Impact of Type 2 Diabetes on Cardiovascular Health
Overview of Diabetes and Cardiovascular Risks
Diabetic patients are at an increased risk for cardiovascular issues. A recent study published in JAMA Network Open explored the cardiovascular effects of medications used for type 2 diabetes. Diabetes mellitus, characterized by elevated blood glucose levels, is categorized into three types: type 1 (insulin-dependent), type 2 (non-insulin dependent), and gestational diabetes. Type 1 diabetes results from insufficient insulin production, while type 2 diabetes involves reduced insulin levels or inadequate insulin response. Gestational diabetes occurs during pregnancy.
Individuals with diabetes face a heightened likelihood of developing cardiovascular diseases, including congestive heart failure, stroke, ischemic heart disease, and peripheral artery disease, which may ultimately lead to amputation.
Study on Second-Line Type 2 Diabetes Medications
Several studies have highlighted the cardiovascular side effects associated with type 2 diabetes medications. The recent research conducted by the Northwestern University Feinberg School of Medicine focused on the cardiovascular risks linked to second-line type 2 diabetes drugs.
Common Second-Line Drugs for Type 2 Diabetes
Metformin is the most frequently prescribed medication for type 2 diabetes. If patients do not respond adequately to metformin or experience adverse effects, second-line medications are introduced. Common second-line drugs include sulfonylureas and basal insulin. The study indicated that 60% of the participants were using one of these two medications, with additional second-line options such as DPP-4 (dipeptidyl peptidase 4) inhibitors, GLP-1 receptor agonists (glucagon-like peptide 1), SGLT-2 inhibitors (sodium-glucose co-transporter 2), and TZDs (thiazolidinediones).
The researchers conducted a retrospective analysis involving 132,737 insured diabetics who were prescribed second-line type 2 diabetes drugs, either after prior metformin use or newly initiated treatment. Data was sourced from the country’s commercial or Medicare Advantage health insurance databases, capturing information from health plan enrollment files, laboratory claims, pharmacy claims, and medical claims. Participants were categorized based on past cardiovascular events, previous metformin use, and HbA1c levels. Individuals with inconsistent medication usage or those who started additional medications later were excluded. The primary focus was the time until the first cardiovascular event after commencing the second-line drug, along with other factors like hospitalization for cardiovascular diseases.
Findings on Cardiovascular Risks with Different Medications
Among the participants, sulfonylureas were prescribed in 47.6% of cases, DPP-4 inhibitors in 21.8%, basal insulin in 12.2%, GLP-1 receptor agonists in 8.6%, TZDs in 5.6%, and SGLT-2 inhibitors in 4.3%. Notably, 5.5% of these patients had a history of cardiovascular disease.
The research revealed that GLP-1 receptor agonists were associated with a lower incidence of composite cardiovascular events. The rates of cardiovascular events among SGLT-2 inhibitors and TZDs were comparable to DPP-4 inhibitors. However, patients on sulfonylureas faced a 36% higher risk, while those on basal insulin experienced double the risk of cardiovascular diseases. Notably, the use of GLP-1 receptor agonists was linked to a significantly reduced risk of stroke. Well-compliant patients and those not taking additional diabetes medications showed improved outcomes during follow-up.
Clarification on TZDs and Cardiovascular Effects
This study provides clarity on the longstanding debate regarding the cardiovascular impacts of TZDs, finding no significant risks associated with them. The results remained consistent regardless of HbA1c levels, suggesting short-term cardiovascular events are not influenced by blood sugar control.
Strengths and Limitations of the Study
The study’s strengths include a large patient sample reflecting real-world outcomes. It also considered stroke risk and encompassed all major type 2 diabetes drugs. However, limitations exist, such as the lack of consideration for the duration of diabetes—a significant factor in cardiovascular disease development. Some participants had a history of heart disease, which may limit the applicability of findings to those at lower cardiovascular risk. Additionally, mortality and cost factors were not addressed.
Need for a Paradigm Shift in Type 2 Diabetes Treatment
Dr. Matthew O’Brien, a senior researcher and assistant professor at Northwestern University Feinberg School of Medicine, emphasized the importance of awareness about the potential cardiovascular risks of diabetes medications. He stated, “This calls for a paradigm shift in the treatment of type 2 diabetes.” While newer medications like GLP-1 agonists, SGLT-2 inhibitors, and DPP-4 inhibitors present lower cardiovascular risks, they are often more expensive than sulfonylureas, leading to their under-prescription.
It is crucial for healthcare providers to remain vigilant in prescribing diabetes medications and consider safer alternatives. Patients should also be informed about the potential side effects of their medications, balancing efficacy with cost considerations.
References
O’Brien M, Karam S, Wallia A, Kang R, Cooper A, Lancki N et al. Association of Second-line Antidiabetic Medications With Cardiovascular Events Among Insured Adults With Type 2 Diabetes. 2019.
Two Type 2 diabetes drugs linked to higher risk of heart disease [Internet]. EurekAlert!. 2019 [cited 18 January 2019]. Available from: https://www.eurekalert.org/pub_releases/2018-12/nu-tt2121818.php