Incident Stenotrophomonas maltophilia infection and lung function decline in cystic fibrosis.

OBJECTIVES: To determine whether incident detection of Stenotrophomonas maltophilia (SM) in patients with cystic fibrosis (CF) is associated with accelerated lung function decline and increased hospitalizations and to determine whether this effect is more pronounced in individuals with subsequent chronic infection.
METHODS: We performed a longitudinal, retrospective single-center, pre-post study of 88 patients with CF, ages 6-51 years, with first positive respiratory culture for SM between 2008 and 2014. Rate of decline in FEV1 and hospitalization rates prior to and following incident SM infection were analyzed using segmented regression analysis of interrupted time series.
RESULTS: Mean (SD) age was 17.4 (9.2) years and the mean (SD) FEV1 % predicted at acquisition was 90.0% (25.2). A total of 44% developed chronic SM infection. In regression analysis adjusted for clinical and demographic factors, there was worsening of the mean annual decline in FEV1 % predicted from -1.79 (95%CI: -2.43, -1.15) pre-acquisition to -2.14 (95%CI: -2.61, -1.67) post-acquisition (P = 0.005). A significant change was observed in those with either subsequent intermittent or chronic infection. The mean annual hospitalization rate increased significantly in the subgroup with chronic infection from 0.46 (95%CI: 0.33, 0.60) to 0.88 (95%CI: 0.68, 1.07) (P = 0.007).
CONCLUSIONS: In this single-center cohort, acquisition of SM in CF was associated with an acceleration in lung function decline. Among those with chronic colonization, acquisition was also associated with increased hospitalization rates.