Females with cystic fibrosis (CF) have been shown to have worse pulmonary exacerbation (PEx) related outcomes compared to males. However, it is unknown if sex differences in treatment patterns are contributing to these outcomes. Thus, we sought to explore sex differences in treatment patterns in the Standardized Treatment of Pulmonary Exacerbations (STOP) cohort.

Data for 220 participants from the STOP cohort were analyzed. Multivariable regression models were used to assess if female sex was associated with duration of treatment with IV antibiotics and inpatient length of stay. Secondary outcomes included antibiotic selection, adjunctive therapies, mean FEV1pp and CFRSD-CRISS respiratory symptom scores at the four study assessments.

In our adjusted model, the average number of IV antibiotic treatment days was 13% higher in females compared to males (IRR 1.13, 95% CI=1.02,1.25; p=0.02). We found no sex differences in inpatient length of stay, number of IV antibiotics, antibiotic selection or initiation of adjunctive therapies. Overall, females had higher CFRSD-CRISS scores at the end of IV therapy indicating worse symptom severity (23.6 for females vs. 18.5 for males, p=0.03).

Despite females having a longer treatment duration, our findings demonstrate that males and females are receiving similar treatments which suggest that the outcome disparities in females with CF may not be due to failure to provide the same level of care. Further research dedicated to sex differences in CF is necessary to understand why clinical outcomes differ between males and females.