators at admission (blood routine, biochemical indicators, inflammatory markers, coagulation function), imaging characteristics (abscess characteristics and fatty liver severity assessment), surgery-related indicators, and pathogenic examination results.

Fatty liver severity was classified based on CT liver-spleen density differences according to established criteria: Mild fatty liver was defined as liver CT values 10 HU-20 HU lower than spleen density, moderate fatty liver as 20 HU-30 HU lower, and severe fatty liver as > 30 HU lower than spleen density. This classification system has been validated against histopathological grading and is widely used in clinical practice for non-invasive assessment of hepatic steatosis severity.

The primary endpoint was the incidence of poor prognostic events within 30 days post-procedure, and secondary endpoints included hospitalization time, drainage tube indwelling time, various recovery times, and complication rates.

Data collection and quality control

All clinical data were extracted from electronic medical records by two independent investigators using standardized data collection forms. Discrepancies were resolved through discussion with a third senior investigator. Missing data were handled using complete case analysis, and sensitivity analyses were performed to assess the impact of missing data on study conclusions. Imaging studies were reviewed by experienced radiologists blinded to clinical outcomes to ensure objective assessment of fatty liver severity and abscess characteristics.

Statistical analysis

Statistical analysis was performed using SPSS 26.0 software. Continuous variables were expressed as mean ± SD or median (interquartile range), and group comparisons were made using t-test or Mann-Whitney U test. Categorical variables were expressed as number (percentage), and group comparisons were made using χ² test or Fisher's exact test. Univariate analysis was used to screen potential risk factors, and variables with P < 0.1 were included in multivariate logistic regression analysis to determine independent risk factors. All statistical tests were two-sided, with P < 0.05 considered statistically significant.

RESULTS

Patient baseline characteristics

Based on the table data, this study compared baseline characteristics between patients with good prognosis (n = 121) and poor prognosis (n = 44), revealing several significant differences. Demographic and clinical characteristics showed that the poor prognosis group was significantly older (65.2 ± 11.8 years vs 56.1 ± 11.9 years, P = 0.001) and had higher body mass index (28.9 ± 4.6 kg/m² vs 26.1 ± 3.8 kg/m², P = 0.001). These patients also experienced longer duration from onset to admission (12.4 ± 5.2 days vs 8.7 ± 4.1 days, P = 0.001), higher admission temperature (39.4 ± 0.9 °C vs 38.7 ± 0.7 °C, P = 0.001), and more comorbidities (3.2 ± 1.5 vs 1.7 ± 1.1, P = 0.001). The poor prognosis group had lower education levels, with 81.8% having junior high school education or below compared to 74.4% in the good prognosis group (P = 0.031). Lifestyle factors revealed that poor prognosis patients had significantly higher rates of smoking (61.4% vs 42.1%, P = 0.005) and alcohol consumption (68.2% vs 51.2%, P = 0.008). No significant differences were found in gender distribution or residence location. These findings indicate that advanced age, obesity, multiple comorbidities, delayed medical care, lower education, and adverse lifestyle habits are significantly associated with poor patient prognosis (Table 1).

Table 1 Baseline characteristics of patients with liver abscess and fatty liver, mean ± SD/n (%).

Characteristics	Good prognosis group (n = 121)	Poor prognosis group (n = 44)	Test statistic	P value
Gender			χ² = 0.901	0.342
Male	77 (63.6)	26 (59.1)
Female	44 (36.4)	18 (40.9)
Age (years)	56.1 ± 11.9	65.2 ± 11.8	t = 4.852	0.001
Body mass index (kg/m²)	26.1 ± 3.8	28.9 ± 4.6	t = 4.176	0.001
Duration from onset to admission (days)	8.7 ± 4.1	12.4 ± 5.2	t = 5.063	0.001
Temperature on admission (°C)	38.7 ± 0.7	39.4 ± 0.9	t = 5.547	0.001
Number of comorbidities	1.7 ± 1.1	3.2 ± 1.5	t = 7.329	0.001
Smoking history	51 (42.1)	27 (61.4)	χ² = 7.841	0.005
Alcohol consumption history	62 (51.2)	30 (68.2)	χ² = 7.026	0.008
Residence			χ² = 0.628	0.428
Urban	84 (69.4)	24 (54.5)
Rural	58 (47.9)	20 (45.5)
Education level			χ² = 4.658	0.031
Junior high school or below	90 (74.4)	36 (81.8)
High school or above	52 (43.0)	8 (18.2)

Continuous variables are presented as mean ± SD and compared using independent samples t-test. Categorical variables are presented as number (percentage) [n (%)] and compared using χ² test. P < 0.05 was considered statistically significant.

Distribution of comorbidities

In terms of organ dysfunction, chronic kidney disease showed a significantly higher proportion in the poor prognosis group (27.3% vs 11.6%, P = 0.004), and the prevalence of biliary disease was also markedly increased (43.2% vs 28.9%, P = 0.017). These organ dysfunctions may directly impact patients' overall health status, drug metabolism capacity, and disease recovery potential. Regarding cardiopulmonary system diseases, although the poor prognosis group showed numerically higher rates of hypertension (47.7% vs 45.5%), coronary heart disease (22.7% vs 18.2%), and chronic obstructive pulmonary disease (13.6% vs 9.9%), none of these differences reached statistical significance (P values of 0.296, 0.271, and 0.324, respectively). Overall, diabetes mellitus, dyslipidemia, chronic kidney disease, and biliary disease are important comorbidities significantly associated with poor prognosis. These conditions predominantly involve crucial metabolic and excretory functions and may synergistically contribute through multiple mechanisms to decreased bodily reserve function, thereby affecting overall prognosis (Table 2).

Table 2 Distribution of comorbidities in patients with liver abscess and fatty liver, n (%).

Comorbidity	Total (n = 165)	Good prognosis (n = 121)	Poor prognosis (n = 44)	χ²	P value
Diabetes mellitus	98 (59.4)	67 (55.4)	31 (70.5)	6.983	0.008
Hypertension	76 (46.1)	55 (45.5)	21 (47.7)	1.095	0.296
Coronary heart disease	32 (19.4)	22 (18.2)	10 (22.7)	1.211	0.271
Dyslipidemia	84 (50.9)	56 (46.3)	28 (63.6)	7.542	0.006
Chronic kidney disease	26 (15.8)	14 (11.6)	12 (27.3)	8.294	0.004
Chronic obstructive pulmonary disease	18 (10.9)	12 (9.9)	6 (13.6)	0.974	0.324
Biliary disease	54 (32.7)	35 (28.9)	19 (43.2)	5.673	0.017

P < 0.05 was considered statistically significant. Comparisons between groups were performed using χ² test.

Clinical symptoms and signs

Significant differences were found in systemic constitutional symptoms. The poor prognosis group experienced significantly higher rates of night sweats (65.9% vs 41.3%, P = 0.008) and weight loss (54.5% vs 35.5%, P = 0.045), suggesting these symptoms may indicate disease severity and poor outcomes. Common symptoms showed no significant differences between groups, including right-upper-quadrant pain (81.8% vs 84.3%), nausea and vomiting (72.7% vs 64.5%), fatigue (81.8% vs 71.1%), chills (84.1% vs 73.6%), and loss of appetite (90.9% vs 82.6%). Other symptoms such as abdominal distension, cough, and right-shoulder pain also showed no statistical differences. These findings indicate that while most clinical symptoms are similarly distributed between prognostic groups, systemic constitutional symptoms such as night sweats and weight loss may serve as important indicators of poor prognosis (Table 3).

Table 3 Clinical symptoms and signs in patients with liver abscess and fatty liver, n (%).

Variable	Total (n = 165)	Good prognosis (n = 121)	Poor prognosis (n = 44)	χ²/t	P value
Right-upper-quadrant pain	138 (83.6)	102 (84.3)	36 (81.8)	0.168	0.682
Nausea & vomiting	110 (66.7)	78 (64.5)	32 (72.7)	0.872	0.350
Fatigue	122 (73.9)	86 (71.1)	36 (81.8)	1.571	0.210
Chills	126 (76.4)	89 (73.6)	37 (84.1)	1.725	0.189
Loss of appetite	140 (84.8)	100 (82.6)	40 (90.9)	1.476	0.226
Abdominal distension	85 (51.5)	59 (48.8)	26 (59.1)	1.176	0.279
Jaundice	46 (27.9)	29 (24.0)	17 (38.6)	3.060	0.080
Cough & sputum	60 (36.4)	40 (33.1)	20 (45.5)	2.006	0.182
Night sweats	79 (47.3)	50 (41.3)	29 (65.9)	7.086	0.008
Weight loss	67 (40.6)	43 (35.5)	24 (54.5)	4.024	0.045
Right-shoulder/back pain	38 (23.0)	25 (20.7)	13 (29.5)	1.236	0.266

P < 0.05 was considered statistically significant. Categorical variables are presented as number (percentage) [n (%)] and compared using χ² test. Continuous variables are presented as mean ± SD and compared using independent samples t-test.

Laboratory test results comparison

Inflammatory markers were markedly elevated in the poor prognosis group, with higher white blood cell count (18.2 ± 6.4 × 10⁹/L vs 13.7 ± 4.8 × 10⁹/L), C-reactive protein (145.8 ± 42.3 mg/L vs 98.6 ± 35.7 mg/L), and procalcitonin levels (8.9 ± 3.6 ng/mL vs 4.2 ± 2.1 ng/mL), all P < 0.001, indicating severe systemic inflammation. Liver function and nutritional status showed significant impairment in poor prognosis patients. Serum albumin was markedly lower (26.8 ± 4.2 g/L vs 32.1 ± 5.6 g/L), while total bilirubin (45.7 ± 18.3 μmol/L vs 28.4 ± 12.1 μmol/L) and alanine aminotransferase (89.4 ± 28.7 U/L vs 62.3 ± 21.4 U/L) were significantly elevated, all P < 0.001. Hematologic parameters revealed concerning abnormalities in the poor prognosis group, including lower hemoglobin (106.8 ± 18.2 g/L vs 118.4 ± 16.7 g/L), reduced platelet count (156.7 ± 45.3 × 10⁹/L vs 198.2 ± 52.8 × 10⁹/L), and prolonged prothrombin time (16.8 ± 2.9 seconds vs 14.2 ± 2.1 seconds), all P < 0.001. These findings demonstrate that poor prognosis is associated with severe systemic inflammation, compromised liver function, and hematologic abnormalities (Table 4).

Table 4 Laboratory test results comparison.

Parameter (unit)	Good prognosis (n = 121)	Poor prognosis (n = 44)	t/χ²	P value
White blood cells (× 109/L)	13.7 ± 4.8	18.2 ± 6.4	t = 4.62	< 0.001
C-reactive protein (mg/L)	98.6 ± 35.7	145.8 ± 42.3	t = 6.31	< 0.001
Procalcitonin (ng/mL)	4.2 ± 2.1	8.9 ± 3.6	t = 7.54	< 0.001
Serum albumin (g/L)	32.1 ± 5.6	26.8 ± 4.2	t = 5.74	< 0.001
Total bilirubin (μmol/L)	28.4 ± 12.1	45.7 ± 18.3	t = 5.93	< 0.001
Alanine aminotransferase (U/L)	62.3 ± 21.4	89.4 ± 28.7	t = 5.48	< 0.001
Hemoglobin (g/L)	118.4 ± 16.7	106.8 ± 18.2	t = 3.89	< 0.001
Platelet count (× 109/L)	198.2 ± 52.8	156.7 ± 45.3	t = 4.27	< 0.001
Prothrombin time (s)	14.2 ± 2.1	16.8 ± 2.9	t = 5.12	< 0.001

Distribution and impact of fatty liver severity

The distribution of fatty liver severity among 165 patients demonstrated a distinct gradient pattern. Based on liver-spleen density difference assessment on non-contrast CT imaging, mild fatty liver was predominant with 90 cases (54.6%), followed by moderate fatty liver with 51 cases (30.9%), and severe fatty liver with 24 cases (14.5%). Further stratified analysis revealed that fatty liver severity was significantly correlated with patient prognosis. The proportion of moderate to severe fatty liver (moderate + severe combined) was markedly higher in the poor prognosis group compared to the good prognosis group (Figure 1).

Figure 1 Distribution of fatty liver severity between good and poor prognosis groups. Distribution of fatty liver severity among 165 patients based on liver-spleen density difference on non-contrast computed tomography imaging. Mild fatty liver was most common (54.6%), followed by moderate (30.9%) and severe (14.5%) fatty liver. Moderate to severe fatty liver was significantly more prevalent in the poor prognosis group compared to the good prognosis group. ^aP < 0.05.

Univariate analysis results

This study systematically evaluated potential risk factors affecting prognosis after percutaneous drainage in liver abscess patients with fatty liver through univariate analysis. The analysis results showed that multiple demographic characteristics, clinical features, laboratory indicators, and imaging parameters were significantly associated with poor prognosis. Regarding demographics and underlying diseases, patients aged ≥ 65 years had significantly increased risk of poor prognosis (OR = 3.24, 95%CI: 1.58-6.63, P = 0.003), and diabetes history was an important prognostic factor (OR = 2.87, 95%CI: 1.42-5.81, P = 0.008), reflecting the adverse effects of decreased body reserve function in elderly patients and diabetes-related immune dysfunction on prognosis. Regarding abscess characteristics, abscess diameter ≥ 8 cm (OR = 2.45, 95%CI: 1.21-4.96, P = 0.012) and multiple abscesses (OR = 4.12, 95%CI: 1.85-9.17, P = 0.001) were both closely related to poor prognosis, suggesting that lesion extent and complexity are key factors determining treatment effectiveness. Laboratory indicator analysis showed that white blood cell count ≥ 15 × 10⁹/L (OR = 3.98, 95%CI: 1.94-8.16, P < 0.001) reflects severe systemic inflammatory response, serum albumin < 30 g/L (OR = 4.25, 95%CI: 2.08-8.69, P < 0.001) indicates malnutrition and impaired liver synthesis function, and total bilirubin ≥ 34.2 μmol/L (OR = 2.73, 95%CI: 1.35-5.52, P = 0.002) indicates the degree of liver function damage. All these indicators were significantly associated with poor prognosis. Imaging assessment showed that moderate-to-severe fatty liver (OR = 3.52, 95%CI: 1.71-7.24, P = 0.001) was an important prognostic predictor, while drainage tube duration ≥ 10 days (OR = 2.28, 95%CI: 1.15-4.52, P = 0.018) among treatment-related factors was also associated with poor prognosis, possibly reflecting poor treatment response and disease complexity. These univariate analysis results laid the foundation for subsequent multivariate analysis and helped identify independent prognostic risk factors (Figure 2).

Figure 2 Risk factors for poor prognosis after percutaneous drainage in hepatic abscess patients with fatty liver. This forest plot presents the univariate analysis results identifying nine significant risk factors associated with poor prognosis following percutaneous drainage in hepatic abscess patients with concurrent fatty liver disease. The most significant predictors include hypoalbuminemia (< 30 g/L, OR = 4.25), multiple abscesses (OR = 4.12), elevated white blood cell count (≥ 15 × 10⁹/L, OR = 3.98), and moderate to severe fatty liver (OR = 3.52), with all factors demonstrating statistical significance (P < 0.05).

DISCUSSION

Liver abscess, as a serious infectious disease of the liver, has undergone significant changes in disease patterns and treatment strategies over the past several decades. Traditionally, liver abscess was mainly seen in malnourished, immunocompromised populations, but with the acceleration of population aging and lifestyle changes, the patient population with liver abscess presents new characteristics. Particularly in recent years, with the rapid rise in incidence of metabolic syndrome, diabetes, and NAFLD, the number of patients with liver abscess combined with fatty liver has shown an obvious increasing trend, attracting widespread attention from clinicians[15-17].

NAFLD has become the most common chronic liver disease globally, with its prevalence showing rapid upward trends in both developed and developing countries. In China, the prevalence of NAFLD in adults has exceeded 25%, reaching over 30% in some regions. The pathogenesis of fatty liver is complex and diverse, mainly involving insulin resistance, lipid metabolism disorders, oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress, and gut-liver axis abnormalities. These pathophysiological processes not only lead to abnormal lipid accumulation in hepatocytes but more importantly cause profound changes in the liver microenvironment, including liver sinusoidal endothelial cell dysfunction, altered Kupffer cell activation states, active stellate cell proliferation, and intrahepatic inflammatory cell infiltration[18-20].

The impact of fatty liver on liver immune function is multifaceted. First, the local immune microenvironment of the liver in fatty liver patients undergoes significant changes. Kupffer cells, as the main innate immune cells of the liver, have significantly decreased phagocytic function and antigen presentation ability in fatty liver states, directly affecting the liver's ability to clear pathogenic microorganisms. Second, chronic low-grade inflammatory states associated with fatty liver lead to sustained elevation of pro-inflammatory factors such as tumor necrosis factor-α, interleukin-6, and interleukin-1β. Although this inflammatory environment may appear hyperactivated during acute infection, chronic inflammation actually leads to immune tolerance and decreased immune function. Additionally, fatty liver patients often have intestinal flora imbalance and impaired intestinal barrier function, making bacterial endotoxins and other harmful substances more likely to enter portal circulation, increasing the risk of liver infection[21-24].

The impact of fatty liver on liver structure and function is equally significant. At the histological level, fatty liver presents as massive lipid droplet deposition in hepatocytes, leading to enlarged hepatocyte volume, loose cytoplasm, and loose intercellular connections. These structural changes not only affect normal liver metabolic function but may also influence drug distribution and metabolism within liver tissue. At the vascular level, intrahepatic hemodynamics change in fatty liver patients, with increased liver sinusoidal capillarization and abnormal vascular endothelial function. These changes may affect the effective concentration of therapeutic drugs such as antibiotics at infection sites. At the cellular molecular level, autophagy function in hepatocytes is impaired in fatty liver states, with decreased intracellular waste clearance capacity and weakened antioxidant capacity. All these factors may affect the liver's resistance to infection and tissue repair capacity[25-27].

From a clinical treatment perspective, the presence of fatty liver brings new challenges to liver abscess treatment. Percutaneous drainage, as the current gold standard for liver abscess treatment, depends not only on abscess characteristics but also on the host's overall condition. Changes in liver tissue texture in fatty liver patients may affect puncture tract healing and drainage tube fixation; coagulation dysfunction associated with fatty liver may increase the risk of puncture-related bleeding; common malnutrition in fatty liver patients, particularly protein-energy malnutrition, affects wound healing and tissue repair processes[28,29].

Diabetes, as an important comorbidity of fatty liver, plays a crucial role in the development and progression of liver abscess. Due to chronic hyperglycemic states, diabetic patients have impaired neutrophil function, decreased complement system activity, and abnormal cellular and humoral immune functions. These immune deficiencies make diabetic patients more susceptible to various infectious diseases. Additionally, diabetes-related microvascular and macrovascular diseases affect local blood supply, which is unfavorable for infection control and tissue repair. Hyperglycemic environments also provide favorable nutritional conditions for bacteria, promoting bacterial proliferation and aggravating infection severity[30,31].

Age factors play an important role in liver abscess patients with fatty liver. Elderly patients, due to immunosenescence phenomena, experience varying degrees of decline in the number and function of various immune cells, including T cell subset imbalance, weakened B cell antibody production capacity, and decreased natural killer cell activity. Elderly patients usually have poor nutritional status, with common protein intake deficiency and vitamin and trace element deficiencies. These nutritional factor deficiencies directly affect immune function and tissue repair capacity. Additionally, elderly patients often have multiple chronic diseases such as hypertension, coronary heart disease, and chronic kidney disease. These diseases and their therapeutic drugs may all affect the body's response to infection and recovery process[32].

From a pathophysiological perspective, the development and progression of liver abscess on the basis of fatty liver follow special patterns. Liver microcirculation disorders in fatty liver patients may lead to local ischemia and hypoxia, providing favorable conditions for anaerobic bacterial growth and reproduction. Cholestasis phenomena associated with fatty liver may affect the antibacterial effect of bile, increasing the risk of biliary-origin infections. Portal hypertension and collateral circulation formation common in fatty liver patients may change intrahepatic blood flow distribution, affecting antibiotic distribution and concentration in liver tissue[33].

Limitations

This study has several important limitations that must be acknowledged. First, the single-center retrospective design may limit the generalizability of our findings, as patient characteristics, treatment protocols, and outcomes may vary across different institutions and healthcare systems. The retrospective nature of data collection introduces potential selection bias and information bias, as certain clinical variables may have been incompletely documented or missing. Second, we were unable to collect several potentially important variables that could influence outcomes, including specific antibiotic regimens, treatment duration, patient adherence to therapy, and detailed glycemic control parameters (such as glycated hemoglobin levels) in diabetic patients.

CONCLUSION

This study demonstrates that fatty liver disease significantly impacts the prognosis of liver abscess patients undergoing percutaneous drainage. Five independent risk factors were identified: Advanced age (≥ 65 years), diabetes history, large abscess diameter (≥ 8 cm), hypoalbuminemia (< 30 g/L), and moderate-to-severe fatty liver disease.