Optimal Estimate for Energy Requirements in Adult Patients With the m.3243A>G Mutation in Mitochondrial DNA

AIM: We aimed to identify the optimal method to estimate total energy expenditure (TEE) in mitochondrial disease (MD) patients. METHODS: Resting energy expenditure (REE) was measured in MD patients carrying the m3243A>G mutation using indirect calorimetry (IC) and compared with results of 21 predictive equations (PEs) for REE and with REE‐IC measurements in healthy controls. Physical activity level (PAL) was measured using accelerometery (SenseWear) and compared with a fixed average PAL (1.4) as well as patients’ self‐estimated activity levels. TEE was calculated as REE‐IC × PAL SenseWear and compared with usual care and energy recommendations for healthy adults. RESULTS: Thirty‐eight MD patients (age: 48 ± 13 years; body mass index 24 ± 4 kg/m(2); male 20%) and 25 matched controls were included. The accuracy of most PEs was between 63% and 76%. The difference in REE‐IC in healthy controls (1532 ± 182 kcal) and MD patients (1430 ± 221) was borderline not significant (P = .052). Patients’ estimations PAL were 18%–34% accurate at the individual level. The fixed activity factor was 53% accurate. Patients overestimated their PAL. Usual care predicted TEE accurately in only 32% of patients. CONCLUSION: TEE is lower in these MD patients than the recommendations for healthy adults because of their lower physical activity. In MD patients, 6 PEs for REE provide a reliable alternative for IC, with an accuracy of 71%–76%. As PAL is highly variable and not reliably estimated by patients, measurement of PAL using accelerometery is recommended in this population.