AP is an inflammatory disorder of the pancreas characterized by rapid onset and has multiple possible etiologies. The association between severe HTG and AP has long been recognized . Yet the exact threshold of serum TG level to trigger AP has not been defined. AP is conventionally thought to be triggered when TG levels exceed 1,000 mg/ dL (11.3 μmol/L). It was also proposed that the TG level > 500 mg/dL should raise a high-degree suspicion of HTG-AP, especially in the absence of other probable etiologies . The incidence of HTG-AP was increasing year by year especially in China [11-12]. Moreover, HTG-AP was reported to increase at a faster rate than alcoholic AP . In some regions, HTG had exceeded alcohol and become the second cause of AP [3,13].
Clinical presentation of HTG-AP is similar to that of pancreatitis of other etiologies , but patients with HTG-AP were more likely to have pancreatic necrosis and organ failure, severe acute pancreatitis, and systemic inflammatory response Syndrome [4,11]. Compared to other causes of AP, HTG-AP patients were younger, had more hospital stays and higher recurrence rate in previous study . A multicenter study showed that alcoholic pancreatitis and HTG-AP were mainly distributed in patients before the age of 49 years . In the present study, half (55.5%) of patients were 31-45 years and HTG-AP appeared to be more prevalent in males than females, which is similar to other studies, but the exact reason is not clear. HTG is common in patients with the metabolic syndrome, type 2 diabetes and obesity which can contribute to elevated TG levels substantial enough to provoke pancreatitis . In the present study, the prevalence of obesity and diabetes was lower than other studies, obesity was found only in 6.8% of patients, diabetes in 17.3% of patients.
RAP is a syndrome of multiple distinct acute inflammatory responses originating within the pancreas in individuals with genetic, environmental, traumatic, morphologic, metabolic, biologic, and/or other risk factors who experienced 2 or more episodes of documented AP . If unchecked, recurrent episodes of AP may lead to chronic pancreatitis. Approximately 9% to 31 % of patients with AP develop recurrent attacks of pancreatitis [1,17-18]. The etiological factors of RAP are similar to those of first attack AP. Recently HTG is accepted as a major cause of RAP particularly in China. Deng et al reported that HTG accounted for 21% of RAP and biliary factor was still the leading causes of RAP in a region of China . A multicenter study showed the recurrence rate of HTG-AP was obviously higher than other causes (15.29%, 7.73% and 9.75% for HTG-AP, biliary AP and alcoholic AP respectively) . The present study showed that 24.1 % of patients with HTG-AP develop a recurrent disease. Patients with RAP seemed younger than non-recurrent cases. In contrast, serum amylase levels, hospitalization duration and mortality rate were almost identical in the two groups. Patients with RAP in the present study presented with higher blood TG levels at the time of admission, suggesting that blood TG level is likely associated with the relapse of HTG-AP.
Potential causes should be carefully evaluated in patients with an initial episode of AP. If the underlying cause is not corrected, any factor responsible for pancreatitis can lead to recurrent episodes. At present, there is a lack of consensus on the most appropriate treatment options for patients with HTG-AP. Although there are conflicting opinions regarding the lipid-lowering therapy for asymptomatic HTG to prevent AP [20-21]. However, when TG levels are ≧500 mg/dL, and especially when they are ≧1000 mg/dL, the primary treatment strategy is to reduce TG levels with a TG-lowering drug to reduce the risk of pancreatitis . For those who had suffered HTG-AP, diet control, exercise program, lipid-lowering agents and plasma exchange are recommended to reduce TG levels during the acute phase of HTG-AP, and in the prevention of recurrence. In present study, the follow-up of blood TG levels after hospital discharge were investigated. We found that the TG levels were higher in patients with RAP than that of non-RAP. Among the patients who had measured TG levels after discharge, the majority (83.3%）of RAP had at least 1 follow-up of TG laboratory result higher than 500 mg/dL, while there was no patient who had one episode displayed TG levels higher than 500 mg/dL. The risk of AP increases in a direct relationship to the level of TG . In a retrospective cohort study, the risk of incident AP increased by 4% for every 100-mg/dL increase in TG concentration . Lower follow-up of TG levels was associated with a lower incidence of important clinical events for patients with severe HTG . It is generally accepted that it is important to treat HTG to minimize the risk of recurrence of AP by reducing TG levels to <500 mg/dL [15,25]. Our results also supported that follow-up of TG levels were <500 mg/dL have less chance of pancreatitis episode and may be helpful in reducing the recurrence of pancreatitis.
Once the HTG-AP attack has been resolved, prevention of a next episode is compulsory. The long-term management consists of dietary intervention, long-term medications, regular monitoring of serum TG levels and lifestyle modifications . In the present study, there were only 7.5% of patients continued to use the lipid-lowering drugs after hospital discharge. The unsatisfied medication compliance is likely an important contributing factor to the high frequency of RAP in our study. Lipid monitoring might improve control of lipid parameters and the dietary compliance of patients with HTG . However, the percentage of follow-up of TG level monitoring was relatively low in our study, only 12.8 % of patients had their TG levels measured after discharge, showing that majority of the patients in present study lacked the understanding of HTG control for the prevention of AP attack. Although strategies of community based chronic disease treatment have been established in China, identifying and resolving compliance issues of HTG management should be improved and valued in these HTG-AP patients as well as decrease the recurrence rate.