Body mass index is inversely associated with capillary ketones at the time of colonoscopy: Implications for SGLT2i use

OBJECTIVE: Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have been associated with diabetic ketoacidosis at the time of colonoscopy. This study aimed to identify factors associated with ketone concentrations in SGLT2i-treated type 2 diabetes compared with non-SGLT2i-treated diabetes, and those with impaired fasting glycaemia (IFG) and normoglycaemia. DESIGN: Cross-sectional, multicentre, observational study June-December 2020 in four Australian tertiary hospitals. PARTICIPANTS: Capillary glucose and ketones were measured in people undergoing colonoscopy: 37 SGLT2i-treated and 105 non-SGLT2i-treated type 2 diabetes, 65 IFG and 151 normoglycaemia. MEASUREMENTS: Body mass index (BMI), age, glucose, fasting duration and where relevant, HbA1c and time since last SGLT2i dose. RESULTS: In SGLT2i-treated diabetes, BMI (ρ = -0.43 [95% confidence interval: -0.67, -0.11]) and duration since last SGLT2i dose (ρ = -0.33 [-0.60, 0.00]) correlated negatively with increasing ketones, but there was no correlation with fasting duration. In non-SGLT2i-treated diabetes, BMI correlated negatively (ρ = -0.24 [-0.42, -0.05]) and fasting duration positively (ρ = 0.26 [0.07, 0.43]) with ketones. In IFG participants, only fasting duration correlated with ketones (ρ = 0.28 [0.03, 0.49]). In normoglycaemic participants, there were negative correlations with BMI (ρ = -0.20 [-0.35, -0.04]) and fasting glucose (ρ = -0.31 [-0.45, -0.15]) and positive correlations with fasting duration (ρ = 0.20 [0.04, 0.35]) and age (ρ = 0.19 [0.03, 0.34]). Multiple regression analysis of the entire cohort showed BMI, age and fasting glucose remained independently associated with ketones, but in SGLT2i-treated participants only BMI remained independently associated. CONCLUSIONS: In SGLT2i-treated diabetes, lower BMI was a novel risk factor for higher ketones precolonoscopy. Pending larger confirmatory studies, extra vigilance for ketoacidosis is warranted in these people.