The target is for 95 per cent of emergency department (ED) patients to be admitted to hospital, transferred or discharged within six hours.
In the three months after it was introduced in July 2009, the district health boards nationally achieved six hours or less for 80 per cent of patients. Waitemata DHB performed worst, at just 61 per cent.
National performance improved sharply among the 20 DHBs to 92 per cent in the latest Health Ministry figures, for the three months to December. Waitemata too was on 92 per cent, but says it has consistently met the target since then.
Counties Manukau has been above 95 per cent since early 2010.
Auckland DHB began hitting the target last April to June, but often dips back below 95.
All other upper North Island DHBs fell among the 11 nationally below the cut in the October to December count. Wellington's Capital & Coast DHB came last, at 82 per cent.
Health Minister Tony Ryall is pleased with the progress, which results from extra staff and ward beds, some new EDs, smarter processes and, crucially, acceptance that a leading cause of ED delays is overcrowding elsewhere in a hospital.
"It has been a slow and steady increase, which is what you would expect from a whole-of-hospital response," Mr Ryall said.
He no longer received letters from patients complaining they had languished for days in ED, even from the 8 per cent who waited more than six hours.
"Capital & Coast say 95 per cent are waiting no more than eight hours, so things are improving right across the country, but it's a gradual thing. I think that's good because it indicates it's genuine."
Research published in February on Western Australia's four-hour ED rule found it reversed overcrowding and coincided with a 13 per cent reduction in hospital mortality - the avoidance of one patient death every two days across three major hospitals.
Counties Manukau ED head Dr Vanessa Thornton said: "I'm sure that if it has been shown to reduce [mortality] in other places, the same will have happened with us."
Other emergency physicians echo this view.
The Government was careful to avoid making the target too tight and shunned the financial incentives and penalties of Britain's four-hour rule, which had been undermined by hospitals keeping patients waiting in ambulances and moving large numbers of patients out of EDs just before four hours - in some cases without proper medical care, leading to an increased death rate.
The Health Ministry's clinical director for EDs, Professor Mike Ardagh, said there was no evidence of this "gaming" in New Zealand.
He said the effect of the target on patient outcomes would remain uncertain until the research report, but the indications from ministry statistics, such as ongoing reductions in hospital mortality before and after the target's introduction, were positive.
Long wait over in north and west
This is a historic milestone for our DHB. Dale Bramley, chief executiveFor the first time, the Waitemata District Health Board has met - and exceeded - the time target for emergency department patients.
The remarkable change is of huge benefit to the sick and injured of western and especially northern Auckland.
For the first three months of this year, the board's EDs at North Shore Hospital and Waitakere Hospital have discharged, admitted to a ward, or transferred 96 per cent of their patients, up from 61 per cent in mid-2009, when Waitemata was the worst performer nationally.
And this improvement is set against a rise in the number of patients. Last year the EDs saw 102,261 - 31 per cent more than in 2009.
"This is a historic milestone for our DHB and has only been made possible through the commitment and hard work of all our people," said chief executive Dale Bramley.
It is a dramatic change from the winter of 2007, when numerous patients waited on trolleys in corridors for admission to hospital wards, sometimes for days on end.
North Shore was among the worst, but not alone in its difficulties. Two-day waits in EDs were "not unusual in larger New Zealand hospitals", an expert adviser told the Health and Disability Commissioner during an investigation into a 2006 case at North Shore, in which an 84-year-old man had to wait that long for an inpatient bed.
Trolleys are less comfortable than a bed, and being kept in a corridor increases the risk of being overlooked for medical care, meals and for assistance in getting to the toilet.
But now North Shore reports only 25 patients since last July have stayed in the ED for more than 24 hours and says it will have been for medical reasons, such as monitoring someone after a large drug overdose.
The average length of stay in the North Shore ED was 3.7 hours in the past 12 months, down from 6.2 hours during the 12 months to last March.
A new ED and assessment and diagnostic unit were commissioned at North Shore - part of the $53.5 million Lakeview development - to help address the overcrowding.
The DHB's clinical head of emergency medicine, Dr Bhavani Peddinti, said short-stay units within the EDs and faster ways of discharging ward patients had also helped. "ED patients didn't have to wait for hours ... simply because we were waiting for a bed to be freed up."
Waikato aims to do even better
The speed of managing emergency department patients at Waikato Hospital in Hamilton is lagging behind most of the country's big hospitals.
But it is improving.
The Waikato District Health Board's performance on the six-hour ED target rose from 67 per cent of patients in mid-2009, to 89 per cent in the December quarter last year.
Since then it has crept up to 92 per cent and the board expects to get Health Ministry approval for an administrative change that pushes its official performance to 93 per cent.
The change is to include the board's three smaller hospitals - Taumarunui, Te Kuiti and Tokoroa, all performing well against the target - in the statistics which, to date, have reported the combined results of only the Waikato and Thames hospital EDs.
Thames is meeting the target, leaving the large, city hospital, which opened a new ED last year, to catch up.
Part of the problem for Waikato Hospital is the big increase in the number of patients coming to the ED, up 11 per cent so far this year - but other hospitals have coped with this sort of rise. Senior managers fear the hospital's reputation is being damaged and are applying pressure to comply.
An assistant group manager, Kevin Harris, said he was confident the board would reach 95 per cent for the three months that started yesterday - "because in the last few months we have had a solid focus on that."
The average length of stay for ED patients was just over six hours, but there were big variations. He said that part of the improvement against the target in January was due to the efforts of two inpatient departments.
Plastic surgery and orthopaedics "have shown significant and consistent improvements in their drive to have patients that are referred to the specialty assessed, diagnosed and dispatched from the ED within six hours".
The hospital's general principle was to allow three hours for the ED to examine, test and start treating a patient; two hours for specialty teams to assess and decide whether to admit or discharge; and one for an inpatient bed to be assigned and the patient to be moved there or discharged.
