Evidence of suboptimal management of cardiovascular risk in patients with type 2 diabetes mellitus and symptomatic atherosclerosis

There is no doubt that today aggressive control of common risk factors is of paramount importance in the management of diabetic patients with atherosclerotic disease to prevent cardiovascular morbidity and mortality. However, the authors in this study[1] applied the evidence gathered after year 2000 to the data collected before 2000 and it was no surprise that the management was found to be sub-optimal based on current recommendations.

In the methods section, the author’s identified this cohort between 1991 and 1996 and followed the cohort until 2000. The evidence regarding the use therapies ‘proven to reduce cardiovascular risk and mortality,’ became available with after 2000, as eluded by the authors, and was not available with that confidence before 2000. The recommendation about anti- platelet agent use to prevent CV events that authors quote was published in 2002[2]. Concerning ACE-inhibitor use in diabetics, the Heart Outcomes Prevention Evaluation [HOPE][3] was in fact published in 2000; since when ace-inhibitors are recommended for CV protection in high-risk patients, including diabetics. Although there was some evidence concerning statin therapy from sub-group analysis of 4S[4] that these agents are effective in diabetics in preventing CV morbidity and mortality but the evidence with confidence became available after the results of Heart Protection Study [HPS] were published in 2003[5]. Then, how can the authors evaluate and conclude that the management of the said cohort was sub-optimal when there were no strong recommendation(s) to use these agents broadly in diabetics.

It would have been best if ‘the 1998 guidelines[6] for the management of diabetes’ were utilized to evaluate the care provided to this cohort. I agree that likely the authors would have found similar findings as it takes few years to implement guidelines in general public and by that time either the guidelines are changed or are in the process of changing and is one of the factors for poor implementation of guidelines. None of the above therapies were strongly recommended for CV protection in 1998 guidelines, as there was no strong evidence to support such recommendations. In fact, UKPDS[7] was published at the same time that highlighted the importance of controlling both blood glucose and blood pressure effectively to improve micro- and macro-vascular complications and did not favor one agent over the other [beta-blocker versus ace- inhibitor].

Since then evidence has accumulated and the recent 2003 guidelines[8] incorporates these therapies and make appropriate recommendation about these therapies. In this study, authors highlights the importance of peripheral arterial disease as an important group of patients that are at increased risk for CV mortality but interestingly the recently published current Canadian guidelines do not even mention even a word about peripheral arterial disease in the 140 pages[8]. How amazing! If guidelines developers are not going to incorporate such information then how one expects for the common practicing physician to apply the accumulating and rapidly changing evidence into their day to day practice.

References:

1. Brown LC, Johnson JA, Mazumdar SR, Tsuyuki RT, McAlister FA: Evidence of suboptimal management of cardiovascular risk in patients with type 2 diabetes mellitus and symptomatic atherosclerosis. CMAJ 2004; 171:1189-92.

2. Antithrombotic Trialists' Collaboration. Collaborative meta- analysis of randomised trials of antiplatelet therapy for prevention of death, myocardial infarction, and stroke in high risk patients [published erratum in BMJ 2002; 324: 141]. BMJ 2002; 324:71-86.

3. Heart Outcomes Prevention Evaluation (HOPE) Study Investigators. Effects of ramipril on cardiovascular and microvascular outcomes in people with diabetes mellitus: results of the HOPE study and MICRO-HOPE substudy [published erratum in Lancet 2000; 356:860]. Lancet 2000; 355:253-9.

4. Pyorala K, Pederson TR, Kjekshus J, et al. Cholesterol lowering with simvastatin improves prognosis of diabetic patients with coronary heart disease. A subgroup analysis of the Scandinavian Simvaststin Survival Study (4S). Diabetes Care. 1997; 20: 614-20.

5. Heart Protection Study Collaborative Group. MRC/BHF Heart Protection Study of cholesterol lowering with simvastatin in 5963 people with diabetes: a randomized placebo-controlled trial. Lancet 2003; 361:2005-16.

6. Meltzer S, Leiter L, Daneman D, et al: 1998 clinical practice guidelines for the management of diabetes in Canada. CMAJ 1998; 159)8 Suppl):S1-29.

7. UK prospective Diabetes Study Group. Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes. UKPDS 38. BMJ 1998; 317:703-13.

8. Canadian Diabetes Association 2003 Clinical Practice Guidelines for the Prevention and management of Diabetes in Canada. Canadian Journal of Diabetes. 2003; 27(Suppl 2):S1-140.

Conflict of Interest:

None declared