Its people also had good access to healthcare.
"We've just doubled our capacity to do acute cardiac catheterisation [non-surgical heart interventions]. If you have a [heart attack] you can be taken straight to the cath lab. There's lots of high-end services available close to a large proportion of the population, plus the services at Auckland DHB.
"If you are up on the Coromandel and have to go to Waikato Hospital for major trauma or a heart attack for acute treatment it's going to take you a lot longer."
The annual number of Waitemata hospital inpatient deaths declined to 711 by June last year, from 727 five years earlier, although the lowest toll was 695 in 2008/9.
Measured against patient discharges and weighted by population characteristics to allow comparisons, Waitemata's annual in-hospital mortality rate has mostly reduced each year. Typically its rate has been in the lowest five DHBs and statistically significantly lower than the national average. Only once in the five years to 2009/10 did the rate rise to the mid-range.
Dr Bramley, a public health physician, said this trend was consistent with Waitemata's above-average health status.
Biostatistician Associate Professor Chris Frampton, however, has said variation in the national hospital mortality figures that might have been attributable to a local population's being healthier and wealthier than average had been accounted for by the standardising for age, gender, rurality, ethnicity and deprivation.
Dr Bramley said the rates nationally were "fairly closely clustered. In some countries there is much bigger variance that you would be worried about".
Asked if hospital mortality rates and quality of care were linked, he said they were, but indicated this was best understood at a deeper level than whole hospital.
"For example what happens when you have an acute [heart attack] ... How fast do they get access to gold-standard treatment and what were the outcomes?"
Among the quality and patient safety programmes now undertaken by all DHBs, Waitemata has a particular focus on medication safety. It makes extensive use of electronically controlled Pyxis drug dispensing machines, which will soon be linked to a pilot programme of electronic drug prescription.
Northland DHB's standardised hospital mortality rate has oscillated between being one of the lowest and sitting in the mid-range. Its number of inpatient deaths has varied significantly too, from 296 in 2006/7, to 361 the following year, declining progressively to 307 in 2010/11.
Chief medical officer Dr Mike Roberts said the DHB was committed to comprehensive quality and patient safety programmes and had lately hired two new staff in this area.
"The results for Northland are reassuring but our intention is not to relax because figures here look good; rather it is to make them even better."