The real-world economic impact of herpes zoster disease in patients with selected underlying conditions in Spain

People with underlying diseases are at-increased-risk of suffering from herpes zoster (HZ). However, the economic impact of HZ on these populations is not well described. This study aimed to quantify the clinical and economic impact of HZ in patients with comorbidities (diabetes, chronic obstructive pulmonary disease, heart disease, kidney disease, asthma) and immune disorders (inflammatory bowel disease, rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, psoriasis, COVID-19 and psoriatic arthritis) in Spain. This is an observational, retrospective case-control study using the BIG-PAC electronic records from 01 Jan 2014 to 31 Aug 2021. Healthcare resource use and costs over 12 months following HZ diagnosis were compared between patients and controls, matched by propensity scores. The total annual economic burden was estimated using HZ-related costs per patient and HZ crude incidence over the study period, together with the estimated prevalence of each comorbidity in the Spanish population aged ≥18 y. Mean incremental costs per HZ episode were €1,108 in patients with comorbidities and €1,203 in patients with immune disorders. Indirect costs accounted for 4.7% and 22.9% of incremental costs in people with comorbidities and immune disorders, respectively. Mean annual crude HZ incidence rates were 613.6 cases per 100,000 people with comorbidities and 659.0 cases per 100,000 people with autoimmune disorders. Total annual costs due to HZ in these populations were estimated at €121 million. HZ may cause a significant economic burden in Spain from a societal perspective in patients with underlying conditions, highlighting the importance of improving vaccination programs. Herpes zoster, commonly known as shingles, is a viral infection characterized by a painful rash, typically presenting as a band of blisters on one side of the body. It is caused by the reactivation of the varicella-zoster virus, the same virus responsible for chickenpox that stays dormant in the body after this childhood disease. While herpes zoster can affect individuals of any age, it predominantly impacts older adults and those with a weakened immune system. This study describes populations with a weakened immune system because of diseases and comorbidities that are currently not completely included in the Spanish National Immunization Program for herpes zoster vaccination (diabetes, chronic obstructive pulmonary disease, heart disease, kidney disease, asthma, inflammatory bowel disease, rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, psoriasis, COVID-19, or psoriatic arthritis). Furthermore, the study estimates the number of people within these at-risk populations who may develop herpes zoster and evaluates the burden of herpes zoster on patients, the Spanish healthcare system, and the Spanish economy as a whole. The impact of herpes zoster on patients is high because they have more healthcare visits, need to see more specialists, have longer hospital stays, need to take more medication, and have more leaves of absence from work compared to control patients without herpes zoster. Due to this, people with herpes zoster have higher related healthcare costs, leading to a huge annual economic burden of €121 million when estimating the entire Spanish population with those underlying conditions. Vaccination can prevent herpes zoster; the study suggests a high potential benefit of herpes zoster vaccination, highlighting the importance of extending and improving vaccination programs for individual patients, the Spanish healthcare system, and the overall Spanish economy.