Introduction:
Hyperglycemic crisis episode (HCE) suggests a poor control of diabetes, which may increase the risk of Parkinson disease (PD). This study aimed to clarify this issue since literature remains unclear.

Material and methods:
Patients with diabetes with and without HCE matched at a 1:1 ratio by age, sex, and index date between 2000 and 2002 from the Taiwan National Health Insurance Research Database were identified for analyses. Comparison of PD between patients with diabetes with and without HCE was performed by follow-up until 2012. Independent predictors for PD were also investigated among all patients.

Results:
A total of 10,056 patients with diabetes with HCE and an identical number of patients with diabetes without HCE were included in the study. The mean age and male ratio were 62.0 years and 52.1%, respectively in both cohorts. Patients with HCE were found to have higher prevalence rates of hypertension, renal disease, hyperlipidemia, mental disorder, chronic obstructive pulmonary disease, liver disease, and head injury than those without HCE. Patients with HCE for ≥3 times had a higher risk for PD (adjusted hazard ratio [AHR]: 1.27; 95% confidence interval [CI]: 1.05-1.54) compared to those without HCE; however, patients with HCE for 1 or 2 times were not at high risk. Older age except ≥85 years, hypertension, hyperlipidemia, and mental disorder were also independent predictors for PD.

Conclusions:
HCE for ≥3 times is associated with PD. Close follow-up in older patients with HCE as well as control of hypertension, hyperlipidemia, and mental disorder are warranted.