The Australian guidelines were written at a time when there was considerable discussion about the outcomes of trials which aimed to lower glucose levels to 'normal' in the hope of reducing heart disease in people with diabetes. These trials were using medications rather than 'lifesyle'
The Accord trial which was the one that showed poorer outcomes used very agrressive treatments (multiple medications and reduced levels quickly with an aim of getting HbA1c below 6 in a few months) This trial was stopped early because there were more deaths in the intense control arm than the control arm.
Neither of the other trials, which lowered levels more slowly showed any benefit for CVD outcomes (no detrimental effect either). The Advance trial was actually an Australian trial and compared the outcomes of those whose target was below 6.5% with those whose target was 7%.
The other from the US compared a target of less than 6% and 8-9%
Most of the subjects in all three trials were over 60
Here is what seems a straightforward and balanced account written to explain about the three trials and some of the important issues/questions related to them.
The list of caveats they give is important.
http://diatribe.org/issues/10/learning-curve
Since then there has been far more analysis of the data from these trials and the more recent Canadian guidelines have a range of targets with age and other illnesses taken into account. Again though hypoglycaemia is the 'barrier' to lower levels in those who are younger and have no other 'co-morbidities'
Of course as individuals we tend to believe (or want to believe ) that we still have longer life expectancy etc The guidelines tend to take a more pragmatic view but they are looking at PWD as a whole not highly motivated individuals.
(evidence comes first then scroll down for actual guidelines)
http://guidelines.diabetes.ca/Browse/Chapter8
this is the written conclusion
Conclusions
Contrasting results from recent studies should not discourage physicians from controlling blood glucose levels. Intensive glucose control, lowering A1C values to ≤7% in both type 1 and type 2 diabetes, provides strong benefits for microvascular complications and, if achieved early in the disease, might also provide a significant macrovascular benefit, especially as part of a multifactorial treatment approach. More intensive glucose control, A1C ≤6.5%, may be sought in patients with a shorter duration of diabetes, no evidence of significant CVD and longer life expectancy, provided this does not result in a significant increase in hypoglycemia. An A1C target ≤8.5% may be more appropriate in type 1 and type 2 patients with limited life expectancy, higher level of functional dependency, a history of severe hypoglycemia, advanced comorbidities, and a failure to attain established glucose targets despite treatment intensification