Nutrition support in cystic fibrosis

Nutrition in the pediatric double lung transplant patient with cystic fibrosis

Cystic fibrosis (CF) is the most common lethal genetic disease in the white population. The pulmonary infections and pancreatic insufficiency make CF a medically challenging disease. Although the importance of nutrition in the CF patient is known, approximately 50% of CF patients are in less than the 10th percentile for weight and height as reported by the 1991 CF Foundation Registry of 114 CF Centers in the United States. This paper addresses the nutritional status of 10 pediatric CF patients who underwent double lung transplant at Children's Hospital of Pittsburgh between August 1991 and May 1993. Patients who survived beyond 1 year gained a significant amount of weight sooner after transplant than those who survived less than 1 year. Gastrostomy tube feedings were more effective than oral intake for weight gain after transplant. CF patients with pancreatic insufficiency have more difficulty with adjustment of doses of immunosuppressive agents for reasons that are not clearly understood.

Resting energy expenditures measured by indirect calorimetry are higher in preadolescent children with cystic fibrosis than expenditures calculated from prediction equations

OBJECTIVE

This study compared measured resting energy expenditures to resting energy expenditures calculated using Harris-Benedict equations (HBEs) and the Cystic Fibrosis Consensus Committee equations (CFCCEs).

DESIGN

We studied 31 preadolescent boys and girls with cystic fibrosis who ranged in age from 3.25 to 12.75 years old. The patients were afebrile and not in pulmonary distress. Measured resting energy expenditures were determined using a portable metabolic measurement cart with fully automated calibration and data management. The measured resting energy expenditures obtained were compared with values obtained using HBEs and CFCCEs.

RESULTS

For each patient, the measured resting energy expenditure value was above the predicted resting energy expenditure values derived from HBEs (P < or = .0001) and CFCCEs (P < or = .01).

APPLICATIONS

The HBEs and the CFCCEs underestimated the energy expenditures of the study population by 13% and 8%, respectively. These findings support the usefulness of the measurement of energy expenditures in determining the energy needs of preadolescent patients with cystic fibrosis. In clinical practice, the resting energy expenditures would be multiplied by activity coefficients to determine the total daily energy expenditures of this population.

Cost-benefit analysis of a national screening programme for cystic fibrosis in an Israeli population

The recently acquired ability to identify 97% of CF carriers in an Israeli Ashkenazi population, prompts an evaluation of a nationwide screening programme. In 1993, the programme would first screen and counsel 9,261 parents, then 396 spouses of carrier parents and finally screen 16.5 fetuses where both parents are carriers. Assuming 92% of screened parents choose abortion of fetus screened positive, 2.33 cases of CF will be prevented in 1993 at a direct cost of $781,000. The $326,000 direct costs of preventing a CF case, exceed the lifetime excess direct costs per case of $297,000. However, benefits of screening also accrue to subsequent pregnancies, resulting in a direct benefit ($14.45 million) to cost ($10.39 million) ratio of 1.39/1 for the period 1993-2032. When benefits and costs resulting from mortality changes, work absences and transport costs are included, the benefit ($15.95 million) to cost ($13.88 million) ratio falls to 1.15/1. Benefit-cost ratios are lower for other ethnic groups in Israel, due to lower carrier rates and lower mutation detection abilities. A CF screening programme will increase the freedom of individuals choice, but should be carried out carefully in order to minimize stigmatization and even discrimination against CF carriers.

Feeding practices and nutrition recommendations for infants with cystic fibrosis

Cystic fibrosis (CF) is an autosomal recessive disease characterized clinically by recurrent respiratory tract infections and malabsorption caused by pancreatic insufficiency. Typically diagnosed during infancy or childhood, CF impairs weight gain and growth, increases susceptibility to infection, and decreases longevity. Until recently, no guidelines for infant feedings were available. A consensus report prepared through the Cystic Fibrosis Foundation summarizes guidelines for the optimal nutrition management of patients with CF. This study identified current feeding practices and nutrition recommendations of dietitians who treat infants with CF and compared them with the recommendations of the consensus report. A survey was developed and sent to dietitians (n = 130) who work in accredited cystic fibrosis centers. Eighty-six dietitians (66%) responded after two mailings, and 75 usable surveys were analyzed. The survey investigated practitioners' recommendations for infant formulas, energy intake, nutritional supplements, and pancreatic enzyme supplementation. Protein hydrolysate infant formulas were recommended by most respondents (69%). Energy intake greater than 130% of the Recommended Dietary Allowances (RDAs) was recommended for well-nourished infants with CF and greater than 140% of the RDAs for malnourished infants with CF at 1 year of age. Formula additives, including fat and carbohydrate modules, were used by all respondents and were frequently added to infant foods to increase caloric density. Enteric coated pancreatic enzymes were used by the majority (76%) of dietitians. These findings indicate that most dietitians follow the nutrition guidelines established by the Cystic Fibrosis Foundation consensus report for goals for energy and protein intake, use of nutritional supplements, and replacement of pancreatic enzymes in infants with CF.

Gastrointestinal dysfunction and its effects on nutrition in CF

Prevention of malnutrition, a consequence of elevated energy requirements, increased losses and low caloric intake, is one of the main goals in the treatment of cystic fibrosis. Caloric stool losses, catch-up growth and an elevated energy expenditure, even in the absence of overt lung disease and malabsorption, have led to recommendations for a caloric intake of 120-150% of the recommended daily allowances. A high energy intake with a fat content of at least 40 calorie % and adequate pancreatic supplementation has shown to improve growth and median age of survival. As a rational treatment of the fundamental disturbance in cystic fibrosis, a decrease in chloride permeability across epithelia, is not yet available, treatment should be concentrated on adequate nutritional support in combination with optimal correction of those gastrointestinal abnormalities including faecal bile acid loss, small intestinal abnormalities, pancreatic insufficiency, hormonal abnormalities and disturbances in gastrointestinal motility, which may aggravate maldigestion and malabsorption.