“…The diagnosis of diabetes and HZ was based in general on the international ICD-9 and ICD-10 CM diagnosis system. The risk of HZ was significantly higher in patients with diabetes as compared to controls in 11 studies out of 16 [5,18,23,24,26,29,30,32,33,34,36] (Table 1). However, the magnitude of risk associated to diabetes varied widely, ranging from 1.06 (95%CI: 1.03-1.09) in a population-based case-control study carried out in the UK [27] to 2.38 (95%CI: 2.04-2.78) in the population-based retrospective cohort study carried out in Japan [23].…”