Lung function trajectories in very preterm infants

<bold>Background:</bold> BPD is an evolving disease that can be detected early during hospitalization and not only at 36 weeks’ post-menstrual age (PMA). Identification of specific lung function trajectories would be important to characterize the disease and possibly guide treatment. <bold>Methods:</bold> In infants with gestational age (GA) below 32 weeks, we assessed respiratory system reactance (Xrs) and lung ultrasound score (LUS) at 5 time points (7, 14, 28 days of life, 36 and 40 weeks PMA) and applied group-based trajectory modelling to identify subgroups of individuals with similar lung function patterns over time. We related such patterns with several prenatal and clinical factors. <bold>Results:</bold> We included 110 infants with a mean (SD) GA of 28.99 (2.22) weeks, 18 (16 %) of whom developed BPD. We identified 3 trajectories: 1) early bad, improvement, 2) persistently bad, 3) persistently good <fig><object-id>erj;64/suppl_68/PA4088/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig> The table below summarizes the characteristics of individuals belonging to the three different groups. <table-wrap><object-id>erj;64/suppl_68/PA4088/T1</object-id><object-id>T1</object-id><object-id>t1</object-id><table><colgroup><col></col><col></col><col></col><col></col></colgroup><tbody><tr><td>Group</td><td>1 [N = 13]</td><td>2 [N = 16]</td><td>3 [N = 81]</td></tr><tr><td>GA, weeks</td><td>25. 42 (24.29, 27.71)</td><td>26.71 (25.50, 29.46)</td><td>30.42 (29.14, 31.14)</td></tr><tr><td>Fetal growth restriction, %</td><td>0%</td><td>19%</td><td>11%</td></tr><tr><td>Antenatal steroids, %</td><td>46%</td><td>88%</td><td>64%</td></tr><tr><td>Sepsis, %</td><td>54%</td><td>75%</td><td>25%</td></tr><tr><td>Surfactant, %</td><td>77%</td><td>100%</td><td>59%</td></tr><tr><td>Intubation, days</td><td>9 (0, 16)</td><td>16 (5, 24)</td><td>0 (0, 0)</td></tr><tr><td>BPD, %</td><td>15%</td><td>95%</td><td>1%</td></tr></tbody></table></table-wrap> <bold>Conclusion:</bold> We identified 3 subgroups of individuals. Those with persistently poor lung function had higher fetal growth restriction rates, more infections, longer intubation and higher BPD rates.