MELAS Mortality: Why Levetiracetam Alone Isn’t the Whole Story

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MELAS Mortality: Why Levetiracetam Alone Isn’t the Whole Story

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is a rare, multisystem disorder where epilepsy often complicates care. For patients and doctors, finding treatments that improve survival is a critical goal—but a recent study linking the antiepileptic drug levetiracetam (LEV) to lower mortality has sparked important questions about what really drives outcomes.

In 2019, researchers led by Zhang et al. published a retrospective study of 102 MELAS patients with epilepsy, followed for a median of 4 years. They found that those taking LEV had better outcomes compared to patients on other antiepileptic drugs (AEDs). The study offered hope that LEV might be a key to longer survival—but a subsequent critique argues the conclusions need careful scrutiny.

Josef Finsterer, a researcher at Krankenanstalt Rudolfstiftung and the Messerli Institute at the Veterinary University of Vienna, highlights major limitations in the study’s design and missing data that suggest LEV alone isn’t the sole driver of lower mortality. His comment, published in the Chinese Medical Journal, breaks down why MELAS outcomes depend on far more than just one drug.

The Problem with Retrospective Design

First, the study’s retrospective approach—relying on existing medical records and telephone interviews—poses significant challenges. Retrospective research depends on the quality of past documentation, which can vary widely between patients. Telephone follow-ups, while convenient, also can’t accurately assess physical abilities—a critical factor for MELAS patients, since the disease often causes muscle weakness (myopathy) that impacts daily life and survival.

Worse, the design doesn’t track whether patients actually took their medication as prescribed. Adherence to AEDs is vital for controlling seizures, which are a major source of risk in MELAS. Without this data, it’s hard to know if LEV itself (or consistent use of any AED) drove results.

MELAS Is a Multisystem Disease—Comorbidities Matter

MELAS doesn’t just affect the brain; it damages mitochondria (the cell’s energy factories) throughout the body. Survival often hinges on factors like:

  • Myopathy severity: How much muscle weakness limits movement and organ function.
  • Stroke-like episodes (SLEs): The frequency and severity of these “stroke-like” events (a hallmark of MELAS) directly impact brain health.
  • Psychiatric conditions: Depression, anxiety, or psychosis are common in MELAS and require separate treatment—yet their effect on outcomes was unmeasured.
  • Cardiac disease: Cardiomyopathy, heart failure, or dangerous heart rhythms can cause sudden death in MELAS patients.

Zhang et al.’s study didn’t report how many patients had these comorbidities. Finsterer argues that without this data, it’s impossible to separate LEV’s effects from the broader impact of the disease itself.

Toxic AEDs Confound Results

Another critical issue: the LEV and non-LEV groups used very different numbers of mitochondrial-toxic AEDs—drugs like carbamazepine (CBZ), valproic acid (VPA), phenobarbital, and phenytoin that damage mitochondria (the same structures already harmed by MELAS).

In the LEV group, only 10 patients took these toxic drugs. In the non-LEV group? 41 patients—including 4 on both CBZ and VPA, a particularly risky combination. Finsterer notes that this gap suggests the lower use of toxic drugs in the LEV group, not LEV itself, might explain better outcomes.

Missing Seizure Data Leaves Big Gaps

Seizures are a core challenge in MELAS, but the study didn’t report:

  • How well seizures were controlled: Better seizure control (regardless of AED) would logically improve survival.
  • Seizure type and frequency: Severe seizures like generalized tonic-clonic seizures or status epilepticus (prolonged seizures) are far riskier than milder types.

If LEV patients had fewer severe seizures, that could explain better survival—but without this data, it’s impossible to rule out seizure severity as a confounder.

The Bottom Line: LEV Isn’t a Silver Bullet

Finsterer’s critique doesn’t dismiss Zhang et al.’s work—it calls for a more complete picture. To truly understand MELAS mortality, researchers need to analyze:

  • Seizure frequency and type
  • Quality of seizure control
  • Comorbidities like myopathy, cardiac disease, and psychiatric conditions
  • Use of mitochondrial-toxic AEDs

As Finsterer puts it: “It is not permissible to draw the conclusion that administration of LEV was associated with a lower mortality in MELAS.”

For patients and clinicians, the takeaway is clear: MELAS requires personalized care that accounts for the whole patient—not just their epilepsy medication. While LEV may be a useful tool, survival depends on managing the full range of the disease’s effects.

Zhang Z, Zhao DH, Zhao XT, Zhang X, Xiong H, Bao XH, et al. Levetiracetam administration is correlated with lower mortality in patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes: a retrospective study. Chin Med J 2019;132:269–274.

Finsterer J. Mortality in mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes does not depend on levetirazetam alone. Chin Med J 2019;132:1512.

doi.org/10.1097/CM9.0000000000000163

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