Impact of 1h oral glucose tolerance test on the clinical status of adult cystic fibrosis patients over a 4-year period.

OBJECTIVE: To report the clinical profile associated with G60 and I60 over a 4-year prospective observational period in 2 large cohorts of adult patients with CF. METHODS: 319 patients were included (210 Canadian and 119 French) and classified according to their inclusion G60 (≥ or < 11.1 mmol/L) and the median inclusion I60 (≥ or < 24 mU/I). Forced expiratory volume in 1 second (FEV1), body mass index (BMI) were collected on OGTT days. Linear mixed regression models were used to assess the effect of G60 and I60. RESULTS: High G60 was not associated to a lower FEV1 at inclusion and the follow-up decline was not higher in the high G60 group (Coefficient [95% CI]: -3.4 [-7.4;0.6], p = 0.0995.). There was no significant association between BMI and G60. Patients with high I60 tended to have a higher mean BMI (+0.5 kg/m2 [0.0 to 1.1], p = 0.05) but no interaction over time was observed. CONCLUSIONS: High G60 is not associated with a lower lung function at inclusion nor its decline over a 4-year follow-up. High I60 is slightly associated to a higher weight at inclusion, but not with BMI evolution over time in adult patients.

Glucose tolerance in Canadian and French cystic fibrosis adult patients.

Cystic fibrosis (CF)-related diabetes is associated with increased mortality. We analysed the clinical and glycemic profiles of two cohorts of patients treated according to the same guidelines in France and Canada. To investigate incidence differences in phenotypic and glucose abnormalities and to explore the evolution over a 4-year follow-up period, two cohorts of 224 Canadian and 147 French adult CF patients (≥18 years) without treated CF-related diabetes (CFRD) were followed over a 4 year period. In each of these groups, we investigated the longitudinal relationship between glucose tolerance and pulmonary function. An annual 2-hour oral glucose tolerance test was performed: fasting blood glucose (G0) and 2-h blood glucose (G2) were measured. Patients were classified at inclusion according to their glucose tolerance status: Normal glucose tolerant, abnormal glucose tolerant or de novo CFRD. Age, sex ratio and proportion of F508del homozygous patients were not statistically different between both cohorts. Canadian patients had better pulmonary function (median %FEV1 (IQR): 71.0 (55.0-82.0) vs. 64.0 (40.0-78.0), p < 0.001) and greater body mass index (BMI; median BMI in kg/m2) (IQR) 21.1 (19.5-22.8) vs. 19.9 (18.4-21.4), p < 0.001). Glucose values: G0 (5.4 (5.0-5.9) vs. 4.8 (4.5-5.1) mmol/L, p < 0.001) and G2 (7.6 (5.8-9.7) vs. 6.5 (5.2-8.5) mmol/L, p = 0.001) were higher in the Canadian cohort translating into a higher incidence of de novo CFRD diagnosis (19.2 vs. 9.8%, p = 0.003). Decline in FEV1 over time was not different between patients according to glucose tolerance groups. Despite higher glucose levels and incidence of de novo CFRD, Canadian CF patients have a better lung function and a higher BMI than French patients. In spite of these differences between the cohorts, the decline in FEV1 in patients with abnormal glucose tolerance is similar between these groups.