The goal of this study was to explore the changes in the lipid profile following DFPP and how they were related to clinical results in sHTGP patients. It is generally recognized that a higher TG level correlates with illness severity(4), so timely lowering of the lipid profile is a critical goal. To compensate for the slow effect of pharmacological therapies, DFPP was performed in sHTGP patients and has been proven effective for decades. The efficacy of DFPP was tested in 47 sHTGP patients by Zheng et al., who discovered that the parameters were altered dramatically on the first day after DFPP(5). This study revealed similar results, and the effect was maintained until discharge.
Despite its well-known TG-lowering efficacy, DFPP is not the recommended extracorporeal therapy in the guideline of the American Society for Apheresis(6). The potential mechanism of DFPP modulation in sHTGP is still unclear. Free fatty acids, identified as a critical mediator of organ failure, could not be removed by DFPP(7). However, DFPP could rapidly eliminate TG lipoproteins, theoretically limiting the accumulation of free fatty acid metabolized from TG. Elevated TG levels have been independently and proportionally associated with persistent organ failure(8). Consequently, the efficacy of DFPP in intervening in disease severity and clinical results in sHTGP patients has yet to be confirmed. Lu et al. conducted a propensity score matching analysis of DFPP and conservative treatment(9). They found that early implementation of DFPP could effectively reduce TG levels while manifesting no benefit on the clinical results of sHTGP patients. In this study, the TG levels on admission were 39.7 mmol/L and 31.1 mmol/L in the two groups. In the other study, Chang et al. reported that DFPP could eliminate inflammatory and oxidized lipoproteins and significantly reduce the incidence of complications when applied to patients with TG levels > 56.5 mmol/L (5000 mg/dL) (10). A TG level higher than the current TG standard could be a better indication for DFPP and a better predictor of clinical outcomes. This hypothesis was partly verified by our research. The APACHE II score change was more obvious in the higher TG group than in the lower TG group, with a significant difference (P < 0.05). This clinical improvement was related to TG and TC reductions, according to linear regression analysis, but the potential mechanism required more investigation.
Moreover, it was controversial whether performing DFPP was associated with shortening hospital durations in previous studies(10). In Lu’s study, DFPP imposed no effect on the length of hospital stay. However, Chang et al. inferred that DFPP could shorten the disease course and reduce hospital duration. This outcome was partly associated with the clinical improvement discussed above. In our study, the ICU and hospital stays in both groups were not significantly different (P = 0.245 and 0.180, respectively), contrary to previous expectations(11). Furthermore, due to the extra expenses, DFPP was reported to increase the hospital charges(9). However, except for material fees related to DFPP (P = 0.019, < 0.05), hospital expenses were not significantly different, including total, professional, nonprofessional, and medication fees. As mentioned above, it was reasonable to infer that DFPP could offset costs by alleviating disease severity and shortening the course of illness.
This was one of the largest studies to evaluate the efficacy and cost of DFPP in sHTGP patients. However, this study possessed several shortcomings. First, some latent and confounding factors might exist in this retrospective observational study, which could influence patient outcomes. Second, relatively small sample sizes from a single center undermined the ability to measure some clinical results and reveal relationships. Therefore, further large-scale and multicenter prospective studies and randomized clinical trials are needed.