Prognostic prediction by hypermetabolism varies depending on the nutritional status in early amyotrophic lateral sclerosis

Abstract

To examine whether hypermetabolism could predict the prognosis of early amyotrophic lateral sclerosis (ALS) patients with differing nutritional profiles. This single-center, retrospective study examined the prognosis of ALS patients with hypermetabolism in relation to their nutritional status at hospitalization. The metabolic state was estimated by the ratio of measured resting energy expenditure (mREE) to lean soft tissue mass (LSTM) (mREE/LSTM), wherein patients with ratios ≥ 38 were defined as hypermetabolic. Malnutrition was defined as %ideal body weight < 0.9. Forty-eight patients were enrolled in this study. The hypermetabolic group had shorter survival in the normal-weight group but more prolonged survival in the malnutrition group. Multiplication of nutritional and metabolic factors, such as [(body mass index (BMI) − 19.8) × (mREE/LSTM − 38)], designated as BMI-muscle metabolism index (BMM index), successfully predicted the prognosis in the group with a high BMM index (≥ 1), which showed shorter survival and a faster rate of weight loss and functional decline. Multivariate analysis using the Cox model showed high BMM index was an independent poor prognostic factor (hazard ratio: 4.05; p = 0.025). Prognostic prediction by hypermetabolism varies depending on the nutritional status in ALS, and the BMM index is a consistent prognostic factor.

Investigation of the prognostic predictive value of serum lipid profiles in amyotrophic lateral sclerosis: roles of sex and hypermetabolism

“…This discrepancy led us to formulate the BMI-muscle metabolism index (BMM index), defined as (BMI − 19.8) × (mREE/LSTM − 38); a high BMM index is an independent factor for poor prognosis. Furthermore, we showed that low body fat percentage was associated with poor prognosis 8 , as reported elsewhere 9 . These findings may indicate that the prognostic value of hypermetabolism depends on nutritional status and that lipid metabolism plays a crucial role in determining the prognosis of ALS.…”

“…), and LSTM (kg) was measured through a bioelectrical impedance analysis with a body composition analyzer (InBody S10; InBody, Tokyo, Japan). We used indirect calorimetry as reported previously 8 , 24 . In this study, as an indicator of the metabolic status, we used mREE/LSTM, which approximately reflects the skeletal metabolic status during the resting state; additionally, the relationship of this indicator with hypermetabolism was described in previous studies 4 , 25 .…”

“…In this study, as an indicator of the metabolic status, we used mREE/LSTM, which approximately reflects the skeletal metabolic status during the resting state; additionally, the relationship of this indicator with hypermetabolism was described in previous studies 4 , 25 . We defined hypermetabolism as mREE/LSTM ≥ 38, according to our previous report 8 . The ratio of mREE to calculated REE (cREE) obtained using the Harris-Benedict equation 26 is universally used to estimate metabolism 4 – 6 , 26 .…”

“…However, cREE might be overestimated in Japanese people 27 , and thus, we used our own formula in order to exclude the effects caused by population-based differences. The BMM index was used as a prognosis prediction formula, defined as (BMI − 19.8) × (mREE/LSTM − 38), as we have reported previously 8 .…”

“…On the other hand, Steyn et al demonstrated that increased fatty acid oxidation enhances resting energy expenditure, which leads to slower progression in superoxide dismutase (SOD) mice 7 . We previously showed that patients with hypermetabolism, defined as the ratio of measured resting energy expenditure (mREE) to lean soft tissue mass (LSTM) (mREE/LSTM) ≥ 38, exhibited significantly shorter survival than patients with normal metabolism only when their body mass index (BMI) was ≥ 19.8 8 . Contrarily, patients with hypermetabolism and BMI < 19.8 exhibited a clear trend of prolonged survival.…”