Effect of diabetes mellitus on short-term prognosis of 227 pyogenic liver abscess patients after hospitalization

In this retrospective study, we examined the patients who were diagnosed primarily as PLA in the First Affiliated Hospital of Xi’an Jiaotong University between January 2011 to January 2018. All diagnoses of PLA were based on the clinical features, imaging and laboratory results, blood and pus cultures. Details of 422 patients were retrieved through the hospital’s electronic medical record system. Patients with the following conditions were excluded: those who were diagnosed with malignant tumors or other serious cardiovascular diseases, those who were not the first-time suffering from liver abscess, those who had not finished the hospitalization in our center and those who had incomplete medical records or a 180 days follow-up. Finally, 227 patients entered this study (Additional file 1: Table S1). Patients were firstly divided into two groups based on the diagnoses with or without diabetes, and then the patients with diabetes were further divided into two subgroups, good- and poor-control groups of glycaemia. Patients of type II diabetes mellitus all had a clear history of diabetes at admission, and none of them were diagnosed after admission. We defined DM patients with HbA1C level < 7% included in the good-control group and ≥ 7% in the poor-control group. This study was strictly complied with the Treaty of Helsinki and approved by the ethics committee of the First Affiliated Hospital of Xi’an Jiaotong University. Written informed consent were waived as a retrospective research.

Diabetic macro-angiopathy collected cardio- and cerebrovascular accidents and lower extremity gangrene, and micro-angiopathy included microvascular lesions of retina and kidney caused by high blood glucose levels. Complications, treatments and outcomes were also gained. Abscess number, diameter, site and gas-forming were measured by ultrasonography and computerized tomography (CT).

Follow-up for all patients was until June 2018 and lasted for at least 6 months after discharge. The average follow-up time was 820 (IQR: 308, 1261) days. The main contents of the follow-up included the disease status and recurrence of all patients. All patients achieved full follow-up data. The mortality outcome was ascertained from discharge time to the last follow-up. To minimize classification errors, the follow-up was completed by two clinical researchers independently.

For continuous variables, the study was expressed as mean ± standard deviation or median (min-max) whereas categorical variables used frequency and percentage. To calculate the difference between the two groups, we applied the Student’s t-test or Wilcoxon test for continuous variables and the chi-squared test or Fisher’s exact test for categorical data. For three or more groups, we applied the analysis of variance. The factors that found P < 0.10 in the univariate analysis were carried forward through the multivariate analysis. Survival curves were calculated by the Kaplan–Meier curve method, and statistical differences were calculated through the Log-Rank test. All statistical analyses were finished by SPSS 23.0 software (IBM Corporation, Armonk, NY, USA). Graphpad prism 8.0 software was used to beautify the survival curves (GraphPad Software, Inc. La Jolla, USA). P < 0.05 was considered as statistically significant.

A total of 227 patients with PLA were enrolled in this retrospective study. As shown in Table 1, the average age of total patients was 56 years (range: 11–84 years), and 135 (59.47%) of them were male. Among them, 66 (29.07%) patients had a history of smoking, 43 (18.94%) patients had alcohol drinking history. 43 (18.94%) and 8 (3.52%) patients had hypertension and cirrhosis, respectively. Most patients had a normal (60.79%) or low-grade fever temperature (34.80%) at admission, and the medium time for temperature normalization was 6.39 (range: 0–40). leucocytes abnormally increased in 119 patients (52.42%) on the first day of admission. In this cohort, the number of the abscess was mainly single (75.77%). The maximum diameter of the abscess in 132 patients (58.15%) was between 5 and 10 cm, then followed by a small abscess in 75 cases (33.04%). In 137 (60.35%) patients, the abscess located in the right liver lobe, 34 (14.98%) in the left, and 41 (18.06%) in both. Gas formation was observed in 45 patients (19.82%). In Table 2, 116 blood cultures were collected and only 28 patients (24.14%) were positive. There was no significant difference in the positive proportion between the two groups. Based on pus culture from 148 cases, positive growth was found in 98 patients (66.22%). Among the positive patients, 114 patients (85.07%) were Gram-negative bacteria, 18 (13.43%) were Gram-positive bacteria, and 2 (1.49%) were Candida spp. infections. Klebsiella pneumonia and Escherichia coli in the Gram-negative organisms were the two most common bacteria in this study, accounting for 57.46 and 17.91%, respectively. In the Gram-positive organisms, Streptococcus spp. (6.72%) was the most pathogens cultured. It was documented that pleural and celiac effusion were the most common complications (18.41, and 7.58%, respectively, Table 3). 136 (59.91%) patients received percutaneous drainage, 28 (12.33%) underwent surgical drainage, and the rest 63 (27.75%) were administrated conservative treatment. 125 (55.07%) patients presented combined antibiotic use. All patients showed outcomes with cured or improved and no patient died during the hospital stay. The average cost of total patients was 4096 dollars.

In this study, 227 patients were divided into two groups based on DM. The Non-DM group included 166 (73.13%) patients and the DM group included 61 (26.87%) patients, with an average diabetes duration time of 5.5 years (range: 0.2–30 years). There was no significant difference in gender, age, body temperature at admission, abscess number, size, site, and gas-forming between the two groups (Table 1). However, patients in the DM group exhibited more hypertension but lower leucocytes count (P < 0.001, and P = 0.007, respectively). Interestingly, the use of steroid hormone (34.43% vs. 21.69%) and immune response enhancer (39.34% vs. 10.84%) was significantly higher in PLA patients with DM than in the non-DM group (P < 0.05). Although the infection of Gram-negative and –positive in this study were similar between the two groups, patients in the DM group had higher Candida spp. infection than that of in Non-DM group (P = 0.052, Table 2). In Table 3, no significant difference had been found in complications, intravenous antibiotics use, outcomes, hospital stay, total costs and reoccurrence in 3 months between the two groups. While the choice of treatments was different between the two groups (P = 0.024). Percutaneous drainage was mainly adopted in patients without DM (64.46%), while percutaneous drainage and conservative treatment were mainly performed in patients with DM (47.54 and 40.98%).

During the follow-up period, 24 (10.57%) died within 6 months and 14 (6.17%) were diagnosed with PLA recurrence within 3 months after discharge. The PLA patients with DM had lower six-month survival than that of in Non-DM group (81.97% vs. 92.17%, P = 0.027) and no significant difference had been found with the reoccurrence rate between the two groups (P = 0.164, Table 3). To explore risk factors independently associated with short-term survival after hospitalization in PLA patients, univariable and multivariable analysis were made. Univariate variables with P < 0.10 were further analyzed with a multivariate model. As shown in Table 4, diabetes mellitus (OR: 3.019, 95% CI:1.138–8.010, P = 0.026) was the only independent risk factor for six-month survival after discharge. Other factors including age > 60 years, gender, cirrhosis, biliary tract infection, abscess number and size, gas forming, Escherichia coli infection, and treatment methods were not found to be independent risk factors. The Kaplan-Meier curve of six-month survival after discharge was further estimated concerning DM in Fig. 1. It was found that PLA patients with DM had worse short-term survival than those in the Non-DM group (Log-Rank test, P = 0.021).

Abnormal glycaemia level in the DM group was considered as a potent risk factor of short-term survival in PLA patients, which was further investigated in subgroups. All the patients were classified into two subgroups according to the HbA1C level. The clinical characteristics, laboratory results, abscess information, treatments and outcomes were compared between the two subgroups in Table 5. No difference was presented between the two subgroups in age, gender, diabetes duration time, underlying conditions, diabetic vascular diseases, laboratory tests, abscess characteristics, medicine use, outcomes, and hospital stay, etc. However, there was an obvious difference in the selection of treatments between the two subgroups (P = 0.027). Percutaneous drainage was mainly performed in patients with poor-control of glycaemia (60.53%) and conservative treatment was mainly adopted in patients with good-control of glycaemia (60.87%). Besides, combined intravenous antibiotics showed a higher proportion in poor-control group (71.05%, P = 0.033). Although there was no significant difference, total hospitalization costs and relapsed PLA within 3 months after discharge showed an obvious increase in the poor-control group compared to good-control group (6037 vs. 3154 dollars, 13.16% vs. 4.35%, respectively). Kaplan-Meier curve with different glycaemia levels in terms of six-month survival was shown in Fig. 2. No difference was unfolded between the two groups in Kaplan-Meier plots (Log-Rank test, P = 0.218).