Efforts by hospital trusts in England to comply with the NHS 18-week referral-to-treatment standard resulted in "a distinct threshold effect" around the target time, according to a new data analysis from the University of Birmingham.
The findings suggested that hospital trusts may "choose whom to treat based on the target instead of clinical need", the researchers said.
The target, introduced in 2012, stipulates that at least 92% of patients requiring hospital treatment should be waiting for less than 18 weeks since referral. For their study, published online in BMJ Quality & Safety, the researchers retrospectively scrutinised monthly data on treatment waiting times for all 144 non-specialist acute NHS hospital trusts in England between January 2016 and September 2021.
Hospitals Motivated by Meeting the Target Rather Than by Clinical Need
Inevitably, not all hospitals met the target standard. From 2015-16 to 2019-20, on average, trusts had only 87% of patients waiting less than 18 weeks. The proportion that did so gradually worsened, falling from 92% in 2015-16 to 64% in 2021-22, with attainment falling sharply in 2020-21 due to pandemic treatment restrictions that "made it virtually impossible for most hospitals to meet the target".
Otherwise, there was "strong evidence of a threshold effect", the researchers said, with "discontinuity" around the threshold: the data repeatedly showed stable density in the percentage of patients waiting less than 18 weeks before this, then a large spike at the 92% target, followed by a sharp drop after it was reached.
This suggested that hospitals were "motivated by meeting this target, rather than by clinical need", and that some trusts treated the minimum number of patients necessary to comply with the standard. Hospitals that got close to the target likely acted to clear it, while those further from meeting it didn't bother, perhaps feeling that it would be futile to do so, the authors suggested.
So rather than instigating improvements in practice, the target's effect was to focus activity on meeting the minimum threshold requirement, and clinical need seemed to have been "a secondary consideration", they said.
'Reputational' Sanctions had Less Impact Than Financial Ones
The authors noted that sanctions for failure to meet the target had constantly included potential downgrading of Care Quality Commission (CQC) ratings. However, there was also initially a financial penalty, of up to 2.5% of healthcare income, which was formally removed in 2017-18, "leaving only the arguably attenuated bureaucratic and reputational sanction", they said. Certainly, after this, the analysis showed further substantial declines in the proportion of hospitals meeting the target.
Asked to comment by Medscape News UK, a CQC spokesperson said: "Waiting time targets are one of a number of measures we consider during our inspections." While recognising current pressures and the large elective care backlog, the CQC said it would "always look at how trusts manage risks to safety of those who face delays for treatment, and the steps trusts are taking to prioritise resources and ensure those in the greatest need are seen first".
"No Encouragement" To Treat Patients Outside the Target Window
However the study authors concluded that the target provided "no encouragement" to treat patients who had waited only a short time, nor those who had already passed the 18-week point. In addition, they said, it could incentivise "low rectitude behaviour" in manipulating data to meet the target.
They urged NHS policymakers to be "circumspect" in imposing targets which, if used, should be "carefully designed to mitigate threshold effects", and routinely assessed as to whether these are occurring.
Also asked to comment by Medscape News UK, an NHS spokesperson said: "The suggestion that the NHS is incentivising trusts not to bother treating people once they pass 18 weeks is nonsense – treatment priority is determined by the clinical needs of patients as identified by clinicians, as well as those waiting longest."
The spokesperson added that the NHS had "a clear plan in place" for reducing the current backlog, with "significant progress reducing the longest waits".
"Long Litany of Unintended Impact of Targets"
The study "joins a long litany of examples of the unintended impact of targets", commented Nigel Edwards, chief executive of the Nuffield Trust, and independent analyst Steve Black, in a linked editorial.
They noted that, while important for public accountability, targets may have
"unanticipated consequences". These can include distortion of clinical decision-making; hospitals with no chance of meeting the target choosing to direct their efforts elsewhere, and those that surpass it allowing performance to slip back to target levels.
With insufficient resources, hospitals may demand "unsustainable levels of work from staff to meet the target, to the exclusion of almost everything else", including a lack of attention to quality and safety.
'Gaming' the target may occur, particularly when linked to high-powered incentives and punishments – for example, finding ways to exclude patients from the waiting list. It can mean not only failing to meet target aims but also generating other adverse outcomes, which can "lead to an arms race of increasingly complex rules designed to eliminate gaming, followed by even more ingenious methods to meet the target".
Good targets focus on desired outcomes, whereas badly designed targets focus on easy-to-measure inputs, they said. The NHS has often pursued a failed approach focused on input targets, not outcomes, and promoted 'achieving the numbers' over understanding the problem. "Over-reliance on a small number of high-profile measures is risky," they suggested, and "measurement is not an alternative to judgement". NHS management needs to avoid gaming, overpromising, and "other perverse ways of pursuing the metric while missing the point", the editorial concluded.