Ultra-Early Indicators of Acute Hypertriglyceridemic Pancreatitis May Inuence Treatment Decision-Making By Chinese Doctors

Background: This study investigates whether ultra-early indicators can predict severity of acute hypertriyceridemic pancreatitis (HTGP) and affect clinical decisions. Methods: For this observational retrospective study, we analyzed data of 110 HTGP patients enrolled between January 2017 and February 2020. HTGP patients were categorized into mild acute pancreatitis (MAP) and moderately severe acute pancreatitis-severe acute pancreatitis (MSAP-SAP) groups, based on their nal clinical outcomes. Demographic and clinical data were collected and ultra-early indicators (serum calcium, triglyceride (TG), interleukin-6(IL-6), D-dimer, hemoglobin A1c(HbAc1), arterial lactate) levels were measured within 6 hours of admission. A multivariate logistic regression analysis model and receiver operating characteristic curve were used to determine ultra-early indicators values of high-risk patients. The chi-square test method was applied to estimate the hospitalization time and associated complications in MSAP-SAP group post-plasma exchange within or more than 24 hours. Results: Among the 110 HTGP patients, 56 were in the MAP group whereas, 54 were in the MSAP-SAP group. TG, IL-6, D-dimer, HbAc1, and arterial lactate levels measured within 6 hours after admission were signicantly higher in the MSAP-SAP group, but serum calcium was signicantly lower, versus the mild AP group. IL-6, D-dimer and serum calcium were identied as the risk factors for MSAP-SAP and were potential ultra-early indicators for predicting HTGP severity within 6 hours of admission. MSAP-SAP patients that underwent blood purication therapy within 24 hours of admission had a shorter hospitalization time than those treated 24 hours post-admission. Conclusion: The present study reveals IL-6, D-dimer, and serum calcium - ultra-early indicators - as promising biomarkers in the assessment of AP severity in HTGP patients within 6 hours. Early blood purication presents a novel therapy among MSAP-SAP patients within 24 hours and is associated with fewer complications and a shorter hospitalization time. However, traditional therapy can be further integrated to manage

stroke in the brain. The occurrence of high triglycerides in the fundus of the eye can cause impaired vision and blindness and renal failure in the kidney. The presence of blood in the limbs is attributed to high triglycerides. Consequently, poor blood ow causes necrosis. Hypertriglyceridemia is the main risk factor for HTGP. Triglycerides are broken down into a large amount of free fatty acids that exceed the binding capacity of albumin, causing cell membranes toxicity through lipid peroxidation. This mechanism consequently damages acinar cells and capillary endothelial cells [7]. Moreover, hypertriglyceridemia is associated with the hypercoagulable state of blood and induces pancreatic microcirculation disturbance [8].
Reduction in blood lipid level is the key treatment for hyperlipidemic pancreatitis. Integration of targeted lipidemia-suppression with general therapy, for example, fasting and administration of low molecular weight heparin and insulin can reduce blood lipid and recuperation among non-severe patients. The use of drug therapy alone in severe patients is unlikely to reduce blood lipid rapidly. Early application of blood puri cation therapy has been widely adopted to rapidly reduce blood lipid level among patients with severe pancreatitis. Therefore, identifying high-risk patients at the early stages of the disease is crucial since it can help clinicians to formulate an effective management approach or refer the diagnosed patients to expert care for advanced clinical prognosis.
Methods of risk strati cation and severity prediction at the early stage of AP have been developed for decades, including some clinical scoring systems and laboratory parameters. Previous studies had identi ed several indicators that could predict severity of acute pancreatitis such as D dimer [9], serum calcium [10], IL-6 [11,12], arterial lactate [13], C-reactive protein(CRP), red cell distribution width (RDW) [14,15], MCTSI [16], TG [5], among other indicators. However, these indicators are frequently detected within 24-48 hours post-admission. In most cases, patients with severe pancreatitis do not enjoy, the best opportunity for blood puri cation therapy, which prolong their hospitalization time and increase medical expenses. Early identi cation of severe form of pancreatitis is among the major challenges for its management.
Numerous studies have investigated the differences in clinical characteristics between HTGP and non-HTGP [13,17]. To date, only a few studies have assessed the ultra-early risk factors of HTGP. In this study, we collected blood samples and tested the six indicators within 6 hours after the patients are admitted to the hospital. Data from HTGP patients obtained within 6 hours of admission were analyzed to characterize their early risk factors of HTGP and provide novel approaches for its prevention and treatment. Early evaluation of HTGP is key in determining the immediate use of blood puri cation and drug lipid-lowering therapies. Therefore, drug lipid reduction therapy will be bene cial in the recovery of patients condition and save medical expenses when blood puri cation therapy is not needed.

Study population and study design
We acquired data for 110 patients with HTGP during admission at the Second A liated Hospital, Fujian Medical University, (Quanzhou, China) between January 2017 to February 2020. Complete case data for the participants were retrospectively analyzed. The present study was approved by the Ethics Committee of the Second A liated Hospital, Fujian Medical University. Because this was a retrospective study, approved by the ethics committee of our hospital,there was no patient informed consent. However, all patients' personal information was kept con dential and the principle of con dentiality was observed.This was a retrospective study performed in accordance with local and national laws and abiding by the guidelines of the Helsinki Declaration. Initially, the enrolled patients received targeted lipidemia-lowering and general therapies which include fasting, low molecular weight heparin and insulin to reduce blood lipid, gastrointestinal decompression, uid resuscitation, nutritional therapy, organ function maintenance, preventive usage of antibiotics against gram-negative bacilli and Traditional Chinese Medicine approach, taking raw rhubarb to restore gastrointestinal tract dynamics and treat pancreatitis. Blood puri cation therapy which includes plasma exchange and hemo ltration were conducted in patients diagnosed with a severe tendency on admission.
According to the nal clinical outcomes, HTGP patients were divided into MAP and MSAP-SAP groups. Patients demographic and clinical data were collected and their ultra-early indicators (serum calcium, TG, IL-6, D-dimer, HbAc1, arterial lactate) levels were measured within 6 hours of admission. A multivariate logistic regression analysis model and receiver operating characteristic curve were used to determine the value of ultra-early indicators in high-risk patients. A chi-square test method was applied to estimate the time of hospitalization and complications in the MSAP-SAP group post-plasma exchange within or more than 24 hours.

Data collection
We recorded information on patient's, age, sex, body mass index (BMI), medical history, admission data and length of stay were collected to form the baseline demographic data. Moreover, on admission, data on vital signs were collected also, whereas important laboratory tests, radiological data and clinical outcomes were determined after hospitalization. Within 6 hours of admission, the following laboratory parameters were determined: TG, IL-6, D-dimer, HbAc1, and arterial lactate levels. Enhanced CT was performed to examine the extent of necrotic tissue and the uid locus. The modi ed Marshall score was used to evaluate the severity of acute pancreatitis.
Statistical methods IBM Statistical Package for Social Sciences (SPSS) software version 20.0 (Chicago, USA) was used to perform the statistical analysis. The results were presented as a percentage (%) or mean ± SD. Comparisons were performed using the Student's t-test and Mann-Whitney U test for two groups of independent samples. Categorical data were presented as n (%) prevalence whereas the between-group differences were assessed using either χ2-test or Fisher's exact test, accordingly. Logistic regression analysis was performed to predict risk factors with categorical dependent variables. Differences were statistically signi cant at p < 0.05. The area under the receiver operating characteristic (ROC) curve (AUC) was determined to evaluate the performance of the predictive model. Given the range of 0-1 of AUC, a variable with > 0.7 was considered useful whereas an AUC value of 0.8-0.9 denoted excellent diagnostic accuracy.

Demographic and clinical characteristics of the study population
Of the 110 patients with HTGP, 56 were classi ed with mild AP and 54 with moderately severe and severe AP (MSAP-SAP). Though the age of onset in the mild AP group was higher (44.3 ± 4.1 versus 33.6 ± 4.9 years), their incidence of type 2 diabetes mellitus disease was lower (32 versus 43 patients) compared with the MSAP-SAP group (P < 0.05). The sex of patients among the groups was not statistically different (P > 0.05). MAP group have patients with a lower BMI than in SAP group (P < 0.05) as shown in Table 1.  Indicators for predicting the severity of HTGP We summarized the sensitivity, speci city and AUC results in the prediction of HTGP severity in Fig. 1.
Some parameters were highly accurate in the prediction of HTGP severity. In the prediction of MSAP-SAP, IL-6 ≥ 27.4 pg/ml had the highest accuracy with 87% sensitivity, 73% speci city and 0.86 area under the curve. D-dimer ≥ 2.65 mg/l had 63% sensitivity, 94% speci city and 0.82 area under the curve for serum D-dimer in the prediction of HTGP severity. Arterial lactate ≥ 1.69 mmol/L had 57% sensitivity, 79% speci city and 0.73 AUC in the prediction of HTGP severity. Serum calcium < 2.14 mmol/l had 72% sensitivity, 70% speci city and 0.77 AUC (Table 3).

Independent prognostic factors in the MSAP-SAP group at admission
To further evaluate the relationship between admission indicators and MSAP-SAP, we constructed a multivariate logistic regression analysis model consisting of four parameters (IL-6, D-dimer, Arterial lactate, Serum calcium) within 6 hours of admission. The multivariate logistic regression model identi ed IL-6, D-dimer, and Serum calcium as independent risk factors for AP. The odds ratio (OR) were respectively listed in Table 4. With a D-dimer ≥ 2.65 mg/l, IL-6 ≥ 27.4 pg/ml or serum calcium < 2.14 mmol/l, greatly increased the risk of transformation of HTGP to severe. Therefore, the combination of the three independent risk factors in the prediction of HTGP severity further improved the prediction accuracy with a 0.88 AUC (Fig. 2).
The effect of early blood puri cation treatment on MSAP-SAP patients Early blood puri cation therapy within 24 hours after admission could shorten the hospitalization time of HTGP patients with severe tendency. Among the 50 SAP patients with higher-level clinical indicators (Ddimer ≥ 2.35 mg/L or IL-6 ≥ 27.4 pg/ml) at admission, 28 received early blood puri cation therapy within 24h whereas the 22 were delayed. Patients who received early blood puri cation therapy had a shorter time of hospitalization with fewer complications than those whose treatment was delayed as shown in Table 5. Blood puri cation treatment could not shorten hospitalization time and greatly increased medical expenses, however, the traditional lipidemia-lowering treatment scheme could yield a better therapeutic effect on MAP patients.

Discussion
Recently, the incidence of HTGP has been increasing and is frequently associated with more severe clinical processes. HTGP is mostly reported in young people especially those who are obese, alcoholic and diabetic. Hypertriglyceridemia is the main risk factor for HTGP. Studies have shown that HTGP patients are prone to persistent organ failure and the incidence of complications and mortality are signi cantly higher than those of AP due to other causes. Therefore, an immediate decrease in serum triglyceride level to below 5.65 mmol/L in the early stage of the disease interrupts the vicious cycle between triglyceride and in ammation, hence lowers the disease severity and improve the prognosis. Heparin and insulin have a synergistic effect to reduce serum triglyceride. The synergistic effect of heparin and insulin on HTGP has been clinically recognized and is adopted as a rst-line treatment on severe HTGP [20,21]. Blood puri cation including plasma exchange and hemo ltration can be used in HTGP treatment. A recent systematic review showed that serum triglyceride in most HTGP patients decreases signi cantly after plasma exchange followed by improvement of clinical symptoms or laboratory indicators, but cannot reduce the mortality of patients [22]. Moreover, the blood puri cation is not superior in terms of clinical outcomes and costs. There are some research deviations in these conclusions. For example, the patients in the HTGP group are not graded for severity, which cannot re ect the advantages of blood puri cation therapy for severe patients and whether blood puri cation therapy is necessary for non-severe patients. On the other hand, the time of plasma exchange might be the critical point. If severe patients with HTGP can receive plasma exchange as soon as possible, a better result may be predicted [23]. In addition, at present, the main drugs for HTG are feno brate, gem brozil and other brates, niacin, statins and omega-3 fatty acids. Niacin is restricted due to its multiple side effects [24]. In a randomized double-blind controlled trial, the dual treatment of omega-3 fatty acids and feno brate reduced the median TG concentration by 60.8% whereas, feno brate monotherapy alone reduced it by 53.8%. However, these two treatments were not statistically signi cant [25]. The role of statins is controversial. For instance, statins mainly act on hyperlipidemia with elevated cholesterol but some studies have shown that it has a protective effect while others have reported it to cause pancreatitis [26]. Currently, brates are the recommended rst-line drug treatment in clinical practice.
Our research has two main ndings. First, we found that during the ultra-early stage of HTGP, there still exist indicators that can better predict the severity of pancreatitis. This is key for an immediate evaluation of the disease progression and actively adopt targeted treatment measures. Therefore, effective intervention can be performed in the early stage of HTGP to achieve the goal of timely control of disease development. We found that ultra-early indicators of IL-6, D-dimer may be useful biomarkers in the assessment of AP severity in patients with HTGP, which facilitate the timely identi cation of HTGP patients with severe tendency using these indicators. Numerous studies have shown that HTG is often accompanied by leukocyte chemoattractant protein-1 (MCP-1), malondialdehyde (MDA), nitric oxide (NO) and catalase (catalase, CAT) and other indicators of oxidative stress [27]. Clinical studies have also found that for patients with LPL or Apo-C2 gene defects and repeated HTG-AP [28,29], the use of antioxidant therapy has a clear clinical effect in the prevention of AP and suggests that oxidative stress may be an important mechanism for HTG to induce AP [27]. Given these approaches, early intervention can be suggested as they are conducive to the rehabilitation of patients.
Second, we found that for patients diagnosed with MSAP-SAP, blood puri cation therapy within 24 hours of admission can shorten their hospitalization time. This shows that early blood puri cation therapy to reduce blood lipid level and eliminate in ammatory factors can block the progress of pancreatitis and is conducive for disease recovery. Considering the high medical cost of blood puri cation therapy and the potential risk of blood-borne infection, our research found that for patients diagnosed with MAP, the conventional treatment scheme can still result in a good therapeutic effect whereas the blood puri cation method will prolong their hospitalization time. Therefore, early assessment after admission is important and can determine the preliminary outcome of the disease through indicative indicators. Immediate blood puri cation therapy should be implemented in patients with severe manifestations, however, for patients without severe manifestations, cheap traditional treatment schemes can be adopted cheap which have a shorter hospitalization time. Our study has limitations in several aspects. This is a retrospective study that is prone to selection bias. To minimize the possibility of selection bias, we adopted strict inclusion criteria and expanded the sample size. Despite these limitations, this retrospective study provides effective information on treatment strategies for HTGP. We are currently conducting a prospective cohort study to obtain more accurate data to support our view.

Conclusion
Our results indicate that early detection of IL-6, D-dimer and blood calcium concentration may predict the development of pancreatitis after admission of patients with HTGP. Therefore, early detection facilitates the implementation of different effective treatment schemes in the early stage of HTGP which accelerate the recovery of pancreatitis and reduce medical expenses.

Consent for publication
Not applicable.

Availability of data and materials
The analyzed data sets generated during the present study are available from the corresponding author on reasonable request. ROC curve for blood parameters to predict the MSAP-SAP in HTGP within 6h after admission. ROC curve for ultra-early indicators measured within 6h after admission to predict MSAP-SAP in HTGP. ROC, receiver operating characteristic; AUC, area underthe curve.