Fasting plasma glucose level-based formula for estimating starting daily dose in basal-bolus insulin therapy

There is no standard formula for estimating the starting daily dose (SDD) of basal-bolus insulin therapy (BBT). We aimed to develop a formula for estimating SDD and evaluate its efficacy and safety in patients with type 2 diabetes hospitalized for BBT. In the first study (n = 104), we retrospectively analyzed the relationship between peak daily dose (PDD) during hospitalization and clinical parameters. The PDD was significantly associated with fasting plasma glucose (FPG) (R = 0.449, P < 0.0001) and HbA1c levels (R = 0.384, P < 0.0001) but not body weight, body mass index, body surface area, or serum C-peptide levels. Based on the results, we developed a formula for estimating SDD using FPG levels: SDD (U/day) = 0.08 × FPG (mg/dL). In the second study (n = 405), we assessed efficacy and safety of the formula by evaluating the M-value from the daily glucose profile and assessing the frequency of hypoglycemia (blood glucose level < 70 mg/dL). When BBT was initiated using the FPG level-based formula, the M-values decreased from 61.0 ± 52.8 to 12.8 ± 10.8 (P < 0.0001), and hypoglycemia was observed in only 3/405 cases (0.74%) under the SDD. The FPG level-based formula is useful for estimating SDD in BBT and is safe for clinical use.