Risk factors for Herpes Zoster infections– a systematic review and meta-analysis unveiling common trends and heterogeneity patterns

Abstract Purpose: The burden of herpes zoster (HZ) is substantial and numerous chronic underlying conditions are known as predisposing risk factors for HZ onset. Thus, a comprehensive study is needed to synthesize existing evidence. This study aims to comprehensively identify these risk factors. Methods: A systematic literature search was done using MEDLINE via PubMed, EMBASE and Web of Science for studies published from January 1, 2003-January 1, 2023. Eligible studies were case-control or cohort studies. A random-effects model and multiple meta-regression were used to summarize the odds ratios (OR) with a 95% confidence interval (CI). Heterogeneity was analyzed with influence analyses. Results: Of 6,392 considered records, 80 were included in the meta-analysis. 21 different conditions were identified as potential risk factors for HZ. Transplantation was associated with the highest risk for HZ with a pooled OR = 4.51 (95% CI [1.9–10.7]). Other risk factors ranged from OR = 1.17–2.87, indicating an increased risk for all underlying conditions included in these analyses. Heterogeneity was substantial in all provided analyses. Sensitivity analyses showed comparable results regarding the pooled effect estimates and heterogeneity. Conclusions: We identified 21 potential risk factors: asthma, autoimmune disorders, cancer, cardiovascular disorders, chronic heart failure (CHF), COPD, depression, diabetes, digestive disorders, endocrine and metabolic disorders, hematological disorders, HIV, inflammatory bowel disease (IBD), mental health conditions, musculoskeletal disorders, neurological disorders, psoriasis, renal disorders, rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and transplantation. This study showed an increased risk for HZ infections for all identified factors.