Glucose Intolerance in Patients With Cystic Fibrosis: Sex-Based Differences in Clinical Score,Pulmonary Function,Radiograph Score,and 6-Minute Walk Test

Abstract

OBJECTIVE:

To determine the sex-specific relationships between glucose intolerance and Shwachman-Kulczycki clinical score, lung function, Brasfield chest-radiograph score, and exercise capacity in patients with cystic fibrosis (CF).

METHODS:

We used a cross-sectional study design and included CF patients ≥ 10 years old. All patients had clinical and nutritional evaluation, oral glucose tolerance test, spirometry, chest radiograph, and 6-min walk test (6MWT). Patients were classified as having normal glucose tolerance, impaired glucose tolerance, or CF-related diabetes mellitus.

RESULTS:

We included 88 patients: 59 with normal glucose tolerance, 15 with impaired glucose tolerance, and 14 with CF-related diabetes. Shwachman-Kulczycki clinical score (P = .04), at-rest S_pO2 (P = .001), S_pO2 difference before versus after 6MWT (P = .001), and Brasfield chest-radiograph score (P = .01) were significantly lower in the impaired-glucose-tolerance group than in the normal-glucose-tolerance group, but did not differ from the CF-related-diabetes group. In female patients only, percent-of-predicted FEV₁ was significantly lower in the impaired-glucose-tolerance group than in the normal-glucose-tolerance group (P = .02), but did not differ from the CF-related-diabetes group (P = .10). There was a significant relationship between glucose intolerance and sex when clinical score, 6-min walk distance, FEV₁, and radiograph score were combined in a multivariate analysis.

CONCLUSIONS:

In patients with CF, glucose intolerance was associated with poor clinical score, lower at-rest S_pO2 , greater S_pO2 difference before versus after 6MWT, poor lung function, and lower radiograph score. Overall, multivariate analysis indicated poorer performance in the latter variables in female patients with glucose intolerance than in male patients with glucose intolerance.