The benefits of hospital mergers are called into question in unpublished findings from a study into links between clinical outcomes and patient numbers.

The research, commissioned by the cooperation and competition panel, found only a “weak relationship” between clinical outcomes and numbers of patients treated at trusts. The finding calls into question the common assumption that merging trusts into bigger organisations will benefit patients.

Trusts should focus on the specific benefits of their merger - what benefits are they going to bring to bear to ensure that patients are better off from this change?

Panel director Andrew Taylor told HSJ: “It’s very difficult for people to rely on a general argument that says ‘we’re going to lead to lower costs or [better] patient outcomes [by merging]’.

“People really need to make their own case when it comes to a merger. They have to explain how they’re going to do things better.”

Presenting the findings at the Nuffield Trust’s annual health strategy summit two weeks ago, Mr Taylor said the findings demonstrated the “problem in realising the benefits of mergers”.

The research, carried out by the York health economics consortium, will be used by the panel as a “conversation starter” with trusts that are considering merging.

Mr Taylor said: “Trusts should focus on the specific benefits of their merger - what benefits are they going to bring to bear to ensure that patients are better off from this change?”

Future discussions with trusts about mergers are also likely to consider whether the changes will encourage the transfer of management techniques from one hospital to another.

Analysis does not seem to show that larger hospitals are more efficient or have a lower cost base than smaller hospitals, Mr Taylor said. The panel is carrying out its own work into the financial benefits of mergers.

Mr Taylor said previous research has shown mergers have had no positive impact on recruitment and retention of clinical staff and can affect service delivery due to a loss of managerial focus.

A survey of 300 US hospital mergers concluded few involved the service consolidation necessary for significant cost saving, and improved service coordination was rarely achieved.

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