Is there still a gender gap in cystic fibrosis?

Objectives: Previous studies have shown that female patients with cystic fibrosis (CF) have a significantly poorer prognosis than male patients. Such studies investigating gender-related differences have generally combined data from several centers. The aim of this study was to determine whether with modern aggressive treatment of CF this is still true when care is standardized within a single center.

Design: Retrospective analysis of annual assessment data constructing two cross-sectional studies for the year 1993 (56 female patients, 49 male patients) and 2002 (115 female patients, 94 male patients) and two longitudinal studies, each lasting 5 years, starting in 1993 (21 female patients, 19 male patients) and 1998 (40 female patients, 41 male patients). Outcome measures included mortality, height, and weight SD scores (z scores), and percent predicted for lung function.

Results: In neither cross-sectional study were there significant differences between the sexes for median FEV(1) percent predicted (1993: female patients, 86%; male patients, 84%; 2002: female patients, 93%; male patients, 92%). Female height and weight z scores were at least as good as those of male scores. In the longitudinal studies, there were no clear trends toward declining lung function or growth, but the overall FEV1 percent predicted appeared to be better in female patients than male patients for both cohorts. This was statistically significant for the 1998 cohort (female median FEV1, 91.5% [range, 28 to 134%]; male median FEV1, 84.8% [range, 32 to 145%]; p < 0.05). Female nutritional status was at least as good as male nutritional status, other than the 1998 weight z scores (-0.54 vs -0.21, respectively; p < 0.02). Since 1993, there have been 13 deaths altogether (7 female patients).

Conclusion: During childhood and adolescence, the lung function and nutrition of CF patients should be at least as good in female patients as in male patients. Individual clinic practice should be reviewed if a gender gap persists.