Sample size: for its determination in each of the four groups, the investigators considered the change in haemoglobin A1c (from baseline to the end of the study) as the primary outcome variable. This was done using a two-sided test at the 5% level of significance and 80% power using a paired t-test. The sample size was increased by 25% to account for non-independence and dropout, resulting in the number of providers and patients listed in table 1.