Study Links Dihydropyridine Calcium-Channel Blockers to Increased Kidney Risks in Type 2 Diabetes Patients

Recent research presented at the 63rd ERA Congress indicates that dihydropyridine calcium-channel blockers (DCCBs), a frequently prescribed class of blood pressure medications, may be associated with worsened kidney outcomes in patients with type 2 diabetes (T2D). This includes individuals already receiving newer therapies aimed at preserving kidney function.

DCCBs work by relaxing blood vessels to reduce blood pressure and are commonly used as second-line treatments for those suffering from diabetic kidney disease (DKD). The study revealed that patients using DCCBs alongside standard therapies faced a significantly higher risk of major adverse kidney events compared to those on alternative blood pressure medications.

Understanding Diabetic Kidney Disease

DKD is a leading cause of kidney failure globally, resulting from prolonged elevated blood sugar that damages the tiny blood vessels in the kidneys. This damage compromises the kidneys’ ability to filter waste, making blood pressure control crucial in managing the disease, as high blood pressure can exacerbate kidney damage.

Advancements in DKD treatment have introduced two major classes of medications. Renin-angiotensin system (RAS) inhibitors not only lower blood pressure but also alleviate pressure within the kidney’s filtering units. Meanwhile, sodium-glucose cotransporter-2 (SGLT2) inhibitors, originally developed for diabetes management, are now acknowledged for their kidney-protective attributes, thereby becoming standard treatment options for many patients with DKD.

Study Methodology and Findings

The research analyzed health data from 31,031 adults diagnosed with T2D from 2016 to 2021, all of whom were receiving both RAS and SGLT2 inhibitors. Among these, 39.2% (12,172 patients) were also on DCCBs, while 60% (18,859 patients) were treated with other antihypertensive drugs. The participants were followed for an average of 3.5 years.

After adjusting for various demographic and clinical variables, findings indicated that the use of DCCBs correlated with a 33% increased risk of experiencing a major adverse kidney event, represented by a significant decline of 40% or greater in estimated glomerular filtration rate (eGFR) or progression to end-stage kidney disease necessitating dialysis or transplantation.

Dr. Timna Agur, the study’s lead author, noted, “DCCBs are widely used as second-line blood pressure treatments in patients with DKD. Our findings raise important questions about whether these medications are always the best option for patients already receiving modern kidney-protective therapies.”

Potential Mechanisms Behind the Findings

Researchers propose that the observed association may be tied to the way DCCBs influence blood flow in the kidneys. In the context of DKD, kidneys are already exposed to higher pressures and hyperfiltration, which stresses their filtering systems. The research suggests that DCCBs may dilate the incoming blood vessels more than those that carry blood away, potentially escalating pressure within the kidney and contributing to further damage.

“We initially thought the kidney-protective effects of SGLT2 inhibitors might counterbalance the potential harms associated with DCCBs,” Dr. Agur explained. “However, the increased risk of kidney disease progression appeared to persist even in this group.”

Call for Further Research

Given the observational nature of this study, the researchers caution that it doesn’t establish a direct cause-and-effect relationship between DCCBs and poorer kidney outcomes. However, they stress that the findings warrant further investigation, especially since these medications are commonly prescribed in DKD management.

Dr. Agur concluded, “Further prospective studies and randomized controlled trials are needed to confirm these observations and better define the safest blood pressure treatment strategies for patients with DKD. However, given how commonly these medications are prescribed, any increase in kidney risk could have important implications for large numbers of patients with DKD.”