The revelation that NHS Lothian had been doctoring waiting lists by marking patients who turned down an operation in England at short notice as "unavailable for social reasons" has had far-reaching repercussions throughout the NHS in Scotland.

One of those is a full-scale inquiry by Audit Scotland into how waiting lists are being managed and whether there is manipulation to meet targets. It is now nearing conclusion and is expected to report next month.

Another is a £10 million programme in NHS Lothian including an additional 250 theatre staff. This was instigated specifically to bring down waiting times by the new chief executive, Tim Davison, who took over in the wake of the scandal.

NHS Lothian, having sought to put its house in order, ought to be keen to gain a clean bill of health from the Audit Scotland inquiry and lead the way in a new era of transparency. That makes it particularly puzzling that the chairman and senior staff appear keen to set limits on information provided to the investigation. Emails from Dr Charles Winstanley, the board's chairman, to board members and senior staff show they are extremely reluctant to provide Audit Scotland with briefing papers for meetings held in private. Normally closed-door sessions involve commercially sensitive contract details or personnel matters. Even if there is a genuine justification for also discussing waiting lists in private, that cannot reasonably be extended to drip-feeding information on the background of these discussions to the official body investigating health board practices.

On Monday, Dr Winstanley wrote "there should be nothing 'to hide' from official bodies like Audit Scotland. However we have no control over the conclusions that Audit Scotland might draw from papers they received". It would appear he is concerned about their likely conclusions because in a second email yesterday he proposed the board should provide only the latest and future minutes. His apparent reassurance that these were written with "discretion" does nothing to allay suspicion that the board would like to hide material that might have been included in a fuller record or in briefing papers.

Last month the results of an internal audit undertaken by each of the 14 boards into the management of waiting lists showed a significant drop in the overall figures for the number of patients recorded as socially unavailable. From a total 17,000 when the NHS Lothian scandal broke, it had nearly halved by September last year.

That indicates that some lessons have been learned about fiddling the lists. Yet the internal audits also revealed unacceptable practices. The benefit of the Audit Scotland inquiry is that it has powers to investigate fully. The actions of the chairman of NHS Lothian suggest it has not yet realised transparency is now necessary. Public trust has been lost by putting bureaucratic targets above patients' best interests. Hiding the basis of decision-making is no way to regain it.