Plasma Lactate Response to a 12‐Min Walk Test Is a Poor Diagnostic Biomarker for Mitochondrial Myopathy
Source: PubMed Central Open Access, NCBI / U.S. National Library of Medicine
ABSTRACT Mitochondrial myopathy (MM) represents a group with a broad phenotypic spectrum which complicates the diagnostic process. This study investigated whether plasma lactate changes following a 12‐min walk test (12MWT) and 20‐min recovery could be a diagnostic screening tool for MM. Thirty patients with MM and 19 healthy controls (HC) participated. Total walking distance and heart rate during the test were measured, along with plasma lactate at rest, after exercise, and during recovery. For the latter, we calculated the area under the curve (AUC). The results were compared between groups. MM patients walked shorter (1082 m [994–1143] m vs. 1349 m [1149–1435],= 0.0005) and had higher resting lactate (1.7 ± 1.2 mmol/L vs. 0.9 ± 0.3 mmol/L,= 0.003). No significant difference in plasma lactate was observed after exercise. Plasma lactate AUC during recovery was similar between groups. Thus, the 12MWT is not a reliable screening tool for MM as changes in plasma lactate during exercise and recovery did not differentiate MM from HC. Key Points The 12‐min walk test is not a reliable diagnostic screening test for mitochondrial myopathy. jmd270112-li-0222 Plasma lactate responses to a 12‐min walk test did not reliably distinguish patients with mitochondrial myopathy from healthy controls. jmd270112-li-0333 Resting lactate was higher in patients with mitochondrial myopathy compared to healthy controls. jmd270112-li-0444 The 12‐min walk test may serve as a functional outcome measure,
Abstract
ABSTRACT Mitochondrial myopathy (MM) represents a group with a broad phenotypic spectrum which complicates the diagnostic process. This study investigated whether plasma lactate changes following a 12‐min walk test (12MWT) and 20‐min recovery could be a diagnostic screening tool for MM. Thirty patients with MM and 19 healthy controls (HC) participated. Total walking distance and heart rate during the test were measured, along with plasma lactate at rest, after exercise, and during recovery. For the latter, we calculated the area under the curve (AUC). The results were compared between groups. MM patients walked shorter (1082 m [994–1143] m vs. 1349 m [1149–1435],= 0.0005) and had higher resting lactate (1.7 ± 1.2 mmol/L vs. 0.9 ± 0.3 mmol/L,= 0.003). No significant difference in plasma lactate was observed after exercise. Plasma lactate AUC during recovery was similar between groups. Thus, the 12MWT is not a reliable screening tool for MM as changes in plasma lactate during exercise and recovery did not differentiate MM from HC. Key Points The 12‐min walk test is not a reliable diagnostic screening test for mitochondrial myopathy. jmd270112-li-0222 Plasma lactate responses to a 12‐min walk test did not reliably distinguish patients with mitochondrial myopathy from healthy controls. jmd270112-li-0333 Resting lactate was higher in patients with mitochondrial myopathy compared to healthy controls. jmd270112-li-0444 The 12‐min walk test may serve as a functional outcome measure, but further studies are needed to establish its validity and reliability. jmd270112-li-0777 bullet jmd270112-list-0111 highlights jmd270112-abs-5002