Persistent early life growth patterns through age 12 years are associated with pulmonary outcomes

Objectives: CF infants diagnosed via newborn screening (NBS) and receiving high calorie and essential fatty acid diets are more likely to recover their birth weight z-score by 2 years ("responders"), and maintain better growth through age 12 years as shown in the Wisconsin RCTof NBS. This study examined whether responders had better pulmonary outcomes through age 12 years. Long term studies after NBS are rare but important. Methods: Seventy-six children with CF who were enrolled in the RCT were studied. Responders were further classified into R2 (did not maintain adequate growth beyond 2 years), R6 (maintained adequate growth through 6 years) or R12 (maintained adequate growth through 12 years). Non-responders were further classified into I6 (improved growth at 2-6 years) and N6 (no improvement at 2-6 years). Percent predicted FEV1 and Wisconsin chest radiographic (CXR) scores were used to assess pulmonary outcomes. Results: Overall, 47 (62%) were responders and 29 (38%) were non-responders. Of the responders, 47% were R12, 28% were R6, and 25% were R2. Of the non-responders, the majority (76%) were N6; only 7 (24%) had improved to I6. Responders had better pulmonary outcomes at age 6-12 years than non-responders. More specifically, R12 group had significantly higher FEV1 (99-103% predicted) at 6-12 years than the N6 group (85-90% predicted), p = 0.009, as well as better CXR scores, p = 0.003. R6 and R2 groups had ∼100% FEV1 at age 6 that declined to ∼90% at 12 years. Compared to N6, the I6 group had better FEV1 and CXR scores during ages 6-10 years that declined rapidly at age 11-12 years. At age 12 years, R12 had the best FEV1 and CXR scores, followed by R6 and the other groups. Conclusion: Early growth recovery in CF is critical, as growth patterns established in infancy tend to persist and catch-up growth after 2 years of age is difficult to achieve. The longer adequate growth maintained, the better pulmonary outcomes.