Liver transplantations: Better results with larger case numbers

In elective surgery, does the likelihood of treatment success depend on how often the hospital or the team of doctors performs the operation? This is the question addressed in eight commissions on minimum volumes awarded in Germany by the Federal Joint Committee (G-BA) to the Institute for Quality and Efficiency in Health Care (IQWiG). The IQWiG report is now available for the second indication investigated, liver transplantation.

According to the findings, for liver transplantations (including living partial liver donations) there is a positive correlation between the volume of services provided and the quality of treatment results: In hospitals with larger case numbers, the chances of survival for transplanted patients are higher overall. The results for transplant failure vary depending on the number of cases. There are no studies on the effects of specific minimum case numbers introduced into health care; IQWiG could thus not assess this question.

795 liver transplantations in 2017 in Germany

In a liver transplantation, the entire organ or part of it (in the case of living donations) is removed from the donor and transplanted into the recipient in place of the diseased organ. The most common indication is chronic liver failure due to liver cirrhosis. A liver transplantation may also be required in patients with acute liver failure (e.g. due to poisoning) or with malignant tumours.

In most cases, the medical team transplants the organ of a deceased person into a recipient. There is also the option of dividing the donor organ between two persons: Then an adult usually receives the larger right hepatic lobe and a child the smaller left hepatic lobe. In contrast to a post-mortem donation, in a living donation the surgeons remove only a part of the liver from the organ donor and transplant it into the recipient.

In 2017, a total of 795 liver transplantations were performed in Germany.

Despite the use of immunosuppressants, up to 30 percent of transplanted patients experience at least one acute rejection reaction of the donor liver in the first three months after transplantation. Later chronic rejection reactions are observed in 3 to 17 percent of patients.

Positive correlation between volume and quality

On the basis of six observational studies included in the assessment, IQWiG sees a positive correlation between the number of liver transplantations performed in a hospital and the quality of treatment results. Especially the chances of survival are higher overall in hospitals with a larger number of cases. However, the Institute classifies the certainty of this conclusion as low due to the rather low data quality.

As far as transplant failure is concerned, the IQWiG researchers see a correlation between the volume of services provided and the quality of treatment results at the hospital level (although the results are also of low informative value), but this correlation is not linear. For example, the transplant rejection rate in a relevant study decreased only up to a number of 50 liver transplantations per year, then increased, and decreased again from about 90 liver transplantations per year. Should this result be confirmed in further high-quality studies, in addition to the minimum volumes to be fulfilled, annual maximum volumes would also be conceivable.

Due to a lack of data, the IQWiG researchers were unable to derive a correlation between the number of liver transplantations and the quality of treatment for the defined outcomes "adverse effects of treatment", "health-related quality of life" and "length of hospital stay". Since none of the included studies considered the volume of services achieved by the individual physicians, the results of the IQWiG report refer exclusively to the level of the hospitals in which the liver transplantations were performed.

No conclusion on the German minimum volume regulation possible

The current minimum annual volume for liver transplantations in Germany is 20 procedures per hospital site (including living partial liver donations). This number also includes the removal of organs. However, for the current assessment, the procedures including only organ removals were not taken into account, also because the studies included do not provide any corresponding data.

There are no studies on the effects of specific minimum case numbers introduced into health care; IQWiG could thus not assess this question.

Process of report production

In December 2018, the Federal Joint Committee (G-BA) commissioned IQWiG to prepare the report on the correlation of the volume of services and the quality of treatment in liver transplantations in an accelerated procedure as a so-called rapid report. Interim products were therefore not published or made available for a hearing. This rapid report was sent to the contracting agency, the G-BA, in September 2019.