Diabetic ketoacidosis and diabetes associated with antipsychotic exposure among a previously diabetes-naive population with schizophrenia: a nationwide nested case-control study.

ABSTRACT

AIMS/HYPOTHESIS: Diabetic ketoacidosis (DKA) is a potentially fatal metabolic emergency of both type 1 and type 2 diabetes. Although there is a reduced risk of type 1 diabetes in schizophrenia, the incidence of DKA is tenfold higher than that of the general population. Thus, we aimed to investigate associations between exposure to antipsychotic medication (within 3 months prior to event) and DKA, type 1 diabetes and type 2 diabetes. We also reported related, clinically relevant outcomes. METHODS: Using a nested case-control study design, we identified cases of DKA, type 1 diabetes and type 2 diabetes in a previously diabetes-naive population with schizophrenia in Denmark from 1995 to 2014. Cases were matched (by age, sex and year of schizophrenia onset) 15 to schizophrenic control individuals who were alive and had not emigrated prior to event. Conditional logistic regression was used to compute ORs with 95% CIs. Other outcomes included diabetes aetiology of DKA, in-hospital mortality, DKA readmissions and temporal trends of use of insulin and oral glucose-lowering agents. RESULTS: Of 29,955 individuals with schizophrenia, we identified 28 individuals with DKA, 90 with type 1 diabetes and 2140 with type 2 diabetes. These were matched to 137, 410 and 9861 individuals in the control group, respectively. Antipsychotic exposure was associated with DKA (OR 2.60; 95% CI 1.06, 6.38) and type 2 diabetes (OR 1.64; 95% CI 1.48, 1.83). A trend towards increased risk of type 1 diabetes was found but remained insignificant (OR 1.38; 95% CI 0.84, 2.29). Diabetes aetiology of DKA was type 1 in eight cases and type 2 in 14 cases. Of the remaining six cases of DKA, aetiology could not be determined, as four were fatal within 8 days and for two, no prescriptions for insulin and oral glucose-lowering agents were redeemed. Of all DKA cases, six had more than one episode of DKA, and of all type 1 diabetes and type 2 diabetes cases, four and 11, respectively, had at least one episode. Use of insulin and oral glucose-lowering agents was higher among individuals with DKA relative to those with type 1 diabetes and type 2 diabetes. CONCLUSIONS/INTERPRETATION: Antipsychotic exposure was associated with DKA and type 2 diabetes in a previously diabetes-naive schizophrenia population. Antipsychotic-associated DKA is relevant not only for psychiatrists but also for other physicians who may manage and admit such patients.