Medical treatment of primary biliary cholangitis

Background

Primary biliary cholangitis (previously called primary biliary cirrhosis) is a chronic liver disease caused by the destruction of small bile ducts within the liver (tubes that carry the bile produced by the liver) resulting in stagnation of bile (cholestasis) and liver damage and replacement of liver cells with scar tissue (liver cirrhosis). The best way to treat people with primary biliary cholangitis is unclear. We sought to resolve this issue by searching for existing trials on the topic. We included all randomised clinical trials (clinical studies where people are randomly put into one of two or more intervention groups) reported to February 2017. We included only trials in which participants with primary biliary cholangitis had not undergone liver transplantation previously. Apart from using standard Cochrane methods which allow comparison of only two treatments at a time (direct comparison), we planned to use an advanced method which allows comparison of the many different treatments that are individually compared in the trials (network meta-analysis). However, because of the nature of the information available, we could not determine whether the network meta-analysis results were reliable. Therefore, we used standard Cochrane methodology.

Study characteristics

We identified 74 randomised clinical trials (5902 participants). Of these, 46 randomised clinical trials (4274 participants) provided information for one or more measures (outcomes). The trials included people with primary biliary cholangitis with and without symptoms; with and without antimitochondrial antibody (AMA) (an indicator of primary biliary cholangitis) regardless of whether they received previous treatments. The average follow-up period in the trials ranged from one month to eight years in the trials that reported this information.

Funding: nine trials receive no additional funding or were funded by parties with no vested interest in the results. Thirty-one trials were partially or fully funded by the pharmaceutical companies that would benefit based on the results of the trial. The source of funding was not available from the remaining trials.

Quality of evidence

The overall quality of evidence was very low and all the trials were at high risk of bias, which means that there is possibility of making wrong conclusions overestimating benefits or underestimating harms of one treatment or the other because of the way that the trials were conducted.

Key results

There was no reliable evidence of decrease in the deaths between any of the interventions versus no intervention. There was no evidence of decrease in serious complications or complications of any severity between any of the treatments and no treatment. None of the trials reported health-related quality of life (a measure of a person's satisfaction with their life and health) at any time point.

Overall, there is currently no evidence of benefit of any intervention in primary biliary cholangitis. There is significant uncertainty in this issue and further high-quality randomised clinical trials are required.

Authors' conclusions: 

Based on very low quality evidence, there is currently no evidence that any intervention is beneficial for primary biliary cholangitis. However, the follow-up periods in the trials were short and there is significant uncertainty in this issue. Further well-designed randomised clinical trials are necessary. Future randomised clinical trials ought to be adequately powered; performed in people who are generally seen in the clinic rather than in highly selected participants; employ blinding; avoid post-randomisation dropouts or planned cross-overs; should have sufficient follow-up period (e.g. five or 10 years or more); and use clinically important outcomes such as mortality, health-related quality of life, cirrhosis, decompensated cirrhosis, and liver transplantation. Alternatively, very large groups of participants should be randomised to facilitate shorter trial duration.

Read the full abstract...
Background: 

Primary biliary cholangitis (previously primary biliary cirrhosis) is a chronic liver disease caused by the destruction of small intra-hepatic bile ducts resulting in stasis of bile (cholestasis), liver fibrosis, and liver cirrhosis. The optimal pharmacological treatment of primary biliary cholangitis remains uncertain.

Objectives: 

To assess the comparative benefits and harms of different pharmacological interventions in the treatment of primary biliary cholangitis through a network meta-analysis and to generate rankings of the available pharmacological interventions according to their safety and efficacy. However, it was not possible to assess whether the potential effect modifiers were similar across different comparisons. Therefore, we did not perform the network meta-analysis and instead assessed the comparative benefits and harms of different interventions using standard Cochrane methodology.

Search strategy: 

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 2), MEDLINE, Embase, Science Citation Index Expanded, World Health Organization International Clinical Trials Registry Platform, and randomised controlled trials registers to February 2017 to identify randomised clinical trials on pharmacological interventions for primary biliary cholangitis.

Selection criteria: 

We included only randomised clinical trials (irrespective of language, blinding, or publication status) in participants with primary biliary cholangitis. We excluded trials which included participants who had previously undergone liver transplantation. We considered any of the various pharmacological interventions compared with each other or with placebo or no intervention.

Data collection and analysis: 

We used standard methodological procedures expected by Cochrane. We calculated the odds ratio (OR) and rate ratio with 95% confidence intervals (CI) using both fixed-effect and random-effects models based on available-participant analysis with Review Manager 5. We assessed risk of bias according to Cochrane, controlled risk of random errors with Trial Sequential Analysis, and assessed the quality of the evidence using GRADE.

Main results: 

We identified 74 trials including 5902 participants that met the inclusion criteria of this review. A total of 46 trials (4274 participants) provided information for one or more outcomes. All the trials were at high risk of bias in one or more domains. Overall, all the evidence was low or very low quality. The proportion of participants with symptoms varied from 19.9% to 100% in the trials that reported this information. The proportion of participants who were antimitochondrial antibody (AMA) positive ranged from 80.8% to 100% in the trials that reported this information. It appeared that most trials included participants who had not received previous treatments or included participants regardless of the previous treatments received. The follow-up in the trials ranged from 1 to 96 months.

The proportion of people with mortality (maximal follow-up) was higher in the methotrexate group versus the no intervention group (OR 8.83, 95% CI 1.01 to 76.96; 60 participants; 1 trial; low quality evidence). The proportion of people with mortality (maximal follow-up) was lower in the azathioprine group versus the no intervention group (OR 0.56, 95% CI 0.32 to 0.98; 224 participants; 2 trials; I2 = 0%; low quality evidence). However, it has to be noted that a large proportion of participants (25%) was excluded from the trial that contributed most participants to this analysis and the results were not reliable. There was no evidence of a difference in any of the remaining comparisons. The proportion of people with serious adverse events was higher in the D-penicillamine versus no intervention group (OR 28.77, 95% CI 1.57 to 526.67; 52 participants; 1 trial; low quality evidence). The proportion of people with serious adverse events was higher in the obeticholic acid plus ursodeoxycholic acid (UDCA) group versus the UDCA group (OR 3.58, 95% CI 1.02 to 12.51; 216 participants; 1 trial; low quality evidence). There was no evidence of a difference in any of the remaining comparisons for serious adverse events (proportion) or serious adverse events (number of events). None of the trials reported health-related quality of life at any time point.

Funding: nine trials had no special funding or were funded by hospital or charities; 31 trials were funded by pharmaceutical companies; and 34 trials provided no information on source of funding.

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