Objective To estimate the incidence of hospitalisation due to varicella zoster virus (VZV) infection in patients treated with tumour necrosis factor (TNF) antagonists for inflammatory rheumatic conditions and to compare it with the expected rate in the general population.
Methods Secondary data analysis was performed of two large databases: (1) the national registry of rheumatic diseases patients treated with biological agents (BIOBADASER); and (2) the national hospital discharge database Conjunto Mínimo Básico de Datos al Alta Hospitalaria. Hospitalisations due to shingles or chickenpox were analysed. For each condition the incidence rate (IR) and the age and gender standardised IR per 100 000 person-years plus the standardised incidence ratio (SIR) and the standardised incidence difference (SID) were estimated.
Results In patients exposed to TNF antagonists, the estimated IR of hospitalisation due to shingles was 32 cases per 100 000 patient-years (95% CI 14 to 78), the expected rate in the general population was 3.4 (95% CI 3.2 to 3.5), the SIR was 9 (95% CI 3 to 20) and the SID was 26 (95% CI 14 to 37). The estimated IR of hospitalisation due to chickenpox was 26 cases per 100 000 (95% CI 10 to 69), the expected rate was 1.9 (95% CI 1.8 to 2.0), the SIR was 19 (95% CI 5 to 47) and the SID 33 (95% CI 21 to 45).
Conclusions Patients suffering rheumatic diseases exposed to TNF antagonists are hospitalised due to VZV infections significantly more frequently than expected in the general population. Since the absolute IR of hospitalisations due to chickenpox and shingles is low in these patients, the implementation of risky preventive measures may not be justified at present.
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The BIOBADASER 2.0 Study Group Agustí Sellas, Basilio Rodríguez y Mireia Barceló (Ciudad Sanitaria Vall d'Hebron); Laura Cebrián, María Montoro (Hospital Gregorio Marañon); Dolores Montesinos (Hospital Universitario Virgen Macarena); Eva Pérez-Pampín (Hospital Clinico Universitario de Santiago); Ana Mª Ortiz, (Hospital Universitario de La Princesa); Fred Antón, Antonio Zea (Hospital Ramon y Cajal); Francisco Javier Manero Ruiz, Chesús Beltrán, Eugenio Gimenez Úbeda, Fernando Jimenez Zorzo, Jesús Marzo, Marta Medrano, Ángela Pecondón (Hospital Universitario Miguel Servet); Mª Victoria Hernández, Raimon Sanmartí, Juan D Cañete (Hospital Clinic I Provincial); Carlos Rodriguez Lozano, Antonio Naranjo, Soledad Ojeda, Félix Francisco Hernández, Celia Erausquin, Íñigo Rúa, (Hospital de Gran Canaria Dr Negrin); Inmaculada Ureña, Maria Victoria Irigoyen, Laura Cano (Hospital General Carlos Haya); Rosa Roselló Pardo, Carlos Vazquez Galeano, (Hospital General San Jorge); Alexia de Juanes, Beatriz Joven, Javier Garcia (Hospital 12 de Octubre); Javier Calvo, Cristina Campos (Hospital General Universitario de Valencia); Juan Jose Garcia Borras, Rosa Negueroles, Luisa Muñoz, J L Valero, D Ybañez (Hospital La Fe).
Funding BIOBADASER is supported by the Spanish Society of Rheumatology and the Spanish Agency of Medicines and Healthcare Products. Grants in approximately equal amounts (all under €25 000/year) from Roche, Abbott, BMS, Schering and Wyeth contribute to the support of the registry. This work was partially supported by RETICS Program, RD08/0075 (RIER) from Instituto de Salud Carlos III (ISCIII).
Competing interests IGD has no competing interest. MAD has no competing interest. BPZ has received lecture fees from Wyeth (€2000 total). RR has received honoraria from Abbott, Schering-Plough and Roche (€6000, €4000 and €1000/year, respectively). MVH has no competing interest. JJGR is on the Advisory Boards of Schering-Plough, Wyeth, Bristol Meyers Squibb and Roche, and has received lecture fees from Abbott Laboratories, Wyeth, Roche, Bristol Meyers Squibb and Schering-Plough. LC has received lecture fees from Abbott, Schering-Plough and Roche.
Ethics approval Ethical approval for this study was obtained from the Institutional Review Board (IRB) of the Hospital Ramón y Cajal, Madrid.
Provenance and peer review Not commissioned; externally peer reviewed.