Dear Geoffrey,

There are a myriad of potential confounders of this relationship. A list of these confounders may be the following:

Patient characteristics:

Sex, age, age at diagnosis, height, body weight, smoking status, alcohol consumption status, habitation (city, town, rural), health insurance (statutory, private), marital status, children, employment status, arterial hypertension, blood pressure, coronary heart disease, heart insufficiency, myocardial infarction, stroke, peripheral arterial disease, revascularization procedures and bypass surgery, cancer, depression, other chronic disease, other diabetes-related complications and surgeries, hyperlipoproteinemia, hypercholesterinemia, serum cholesterol, serum triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, HbA1c, FBG, serum uric acid, serum creatinine, medication during follow-up (OAD, insulin + dosing, antihypertensives,a lipid-lowering drugs,b uric-acid-lowering drugs, thrombocyte aggregation inhibitors, other), diabetes education program

Center and treating-physician characteristics:

Location (city, town, rural), center size (number of newly diagnosed patients with type 2 diabetes, total number of diabetes patients), qualification of treating physician (general practitioner, internist, specialization in diabetes or in endocrinology)

For more details you may be interested in this paper:

Kolb et al. 

Are Type 2 Diabetes Patients Who Self-Monitor Blood Glucose Special? The Role of Confounders in the Observational ROSSO Study

J Diabetes Sci Technol. 2009 Nov; 3(6): 1507–1515.

Hoping to have been of help,

Best Regards

http://www.jdst.org/November2009/Abstracts/VOL-3-6-COM3-KOLB-ABSTRACT.pdf

Hi,

Kindly see the following:

http://www.ncbi.nlm.nih.gov/pubmed/12738396

http://www.sciencedirect.com/science/article/pii/S1262363608001651

http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/endocrinology/diabetes-mellitus-treatment/Default.htm

http://www.em-consulte.com/en/article/195996

Most probably this is not a direct factor in the relationship you analyze. 

The ineffective self-monitoring would lead to a decrease quality of the glycemic control and/or hypolgycemic events which will lead to the development of complications. 

Regarding the development of complications, this will be the only confounding factor. Others may be regarded as co-factors of the quality of the glycemic control. 

I am agree with Bogdan Timor. The self monitoring of blood glucose is a confounding factor for development of complication of DM. It's major contribution on early onset of treatment on acute onset hypoglycemia. And may be health seeking behavior will reflecting this activity, which can increase the quality of life.

To answer this question one has to define the purpose of SHGM. This is (or should be) done for the purpose of improving overall glycaemic control. It is not an end-point in itself,nor is it a surrogate endpoint. If SHGM is used properly it may improve levels of  glycaemia and thereby HbA1c levels, and indirectly reflect on microvascular disease development. Since SHGM reflects only a moment in time, and its efficacy is related to how many times a day it is done, it cannot be directly related to complications. The advent of continuous glucose monitoring may in time change this paradigm with the ability to assess glycaemic excursions and glycaemic load more completely, but at this time the gold standard of control in relation to the development of complications remains the HbA1c.