Cost-utility of molecular adsorbent recirculating system treatment in acute liver failure

Liver replacement therapy with extracorporeal blood purification techniques current knowledge and future directions

Clinically, it is highly challenging to promote recovery in patients with acute liver failure (ALF) and acute-on-chronic liver failure (ACLF). Despite recent advances in understanding the underlying mechanisms of ALF and ACLF, standard medical therapy remains the primary therapeutic approach. Liver transplantation (LT) is considered the last option, and in several cases, it is the only intervention that can be lifesaving. Unfortunately, this intervention is limited by organ donation shortage or exclusion criteria such that not all patients in need can receive a transplant. Another option is to restore impaired liver function with artificial extracorporeal blood purification systems. The first such systems were developed at the end of the 20^th century, providing solutions as bridging therapy, either for liver recovery or LT. They enhance the elimination of metabolites and substances that accumulate due to compromised liver function. In addition, they aid in clearance of molecules released during acute liver decompensation, which can initiate an excessive inflammatory response in these patients causing hepatic encephalopathy, multiple-organ failure, and other complications of liver failure. As compared to renal replacement therapies, we have been unsuccessful in using artificial extracorporeal blood purification systems to completely replace liver function despite the outstanding technological evolution of these systems. Extracting middle to high-molecular-weight and hydrophobic/protein-bound molecules remains extremely challenging. The majority of the currently available systems include a combination of methods that cleanse different ranges and types of molecules and toxins. Furthermore, conventional methods such as plasma exchange are being re-evaluated, and novel adsorption filters are increasingly being used for liver indications. These strategies are very promising for the treatment of liver failure. Nevertheless, the best method, system, or device has not been developed yet, and its probability of getting developed in the near future is also low. Furthermore, little is known about the effects of liver support systems on the overall and transplant-free survival of these patients, and further investigation using randomized controlled trials and meta-analyses is needed. This review presents the most popular extracorporeal blood purification techniques for liver replacement therapy. It focuses on general principles of their function, and on evidence regarding their effectiveness in detoxification and in supporting patients with ALF and ACLF. In addition, we have outlined the basic advantages and disadvantages of each system.

A head-to-head comparison of the EQ-5D-5L and 15D descriptive systems and index values in a general population sample

BACKGROUND

The EQ-5D-5L and 15D are generic preference-accompanied health status measures with similar dimensions. In this study, we aim to compare the measurement properties of the EQ-5D-5L and 15D descriptive systems and index values in a general population sample.

METHODS

In August 2021, an online cross-sectional survey was conducted in a representative adult general population sample (n = 1887). The EQ-5D-5L and 15D descriptive systems and index values were compared in terms of ceiling and floor, informativity (Shannon's Evenness index), agreement, convergent and known-groups validity for 41 chronic physical and mental health conditions. Danish value sets were used to compute index values for both instruments. As a sensitivity analysis, index values were also estimated using the Hungarian EQ-5D-5L and Norwegian 15D value sets.

RESULTS

Overall, 270 (8.6%) and 1030 (3.4*10^-6%) unique profiles occurred on the EQ-5D-5L and 15D. The EQ-5D-5L dimensions (0.51-0.70) demonstrated better informativity than those of 15D (0.44-0.69). EQ-5D-5L and 15D dimensions capturing similar areas of health showed moderate or strong correlations (0.558-0.690). The vision, hearing, eating, speech, excretion and mental function 15D dimensions demonstrated very weak or weak correlations with all EQ-5D-5L dimensions, which may indicate potential room for EQ-5D-5L bolt-ons. The 15D index values showed lower ceiling than the EQ-5D-5L (21% vs. 36%). The mean index values were 0.86 for the Danish EQ-5D-5L, 0.87 for the Hungarian EQ-5D-5L, 0.91 for the Danish 15D and 0.81 for the Norwegian 15D. Strong correlations were found between the index values (Danish EQ-5D-5L vs. Danish 15D 0.671, Hungarian EQ-5D-5L vs. Norwegian 15D 0.638). Both instruments were able to discriminate between all chronic condition groups with moderate or large effect sizes (Danish EQ-5D-5L 0.688-3.810, Hungarian EQ-5D-5L 1.233-4.360, Danish 15D 0.623-3.018 and Norwegian 15D 1.064-3.816). Compared to the 15D, effect sizes were larger for the EQ-5D-5L in 88-93% of chronic condition groups.

CONCLUSIONS

This is the first study to compare the measurement properties of the EQ-5D-5L and 15D in a general population sample. Despite having 10 fewer dimensions, the EQ-5D-5L performed better than the 15D in many aspects. Our findings help to understand the differences between generic preference-accompanied measures and support resource allocation decisions.

Adverse events, short- and long-term outcomes of extra corporeal liver therapy in the intensive care unit: 16 years experience with MARS® in a single center

Background

Molecular Adsorbent Recirculating System (MARS®) is a non-biological artificial liver device. The benefit risk ratio between uncertain clinical effects and potential adverse events remains difficult to assess. We sought to describe adverse events related to MARS® therapy as well as biological and clinical effects.

Methods

All intensive care unit (ICU) admissions to whom MARS® therapy was prescribed from March 2005 to August 2021 were consecutively and prospectively included. The main endpoint was the incidence of adverse events related to MARS® therapy. Secondary endpoints were the biological and clinical effects of MARS® therapy.

Results

We reported 180 admissions treated with MARS® therapy. Among the 180 admissions, 56 (31.1%) were for acute-on-chronic liver failure, 32 (17.8%) for acute liver failure, 28 (15.5%) for post-surgery liver failure, 52 (28.9%) for pruritus and 12 (6.7%) for drug intoxication. At least one adverse event occurred in 95 (52.8%) admissions. Thrombocytopenia was the most frequent adverse event which was recorded in 55 admissions (30.6%). Overall, platelets count was 131 (± 95) × 10⁹/L before and 106 (± 72) × 10⁹/L after MARS® therapy (p < .001). After MARS® therapy, total bilirubin was significantly decreased in all groups (p < 0.05). Hepatic encephalopathy significantly improved in both the acute-on-chronic and in the acute liver failure group (p = 0.01). In the pruritus group, pruritus intensity score was significantly decreased after MARS® therapy (p < 0.01).

Conclusion

In this large cohort of patients treated with MARS® therapy we report frequent adverse events. Thrombocytopenia was the most frequent adverse event. In all applications significant clinical and biological improvements were shown with MARS® therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-04165-z.

Transplant Hepatectomy With Portacaval Shunt and MARS Therapy for Perioperative Catastrophe: A Series of Four Liver Transplant Cases

Increased worldwide focus on maximal donor utilization and transplantation of patients once considered too ill to survive liver transplantation may increase the otherwise rare frequency of catastrophic graft failure. Although the deleterious effects of an acutely failing allograft have been established for decades, the optimal strategy in this patient population in the perioperative period remains ill-defined.

Cost-Effectiveness Studies in the ICU: A Systematic Review

OBJECTIVES

Cost-effectiveness analyses are increasingly used to aid decisions about resource allocation in healthcare; this practice is slow to translate into critical care. We sought to identify and summarize original cost-effectiveness studies presenting cost per quality-adjusted life year, incremental cost-effectiveness ratios, or cost per life-year ratios for treatments used in ICUs.

DESIGN

We conducted a systematic search of the English-language literature for cost-effectiveness analyses published from 1993 to 2018 in critical care. Study quality was assessed using the Drummond checklist.

SETTING

Critical care units.

PATIENTS OR SUBJECTS

Critical care patients.

INTERVENTIONS

Identified studies with cost-effectiveness analyses.

MEASUREMENTS AND MAIN RESULTS

We identified 97 studies published through 2018 with 156 cost-effectiveness ratios. Reported incremental cost-effectiveness ratios ranged from -$119,635 (hypothetical cohort of patients requiring either intermittent or continuous renal replacement therapy) to $876,539 (data from an acute renal failure study in which continuous renal replacement therapy was the most expensive therapy). Many studies reported favorable cost-effectiveness profiles (i.e., below $50,000 per life year or quality-adjusted life year). However, several therapies have since been proven harmful. Over 2 decades, relatively few cost-effectiveness studies in critical care have been published (average 4.6 studies per year). There has been a more recent trend toward using hypothetical cohorts and modeling scenarios without proven clinical data (2014-2018: 19/33 [58%]).

CONCLUSIONS

Despite critical care being a significant healthcare cost burden there remains a paucity of studies in the literature evaluating its cost effectiveness.

Health-related quality of life and costs of switching originator infliximab to biosimilar one in treatment of inflammatory bowel disease

Effectiveness, efficacy and safety of biosimilar infliximab (CT-P13) in inflammatory bowel disease (IBD) patients has been shown in previous studies. Limited data exist on health-related quality of life (HRQoL) of switching originator to biosimilar infliximab (IFX) in IBD patients. The objective of this study was to evaluate impact of switching originator to biosimilar IFX on HRQoL, disease activity, and health care costs in IBD maintenance treatment.In this single-center prospective observational study, all IBD patients receiving maintenance IFX therapy were switched to biosimilar IFX. HRQoL was measured using the generic 15D health-related quality of life instrument (15D) utility measurement and the disease-specific Inflammatory Bowel Disease Questionnaire (IBDQ). Crohn Disease Activity Index (CDAI) or Partial Mayo Score (pMayo), and fecal calprotectin (FC) served for evaluation of disease activity. Data were collected at time of switching and 3 and 12 months after switching. Patients' characteristics, clinical background information and costs were collected from patient records and the hospital's electronic database.Fifty-four patients were included in the analysis. No statistically significant changes were observed in 15D, CDAI, pMayo, and FC during 1-year follow-up. IBDQ scores were higher (P = .018) in Crohn disease 3 months after switching than at time of switching. Costs of biosimilar IFX were one-third of costs of originator one. Total costs related to secondary health care (excluding costs of IFX), were similar before and after the onset of biosimilar IFX.HRQoL and disease activity were after switching from originator to biosimilar IFX comparable, but the costs of biosimilar IFX were only one-third of those of the originator one.

Decision modelling for economic evaluation of liver transplantation

As the gap between a shortage of organs and the immense demand for liver grafts persists, every available donor liver needs to be optimized for utility, urgency and equity. To overcome this challenge, decision modelling might allow us to gather evidence from previous studies as well as compare the costs and consequences of alternative options. For public health policy and clinical intervention assessment, it is a potentially powerful tool. The most commonly used types of decision analytical models include decision trees, the Markov model, microsimulation, discrete event simulation and the system dynamic model. Analytic models could support decision makers in the field of liver transplantation when facing specific problems by synthesizing evidence, comprising all relevant options, generalizing results to other contexts, extending the time horizon and exploring the uncertainty. For modeling studies of economic evaluation for transplantation, understanding the current nature of the disease is crucial, as well as the selection of appropriate modelling techniques. The quality and availability of data is another key element for the selection and development of decision analytical models. In addition, good practice guidelines should be complied, which is important for standardization and comparability between economic outputs.

Liver dialysis in acute-on-chronic liver failure: current and future perspectives

Patients with acute-on-chronic liver failure (ACLF) are known to have a very high mortality rate as the majority of these patients succumb to multiorgan failure. Liver transplant remains the only option for these patients; however, there are problems with its availability, cost and also the complications and side effects associated with immunosuppression. Unlike advanced decompensated liver disease, there is a potential for hepatic regeneration and recovery in patients with ACLF. A liver support system, cell or non-cell based, logically is likely to provide temporary functional support until the donor liver becomes available or the failing liver survives the onslaught of the acute insult and spontaneously regenerates. Understanding the pathogenesis of liver failure and regeneration is essential to define the needs for a support system. Removal of hepatotoxic metabolites and inhibitors of hepatic regeneration by liver dialysis, a non-cell-based hepatic support, could help to provide a suitable microenvironment and support the failing liver. The current systems, i.e., MARS and Prometheus, have failed to show survival benefits in patients with ACLF based on which newer devices with improved functionality are currently under development. However, larger randomized trials are needed to prove whether these devices can enable restoration of the complex dysregulated immune system and impact organ failure and mortality in these patients.

Liver support systems: will they ever reach prime time?

Liver support systems aim to provide temporary support of liver function while maintaining extra-hepatic function in patients with liver failure. Important advances have been achieved in the design of artificial and bio-artificial devices, but the current systems are far from meeting the ideal. Artificial devices provide detoxification through different dialysis procedures, whereas bio-artificial devices add synthetic functions by incorporating a cellular component into the system. Overall, liver support systems have consistently shown beneficial effects on the pathophysiology of liver failure, especially in acute-on-chronic liver failure. However, these beneficial effects have not been translated into an improvement of survival. Our review discusses the current evidence, paying special attention to the clinical aspects of (bio)-artificial liver support devices.

Molecular Adsorbents Recirculating System dialysis in children with cholestatic pruritus

BACKGROUND

Cholestatic pruritus may severely compromise quality of life. The Molecular Adsorbents Recirculating System (MARS) allows removal of pruritogenic substances without exposure to foreign proteins. Pediatric data, however, are scant.

METHODS

We retrospectively analyzed the efficacy of MARS in three boys with severe cholestatic pruritus. They received a total of 135 MARS sessions during 8, 4, and 13 months prior to liver transplantation. Total serum bilirubin and bile acids were monitored, and pruritus was assessed by a numerical rating scale (NRS 0 = no pruritus, 10 = maximal pruritus).

RESULTS

MARS sessions were initially performed three times weekly at a mean duration of 6.3 ± 1.4 h. Sessions could be reduced to once weekly and once every other week in two patients. Pre-MARS plasma bile acid concentrations averaged 207 ± 67 μmol/l. They declined to 67 ± 9%, 48 ± 3%, 38 ± 14%, and 37 ± 5% of baseline within 2, 4, 6 and 8 h of therapy, respectively (all p < 0.05). The average interdialytic increase of plasma bile acids was 34 ± 33 μmol/l per day. Mean NRS score decreased from 6.5 ± 2.3 to 3.3 ± 2.9 (p < 0.01). Skin lesions from itching disappeared. All MARS treatments were well tolerated.

CONCLUSION

MARS dialysis substantially reduces cholestatic pruritus in children refractory to pharmacological treatment.

Effect of health-related quality-of-life instrument and quality-adjusted life year calculation method on the number of life years gained in the critical care setting

OBJECTIVES

Health-related quality of life (HRQoL) and quality-adjusted life-years (QALYs) gained are basic elements in the cost-utility evaluations of health care. Different HRQoL instruments produce different scores for the same patient, and thus also a different number of QALYs. We examined the effect of these factors on the number of QALYs gained and the cost per QALY in the critical care setting.

METHODS

In 937 patients having been treated in the critical care setting in the Helsinki University Central Hospital the HRQoL scores were measured by the EQ-5D and 15D 6 and 12 months after start of treatment, and QALYs were calculated using four different sets of assumptions regarding recovery from disease.

RESULTS

The mean number of QALYs gained during the first year after treatment ranged from 0.178 ± 0.206 to 0.550 ± 0.508 and the consequent cost per QALY from €38,405 to €118,668 depending on HRQoL instrument and assumptions used in the calculations regarding recovery from disease.

CONCLUSIONS

The HRQoL instrument and the assumptions employed regarding recovery from disease have a great influence on the results of cost-utility analyses and should, therefore, be explicitly described in studies reporting QALYs. Furthermore, a common consensus on which calculation method should be used within critical care would be urgently needed.

Neurological complications of acute liver failure: pathophysiological basis of current management and emerging therapies

One of the major causes of mortality in patients with acute liver failure (ALF) is the development of hepatic encephalopathy (HE) which is associated with increased intracranial pressure (ICP). High ammonia levels, increased cerebral blood flow and increased inflammatory response have been identified as major contributors to the development of HE and the related brain swelling. The general principles of the management of patients with ALF are straightforward. They include identifying the insult causing hepatic injury, providing organ systems support to optimize the patient's physical condition, anticipation and prevention of development of complications. Increasing insights into the pathophysiological mechanisms of ALF are contributing to better therapies. For instance, the evident role of cerebral hyperemia in the pathogenesis of increased ICP has led to a re-evaluation of established therapies such as hyperventilation, N-acetylcysteine, thiopentone sodium and propofol. The role of systemic inflammatory response in the pathogenesis of increased ICP has also gained importance supporting the concept that antibiotics given prophylactically reduce the risk of developing sepsis during the course of illness. Moderate hypothermia has also been established as a therapy able to reduce ICP in patients with uncontrolled intracranial hypertension and to prevent increases in ICP during orthopic liver transplantation. Ornithine phenylacetate, a new drug in the treatment of liver failure, and liver replacement therapies are still being investigated both experimentally and clinically. Despite many advances in the understanding of the pathophysiological basis and the management of intracranial hypertension in ALF, more clinical trials should be conducted to determine the best therapeutic management for this difficult clinical event.

Cost of a quality-adjusted life year in liver transplantation: the influence of the indication and the model for end-stage liver disease score

Cost issues in liver transplantation (LT) have received increasing attention, but the cost-utility is rarely calculated. We compared costs per quality-adjusted life year (QALY) from the time of placement on the LT waiting list to 1 year after transplantation for 252 LT patients and to 5 years after transplantation for 81 patients. We performed separate calculations for chronic liver disease (CLD), acute liver failure (ALF), and different Model for End-Stage Liver Disease (MELD) scores. For the estimation of QALYs, the health-related quality of life was measured with the 15D instrument. The median costs and QALYs after LT were €141,768 and 0.895 for 1 year and €177,618 and 3.960 for 5 years, respectively. The costs of the first year were 80% of the 5-year costs. The main cost during years 2 to 5 was immunosuppression drugs (59% of the annual costs). The cost/QALY ratio improved from €158,400/QALY at 1 year to €44,854/QALY at 5 years, and the ratio was more beneficial for CLD patients (€42,500/QALY) versus ALF patients (€63,957/QALY) and for patients with low MELD scores versus patients with high MELD scores. Although patients with CLD and MELD scores > 25 demonstrated markedly higher 5-year costs (€228,434) than patients with MELD scores < 15 (€169,541), the cost/QALY difference was less pronounced (€59,894/QALY and €41,769/QALY, respectively). The cost/QALY ratio for LT appears favorable, but it is dependent on the assessed time period and the severity of the liver disease.

Bridging Therapies and Liver Transplantation in Acute Liver Failure; 10 Years of MARS Experience from Finland

Acute liver failure is a life-threatening condition in the absence of liver transplantation option. The aetiology of liver failure is the most important factor determining the probability of native liver recovery and prognosis of the patient. Extracorporeal liver assist devices like MARS (Molecular Adsorbent Recirculating System) may buy time for native liver recovery or serve as bridging therapy to liver transplantation, with reduced risk of cerebral complications. MARS treatment may alleviate hepatic encephalopathy even in patients with a completely necrotic liver. Taking this into account, better prognostic markers than hepatic encephalopathy should be used to assess the need for liver transplantation in acute liver failure.