BackgroundHerpes Zoster (HZ) is the reactivation of latent varicella-zoster virus. Diabetes Mellitus (DM) is one of well-known risk factors for HZ. Nowsday, the knowledge on the incidence of and risk factors for HZ among Thai DM patients is limited.MethodsWe conducted a nested case–control study of DM patients who attended the Siriraj DM clinic for ≥6 consecutive months during 2005–2014. Eligible subjects were identified through the DM clinic registry database (n = 1,427). Cases were those who had ≥1 episode of HZ while controls were those without evidence of HZ during the study period. We captured 40 cases and randomly sampled 175 controls (1 case: 4 controls). All data were obtained via chart-review, the ICD-10, pharmacy and laboratory databasesResultsDuring the 10-year study period, the cumulative incidence and the incidence rate of HZ were 0.28% [95% CI: 0.20–0.38%] and 3.96 [95% CI: 2.90–5.28] per 1,000 person-years. The most common sites were trunk (27.5%), followed by herpes opthalmicus (22.5%). Thirty-five percent had post-herpetic neuralgia and only 1 case required hospitalization. Independent risk factors for HZ [adjusted odd ratio; 95% CI; P-value] identified from multivariate analysis included underlying hypertension [3.48; 1.28–9.43; P = 0.01], number of hypoglycemic drug used [1.46; 1.03–2.08; P = 0.04] and previous use of herbal remedies [3.83; 1.06–13.84; P = 0.04]. Furthermore, higher body mass index was an independent protective factor [0.89;0.81–0.98; P = 0.02].ConclusionThe incidence rate of HZ among DM patients at our institute was comparable to other Asian countries. Risk factors for HZ can be used to identify patients who would benefit the most from preventive interventions.Disclosures All authors: No reported disclosures.