North West London Hospitals Trust has admitted its data recording problem may extend wider than performance on the 18-week wait for elective surgery.

HSJ last month revealed the trust failed to properly record the waiting times of 60 per cent of elective inpatients, causing hundreds of them not to receive treatment within the 18-week deadline.

According to board papers for the trust’s November board meeting, it has 4,400 patients on its admitted waiting list and “this number needs to be 2000 to reach a sustainable balance”.

Eight hundred of these patients have been waiting over 18 weeks, and a further 328 have been waiting more than 16 weeks.

The trust has hired KPMG to audit the quality of its data on accident and emergency four-hour waits, 18-week referral to treatment patients and cancer wait times.

“Further issues with the trust data quality may be found through this process of examination,” its board papers state.

A problem has already been identified with a group of urology patients. The trust said that “further investigation is underway across all areas of waiting lists to ensure that all issues are identified at the earliest possible opportunity”.

The trust noted that it would be unable to treat all of the patients on its elective waiting list without outsourcing work to external providers, despite plans to increase elective capacity at Central Middlesex Hospital and emergency capacity at Northwick Park Hospital.

Patients waiting over 16 weeks will be prioritised and sent to private provider BMI, Hillingdon Hospitals Foundation Trust and the Royal National Throat, Nose and Ear Hospital, part of University College London Hospitals Foundation Trust.

Trust director of operations Tina Benson said: “This is a review of data quality frameworks currently in place and the work was already committed to as part of our assurance process for the merger [with Ealing Hospital Trust]. However we thought it sensible to extend the scope to include specific audit on the recording and reporting of 18 week waiting times, so that we can provide further assurances on this issue.

“We are working with our CCGs to outsource care for patients awaiting elective procedures so that we can reduce the time they wait as well as introducing a number of initiatives internally to increase capacity.”