The study is published by a German group called IQWiG, the Foundation for Quality and Efficiency in Health Care, a private law foundation with legal capacity. IQWiG's function according to its charter includes:
1. Search for, assessment and presentation of current scientific evidence on diagnostic and therapeutic procedures for specific diseases;
2. Preparation of scientific reports and expert opinions on quality and efficiency issues of SHI services, taking age, gender, and personal circumstances into account;
3. Appraisal of evidence-based clinical practice guidelines on the epidemiologically most important diseases;
4. Issue of recommendations on disease management programmes;
5. Assessment of the benefits and costs of drugs;
6. Provision of easily understandable information for all citizens on the quality and efficiency of health care services, as well as on the diagnostics and treatment of diseases of high epidemiological relevance.
Its task is to support the Federal Joint Committee in fulfilling its statutory duties in these areas by the submission of recommendations (§139b  SGB V)"
Bearing in mind that the German health-care system is mainly funded by the government, they don't look just at the medical aspects but also at efficiency and costs. That is something to keep in mind when considering these reservations about the efficacy of tight control. Costs are very important when you run a government health-care system, but costs should have no bearing on the medical aspects of whether or not tight control of diabetes is good for patients.
The IQWiG news release includes this:
"Indications that patients with type 2 diabetes benefit from intensive blood glucose control were found only for the outcome "non-fatal heart attacks”. However, at the same time the data provide indications that severe hypoglycaemic episodes as well as other serious events in part occurred considerably more often in the intensive-therapy group than in the group with less intensive lowering of blood glucose levels.
Overall, the results of the current IQWiG report are consistent with those of reviews and meta-analyses recently conducted and presented by other researchers.
Question as to which treatment strategy is better still remains unanswered
The IQWiG Director Jürgen Windeler comments on the current report: "It is quite astonishing: individual interventions, particularly drugs, have in part been well investigated in studies; however, we know relatively little about the advantages and disadvantages of treatment strategies. If doctors are faced with the question as to what they can specifically offer to their diabetes patients, whether they should lower blood glucose levels as much as possible, and in which patients this a promising (or less promising) approach, they still do not receive satisfactory answers.” Even though this is a key question in the care of people with type 2 diabetes, the few studies available do not allow reliable conclusions."
The full IDWiG pdf report is here: Benefit assessment of long-term blood glucose lowering to near normal levels in patients with type 2 diabetes mellitus
They've missed the target again. There are many benefits of lowering blood glucose levels in diabetics to near-normal levels. But there are also many dangers in the intensive use of medications and insulin to achieve that goal.
The problem is not the goals but the methods.
Sadly, all they have done is confirm something that has been discussed by type 2 diabetics on diabetes forums ever since ACCORD and ADVANCE (both are included in this meta-study) were published. Those papers did not show that tight control is harmful, instead they showed that intensive use of oral medications and/or insulin to push A1c or FBG down can be hazardous to the health of a diabetic.
The factor missing from all of these studies is use of lifestyle changes, particularly diet and exercise, to achieve near-normal A1c and blood glucose levels. Repeatedly in all these studies the subjects were advised to follow the traditional (since Keyes) extremely low-fat high-carbohydrate diet and to then use medications and insulin to combat the results of that way of eating. I wrote some brief comments on the ACCORD and ADVANCE trials back in 2008 when they came out; nothing has changed since then.
Easily overlooked in the detail of this IQWIG paper is an even sadder acceptance of very poor targets:
"The goal in the test intervention group had to be long-term BG adjustment to near-normal levels (long-term lowering of HbA1c to levels at least lower than 7.5%, or long-term lowering of fasting BG to levels at least lower than 126 mg/dl or 7 mmol/l). Comparator interventions were those with no goal or a less intensive goal of long-term BG adjustment to near-normal levels."
We have already seen ACCORD used by the UK NHS and some other national diabetes authorities to discourage patients from trying for less than 7%; now they will probably use this to raise it to 7.5%.
One of the more enjoyable parts of being an active participant on several diabetes forums is that I get the opportunity to frequently offer congratulations to excited people reporting dramatic improvements in their diabetes indicators such as HbA1c, or significant improvements in the severity of complications. Often those congratulations are for joining the 5% club for achieving an A1c of less than 6%. Invariably those happy people report that their great results are from their efforts in making changes to their menu, usually as a consequence of post-meal testing, or their increases in exercise or both. Very rarely do they mention it was due to increasing meds but even then the diet and exercise usually changed first.
Those people do not seem to be encountering any of the problems warned about in meta-studies like this or ACCORD and ADVANCE.
To repeat myself, they've missed the target again. But I'll keep aiming for 6% or less.
Cheers, Alan, T2, Australia