Being underweight when they start supported feeding puts patients with amyotrophic lateral sclerosis (ALS) at risk for poor outcomes at later stages of the disease, an Italian study has found.
The study, “Nutritional prognostic factors for survival in amyotrophic lateral sclerosis patients undergone percutaneous endoscopic gastrostomy placement,” was published in the journal Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration.
ALS is characterized by degeneration of nerve cells, resulting in muscular and motor impairments in the early stages, and difficulties in speaking, swallowing, and breathing as the disease progresses.
While respiratory failure is the most common leading cause of death in this population, nutritional status is an important contributing factor to overall survival.
During the disease’s natural course, patients often experience body composition changes, such as reduced body mass index (BMI) and fat-free mass, and changes in tissue permeability, which is mostly due to alterations in eating patterns and to difficulties in swallowing (dysphagia).
To prevent malnutrition, patients may need percutaneous endoscopic gastrostomy (PEG), a procedure in which a feeding tube is placed directly into the stomach. The tube helps to deliver nutrients and aid in their absorption in patients who have difficulty eating and swallowing.
The team reviewed the clinical records of 47 ALS patients who underwent gastric tube placement between 2006 and 2015 at the university hospital.
At the time of tube implantation, all patients had moderate to severe symptoms, were taking riluzole (sold as Rilutek by Sanofi, and as Tiglutik by ITF Pharma, a subsidiary of Italfarmaco), and had experienced a weight loss of at least 10% within the previous six months.
According to BMI, 13 patients were considered underweight, 26 had normal weight, and eight were overweight or obese. Despite their weight differences, all patients showed similar cholesterol levels.
Analysis of body composition confirmed that underweight participants had significantly lower body cell mass index (BCMI) and fat mass index when compared with the overweight group. Tissue reactivity and resistance (phase angle, as determined by bioelectrical impedance analysis) showed significant differences between the three groups, with underweight patients showing lower values.
Overall, the team found that underweight patients had 3.37-fold higher risk of death as compared with normal weight patients, after adjusting for age at symptom onset. Overweight/obese patients were found to have a 2.27-fold increased risk of death as compared to normal weight participants, but this difference was not considered statistically significant.
Supported by these findings, the team suggests that a BMI value below 18.5 kg/m2 “is a nutritional prognostic factor” that is useful to assess risk at late stages of the disease after PEG implantation.
“Older age at the onset of the symptoms is an additional negative prognostic factor,” the researchers said.
In addition, “low BCMI and phase angle characterizing underweight patients support the role of BMI as a predictor of survival,” they said.