Impact of flexible insulin therapy on blood glucose variability, oxidative stress and inflammation in type 1 diabetic patients: the VARIAFIT study.

AIMS: HbA1c only partially predicts vascular risk in patients with type 1 diabetes (T1D), and a role for blood glucose variability (BGV) is a matter of debate. For this reason, this study investigated the impact of an educational programme of flexible insulin therapy (FIT) on BGV and oxidative stress. METHODS: Tests were conducted on 30 adult T1D patients in a prospective, single-centre trial at baseline (M0), and at 3 and 6 months (M3 and M6, respectively) of the FIT programme to determine BGV, as reflected by mean amplitude of glycaemic excursions (MAGE), low blood glucose index (LBGI), lability index (LI), average daily risk range (ADRR), glycaemic lability (scored by two diabetologists), urinary leukotriene E4 (LTE4), 11-dehydro-thromboxane B2 (TXB2) and 8-iso-prostaglandin F2α (PGF2). RESULTS: HbA1c (7.7 ± 0.9%), ADRR, MAGE, LBGI and LI did not change from M0 to M3 and M6, although ADRR and LBGI significantly improved at M3 and M6 in patients with the highest baseline indices (≥ 40 and ≥ 5, respectively). TXB2 declined at M6 (832 ± 625 vs. 633 ± 972 pg/mg; P=0.048), whereas LTE4 and PGF2 remained stable. ADRR showed the strongest correlation with glycaemic lability scores at all visits (r≥0.84, P<0.0001). CONCLUSION: A FIT educational programme improved BGV only in patients with the highest baseline variability, and led to no changes in HbA1c, while ADRR closely correlated with glycaemic lability score. Our data do not support a relationship between BGV and oxidative stress in T1D patients, although the impact of variability on TXB2 deserves further investigation (ClinicalTrials.gov NCT00973492).

Basal insulin dose in 40 type 1 diabetic patients remains stable 1 year after educational training in flexible insulin therapy.

AIM: Basal insulin dose (BID) determination is the key to successful flexible insulin therapy (FIT). As our hypothesis was that BID changes over time, the primary objective of the present study was to determine the changes in BID 1 year after a therapeutic educational programme on FIT. METHODS: This single-centre retrospective study recruited the first 40 type 1 adult diabetic patients undergoing an educational FIT programme, which was conducted over a 4-day hospital stay and included a carbohydrate-fasting test. RESULTS: Patients' BIDs decreased between Day 0 and Day 4 after the programme (0.31±0.11IU/kg/day vs 0.27±0.09IU/kg/day; P<0.0001), and was increased at 1 year (0.29±0.09IU/kg/day; P=0.004). There was no significant variation in prandial insulin requirements. A tendency toward a reduction in HbA(1c) was observed at 1 year (8.3±1.4% vs 8.1±1.6%; P=0.075), with a decrease by more than 0.5% in 37.5% of patients. Body weight increased at 1 year (66.9±10.4 kg vs 68.1±10.7 kg; P=0.003), and the gain was greater than 5% in 7.5% of patients. Frequency of mild hypoglycaemia either remained stable (40%) or decreased (30%). Only nine patients (baseline HbA(1c) 8.03±1.7%, baseline BID 0.27±0.09IU/kg/day) had BID increases more than 20%, with no changes in prandial insulin requirements and no distinctive phenotype. Baseline HbA(1c), and BID have an impact on the BID at 1 year of approximately 0.3IU/kg/day in most patients. CONCLUSION: The stability of BID over 1 year, with values close to 0.3IU/kg/day associated with a trend towards improvement in HbA(1c), reduction in the frequency of mild hypoglycaemic episodes and absence of major weight gain, supports the relevance of FIT educational training.