Statistical Analysis
Analysis was based on the “intention to treat”. We report baseline
characteristics and outcomes as mean (SD), median (IQR), or number and
percentage. We report the effects of the intervention as relative risks
(RRs), with their 95% confidence intervals (CI). The statistical
significance of the differences was tested using the Fisher exact test.
Differences in means of continuous variables were tested with the
Student T-test. We used SPSS (versions 18 and 20, IBM, Chicago, USA) and
Stata (version 15, StataCorp, College Station, USA) for data management
and statistical analysis.
Based on data from our clinic, we expected an incidence of 40% of
insulin prescription in women with gestational diabetes treated
initially with diet only (control group). For a clinically relevant
reduction in insulin prescription with exercise to 20% (number-needed
to treat of 5), the sample size (α=0.05 and power of 80%) was 91
patients in each group. We had to stop the trial before reaching the
complete sample size because of low recruitment, low compliance to the
exercise sessions and lack of funding for the physical therapist salary.