Predicting the occurrence of DKA following sodium glucose co-transporter-2 inhibitors: An international cohort study

Sodium glucose co-transporter 2 inhibitors (SGLT2i) are associated with a small-magnitude but higher risk of diabetic ketoacidosis (DKA). However, objectively identifying patients at lowest and highest risk of DKA is challenging.

We developed a prediction model using outpatient prescription data from Ontario, Canada and externally validated it using data from Denmark. We included adults with type 2 diabetes mellitus who were newly prescribed an SGLT2i. Our candidate predictors in the model were based on prior work and included the following: Sex, insulin use, prior DKA, dementia, hemoglobin A1C, and creatinine. Our outcome was 1-year risk of hospitalization with DKA. We calculated a risk score using an adaptation of penalized regression for each patient reported test characteristics in Ontario (derivation cohort) and Denmark (external validation cohort).

We identified 322,135 in Ontario and 43,377 adults in Denmark who had type 2 diabetes mellitus and received an SGLT2i. The absolute risk of DKA within 1-year was 0.28 % (N = 916) in Ontario and 0.23 % (N = 101) in Denmark. Using data from Ontario, the risk score for each variable were as follows: Insulin use = 4 points, A1C > 9 % = 4 points and prior DKA = 19 points. All other variables received zero points. The overall model AUC was 63 % in Ontario and 66 % in Denmark (external validation set). Within Ontario, at a score threshold of zero, the risk of DKA was 0.19 % and the PPV was 0.3 % and the sensitivity was 100 % and similar results were observed in Denmark. For adults with a score of 19 or higher, the risk of DKA was 35-fold higher but false positives were common yielding a PPV of 6.7 % and sensitivity was lower at 3 %. In Denmark, adults with a score of 19 or higher had a risk of 11 % and the PPV was 10.2 % and sensitivity was 5 %.

Adults with a score of 0 (that is, simply a lack of DKA history, lack of insulin therapy, and A1c < 9 %) can be reassured that 99.8 % will not experience DKA in the subsequent year. In contrast, for adults with a score of 19 or higher the one-year risk of DKA is approximately 9 %, but false positives and false negatives are common and thus more work is needed to improve the predictive performance of the model.