Long-term ursodeoxycholic acid therapy for primary biliary cirrhosis: a follow-up to 12 years

Evaluation of potential hepatic recompensation criteria in patients with PBC and decompensated cirrhosis

BACKGROUND

Aetiological therapy improves liver function and may enable hepatic recompensation in decompensated cirrhosis.

AIMS

We explored the potential for recompensation in patients with decompensated primary biliary cholangitis (PBC) - considering a biochemical response to ursodeoxycholic acid (UDCA) according to Paris-II criteria as a surrogate for successful aetiological treatment.

METHODS

Patients with PBC were retrospectively included at the time of first decompensation. Recompensation was defined as (i) resolution of ascites and hepatic encephalopathy (HE) despite discontinuation of diuretic/HE therapy, (ii) absence of variceal bleeding and (iii) sustained liver function improvement.

RESULTS

In total, 42 patients with PBC with decompensated cirrhosis (age: 63.5 [IQR: 51.9-69.2] years; 88.1% female; MELD-Na: 13.5 [IQR: 11.0-15.0]) were included and followed for 41.9 (IQR: 11.0-70.9) months after decompensation. Seven patients (16.7%) achieved recompensation. Lower MELD-Na (subdistribution hazard ratio [SHR]: 0.90; p = 0.047), bilirubin (SHR per mg/dL: 0.44; p = 0.005) and alkaline phosphatase (SHR per 10 U/L: 0.67; p = 0.001) at decompensation, as well as variceal bleeding as decompensating event (SHR: 4.37; p = 0.069), were linked to a higher probability of recompensation. Overall, 33 patients were treated with UDCA for ≥1 year and 12 (36%) achieved Paris-II response criteria. Recompensation occurred in 5/12 (41.7%) and in 2/21 (9.5%) patients with vs. without UDCA response at 1 year, respectively. Recompensation was linked to a numerically improved transplant-free survival (HR: 0.46; p = 0.335). Nonetheless, 4/7 recompensated patients presented with liver-related complications after developing hepatic malignancy and/or portal vein thrombosis and 2 eventually died.

CONCLUSIONS

Patients with PBC and decompensated cirrhosis may achieve hepatic recompensation under UDCA therapy. However, since liver-related complications still occur after recompensation, patients should remain under close follow-up.

Ursodeoxycholic Acid Use After Bariatric Surgery: Effects on Metabolic and Inflammatory Blood Markers

BACKGROUND

In addition to the reduction of symptomatic gallstone disease, ursodeoxycholic acid (UDCA) might also have beneficial metabolic effects after bariatric surgery. We examined the impact of UDCA on liver enzymes, hemoglobin A1c (HbA1c), lipids, and inflammation markers.

METHODS

Patients in the UPGRADE trial (placebo-controlled, double-blind) were randomized between UDCA 900 mg daily or placebo pills for 6 months after bariatric surgery. Patients without blood measurements pre- or 6 months postoperatively were excluded. The change in liver enzymes, Hba1c, lipids, and inflammation markers after surgery were compared between the UDCA and placebo group, followed by a postoperative cross-sectional comparison.

RESULTS

In total, 513 patients were included (age [mean ± SD] 45.6 ± 10.7 years; 79% female). Preoperative blood values did not differ between UDCA (n = 266) and placebo (n = 247) groups. Increase of alkaline phosphatase (ALP) was greater in the UDCA group (mean difference 3.81 U/l [95%CI 0.50 7.12]). Change in other liver enzymes, HbA1c, lipids, and CRP levels did not differ. Postoperative cross-sectional comparison in 316 adherent patients also revealed a higher total cholesterol (mean difference 0.25 mg/dl [95%CI 0.07-0.42]), lower aspartate aminotransferase (mean difference -3.12 U/l [-5.16 - -1.08]), and lower alanine aminotransferase level (mean difference -5.89 U/l [-9.41 - -2.37]) in the UDCA group.

CONCLUSION

UDCA treatment leads to a higher, but clinically irrelevant increase in ALP level in patients 6 months after bariatric surgery. No other changes in metabolic or inflammatory markers were observed. Except for the reduction of gallstone formation, UDCA has no effects after bariatric surgery.

Treatment of Fatigue in Primary Biliary Cholangitis: A Systematic Review and Meta-Analysis

BACKGROUND AND AIMS

Fatigue is the most common complication of primary biliary cholangitis (PBC) and can be debilitating. Numerous interventions have been trialed targeting several proposed mechanisms of PBC-associated fatigue. We sought to summarize and perform a meta-analysis to determine the efficacy of these interventions.

METHODS

A comprehensive database search was conducted from inception through March 27, 2018. The primary outcome was proportion of fatigued patients or reduction in degree of fatigue. Adverse events were a secondary outcome. We assessed studies for risk of bias, graded quality of evidence, and used meta-analysis to obtain overall effect by pooling studies of the same class.

RESULTS

We identified 16 studies evaluating ursodeoxycholic acid (UDCA) (7), liver transplantation (2), serotonin reuptake inhibitors (2), colchicine (1), methotrexate (1), cyclosporine (1), modafinil (1), and obeticholic acid (1). On meta-analysis, UDCA was not associated with a reduction in risk of fatigue (RR = 0.86, 95% CI 0.69-1.08, p = 0.19, I² = 56.2%). While liver transplantation did reduce degree of fatigue (SMD - 0.57, 95% CI - 0.89 to - 0.24, p = 0.001, I² = 67.3%), fatigue did not return to baseline indicating the underlying cause may not be addressed.

CONCLUSIONS

While there is some improvement in fatigue with liver transplantation, there is a lack of high-quality evidence supporting the efficacy of any other intervention in the treatment of PBC-related fatigue. Further research into the underlying pathophysiology may help guide future trials.

Patterns of disease progression and incidence of complications in primary biliary cholangitis (PBC)

Clinical outcome for patients with primary biliary cholangitis (PBC) is dictated by development of cirrhosis, portal hypertension and its associated complications; including for some, a predisposition toward hepatocellular carcinoma. However rates of clinical progression vary, and accurately identifying disease course is of critical importance to patients, clinicians, as well as industry, who are committed to developing new effective and life-prolonging therapy as well as treating symptoms that appear disproportionate to underlying disease severity. Patients seek reassurance and guidance as to their own prognosis, and clinicians wish to confidently recognise those at highest risk of poor outcomes as equally as they strive to reassure individuals with a more favourable disease trajectory. International registries have facilitated a much greater knowledge of disease incidence and heterogeneity of presenting phenotypes. In so doing they highlight the opportunity to provide a more individualized estimate of the clinical course that patients experience, and have led to a renewed approach to risk stratification; both in terms of 'hard outcomes' and also disease-associated complications in PBC specifically.

Clinical significance of changes in the Th17/Treg ratio in autoimmune liver disease

AIM

To investigate the levels, ratios, and clinical significance of T helper 17 (Th17) cells and regulatory T (Treg) cells in the peripheral blood of patients with autoimmune liver disease (AILD).

METHODS

Forty-two AILD patients were included in the experimental group (group E), and 11 healthy subjects were recruited as the control group (group C). Flow cytometry was performed to determine the percentages of Th17 and Treg cells in peripheral blood lymphocytes. Furthermore, a range of biochemical indices was measured simultaneously in the blood of group E patients.

RESULTS

The percentage of Th17 cells and the Th17/Treg ratio were higher in group E than in group C (P < 0.01), whereas the percentage of Tregs was lower in the group E patients (P < 0.05). Patients in group E who were admitted with AILD in the active stage showed significantly higher Th17 percentages and Th17/Treg ratios than those measured in patients with AILD in remission (P < 0.05). In addition, among patients with AILD in the active stage, individuals that remained unhealed after hospitalization showed significantly higher baseline values of the Th17 percentage and the Th17/Treg ratio than those detected in patients who improved after treatment (P < 0.05). The results suggested that imbalance in the Th17/Treg ratio plays an important role in the pathogenesis and development of AILD.

CONCLUSION

A high Th17/Treg ratio appears to predict poor short-term prognosis in patients with AILD in the active stage.

Evidence-based clinical practice guidelines for liver cirrhosis 2015

The Japanese Society of Gastroenterology revised the evidence-based clinical practice guidelines for liver cirrhosis in 2015. Eighty-three clinical questions were selected, and a literature search was performed for the clinical questions with use of the MEDLINE, Cochrane, and Igaku Chuo Zasshi databases for the period between 1983 and June 2012. Manual searching of the latest important literature was added until August 2015. The guidelines were developed with use of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. This digest version in English introduces selected clinical questions and statements related to the management of liver cirrhosis and its complications. Branched-chain amino acids relieve hypoalbuminemia and hepatic encephalopathy and improve quality of life. Nucleoside analogues and peginterferon plus ribavirin combination therapy improve the prognosis of patients with hepatitis B virus related liver cirrhosis and hepatitis C related compensated liver cirrhosis, respectively, although the latter therapy may be replaced by direct-acting antivirals. For liver cirrhosis caused by primary biliary cirrhosis and active autoimmune hepatitis, urosodeoxycholic acid and steroid are recommended, respectively. The most adequate modalities for the management of variceal bleeding are the endoscopic injection sclerotherapy for esophageal varices and the balloon-occluded retrograde transvenous obliteration following endoscopic obturation with cyanoacrylate for gastric varices. Beta-blockers are useful for primary prophylaxis of esophageal variceal bleeding. The V2 receptor antagonist tolvaptan is a useful add-on therapy in careful diuretic therapy for ascites. Albumin infusion is useful for the prevention of paracentesis-induced circulatory disturbance and renal failure. In addition to disaccharides, the nonabsorbable antibiotic rifaximin is useful for the management of encephalopathy. Anticoagulation therapy is proposed for patients with acute-onset or progressive portal vein thrombosis.

Biochemical criteria at 1 year are not robust indicators of response to ursodeoxycholic acid in early primary biliary cirrhosis: results from a 29-year cohort study

BACKGROUND

In primary biliary cirrhosis (PBC), biochemical criteria at 1 year are considered surrogates of response to ursodeoxycholic acid (UDCA). However, due to the slow natural history of PBC, evaluation at 1 year may be suboptimal to assess the therapeutic response, particularly in early disease.

AIM

To determine whether evaluation of biochemical criteria at 1 year is a reliable surrogate of UDCA response in early PBC.

METHODS

We analysed the prospectively collected data of 215 patients (untreated = 129; UDCA-treated = 86) with early PBC (normal baseline bilirubin/albumin) and a median follow-up of 8 years (range: 1-29.1). The 1-year attainment rates of the Barcelona, Paris-I, Paris-II and Toronto definitions, and their predictive relevance for a poor outcome (death, transplantation, complications of cirrhosis), were assessed either as a result of UDCA or no treatment. Independent associations with attaining each UDCA response definition were identified by multivariate analysis.

RESULTS

Untreated patients displayed 1-year biochemical features compatible with 'treatment response' at rates (Barcelona: 36.4%, Paris-I: 66.7%, Toronto: 59.7%, Paris-II: 40.3%) similar to those obtained under UDCA. Depending on the definition, baseline ALP≤3xULN (OR: 4.80-35.90), AST≤2xULN (OR: 5.63-9.34) and early histological stage (OR: 3.67-3.87) were the stronger predictors for attaining the criteria. UDCA treatment was associated with attaining Barcelona (OR = 2.16) and Paris-II (OR = 2.84), but not Paris-I, and not Toronto definition when excluding late histological cases. Paris-I criteria were significantly predictive of long-term outcomes (HR = 2.83) in untreated patients.

CONCLUSIONS

In early PBC, biochemical criteria at 1 year reflect severity of the disease rather than the therapeutic response to UDCA.

Predicting the advent of ascites and other complications in primary biliary cirrhosis: a staged model approach

BACKGROUND

Current survival models for primary biliary cirrhosis have limited precision for medium and long-term survival. Aim To describe a prognostic model for the advent of complications in primary biliary cirrhosis as the first approach to a staged prognostic model.

METHODS

From an established database of 289 consecutive primary biliary cirrhosis patients referred to Royal Free Hospital over 12 years (mean follow-up of 4.1 years), baseline characteristics at referral were evaluated by Cox-proportional hazards regression modelling.

RESULTS

The following complications occurred de novo: 85 ascites/peripheral oedema, 40 oesophagogastric varices, 63 encephalopathy, 29 spontaneous bacterial peritonitis and/or septicaemia, 59 symptomatic urinary tract infections. Age, albumin, log(10)(bilirubin), presence of ascites at referral, variceal bleeding within 6 weeks before referral, detection of oesophagogastric varices at or before referral were significant at multivariate analysis with different combinations and coefficients for each complication. The model for predicting ascites and/or peripheral oedema best fitted the observed data (ROC = 0.7682, S.E. = 0.0385).

CONCLUSIONS

The known prognostic factors in primary biliary cirrhosis also model the advent of complications. In view of the prognostic importance of ascites and its more robust statistical model, ascites and/or peripheral oedema could represent, following validation, the most suitable staged model in primary biliary cirrhosis to improve precision in survival modelling.

Portal hypertension and primary biliary cirrhosis: effect of long-term ursodeoxycholic acid treatment

BACKGROUND & AIMS

Portal hypertension can complicate primary biliary cirrhosis, but studies evaluating the direct measurement of the portohepatic gradient (PHG) are rare. The aim of the study was to determine the prevalence and prognostic value of portal hypertension in patients treated with ursodeoxycholic acid.

METHODS

A total of 132 patients from a local "PBC clinic" were enrolled in this cohort study. The PHG and biochemical values were measured at inclusion and every 2 years. Factors associated with survival were analyzed.

RESULTS

Mean PHG at inclusion was 7.2 +/- 5.8 mm Hg. It was higher than normal (6 mm Hg) in 46 patients (34.9%) and higher than 12 mm Hg (variceal bleeding risk limit) in 26 patients (19.7%). There was a difference between the 3 subgroups in the probability of survival free of liver transplantation (P < .0003). After 2 years of treatment, a decreased or stable PHG (hazard ratio, 4.64; 95% confidence interval, 2.01-10.72) and normalization of aspartate aminotransferase (AST) level (hazard ratio, 2.89; 95% confidence interval, 1.03-8.05) were predictive of better survival on multivariate analysis. "Responders" (stable or improved PHG and normalized AST level at 2 years) have a 15-year survival similar to that of a control Quebec female population.

CONCLUSIONS

Significant portal hypertension is a common complication of primary biliary cirrhosis. Changes in the PHG and normalized AST level after 2 years of ursodeoxycholic acid treatment can be used to identify a subgroup of responders with survival comparable to that of a control population.

Treatment of primary biliary cirrhosis: therapy with choleretic and immunosuppressive agents

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease of presumed autoimmune etiology affecting predominantly middle-aged women; it is a slowly progressive disease causing loss of intrahepatic bile ducts, resulting in advanced fibrosis, cirrhosis, and liver failure. Many drugs have been studied for treatment, including agents with choleretic and immunosuppressive properties. Ursodeoxycholic acid (UDCA) has been evaluated most widely. After liver failure, the only effective treatment is liver transplantation. Effective therapy reduces the need for transplantation and improves life expectancy. For advanced liver disease or incomplete response to UDCA, new therapies to cure or retard the progression of disease in PBC are needed.

Influence of ursodeoxycholic acid on the mortality and malignancy associated with primary biliary cirrhosis: a population-based cohort study

There is debate over the mortality and malignancy risk in people with primary biliary cirrhosis (PBC) and whether this risk is reduced by use of ursodeoxycholic acid. To investigate this issue, we identified 930 people with PBC and 9,202 control subjects from the General Practice Research Database in the United Kingdom. We categorized regular ursodeoxycholic acid as treatment with 6 or more prescriptions and nonregular treatment as less than 6. We found a 2.7-fold increase in mortality for the PBC cohort compared with the general population [adjusted hazard ratio (HR), 2.69; 95% CI, 2.35-3.09]. In those having regular ursodeoxycholic acid (43%), the mortality increase was 2.2-fold (HR, 2.19; 95% CI, 1.66-2.87) and in those not treated 2.7-fold (HR, 2.69; 95% CI, 2.18-3.33). This apparent reduction in mortality was not explained by less severe disease in the ursodeoxycholic acid-treated group. The increased risk of primary liver cancer in ursodeoxycholic acid-treated patients was 3-fold (HR, 3.17; 95% CI, 0.64-15.62), in contrast to an 8-fold increase in those not treated (HR, 7.77; 95% CI, 1.30-46.65).

CONCLUSION

We found that people with PBC had a 3-fold mortality increase when compared with the general population, which was somewhat reduced by regular treatment with ursodeoxycholic acid. However, the observed effect of ursodeoxycholic acid was not statistically significant.

Incidence, prevalence and clinical course of primary biliary cirrhosis in a Spanish community

BACKGROUND AND AIMS

Primary biliary cirrhosis (PBC) is characterized by the autoimmune inflammatory response of small intrahepatic bile ducts. Prevalence in Spain is estimated as 61.9 cases per million inhabitants, whereas Northern Europe rates over 200 cases/million. Our objective was to determine the incidence and prevalence of PBC in our health area.

MATERIAL AND METHODS

PBC was defined by the presence of abnormal liver tests (dissociated cholestasis) with positive antimitochondrial antibodies and/or compatible liver histology. Medical records from patients diagnosed between 1990 and 2002 were reviewed retrospectively. The following data were collected: diagnostic data, demographic and analytic data, liver histology and stage and treatment and disease outcome.

RESULTS

In a population of 389 758 inhabitants, 87 patients were diagnosed with PBC. Mean age at diagnosis was 63.9+/-12.6 years. Eighty-four (96.6%) were women. Mean annual incidence was 17.2 per 10 inhabitants and the prevalence at the end of study was 195 per 10. Biopsy was performed in 71 (81.6%) patients, 61 of whom (86%) did not have fibrosis. Time of follow-up was 63.6+/-43.2 (2.28-153.9) months.

CONCLUSION

Incidence and prevalence in our reference area are higher than in some Spanish areas, as per the results previously published; however, they are comparable with those obtained in Northern Europe and the US.

Systematic review of controlled clinical trials on the use of ursodeoxycholic acid for the prevention of hepatic veno-occlusive disease in hematopoietic stem cell transplantation

Hepatic veno-occlusive disease (HVOD) is a serious life-threatening complication of hematopoietic stem cell transplantation (HSCT). Currently, there is no optimal therapeutic strategy and preventive measures are ill-defined. Ursodeoxycholic acid (UA) is well-tolerated oral medication that has been associated with possible benefit as a prophylactic agent. We sought to summarize and quantify the clinical effects of prophylactic UA in the context of HSCT. We undertook a systematic review of studies addressing the use of UA as monotherapy or in combination with other agents in patients undergoing HSCT. The Search Strategy included MEDLINE (1966 to fourth week of March 2006), EMBASE (1980 to fourth week of March 2006), all EBM Reviews (fourth quarter of 2005), Ovid Healthstar (1966 to fourth week of March 2006), and Google Scholar on March 20, 2006. Six studies, 4 randomized clinical trials and 2 historically controlled studies, representing 824 patients were included in the review. Three randomized clinical trials comparing prophylactic UA with no treatment demonstrated reduced proportion of HVOD (relative risk [RR], 0.34; 95% confidence interval [CI], 0.17-0.66). When the analysis was limited to higher-quality studies, the beneficial effect of UA remained significant (RR, 0.36; 95% CI, 0.15-0.90). Transplant-related mortality was also reduced with the prophylactic use of UA (RR, 0.58; 95% CI, 0.35-0.95). UA did not significantly attenuate the outcomes of acute graft-versus-host disease (RR, 0.76; 95% CI, 0.53-1.09), relapse (RR, 0.77; 95% CI, 0.46-1.31), or overall survival (RR, 1.22; 95 % CI, 0.96-1.54). UA appears effective for HVOD prophylaxis in patients undergoing HSCT and should be considered as a prevention strategy by HSCT centers to reduce HVOD.

Methotrexate therapy for the symptomatic treatment of primary biliary cirrhosis patients, who are biochemical incomplete responders to ursodeoxycholic acid therapy

BACKGROUND

Ursodeoxycholic acid is widely used as the standard therapy for the treatment of primary biliary cirrhosis and other cholestatic liver diseases. Although it has been shown to improve biochemical markers and delay disease progression, its effect upon fatigue and pruritus, is at best uncertain.

AIM

To assess the safety and efficacy of methotrexate for treating symptomatic primary biliary cirrhosis patients who were biochemical partial responders or non-responders to ursodeoxycholic acid therapy.

METHODS

We treated eight consecutive primary biliary cirrhosis patients with methotrexate who were followed in a single hepatology clinical practice, who were symptomatic, and who had had an incomplete biochemical response to ursodeoxycholic acid therapy. Pruritus and fatigue were assessed at each clinic visit and graded from 0 (asymptomatic) to 4 (incapacitating).

RESULTS

The median dose of methotrexate was 13.75 mg/week (range 7.5-15) and the mean duration of methotrexate therapy was 49 months (range 11-126). At the end of follow-up pruritus in six of seven patients had improved, and fatigue in all patients had improved with the addition of methotrexate therapy (pruritus: baseline 2.9 +/- 1.1 vs. end of treatment 0.6 +/- 1.5, P < or = 0.0175, and fatigue: baseline 3.0 +/- 0.8, vs. end of treatment 1.0 +/- 0.8, P < or = 0.0023). Improvement in symptoms was associated with a significant improvement in biochemical markers of cholestasis. No significant adverse effects of methotrexate were documented.

CONCLUSIONS

Methotrexate should be considered as a potential additive treatment for symptomatic primary biliary cirrhosis patients who are incomplete biochemical responders to ursodeoxycholic acid therapy.

Prognosis of ursodeoxycholic Acid-treated patients with primary biliary cirrhosis. Results of a 10-yr cohort study involving 297 patients

BACKGROUND AND AIMS

The therapeutic potential of ursodeoxycholic acid (UDCA) treatment in primary biliary cirrhosis (PBC) remains controversial. In addition, relatively few data have been reported on the outcome of patients who have been treated long term. The aim of the present study was to document long-term survival of a prospectively followed large cohort of UDCA treated patients in comparison to that predicted by the Mayo model and of a matched control cohort of the Dutch population.

METHODS

Two hundred ninety-seven patients were included and followed during a median period of 68 (range 3-126) months until death or the end of the study.

RESULTS

Survival free of transplantation (1 yr 99.7%, 5 yr 87%, and 10 yr 71%) was significantly better than predicted by the Mayo model (p= 0.01). However, for patients with abnormal serum bilirubin and/or albumin concentrations at entry, observed and predicted survival did not significantly differ. Compared with survival for a standardized cohort of the Dutch population, observed survival for the total group was significantly decreased (p= 0.0003); for noncirrhotic patients and patients with normal entry bilirubin and albumin concentrations survival was comparable. Serum bilirubin and albumin concentrations were the prognostic factors most consistently associated with survival.

CONCLUSIONS

A 10-year prognosis for most UDCA-treated patients with PBC, i.e., those with a normal bilirubin and albumin concentration, is comparable to that of a matched general population. Our finding that observed survival was significantly better than predicted by the Mayo model may suggest that this model did not accurately predict prognosis in our cohort. Alternatively, this finding indicates an important therapeutic effect of long-term UDCA treatment in PBC, particularly in patients with noncirrhotic, nonadvanced disease.

Systematic review: The model for end-stage liver disease--should it replace Child-Pugh's classification for assessing prognosis in cirrhosis?

BACKGROUND

Prognosis in cirrhotic patients has had a resurgence of interest because of liver transplantation and new therapies for complications of end-stage cirrhosis. The model for end-stage liver disease score is now used for allocation in liver transplantation waiting lists, replacing Child-Turcotte-Pugh score. However, there is debate as whether it is better in other settings of cirrhosis.

AIM

To review studies comparing the accuracy of model for end-stage liver disease score vs. Child-Turcotte-Pugh score in non-transplant settings.

RESULTS

Transjugular intrahepatic portosystemic shunt studies (with 1360 cirrhotics) only one of five, showed model for end-stage liver disease to be superior to Child-Turcotte-Pugh to predict 3-month mortality, but not for 12-month mortality. Prognosis of cirrhosis studies (with 2569 patients) none of four showed significant differences between the two scores for either short- or long-term prognosis whereas no differences for variceal bleeding studies (with 411 cirrhotics). Modified Child-Turcotte-Pugh score, by adding creatinine, performed similarly to model for end-stage liver disease score. Hepatic encephalopathy and hyponatraemia (as an index of ascites), both components of Child-Turcotte-Pugh score, add to the prognostic performance of model for end-stage liver disease score.

CONCLUSIONS

Based on current literature, model for end-stage liver disease score does not perform better than Child-Turcotte-Pugh score in non-transplant settings. Modified Child-Turcotte-Pugh and model for end-stage liver disease scores need further evaluation.