Estudio de la prevalencia de infecciones relacionadas con la asistencia sanitaria y factores asociados en un hospital de larga estancia de la comunidad de Madrid

• Autores: María del Pilar Cárdenas Soriano
• Directores de la Tesis: Gil Rodríguez Caravaca (dir. tes.)
• Lectura: En la Universidad Rey Juan Carlos ( España ) en 2026
• Idioma: español
• Tribunal Calificador de la Tesis: Juan José Criado Álvarez (presid.), Ángel Gil de Miguel (secret.), María del Pilar Martínez Barranco (voc.)
• Programa de doctorado: Programa de Doctorado en Ciencias de la Salud por la Universidad Rey Juan Carlos
• Calificación: Sobresaliente Cum Laude
• Enlaces
  • Tesis en acceso abierto en: TESEO
• Resumen
  • español

    ANTECEDENTES Las Infecciones Relacionadas con la Asistencia Sanitaria (IRAS) son aquellas infecciones que se adquieren en el contexto de la recepción de cuidados sanitarios, bien sea en hospitales tradicionales de agudos, centros de salud comunitaria o consultorios, hospitalización a domicilio, o centros y hospitales de larga estancia.

    La aparición de una IRAS está influenciada por la presencia de factores de riesgo clásicos, intrínsecos y extrínsecos, que aumentan la susceptibilidad del huésped.

    Las IRAS suponen un importante problema de salud pública, ubicuo y costoso a nivel de pérdida de la salud, de recursos de los sistemas sanitarios, y de años de vida. Suponen un aumento en el gasto directo e indirecto, y sus efectos deletéreos repercuten en la seguridad de los pacientes y en la reputación de los profesionales y de los sistemas sanitarios. Se ha estimado que el impacto de estas infecciones es incluso mayor cuando están causadas por microorganismos multirresistentes.

    Así, suponen una de las causas más importantes de eventos adversos en el marco de la seguridad del paciente, siendo el más frecuente en el territorio europeo, estimándose que ocurren cerca de 9 millones de IRAS al año. La carga de enfermedad de estas infecciones supera a la de otras infecciones en discapacidad y años de vida perdidos, también incrementan la duración de las hospitalizaciones y precipitan la necesidad de nuevas intervenciones y tratamientos.

    Por todo ello, cobran especial importancia las intervenciones de prevención y control de la infección nosocomial, que podrían disminuir la incidencia de IRAS hasta en un 70 %. De esta manera, desde la Comisión Europea y el Consejo de Europa se insta a los países miembros a establecer la prevención de la infección como una línea de seguridad del paciente esencial. También se han establecido mínimos legales vinculantes para que los países europeos establezcan programas específicos, que incluyan la lucha contra las IRAS entre sus líneas prioritarias, con intervenciones basadas en la evidencia científica y dándole un papel protagonista a los programas de vigilancia.

    La vigilancia epidemiológica de las IRAS se realiza en la actualidad de manera heterogénea en el territorio europeo y español. Para paliar las deficiencias en los sistemas de vigilancia se vienen realizando numerosos esfuerzos en los últimos años, por parte de organismos internacionales como el ECDC, y de las administraciones públicas de las Comunidades Autónomas y el estado. Estos esfuerzos tienen como fin establecer sistemas de calidad que permitan la actuación temprana y la recogida de indicadores comparables.

    Destaca entre estos sistemas el impulsado por la sociedad española de Medicina Preventiva, Salud Pública y Gestión Sanitaria, EPINE (Estudio de la Prevalencia de Infección Nosocomial en España), integrado también en el marco de la vigilancia europea de prevalencia de las IRAS.

    Este relevante estudio se estableció desde sus orígenes como la referencia en cuanto a infecciones nosocomiales por su alta fiabilidad y representatividad de los hospitales españoles, estableciendo como IRAS más frecuentes las de la herida quirúrgica, el tracto respiratorio, y el tracto urinario.

    Teniendo en cuenta la definición de las IRAS, y los sistemas aplicados a su vigilancia, existe una disparidad notable en la investigación en los hospitales de agudos, que han recibido una atención mayoritaria, y los centros de salud, los cuidados a domicilio o los hospitales de larga estancia, que han sido tradicionalmente infraestudiados.

    Los centros de larga estancia fueron originalmente concebidos para dar apoyo a hospitales de agudos, o como recurso habitacional para personas con enfermedades crónicas o problemática social. Hoy en día, siguen siendo un grupo heterogéneo de establecimientos donde se proporcionan cuidados sanitarios de diversa índole. Los hospitales de larga estancia tienen en común, que atienden a pacientes ya diagnosticados y precisan cuidados en régimen de hospitalización por procesos de convalecencia, vigilancia o rehabilitación.

    Es habitual que la mayoría de los pacientes atendidos en los hospitales de larga estancia sean adultos mayores, más envejecidos que los atendidos en centros de agudos, y que, además, tengan una alta frecuencia de comorbilidades. También es habitual la presencia de otros factores de riesgo. La sinergia de estos factores los hace especialmente vulnerables a sufrir eventos adversos. Entre estos cobran una especial relevancia las Infecciones Relacionadas con la Asistencia Sanitaria.

    El aumento de la susceptibilidad a infecciones no sólo se relaciona con el antecedente de múltiples enfermedades crónicas. También está asociado a fenómenos ligados al envejecimiento, como la inmunosenescencia. Por otra parte, la estancia en los hospitales de larga estancia también incrementa el riesgo de brotes, infección y colonización por multirresistentes, lo que perpetúa un complejo ciclo de transmisión de microorganismos entre los distintos tipos de centros.

    La laguna de conocimiento acerca de la frecuencia de las IRAS en hospitales de larga estancia justifica la presente tesis, que pretende contribuir al conocimiento sobre la infección nosocomial en hospitales de larga estancia mediante estudios de prevalencia.

    OBJETIVOS Se estableció como objetivo principal de la presente tesis calcular la prevalencia de las Infecciones Relacionadas con la Asistencia Sanitaria que se adquirieron durante el ingreso en curso en el momento de la encuesta, y los factores que se asociaron al evento de infección en un hospital de larga estancia de la Comunidad de Madrid.

    Los objetivos secundarios fueron identificar las características demográficas de los participantes, y describir la prevalencia de IRAS adquiridas en el ingreso de manera global y a lo largo de las cinco ediciones de la encuesta de prevalencia.

    También se definió como objetivo específico el conocer cuáles fueron las especies de microorganismos causantes de las IRAS identificadas, y analizar qué factores de las variables estudiadas se asociaron con el resultado de infección nosocomial, atendiendo a la localización de dicha infección, en general y en cada año de la encuesta.

    Por último, se plantearon como objetivos secundarios comparar la prevalencia de IRAS detectadas en el hospital de larga estancia local, con la prevalencia de infección nosocomial adquirida en el mismo ingreso en los centros de agudos y crónicos de referencia nacional, y en los centros de larga estancia de referencia a nivel europeo.

  • English

    BACKGROUND Healthcare-Associated Infections (HAIs) are those infections acquired within the context of receiving healthcare, whether the care takes part in traditional acute hospitals, community healthcare centres, home hospitalization or long-term care hospitals and centres.

    Suffering HAIs is related to the presence of classical risk factors, both intrinsic and extrinsic, that increase patient’s vulnerability.

    These infections remain an important public health issue, which is ubiquitous and poses other problems, such as decreased health status and life expectancy, and increased healthcare associated costs. They are related to increased costs, both direct and indirect, and its undesirable effects have great impact on patient safety and the reputation of healthcare professionals and systems. It has been estimated that this impact is even greater when caused by multi-resistant microorganisms.

    Therefore, HAIs are one of the most important adverse effect (AE) causes within the patient safety perspective. Besides, they are one of the most frequent AE in Europe, being estimated that almost 9 million HAIs occur per year. The burden of disease of HAIs suppose greater lost in terms of Disability-Adjusted Life Years and Years of Life Lost than other infections. They also are accountable for increased hospital stays and drive the need for new treatments and interventions.

    Infection prevention and control interventions are of most importance in these settings. These could decrease HAIs incidence up to 70%. The European Commission and the Council of Europe urge member countries to establish infection prevention measures as an essential tool for patient safety. Legal binding procedures have been established to impulse these measures, and strengthen the fight against HAIs as a priority, relying on the best scientific evidence and surveillance programmes.

    Currently, the epidemiological surveillance programmes for HAIs is conducted in a heterogeneous manner across European and Spanish territories. To alleviate deficiencies in surveillance systems, numerous efforts have been made in recent years, both by international bodies (such as the European Centre for Disease Control, or ECDC) and the Autonomous Communities and the state. The aim of these efforts is to establish quality systems that allow for early action and collecting comparable indicators.

    One of the most epidemiological surveillance programmes, EPINE (Nosocomial Infection Prevalence Study in Spain), is promoted by the Spanish Preventive Medicine, Public Health and Health Management society, assimilated in the European prevalence surveillance system. This relevant study has become the reference for HAIs due to its high reliability, representativeness of national hospitals, and other quality standards. It has shown that surgical site infections, respiratory tract infections, and urinary tract infections are the most frequent nosocomial infections in the territory.

    Taking into account HAIs definition and surveillance systems, there is great disparity in research, where acute hospitals have always been prioritized against health community centres, home hospitalization and long-term care.

    Long-term care hospitals (LTCH) were in origin created as a support resource for acute hospital patients, or as home solution for chronic patients or whether social issues were involved. Today, they still are a great group of heterogeneous establishments where different care is provided. Long-term care hospitals usually admit already diagnosed patients who require inpatient care for recovery, monitoring, or rehabilitation.

    Usually, most patients that are taken care in LTCH are older adults (and older than those in acute care hospitals), and have frequent comorbidities. Other risk factors are also frequent. There is a synergy between these factors that increase the vulnerability against adverse effects, being HAIs one of the most relevant ones.

    The increase in infection susceptibility is related to multi-morbidity, and senescence-related changes, such as immunosenescence. Besides, LTCH also have increased risk for outbreaks, infection, and colonization by multi-resistant microorganisms, which perpetuates a complex cycle of pathogens transmission between acute and long-term care hospitals.

    There is a knowledge gap on the frequency of HAIs in LTC. This thesis aims at contributing with knowledge about nosocomial infection prevalence in a long-term care hospital.

    OBJECTIVES The main objective was to calculate the prevalence of HAIs acquired during hospitalization at the time of the survey, and to know infection associated factors in a long-term care hospital in the Autonomous Community of Madrid.

    Secondary objectives included categorizing patient’s demographic features, and describing HAIs prevalence during hospitalization, both globally and on each of the five editions of the survey.

    The study also aimed to characterize the microorganisms species involved in HAIs identified, and analysing associated factors with the infection outcome. The association was calculated globally, by infection location and by year of the study.

    Lastly, other secondary objectives were to compare HAIs prevalence in the present thesis with the prevalence found in acute care hospitals and long-term care hospitals in the national prevalence study, and in the European prevalence study.

    METHODS A descriptive and point-prevalence study took place during five editions (years 2019, 2021, 2023, 2024, and 2025), in order to know HAIs prevalence acquired during hospitalization in a long-term care hospital.

    The chosen hospital was the University Hospital “Virgen de la Poveda”. This is a reference centre in the Community of Madrid for patients who require rehabilitation, continuous care or palliative care. The centre can receive population for the whole region and other parts of the country, but it mainly takes care of people living in the western region administrative area, and serves about 770.000 inhabitants.

    The population within the reference area is considered to be aging. Rehabilitation services suppose half of the activity in the centre annually. Other common activities include the care of complex wounds and ulcers, rehabilitation processes after fractures in older people (who require physical conditioning), recovery after acute cerebral vascular accident, or care of patients with neurodegenerative diseases.

    The centre is able to adapt on its capacity and counts on a maximum of 176 beds for inpatients. About 800 – 1000 hospitalizations take place annually, with a medium hospital length of stay of more than 50 days. We determined a sample size of 76 patients annually to determine an infection prevalence of 10%, with a 95% confidence. Finally, all patients hospitalized with inclusion criteria hospitalized on the day of the survey were included (154 in 2019, 84 in 2021, 142 in 2023, 124 in 2024, and 125 patients 2025).

    Inclusion criteria were being 18 years of age or older at the time of the survey, and being hospitalized since 08:00 that same day or before.

    A subject number was assigned to each patient consecutively and demographic information was obtained about sex and age. Other variables included the presence of extrinsic classical risk factors for infection such as ulcers, urinary catheter or recent surgery.

    Hospitalization unit, day of admission and day of the survey were also included. The event of HAIs was defined as an infection whose symptoms and/or signs were present at the time of the survey and had begun 48 hours after admission; or surgical site infection that appeared in the three months after surgery (with implant), or in the first month if no implant was involved.

    When a HAIs was detected, its location was noted, as well as the presence or absence of samples/diagnostic test. Results were also registered, as well as the presence of meticilin resistance for Staphylococcus aureus, and carbapenemase productive enterobacteriaceae.

    Primary data were registered by an infection prevention and control specialist physician from the University Hospital Fundación Alcorcón. This hospital supports the centre of the study in infection prevention and control. A database was filled in for each edition (that varied every year). All information was anonymized.

    Descriptive analysis was performed globally and stratified per year and unit of hospitalization. Frequencies and 95% confidence intervals were used for qualitative variables; and median and interquartile ranges were used for describing quantitative variables, after the Shapiro-Wilk test was applied.

    The Cochran-Armitage test was used to assess tendency on infection prevalence. Quantitative variables between two groups were compared with the Mann-Whitney U test, and the Kruskal-Wallis test was used to compare more than two groups. The Chi-squared test was used to compare frequencies.

    Z test was used to compare prevalence obtained in the present thesis with those of reference drawn from the EPINE study and the HALT (Healthcare-Associated Infections in Long-Term Care Facilities) study.

    A bivariate analysis was performed with logistic regression to obtain crude Odds Ratios, and multiple logistic regression was used to obtain adjusted odds ratios. These were calculated globally and per year of the study.

    The study was approved by the Ethics Committee with informed consent exemption.

    CONCLUSIONS A high prevalence of Healthcare-Associated Infections in a long-term care hospital was found. Prevalence was higher than in acute care hospitals, which aligns with the hypothesis that states than LTCH are risk environments for adverse effects.

    Inpatients in LTCH have characteristics that increase their risk to acquire HAIs. These are intrinsic risk factors, such as age, and extrinsic, such as long stays or the presence of invasive devices.

    No statistically significant differences, nor tendencies, were found in HAIs prevalence amongst the editions of the study.

    Respiratory tract infections were the most frequent globally, and on the years 2019, 2023, and 2025, and also in patients with any risk factor at the time of the survey.

    The presence of any risk factor was statistically associated with higher odds of HAIs.