Pulmonary function correlates in the prediction of long-term weight gain in cystic fibrosis patients with gastrostomy tube feedings.
BACKGROUND
Gastrostomy tube feedings have a positive effect on nutritional status and are currently recommended for cystic fibrosis patients who fall below 85% ideal weight for height. However, the impact of pulmonary function at the time of gastrostomy tube placement on long-term nutritional status has not been ascertained.


METHODS
We retrospectively evaluated whether nutrition status and/or pulmonary function at gastrostomy tube placement surgery were predictive of subsequent long-term (> or =2 yrs) weight velocity. We identified 21 cystic fibrosis patients (12 male), ages 5-18 years at gastrostomy tube insertion. Patients were divided into two groups according to their weight gain response after 2 years on gastrostomy tube feeding. Responders were defined as having a positive change in weight/age z-score (deltaWAZpost) at 2 years follow-up compared to the 2 year period preceding gastrostomy tube insertion (deltaWAZpre). Nonresponders were defined as having a negative WAZpost.


RESULTS
Responders had significantly better FEV1 at surgery (61 +/- 26 [SE] vs. 24 +/- 3 %pred.; p < 0.05). In responders, epsilonWAZpre was -0.37 +/- 0.08 and was -0.46 +/- 0.07 in nonresponders (p-NS). In contrast, AWAZpost was 0.92 +/- 0.11 in responders and -0.40 +/- 0.07 in nonresponders (p < 0.001). Furthermore, a significant correlation between weight/age z-score change and pulmonary function was found when FEV1 <40% predicted (r = 0.88; p < 0.004) whereas no significant correlation was present when FEV1 > or =40% predicted.


CONCLUSIONS
We conclude that the long-term nutritional benefit of gastrostomy tube placement is critically dependent on pre-surgical pulmonary function. Our findings suggest that gastrostomy tube insertion in malnourished cystic fibrosis patients should be considered an early intervention rather than one of last resort.
Department of Pediatrics, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA.
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D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000503:physiopathology* / Q000628:therapy; D004750:Enteral Nutrition; D005260:Female; D005541:Forced Expiratory Volume; D005774:Gastrostomy; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D009752:Nutritional Status; D012189:Retrospective Studies; D015430:Weight Gain