Type 2 Diabetes Classification - A Straw Man Scale for Progression

Many people in the diabetes online community (DOC) are concerned about the label "prediabetes", its predecessor term "borderline diabetes", and its colloquial counterparts (e.g., "a touch of the sugar"). The prevailing attitude is that one either has diabetes, or one does not. This may seem counterintuitive to the general understanding that a woman who was diagnosed with gestational diabetes (GD), but whose postpartum glucose metabolism has returned to reference normal (RN), does not have Type 2 diabetes mellitus (T2DM), but is at increased risk for developing T2DM later in life. It also contrasts with the popular belief -- even espoused by some in the mainstream medical community -- that if a person diagnosed with T2DM can bring his glucose metabolism back to RN by changes to his diet and exercise regimen (D&E) without the use of antidiabetic medications, then he no longer has diabetes.

Two biases of significant note: (1) current medical understanding is that at the point of T2DM diagnosis, a person has lost 50% of beta cell function (AACE, p. 16), and (2) the diabetes online community is primarily informed by persons with Type 1 diabetes mellitus (T1DM), an autoimmune disorder for which there is currently no cure.

Based on the above attitudes and biases, the belief would be that the new mother, having been diagnosed with GD during pregnancy, would be considered to have T2DM, even if it can be mediated without frank lifestyle adjustments. Similarly, the person who was diagnosed with T2DM is considered to still have T2DM, even if it is mediated completely by D&E.

Unlike most presentations of T1DM, T2DM is currently understood to be a progressive condition. Our understanding of its progression in a given individual is informed by both quantitative and qualitative benchmarks. The most common quantitative benchmarks are the individual's fasting blood glucose level, serum fructosamine level, and amount of glycosylated hemoglobin. Other quantitative benchmarks -- such as c-peptide level -- may be useful in determining both insulin resistance and degree of remaining beta cell function. Qualitative benchmarks include signs and symptoms of known complications of diabetes at all levels of their development.

One analogy for cataloguing the degree of progression of T2DM is that used for cataloguing hypertension or cancer: a stage chart. In Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7), hypertension is categorized from consistently slightly-elevated blood pressure ("prehypertension") through progressively elevated levels, and the response of those levels to pharmacotherapy.

An initial straw man chart can be derived from the American Association of Clinical Endrocrinologists' Medical Guidelines for Clinical Practice for the Management of Diabetes Mellitus (2007) examples for initial pharmacotherapy of T2DM:

Classification of Type 2 Diabetes Mellitus (based on initial therapy algorithms)

Progression Level	HbA1c (untreated)
Stage 1 (Prediabetes)	5.7 - 6.4
Stage 2	6.5 - 7.0
Stage 3	7.0 - 8.0
Stage 4	8.0 - 10.0
Stage 5	> 10.0

Other issues that play into determining the progression of T2DM include the deterioration of endogenous insulin production, the development of complications of diabetes, and the degree to which a person's blood glucose levels and HbA1c are responsive to pharmacotherapy. A more complex table of progression might include these in a manner such as this:

Classifications of Type 2 Diabetes Mellitus (proposed)

Level	HbA1c (Goal)1	Effective Therapy	Evidence of Complications	c-peptide (relative)
Stage 1 (Pre-Diabetes)2	< 6.03	ILM. Oral medication optional for aggressive treatment.	none	high
Stage 2	< 6.5	Oral medication and/or insulin sensitizer required	none	high
Stage 3	< 7.0	Combination therapy and/or insulin required	possible; possible comorbid conditions	varies
Stage 4	< 7.0	Insulin therapy required, with or without oral medications and/or pramlintide (Symlin)	probable; possible comorbid conditions	low
Stage 5	< 8.0	Intensive insulin therapy required, possibly in conjunction with insulin sensitizers	obvious; one or more comorbid conditions	low

1 While the HbA1c goals at the more advanced levels of diabetes progression are high enough that complications are likely to develop or intensify, those goals may not be realistically achievable with current medical and pharmaceutical technology.
2 Includes all previous diagnoses of gestational diabetes or Type 2 diabetes in which pharmacotherapy is not currently indicated
3 More aggressive practitioners may argue for an HbA1c goal of under 5.5 for Stage 1, under 6.0 for Stage 2, and under 6.5 for later stages of T2DM. The less-aggressive goals are informed in part by the (ACCORD) study, in which the tested combination therapy suggested a higher mortality risk for intensive control.

A classification scheme of this sort may remove the ambiguity of a diagnosis of "prediabetes" and its associated laissez-faire ("It's not diabetes") attitude, as well as the popular belief that once diagnosed, one can become "undiagnosed" (or perhaps "de-diagnosed"). It can also alert a medical practitioner to the need for ongoing monitoring and assessment of a person's glucose metabolism. On the other hand, classification will add to the pool of people indicated to have diabetes those who do not consider themselves to be currently affected by diabetes -- and in an environment where a positive diagnosis can mean the denial of employment, medical insurance, or healthcare, this can have worse repercussions than living with undiagnosed or untreated Stage 1 (or even Stage 2) T2DM.