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Maximal work capacity in relation to nutritional status in children with cystic fibrosis
V A Gulmans1, K de Meer, H J Brackel
1Dept of Paediatric Physiotherapy, Wilhelmina Children's Hospital, University Hospital for Children and Youth, Utrecht, The Netherlands.
Insights
Maximal workload (W'max) in children with cystic fibrosis is a practical measure for exercise tolerance in non-specialized centers. Correcting for fat-free mass improves W'max accuracy, aiding patient follow-up.
Area of Science:
- Pediatric Pulmonology
- Exercise Physiology
- Clinical Measurement
Background:
- Objective exercise tolerance parameters are crucial for monitoring children with cystic fibrosis (CF).
- Current methods may require specialized centers, limiting accessibility.
- Maximal workload (W'max) is a potential alternative to maximal oxygen consumption (V'O2,max).
Purpose of the Study:
- To investigate the utility of W'max in pediatric CF patients.
- To assess W'max in relation to body weight and fat-free mass.
- To compare W'max with V'O2,max for exercise tolerance assessment in non-specialized settings.
Main Methods:
- 14 pediatric patients with mild-to-moderate CF underwent incremental maximal exercise testing on a bicycle ergometer.
- Measurements included W'max, V'O2,max, body weight, and fat-free mass.
- Data were analyzed using standard deviation scores and correlations.
Main Results:
- W'max and V'O2,max showed a significant positive correlation (r = 0.91, p < 0.001).
- W'max and V'O2,max, when corrected per kilogram body weight, were higher than uncorrected values.
- Standardized V'O2,max was consistently higher than standardized W'max, even after corrections.
- Maximal workload per kilogram fat-free mass effectively corrects for nutritional status variations.
Conclusions:
- Maximal workload (W'max) is a valuable, easily measurable parameter for assessing exercise tolerance in pediatric CF patients.
- Correcting W'max for fat-free mass aids in accounting for diminished nutritional status.
- W'max, adjusted for fat-free mass, can be reliably used for follow-up in non-specialized clinical settings.
Abstract:
In children with cystic fibrosis, objective parameters of exercise tolerance are needed which are easy to measure in nonspecialized centres. We investigated maximal workload (W'max) in children with cystic fibrosis in relation to body weight and fat-free mass, and compared this with results for maximal oxygen consumption (V'O2,max). Fourteen patients with cystic fibrosis performed an incremental maximal exercise test on a bicycle ergometer. W'max, V'O2,max, body weight and fat-free mass were measured. W'max and V'O2,max were significantly correlated (r = 0.91; p < 0.001). Using standard deviation scores in relation to reference values, W'max and V'O2,max per kilogram body weight were significantly higher than uncorrected W'max and V'O2,max (mean difference (95% CI) 0.63 (0.24-1.01) and 0.91 (0.32-1.49) SD units, respectively). There was no such difference after correction for fat-free mass. Standardized V'O2,max was significantly higher than standardized W'max (mean difference (95% CI): 1.59 (1.14-2.04)), also after correction for body weight and fat-free mass. In children with mild-to-moderate cystic fibrosis, maximal workload per kilogram fat-free mass, but not per kilogram body weight, is a useful parameter to correct for diminished nutritional status. In these patients, maximal workload is consistently lower than maximal oxygen consumption. Taking into account this difference, maximal workload and maximal workload per kilogram fat-free mass can be used for follow-up of paediatric patients with cystic fibrosis in nonspecialized settings.