This paper was published in the VII Brazilian Congress on Cystic Fibrosis proceedings. The event was held from May 1 to 4, 2019, in Campinas, SP, Brazil, organized by the Cystic Fibrosis Group at Instituto do Coração – HCFMUSP.
Cystic fibrosis is a genetic disease caused by a mutation in the cystic fibrosis transmembrane receptor (CFTR) gene, which leads to changes in sodium and chloride ion transport. These changes lead to the production of thick secretions and mucus by the pancreas, intestine, and lungs. In the pancreas, secretions obstruct the intrapancreatic ducts, leading to pancreatic insufficiency. In the intestine, secretions affect nutrient absorption. In the lungs, mucus remains stagnant in the airways, favoring infections and inflammation, and interfering with gas exchange, with decreased delivery of oxygen to tissues and organs.
Malabsorption, associated with the inflammatory and infectious process, increases energy and protein needs, which are not met. The inflammatory and infectious process also reduces appetite, causing the patient to reduce food consumption. Thus, there is an imbalance between energy expenditure and food intake, leading to malnutrition.
This imbalance causes the body to use muscle to make up for the lack of energy, which is named protein catabolism. The amount of muscle is then reduced, and this compromises its ability to generate strength, especially during exertion, and affects multiple aspects of quality of life.
The Cystic Fibrosis Group at Instituto do Coração – HCFMUSP conducted a study with the aim of investigating the association of nutritional status with muscle strength in patients with cystic fibrosis. The study included 51 patients of both genders and over 18 years of age. Nutritional status was assessed with calculations of body mass index (BMI) and body composition – arm circumference (AC), triceps skinfold (TSF), and arm muscle circumference (AMC). Muscle strength was assessed with a dynamometer for measurement of grip strength of the dominant limb.
The mean age of patients was 27 years. Most patients were female (61%) and right-handed (96%). In the BMI assessment, 72% of patients were healthy weight, 18% were overweight, and 10% were underweight. In the AC assessment, 73% of patients had a compromised nutritional status, while 100% were malnourished in the AMC assessment. Regarding TSF, 67% of patients had an adequate amount of body fat and 20% had some degree of fat deficiency. Muscle strength was reduced in 75% of participants, and this was prevalent in women (58%).
These data show that, according to the BMI measurement, most patients are healthy weight, but the assessment of body composition (AC and AMC) indicates malnutrition, with a positive association with muscle strength. This group of patients also showed fat deficiency.
Few studies have evaluated nutritional status and muscle strength in patients with cystic fibrosis. However, recent publications agree that BMI only establishes a ratio of weight to height and does not describe the composition of lean mass and fat mass; however, because it is an easy, quick, low-cost method, BMI has been widely used.
Nonetheless, this study indicates that BMI cannot be the only method for assessing nutritional status in patients with cystic fibrosis. Patients with cystic fibrosis have nutritional depletion compromising the muscle status as measured by other parameters. Therefore, health professionals should be attentive when evaluating these patients.
In conclusion, BMI should not be the only parameter for assessing nutritional status, and anthropometric measurements of AC, TSF, and AMC are of fundamental importance for determining body composition. Grip strength is an excellent parameter to be incorporated into nutritional assessment.
Authors: Maria Ignez Zanetti Feltrim, Anna Carolina Di Creddo Alves, Fabio Isaías Rodrigues, Gabriela Angelo Teles, Rodrigo Abensur Athanazio, Rafael Stelmach – Instituto do Coração – HCFMUSP, São Paulo, SP, Brazil.
Note: The information contained herein is strictly educational in nature. Under no circumstances do they intend to replace medical appointments, examinations, and/or treatments. If you have any questions, please contact your physician.
Source: Brazilian Institute for Cystic Fibrosis Awareness – Unidos Pela Vida – IUPV Communication Advisory – www.unidospelavida.org.br
Accessed on November 24, 2015.
17/01/2020