Background: Diabetes mellitus (DM) is a chronic disease for which continuation of medication, either by oral or injection form, is needed. Severe flooding occurred during September 2011 to December 2011 in Thailand. Thirteen million people were affected, which might lead to poor control of plasma glucose in diabetic patients.
Objective: To study the effect of the flood on glycemic control in patients with diabetes mellitus.
Material and Method: Patients with DM, who had blood chemistry data before, during and up to 6 months after the 2011- flood disaster in Thailand, were included. Medical records and blood chemistry data were reviewed. Telephone interview method was used to assess the effect of the flood on their lifestyles, food and medications.
Results: 300 patients were included. Only 57 patients (19%) had a shortage of medications during the flood. In the subgroup of patients taking all medications (n = 243), mean fasting plasma glucose significantly increased during the flood (153 vs. 142 mg/dL, p-value <0.001). As compared to baseline data, lower mean body weight during the flood (67.7 vs. 68.5 kg, p-value = 0.022) and higher HDL level were also found (50.8 vs. 44.7 mg/dL, p-value <0.001) during flood. In the subgroup of patients with a shortage of medications (n = 57), worsening of plasma glucose control (184 vs. 156 mg/dL, p-value = 0.014) and HbA1c (8.66 vs. 8.09%, p-value = 0.043) was seen during the flood. No significant changes in other lipid profiles were seen in this subgroup. Resumed plasma glucose control was found in 3-6 months after the flood.
Conclusion: The 2011-flood in Thailand caused increased plasma glucose levels among DM patients during the flood, but better control of other metabolic profiles were seen in those diabetic patients who were able to continue taking medications.

Keywords: flood, plasma glucose, diabetes mellitus, lipid, natural disaster