2 - TI Pharma

called the potentiation factor ratio (PFR). In addition, the fasting secretory tone is calculated
from the dose-response curve as insulin secretion at the glucose concentration of 4.5 mmol/L.
The second component of the model describes the insulin response to the rate of change of
glucose concentration. This component is termed rate sensitivity, which is related to early
insulin release [24].
Statistical analyses: Data are presented as mean values ± standard deviation (SD), or as
median (interquartile range) in case of skewed distribution. Non-parametric analysis was
chosen due to uneven sample size over the groups, the relatively small N, and unequal variances
that were observed for some parameters. Between-group comparisons of baseline values
were performed using Kruskal-Wallis test. For treatment-induced effects, absolute changes
from baseline were calculated (on-treatment value minus pre-treatment value) and were
compared by Kruskal-Wallis test with trend analysis (‘the Jonckheere-Terpstra test’). Only in
case of a significant finding, prednisolone 7.5 mg and prednisolone 30 mg were compared
against placebo by posthoc testing, using the Mann-Whitney U test. To correct for multiple
testing, Bonferroni correction was applied. Correlations between the various parameters
were assessed with Pearson’s correlations. All statistical analyses were run on SPSS version
15 for Windows (Chicago, IL, USA). A P < 0.05 was considered statistically significant.
RESULTS
Anthropometric characteristics: No significant differences in subject characteristics were
observed among the groups at baseline (Table 1). Body weight was not altered by prednisolonetreatment
irrespective of the dose (Supplementary Table 1). Systolic blood pressure (6±1.2
mmHg increase; P=0.006), but not diastolic blood pressure was raised by prednisolone 30
mg. Prednisolone 7.5 mg did not affect blood pressure (Supplementary Table 1).
Fasting glucose and hormone levels: A dose-dependent rise in fasting plasma glucose
levels was observed by prednisolone treatment relative to placebo (P=0.04) (Table 2).
Fasting plasma insulin levels were significantly increased (P=0.008) in the prednisolone 30
mg arm. The Prednisolone-induced increase in fasting insulin levels was due to increased
basal secretion, not altered clearance, since fasting C-peptide levels were similarly enhanced
(P=0.001) (Table 2).
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Chapter 5