Type 1 and type 2 diabetes associated with increased risk of herpes zoster

Results of a systematic review and meta-analysis were consistent across age groups, diabetes types, and regions of the world. The study authors suggested that earlier vaccination against herpes zoster in all patients with diabetes, regardless of age, be considered.

Patients with diabetes are at increased risk of herpes zoster regardless of their age, and the risk is even greater if they have concomitant cardiovascular disease (CVD), a recent study found.

Researchers in Taiwan conducted a systematic review and meta-analysis of scientific studies written in English that investigated the incidence, risk, or consequences of herpes zoster among adults with and without type 1 or type 2 diabetes. Results were published Sept. 18 by the Journal of Clinical Endocrinology & Metabolism.

A total of 16 articles met the inclusion criteria, including four case-control studies and 12 cohort studies. Eight studies were from Asia, five were from Europe, two were from the U.S., and one was from Australia, and all but one study used administrative claims or electronic medical record databases. The study population ranged from 750 participants to 51 million participants (median, 272,690 participants), and the follow-up period ranged from 1.5 to 12 years (median, 5 years).

In a pooled analysis of all studies, patients with diabetes had an increased risk of developing herpes zoster compared to the general population (pooled risk ratio [RR], 1.38; 95% CI, 1.21 to 1.57), with a high level of between-study heterogeneity. The results were consistent across case-control (pooled RR, 1.30; 95% CI, 1.08 to 1.55) and cohort study designs (pooled RR, 1.40; 95% CI, 1.21 to 1.62) and across different age groups, type 1 and type 2 diabetes, and different regions of the world, although the association was not significant for the studies conducted in the U.S. Patients with diabetes who were younger than age 50 years had a higher risk of herpes zoster (pooled RR, 1.41; 95% CI, 1.20 to 1.65) than age-matched individuals without diabetes. This result was unchanged after the subgroup analysis was repeated with an age cutoff of 40 years (pooled RR, 1.42; 95% CI, 1.12 to 1.80). The risk of herpes zoster among patients with diabetes increased with age in an analysis of two large cohort studies. The risk was also higher in patients with diabetes who had CVD than in those who did not (pooled RR, 1.16; 95% CI, 1.06 to 1.26), according to a subgroup analysis of three studies.

Among other limitations, there was substantial heterogeneity between studies and a possibility of misclassification of exposures due to coding errors, the study authors noted. They added that the statistical power of the subgroup analyses was limited by the number of studies.

Health officials should consider the added risk of herpes zoster in individuals with diabetes and assess the cost-effectiveness of earlier vaccination, especially in those with concomitant CVD, the authors said. “Currently, the lowest recommended age for varicella vaccination is 50 years in both diabetic patients and in the general population,” they wrote. “Given that DM [diabetes mellitus] is an important risk factor for both [herpes zoster] and [postherpetic neuralgia], vaccination at a younger age should be considered in patients with DM.”