Bed 13 is not worse than any other. A retrospective cohort study.

INTRODUCTION: Risk management and patient safety are closely related, following this premise some industries have adopted measures to omit number 13. Healthcare is not left behind, in some hospital the day of surgery's or bed numbering avoid number 13. The objective was to assess whether it is necessary to redesign the safety policies implemented in hospitals based on avoiding 13 in the numbering of rooms/beds. METHODS: A retrospective cohort study was conducted. Mortality and the number of adverse events suffered by patients admitted to rooms/beds numbering 13 (bad chance) or 7 (fair chance) over a two-year period to Intensive Care Unit, Medicine, Gastroenterology, Surgery, and Paediatric service were registered and compared. RESULTS: A total of 8553 admissions were included. They had similar length-of-stay and Charlson Index scores (p-value=0.435). Mortality of bed 13 was 268 (6.2%, 95% CI 5.5-6.9) and 282 in bed 7 (6.7%, 95% CI 5.9-7.5) (p-value=0.3). A total of 422 adverse events from 4342 admissions (9.7%, 95% CI 8.9-10.6) occurred in bed 13, while in bed 7 the count of adverse events was 398 in 4211 admissions (9.4%, 95% CI 8.6-10.4) (p-value=0.6). Odds Ratio for mortality was equal to 0.9 (95% CI 0.8-1.1) and suffering adverse events when admitted to bed 13 versus bed 7 was 1.03 (95% CI 0.9-1.2). CONCLUSIONS: Bed 13 is not a risk factor for patient safety. Hospitals should pay attention to causes and interventions to avoid adverse events based on evidence rather than beliefs or myths.

Satisfacción versus experiencia del paciente, calidad de diseño versus calidad de conformidad / Patient satisfaction versus patient experience. Quality of design versus quality of conformity

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Dejar de hacer lo que no hay que hacer / Ceasing to do what shouldn't be done

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Cómo pasa la vida, que de pronto son años / How life passes by, and how years fly

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Improving patient safety by detecting obstetric care-related adverse events: application of a new screening guide.

PURPOSE: Determining the magnitude and importance of patient safety-related incidents and the effectiveness of measures to improve patient safety (PS) are high-priority goals in efforts to improve the quality of obstetric care. The aim of this study was to evaluate the usefulness of the MRF1-OBST screening guide in detecting adverse events in women who received obstetric care. METHODS: This retrospective cohort study included 244 women who were hospitalized for delivery. All medical records were reviewed with the MRF1-OBST screening guide to identify adverse events and incidents. This tool is a modified form of the MRF1 screening guide regularly used in epidemiological studies of PS, to which we added items developed specifically for obstetric care. We calculated the positive predictive value and compared the ability of the MRF1 and MRF1-OBST guides to detect incidents related to PS in Obstetrics. RESULTS: The MRF1-OBST guide did not identify any additional complications during hospitalization or incidents related to PS that were not also identified by the MRF1 guide. CONCLUSIONS: The MRF1-OBST guide did not improve the detection of obstetric AE. The modified version of the guide required more work to use as a screening aid than the original MRF1 instrument. Efforts to improve the detection of incidents related to PS in obstetrics require complementary tools to be developed for information analysis.

Eventos adversos relacionados con la medicación informados por los pacientes en atención primaria / Adverse events related to the medication informed by primary care patients

Objetivo: Identificar la frecuencia de eventos adversos (EA) según informe de los pacientes en atención primaria (AP) y determinar si sufrir EA incide negativamente en la valoración de la atención recibida. Pacientes y metodología: Estudio observacional, basado en entrevistas estructuradas a una muestra de pacientes de AP seleccionada aleatoriamente. Se encuestó a 1.952 pacientes, de 1.514 de consultas de medicina general y 438 de pediatría. En 612 casos se inició un nuevo tratamiento. Escogimos una muestra aleatoria definida para un error máximo del 4%, nivel de confianza del 95%. Resultados: En 38 (6,2%) casos se informó de EA; de estos, 25 (4,1%) sufrieron EA relacionados con la medicación. A mayor edad encontramos mayor frecuencia de EA. En 14 de estos 25 pacientes (56%) se solicitó una segunda consulta. La frecuencia de EA relacionado con la medicación se asoció a ineficacia del tratamiento. Quienes sufrieron EA relacionados con la medicación pero recibieron información sobre este episodio valoraron de forma positiva las atenciones sanitarias recibidas. Conclusión: Se precisan prácticas más seguras en AP y recurrir a los pacientes para conocer la frecuencia de EA tiene menor coste y aporta información relevante. Incluso en el caso de sufrir complicaciones derivadas del tratamiento indicado por el médico, la confianza en el profesional de AP se mantiene (AU)

Objective: To identify the frequency of adverse events reported by primary care patients and determine their consequences on patients’ assessment of care. Patients and methods: Observational study based with a sample of randomly primary care patients. A total of 1,952 patients were surveyed (sample defined to a maximum error of 4%, Confidence Interval of 95%), 1,514 from general practices and 438 from pediatrics. In 612 cases began a new treatment. Results: In 38 (6.2%) cases were reported an AE; of these, 25 (4.1%) experienced drug-related AE. Among older we found increased frequency of AE. In 14 of these 25 patients (56%) requested a second query. The frequency of medication-related AE was associated with ineffective treatment. Those who suffered drug-related AE but received information about this episode rated a favorable view of health care received. Conclusion: We need safer practices in primary care. Patients can provide relevant information about patient safety. Even in the event of serious harm from treatment prescribed by a doctor, trust in professional remains (AU)

[Patients informing of adverse events. Results in diabetes and kidney disease]. / Pacientes como informadores de eventos adversos. Resultados en diabetes y enfermedad renal.

BACKGROUND: Diabetes and kidney disease are risk factors for adverse events (AE). There are no other studies on the perception of risk in these patients. This study analyzes the frequency of adverse event triggers reported by diabetic and renal patients and their perception of the risk. MATERIAL AND METHODS: Descriptive study based on interviews with randomly selected patients. Field study conducted between February and May 2010 in three health centers and two hospitals in Alicante and Madrid. RESULTS: A total of 199 patients answered, 98 diabetic patients and 101 renal patients. Renal patients accumulated more AE triggers (21.8% referred to an AE trigger, 17.8% two AE triggers and 3% referred to > 3 AE triggers) than diabetic patients (16.3% referred to one AE trigger, 7.1% to two AE triggers and 7.1% referred to > 3 AE triggers). During the last year 6/98 diabetic patients and 10/101 renal patients required additional treatment due to a clinical error. The probability of the patient being the victim of a clinical error with serious consequences was 1:10. Women with renal illness believed themselves to have a greater probability of suffering an error (Chi2=12.7, p=0.002). Errors were attributed to a lack of time to attend to all patients and a lack of means and resources, without statistically significant differences between the subsamples. Interviewed patients considered that the risks of suffering a traffic accident or robbery were similar to the risk of an error with serious consequences. CONCLUSION: Information provided by patients can help improve safety procedures.

Pacientes como informadores de eventos adversos. Resultados en diabetes y enfermedad renal / Patients informing of adverse events. Results in diabetes and kidney disease

Fundamento. Diabetes y enfermedad renal son factores de riesgo de sufrir eventos adversos (EA). No contamos con estudios sobre la percepción del riesgo de estos pacientes. En este estudio se analiza la frecuencia con la que los pacientes diabéticos y renales describen indicios de un posible EA y su percepción de seguridad de la atención que reciben. Material y métodos. Estudio descriptivo basado en entrevistas a pacientes seleccionados al azar. Estudio de campo realizado entre febrero y mayo de 2010 en 3 centros de salud y 2 hospitales de Alicante y Madrid. Resultados. Respondieron 199 pacientes, 98 diabéticos y 101 con enfermedad renal. Estos últimos acumularon mayor número de indicios de EA (21,8% refirió un EA, 17,8% dos y un 3% 3 o más) que los diabéticos (16,3% un EA, 7,1% dos y 7,1% señaló 3 o más). En el último año, 6/98 diabéticos y 10/101 enfermos renales precisaron un tratamiento adicional. La probabilidad que el paciente cree tener de ser víctima de un error con consecuencias graves fue establecida en 1:10. Las mujeres con enfermedad renal creyeron tener una mayor probabilidad de sufrir un error (Chi2=12,7, p=0,002). Los errores clínicos se atribuyeron a la falta de tiempo para atender a todos los pacientes y a la insuficiencia de medios y recursos, sin diferencias estadísticamente significativas entre las submuestras. Los pacientes entrevistados consideraron similar el riesgo de error clínico, accidente de tráfico, atraco. Conclusiones. La información que proporcionan los pacientes puede contribuir a mejorar la seguridad de los procedimientos de trabajo(AU)

Background. Diabetes and kidney disease are risk factors for adverse events (AE). There are no other studies on the perception of risk in these patients. This study analyzes the frequency of adverse event triggers reported by diabetic and renal patients and their perception of the risk. Material and methods. Descriptive study based on interviews with randomly selected patients. Field study conducted between February and May 2010 in three health centers and two hospitals in Alicante and Madrid. Results. A total of 199 patients answered, 98 diabetic patients and 101 renal patients. Renal patients accumulated more AE triggers (21.8% referred to an AE trigger, 17.8% two AE triggers and 3% referred to > 3 AE triggers) than diabetic patients (16.3% referred to one AE trigger, 7.1% to two AE triggers and 7.1% referred to > 3 AE triggers). During the last year 6/98 diabetic patients and 10/101 renal patients required additional treatment due to a clinical error. The probability of the patient being the victim of a clinical error with serious consequences was 1:10. Women with renal illness believed themselves to have a greater probability of suffering an error(Chi2=12.7, p=0.002). Errors were attributed to a lack of time to attend to all patients and a lack of means and resources, without statistically significant differences between the subsamples. Interviewed patients considered that the risks of suffering a traffic accident or robbery were similar to the risk of an error with serious consequences. Conclusion. Information provided by patients can help improve safety procedures(AU)

Seguridad clínica de los pacientes durante la hospitalización en pediatría / Clinical safety paediatric patients

Objetivo. Describir la incidencia y tipos de eventos adversos (EA) en pacientes en edad pediátrica y su evitabilidad. Material y métodos. Análisis de las hospitalizaciones pediátricas. Se utilizó la fusión de las bases de datos del Estudio nacional de efectos adversos ligados a la hospitalización (ENEAS), del Estudio de los efectos adversos de la asistencia hospitalaria en el Principado de Asturias (EAPAS) y del Estudio de los efectos adversos de la asistencia hospitalaria en Aragón, configurando una muestra de 41 hospitales y 8.407 historias revisadas. Evento adverso fue considerado todo daño causado más por la asistencia sanitaria que por el proceso de enfermedad. Resultados. Identificamos 24 pacientes pediátricos que sufrieron un EA, que acumularon un total de 29 EA. Frente a los pacientes adultos, los niños sufrieron una menor proporción de EA, de tal forma que, tomando como categoría de referencia los pacientes de 16 a 44 años, ser menor de esa edad supone una reducción del riesgo a la mitad. El 3,61% de los pacientes pediátricos sufrieron un EA y el 65,5% (19) fueron evitables. La proporción de EA fue de 3,8% en lactantes (0-18 meses), 4,0% en preescolares, y 2,6% en niños de 6 a 16 años, comparados con un 6,4% en adultos jóvenes. Respecto al tipo de EA, los relacionados con la medicación (37,9%) fueron los EA más frecuentes en niños. Conclusiones. La epidemiología de los eventos adversos en niños es diferente a la de los adultos. Mejorar su conocimiento permitirá desarrollar estrategias para minimizarlos(AU)

Objective. To describe the incidence and types of adverse events in children and how they can be prevented. Material and methods. Analysis of paediatric hospitalisations in the ENEAS Study, the Asturias Study on hospitalisation –related adverse events (EAPAS) and the Aragon Study of the Adverse Effects related to the hospitalisation, which involved a retrospective medical record review of a population-based, representative sample of all paediatric hospital discharges. Adverse events were defined as an injury caused by medical management, rather than by disease processes. Results. We were able to identify 24 paediatric patients suffering 29 AEs directly associated with medical care. Compared to non-elderly adult patients, infants and adolescents suffered lower rates of adverse events. Of these, 65.5% (19 AE) were considered as preventable. Adverse events occurred in 3.61% of paediatric hospitalisations. Adverse events rates were 3.8% in infants (0-1.5 years), 4.0% in children 1.5–6 years of age, and 2.6% in children 7–16 years of age, compared with a rate of 6.4% in non-elderly adults. Medication related (37.9%) events were the most common types of adverse event. Conclusions. The epidemiology of adverse events in children is different to that in adults. To reduce the adverse events that occur in hospitalized children, knowledge of AE epidemiology in paediatric patients will help in the development of prevention strategies to avoid or to minimise them(AU)

[Clinical safety paediatric patients]. / Seguridad clínica de los pacientes durante la hospitalización en pediatría.

OBJECTIVE: To describe the incidence and types of adverse events in children and how they can be prevented. MATERIAL AND METHODS: Analysis of paediatric hospitalisations in the ENEAS Study, the Asturias Study on hospitalisation -related adverse events (EAPAS) and the Aragon Study of the Adverse Effects related to the hospitalisation, which involved a retrospective medical record review of a population-based, representative sample of all paediatric hospital discharges. Adverse events were defined as an injury caused by medical management, rather than by disease processes. RESULTS: We were able to identify 24 paediatric patients suffering 29 AEs directly associated with medical care. Compared to non-elderly adult patients, infants and adolescents suffered lower rates of adverse events. Of these, 65.5% (19 AE) were considered as preventable. Adverse events occurred in 3.61% of paediatric hospitalisations. Adverse events rates were 3.8% in infants (0-1.5 years), 4.0% in children 1.5-6 years of age, and 2.6% in children 7-16 years of age, compared with a rate of 6.4% in non-elderly adults. Medication related (37.9%) events were the most common types of adverse event. CONCLUSIONS: The epidemiology of adverse events in children is different to that in adults. To reduce the adverse events that occur in hospitalized children, knowledge of AE epidemiology in paediatric patients will help in the development of prevention strategies to avoid or to minimise them.

Estudio de la incidencia de los efectos adversos en el Complejo Hospitalario Universitario de Albacete / No disponible

Objetivo: El Objetivo de este estudio es determinar la incidencia de Efectos Adversos (EA) y de pacientes con EA en el Complejo Hospitalario Universitario de Albacete (CHUA). Método: Diseño. Estudio retrospectivo de cohortes.Ámbito de estudio. Pacientes dados de alta del 5 al 19 de Noviembre de 2006. Definición de caso: todo accidente o incidente recogido en la Historia Clínica que ha causado daño al paciente o lo hapodido causar, ligado sobre todo a las condiciones de la asistencia sanitaria y no a la enfermedad de base del paciente. Instrumentalización: Guía de cribado de efectos adversos, adaptada del estudio de Harvard. Versión española del Formulario Modular para revisión retrospectiva de casos, MRF2. Análisis estadístico: Análisis univariante, bivariante y un modelo de regresión logística. Resultados: La incidencia de pacientes con EA relacionados con laasistencia hospitalaria fue de 6,8%. La incidencia fue diferente significativamente según la edad, la presencia de factores de riesgo intrínsecos y ext nsecos (excluyendo el catéter venoso periférico). El 8,2% de los EA se relacionó con los cuidados, el 14,3% con la medicación, el 26,5% con las infecciones nosocomiales, el 35,7% con problemas técnicos durante unprocedimiento, el 11,2% con el diagnóstico y el 4,1% restante con otros tipos de EA. El 12,2% se consideró leve, el 78,6% moderado y el 8,2% grave. El 50% de los EA aumentó la estancia, y en un 34,7% el EA condicionó el ingreso. El 63,3% de los EA se consideró evitable. Conclusiones: El Estudio de EA en el CHUA constituye un aspecto de mejora dentro del programa de calidad del Hospital. Las incidencias de pacientes con EA relacionadas con la asistencia sanitaria se encuentran entre las alcanzadas en el conjunto de estudios cuyo objetivo es la mejora de la calidad (AU)

Objective: To determine the incidence of adverse effects AE in the University Hospital complex of Albacete (CHUA). Method: Retrospective cohort study. Patients discharged from 5 to 19 November 2006. Case definition: every accident or incident in the Medical record that has caused harm to the patient or has been able to cause it, linked to the conditions of health care and noto the patient basel disease. Instrumentalization: Review of the medical records during the stay through the screening guide and the IDEA project adapted MRF2. Statistical analysis: univariate, bivariate analysis and a logistic regression model.Results: The incidence of patients with EA related to hospital healthcare was 6.8%. The incidence was significantly different depending on the age, the presence of intrinsic and extrinsic risk factors (excluding peripheral venous catheter). 8.2% was related to care, 14.3% with medication, 26.5% with nosocomial infections, 35.7% with technical problems during a procedure, 11.2% with diagnosis and 4 % with other types of EA. 12.2% was considered mild, moderate 78.6% and 8.2% serious. 50% increased stay and 34.7% conditioned the entry. 63.3% was considered avoidable. Conclusion: The study of EA in the CHUA is an aspect of improving programme quality hospital. Incidences of patients with EA related to healthcare are among the accomplished throughout the studies aiming to improve quality (AU)

La vulnerabilidad del paciente en la génesis de los efectos adversos en un hospital de crónicos y larga estancia / No disponible

Objetivo: Explorar la asociación de las características del propio paciente y de la asistencia en la aparición de los Efectos Adversos (EA), en un hospital de atención a crónicos y larga estancia. Método: Estudios de prevalencia realizados durante la segunda semana del mes de Mayo durante los años 2005, 2006, 2007 y 2008. Se incluyeron todos los pacientes ingresados en el hospital el día del estudio. Cada cama se examinó sólo una vez. Revisión de las historias durante el ingreso con la guía de cribado y el MRF2 adaptado para el proyecto EPIDEA. Resultados: La prevalencia de pacientes con EA asociados a la asistencia fue de 6,6% (IC95%: 4,4-8,9%). Los EA más frecuentemente encontrados fueron los relacionados con los cuidados, seguidos de los relacionados con la medicación, y en tercer lugar los relacionados con la infección. Los factores de riesgo extrínsecos (excluyendo el catéter venoso periférico que portan un alto porcentaje de pacientes) y la estancia se asociaron a mayor riesgo de EA cuando controlábam por el resto de variables. Los factores de riesgo intrínsecos y las comorbilidades no explicaban la prevalencia en nuestra muestra. Conclusiones: La presencia de factores de riesgo extrínsecos en el enfermo favorece la aparición de EA. Esto nos hace pensar que el verdadero riesgo reside en el número de exposiciones a actos potencialmente iatrogénicos más que a la vulnerabilidad del paciente (AU)

Objective: To explore the association between patient characteristics and health care circumstances with the presence of Adverse Events (AE) in a long stay and chronic care hospital. Methods: Prevalence studies carried out during the second week of May in 2005, 2006, 2007 and 2008. All the patients admitted in hospital were included. Review of the medical records during the stay through the screening guide and the EPIDEA project adapted MRF2. Results: The prevalence of patient with AE related to care was 6,6% (95%CI 4,4-8,9%). The most frequent AE found were those related to nurse care, followed by those related to medication, and in third place those related to infection. The extrinsic risk factors and the length of stay were associated with a higher risk of AE when adjusting with the rest of variables. The intrinsic risk factors and comorbidities didn’t explain the prevalence in our sample. Conclusions: The presence of certain extrinsic risk factors facilitates the appearance of AE. This makes us think th the true risk resides more in the number of expositions to acts potentially dangerous than in the patient's vulnerability (AU)

Evolución de la prevalencia de eventos adversos relacionados con la asistencia en hospitales de la Comunidad Valenciana / Evolution of the adverse effects prevalence related to healthcare in hospitals of the Comunidad Valenciana

Objetivo. Mejorar el conocimiento en relación con la seguridad del paciente por medio de la aproximación a la magnitud, a la trascendencia y al impacto de los eventos adversos (EA) analizando las características de los pacientes y de la asistencia que se asocian a la aparición de estos. Material y método. Estudio transversal de prevalencia llevado a cabo durante una semana de mayo entre los años 2005–2008 en hospitales de la Comunidad Valenciana. Resultados. La prevalencia de EA en los hospitales participantes se mantuvo constante (en torno al 6%) durante los 4 años del estudio. La edad media y la distribución por sexos también se mantuvieron constantes. Los factores causales de EA predominantes en los 4 años fueron la infección nosocomial, los procedimientos y la medicación, en ese orden, aunque apreciamos un aumento de los EA debidos a infección nosocomial en el período de estudio. Respecto a la gravedad, se observó una disminución del porcentaje de EA graves (el 31,5 en 2005 vs. el 17,8% en 2008), así como un aumento de la proporción de evitables desde un 50,8 a un 63,2% en 2008. Conclusiones. El diagnóstico de situación realizado nos acerca a la necesidad de un cambio cultural entre los profesionales, que facilite la promoción de la cultura proactiva para la seguridad del paciente, y permite anticiparse a un problema de creciente repercusión social. Conocer la epidemiología de los EA facilitará desarrollar estrategias y mecanismos de prevención para evitarlos o minimizarlos(AU)

Objective. Improvement of knowledge on patient safety by a study of the number, importance and impact of Adverse Events (AEs), analysing the patient and healthcare characteristics associated with their occurrence. Material and methods. Cross-sectional study of prevalence carried out for one week every year in the years 2005–2008 in hospitals of the Comunidad Valenciana. Results. AE prevalence in participating hospitals remained constant at around 6 % during the four years of study. The mean age and sex distribution were also constant. The predominant causal factors of AEs were nosocomial infection, procedures and medicines, in that order, although we did observe an increase in AEs due to nosocomial infection during the period of study. With regard to severity, we observed a decrease in the percentage of serious AEs (31.5 % in 2005 vs.17.8 % in 2008), as well as an increase in the proportion of avoidable AEs from 50.8 % to 63.2 % in 2008. Conclusions. The results of the study demonstrate the need for a cultural change among professionals that will stimulate the promotion of a proactive culture for patient safety, and allows us to anticipate a social problem of increasing repercussions. Knowledge of EA epidemiology will help in the development of prevention strategies to avoid or to minimise them(AU)

Factores asociados a las infecciones evitables relacionadas con la atención sanitaria identificados en el Estudio EPIDEA / No disponible

Objetivo: Explorar las características de los pacientes y de la asistencia asociadas con la infección relacionada con la atención sanitaria que puede ser evitable (IRASE). Método: Estudio transversal en 14 hospitales de la Comunidad Valenciana, en el que se estudiaron todos los pacientes ingresados en un día dado durante la segunda semana de Mayo de 2008. Para la identificación de las IRASE y sus factores asociados se revisó la historia clínica del paciente pidiendo al revisor un juicio de valor sobre en qué medida la asistencia era la causante de la infección relacionada con la atención sanitaria (IRAS) y si había indicios de que pudiera haberse evitado. Resultados: En el 2,2% de los pacientes se pudo identificar una IRAS evitable (supusieron el 63% de las IRAS). Las localizaciones más frecuentes de la IRASE fueron: herida quirúrgica (41,6%); sangre (20,2%); tracto respiratorio (15,7%) y tracto urinario (7,9%). Los factores que se vieron asociados a la presencia de IRASE fueron que el paciente tuviese insufi iencia renal, obesidad, desnutrición, hipertensión o el hecho de ser prematuro; y que durante su asistencia se le hubiera insertado un catéter central de inserción periférica, un catéter venoso central o se le hubiera practicado una traqueostomía. Conclusión: Los pacientes con IRAS evitables presentan características diferenciadas de los que no las presentan. Tener en cuenta estos factores permitirá diseñar estrategias específicas para favorecer su control (AU)

Objective: To explore the patients and care characteristics that are related to health care-associated infections (HCAI) that can be avoidable. Method: Cross sectional study in 14 hospitals in the Comunidad Valenciana region, in which all patients admitted on a given identify the HCAI and associated factors the medical records were reviewed asking the reviewer a value judgment about how likely the health care was the cause of the infections and whether there was evidence that could have been avoided. Results: A total of 2.2% of patients were identified presenting avoidable HCAI (63% of the HCAI). The most common locations of the HCAI were surgical (41.6%), blood (20.2%) respiratory tract (15.7%) and urinary tract (7.9%). The factors that were associated with the presence of HCAI were the patient's renal insufficiency, obesity, malnutrition, hypertension or being premature, and that during their stay having been used a peripherally inserted central catheter, central venous catheter or performed a tracheostomy Conclusions: Patients with preventable HCAI have identifiable characteristics. Consider these factors will enable specific strategies to facilitate their control (AU)

[Evolution of the adverse effects prevalence related to healthcare in hospitals of the Valencia community]. / Evolución de la prevalencia de eventos adversos relacionados con la asistencia en hospitales de la Comunidad Valenciana.

OBJECTIVE: Improvement of knowledge on patient safety by a study of the number, importance and impact of Adverse Events (AEs), analysing the patient and healthcare characteristics associated with their occurrence. MATERIAL AND METHODS: Cross-sectional study of prevalence carried out for one week every year in the years 2005-2008 in hospitals of the Comunidad Valenciana. RESULTS: AE prevalence in participating hospitals remained constant at around 6 % during the four years of study. The mean age and sex distribution were also constant. The predominant causal factors of AEs were nosocomial infection, procedures and medicines, in that order, although we did observe an increase in AEs due to nosocomial infection during the period of study. With regard to severity, we observed a decrease in the percentage of serious AEs (31.5 % in 2005 vs.17.8 % in 2008), as well as an increase in the proportion of avoidable AEs from 50.8 % to 63.2 % in 2008. CONCLUSIONS: The results of the study demonstrate the need for a cultural change among professionals that will stimulate the promotion of a proactive culture for patient safety, and allows us to anticipate a social problem of increasing repercussions. Knowledge of EA epidemiology will help in the development of prevention strategies to avoid or to minimise them.