LDL Is Under Control—So Why Is Heart Risk Still High? Solving the Lipoprotein(a) Puzzle

For many people with diabetes, lowering LDL cholesterol is a major part of preventing heart attack and stroke. Yet an important clinical puzzle remains. Why do some patients experience cardiovascular events even after LDL reaches recommended targets? Growing evidence points toward lipoprotein(a), or Lp(a), as one possible piece of that puzzle. As a result, screening for lipoprotein(a) in people with diabetes is becoming increasingly relevant when clinicians evaluate residual cardiovascular risk.

Unlike LDL cholesterol, Lp(a) levels are largely determined by genetics and tend to remain relatively stable throughout life. Therefore, a patient may follow a healthy lifestyle, take appropriate lipid-lowering therapy, and achieve an excellent LDL level while still carrying substantial inherited cardiovascular risk.

Table of Contents

• Why LDL control does not eliminate cardiovascular risk
• Why Lp(a) testing matters in diabetes
• Emerging treatments targeting lipoprotein(a)
• Could Lp(a) testing become routine diabetes care?
• Conclusion
• Frequently Asked Questions

Why LDL Control May Not Eliminate Cardiovascular Risk

Diabetes itself increases cardiovascular risk, making aggressive management of LDL cholesterol, blood pressure, glucose, kidney disease, smoking, and other risk factors essential. However, LDL-C does not tell the entire cardiovascular story.

Lipoprotein(a) resembles an LDL particle but carries an additional protein called apolipoprotein(a). Elevated levels have been independently associated with atherosclerotic cardiovascular disease, including heart attack and stroke.

Importantly, the 2026 ACC/AHA dyslipidemia guideline expanded attention beyond conventional LDL-C. The guideline recommends measuring Lp(a) at least once in adulthood. It identifies levels of at least 125 nmol/L, or 50 mg/dL, as a risk-enhancing factor. Levels around 250 nmol/L, or 100 mg/dL, are associated with an estimated twofold higher ASCVD risk.

This matters in diabetes because patients may already carry several overlapping cardiovascular risk factors. Consequently, an elevated Lp(a) level could help explain why someone’s cardiovascular risk appears greater than their LDL-C result suggests.

Another useful marker is apolipoprotein B, or apoB. Current guidance notes that apoB testing may help identify residual lipoprotein-related risk, particularly in people with diabetes, elevated triglycerides, or very low achieved LDL-C.

For clinicians, LDL-C remains central to risk management, but it may not capture every source of lipid-related cardiovascular risk.

Why Lp(a) Testing Matters in Diabetes

Lp(a) testing may be especially useful in people with diabetes whose conventional cardiovascular risk factors appear well managed. A seemingly favorable standard lipid panel does not necessarily reveal every inherited source of cardiovascular risk.

Current ACC/AHA guidance recommends at least one Lp(a) measurement for adults. Because genetics largely determine Lp(a), lifestyle changes generally have limited effects on the level itself. For most patients, this also means repeated testing is usually unnecessary unless a clinical situation or treatment changes.

Testing may be particularly informative when there is premature cardiovascular disease, a strong family history, recurrent cardiovascular events despite treatment, or cardiovascular risk that seems unexpectedly high.

Moreover, knowing that Lp(a) is elevated can change the broader risk conversation even before a dedicated Lp(a)-lowering medication is available. Clinicians can ensure that modifiable risks receive careful attention, including LDL-C, blood pressure, glycemic management, smoking, physical activity, and weight when appropriate.

The 2026 dyslipidemia guideline specifically states that elevated Lp(a) should prompt more intensive LDL-C lowering and management of other cardiovascular risk factors. For people with diabetes, that message fits naturally with today’s broader approach to cardiovascular, kidney, and metabolic risk reduction.

Still, an elevated Lp(a) result should not be viewed in isolation. Instead, clinicians should interpret it alongside the patient’s ASCVD history, LDL-C, apoB when appropriate, kidney function, blood pressure, glycemic status, and other risk indicators.

For additional background, Diabetes in Control has previously reviewed the relationship between LDL-C levels and cardiovascular risk.

Emerging Therapies Could Change the Lp(a) Conversation

Perhaps the biggest reason for growing interest in Lp(a) testing is the rapidly developing pipeline of therapies designed to lower this inherited risk factor.

Several investigational drugs are designed specifically to reduce production of apolipoprotein(a). These include RNA-based approaches such as pelacarsen, olpasiran, and lepodisiran. Another investigational agent, muvalaplin, takes an oral approach to reducing Lp(a).

Early and mid-stage studies have produced substantial reductions in Lp(a). However, lowering a laboratory value is not enough. The critical question is whether lowering Lp(a) actually prevents heart attacks, strokes, cardiovascular deaths, and other major events.

That is why cardiovascular outcome trials are so important.

Pelacarsen is being evaluated in the phase 3 Lp(a)HORIZON cardiovascular outcomes trial. As of August 2026, definitive outcome results have not yet been reported. Meanwhile, the phase 3 OCEAN(a)-Outcomes trial is studying olpasiran in patients with established ASCVD and elevated Lp(a). Other late-stage programs are also evaluating lepodisiran and muvalaplin.

Therefore, clinicians should avoid assuming that dramatic Lp(a) reductions automatically translate into fewer cardiovascular events. Until outcome trials answer that question, these agents remain investigational rather than routine treatment.

Still, the pipeline represents a major shift. Historically, discovering very high Lp(a) offered relatively few options directed specifically at the biomarker. Today, identifying elevated Lp(a) may help clinicians better characterize risk while preparing for a future in which targeted treatment could become possible.

Could Lp(a) Testing Become Routine Diabetes Care?

In one important sense, the conversation has already moved forward. The 2026 ACC/AHA dyslipidemia guideline recommends Lp(a) measurement at least once for every adult, not only those with diabetes.

Meanwhile, the European approach is moving in a similar direction. The 2025 ESC/EAS focused dyslipidemia update recommends considering Lp(a) measurement at least once during adulthood to refine cardiovascular risk assessment.

For diabetes clinicians, this creates a practical opportunity. Lp(a) can potentially be added to cardiovascular risk assessment without turning it into another frequently repeated laboratory test.

However, routine measurement does not mean every elevated result requires a new medication. Instead, the result can help reveal inherited risk that may otherwise remain invisible.

That distinction is important. For people with diabetes, Lp(a) testing should complement proven cardiovascular prevention strategies, not replace them. Statins and other indicated LDL-lowering therapies remain central, while blood pressure control, smoking cessation, physical activity, nutrition, and appropriate glucose-lowering therapies with cardiovascular benefit remain essential.

As outcome data from dedicated Lp(a)-lowering therapies emerge, the value of knowing a patient’s Lp(a) level may become even greater.

Conclusion

Achieving a low LDL-C remains one of the most important cardiovascular prevention strategies for people with diabetes. Nevertheless, an LDL value at goal does not guarantee that cardiovascular risk has disappeared.

Elevated Lp(a) may help explain part of this residual risk because it represents a largely inherited cardiovascular risk factor that conventional lipid testing can miss.

Current guidelines have already moved toward broader testing, with the 2026 ACC/AHA guideline recommending at least one Lp(a) measurement in adulthood. Therefore, measuring Lp(a) in patients with diabetes may help identify people whose cardiovascular risk warrants closer attention and more intensive risk-factor management.

The next major question is therapeutic. If ongoing outcome trials demonstrate that specifically lowering Lp(a) prevents cardiovascular events, Lp(a) could move from an important risk marker to an actionable treatment target.

Frequently Asked Questions

What is lipoprotein(a)?

Lipoprotein(a), or Lp(a), is a cholesterol-carrying particle similar to LDL that includes an additional protein called apolipoprotein(a). Its concentration is largely determined by genetics, and elevated levels are associated with increased cardiovascular risk.

Why consider lipoprotein(a) screening in diabetes?

People with diabetes already face increased cardiovascular risk. Measuring Lp(a) can identify additional inherited risk that may not be apparent from LDL-C alone, particularly when cardiovascular disease occurs despite good conventional risk-factor management.

What level of Lp(a) is considered high?

The 2026 ACC/AHA dyslipidemia guideline considers Lp(a) of at least 125 nmol/L, or 50 mg/dL, a risk-enhancing factor. Cardiovascular risk rises progressively as Lp(a) increases.

Can diet and exercise lower lipoprotein(a)?

Healthy lifestyle habits remain essential for overall cardiovascular health, but they generally have little effect on genetically determined Lp(a) concentrations. Therefore, management currently focuses heavily on controlling other modifiable cardiovascular risks.

Are there medications specifically approved to lower Lp(a)?

Several highly targeted Lp(a)-lowering therapies are in late-stage clinical development, but cardiovascular outcome evidence remains the key missing piece. Clinicians should follow emerging phase 3 results before considering these investigational therapies part of routine care.

This content is not medical advice. For any health issues, always consult a healthcare professional. In an emergency, call 911 or your local emergency services.