Relationship between nutritional status and maximum inspiratory and expiratory pressures in cystic fibrosis.

BACKGROUND Malnutrition might be expected to result in reduced maximum respiratory pressure and pulmonary function in cystic fibrosis (CF). OBJECTIVE To assess the relationship between nutritional status and maximum respiratory pressures in patients with CF. METHODS We performed a prospective cross-sectional study of patients > or = 16 y old attending the Adult CF Program at Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil. Maximum inspiratory and expiratory pressures (MIP and MEP) were measured as indexes of respiratory muscle strength. Nutritional status was assessed via body mass index (BMI), triceps-skin-fold thickness and mid-upper-arm-muscle circumference. The patients were classified into 2 groups according to BMI: normal and nutritional depletion. Spirometry was performed by all subjects. RESULTS The study included 39 patients (23 female/16 male) with a mean age of 23.7 +/- 6.4 y. The mean +/- SD percent-of-predicted MIP was 88.0 +/- 28.5% in the normal group and 83.2 +/- 27.3% in the nutritional-depletion group (p = 0.605). The mean +/- SD percent-of-predicted MEP was 84.7 +/- 24.2% in the normal group and 86.1 +/- 26.3% in the nutritional-depletion group (p = 0.874). The mean +/- SD percent-of-predicted forced expiratory volume in the first second (FEV(1)) was 55.2 +/- 27.5% in the normal group and 50.0 +/- 25.6% in the nutritional-depletion group (p = 0.568). MEP and MIP had no significant correlation to BMI or FEV(1). CONCLUSION MEP and MIP had no significant relationship to nutritional status, clinical score, chest radiograph score, and pulmonary function.