Incidencia y costes de la hospitalización por bronquiolitis y de las infecciones por virus respiratorio sincitial en la Comunidad Valenciana. Años 2001 y 2002

A Multivariate Age-Structured Stochastic Model with Immunization Strategies to Describe Bronchiolitis Dynamics

Bronchiolitis has a high morbidity in children under 2 years old. Respiratory syncytial virus (RSV) is the most common pathogen causing the disease. At present, there is only a costly humanized monoclonal RSV-specific antibody to prevent RSV. However, different immunization strategies are being developed. Hence, evaluation and comparison of their impact is important for policymakers. The analysis of the disease with a Bayesian stochastic compartmental model provided an improved and more natural description of its dynamics. However, the consideration of different age groups is still needed, since disease transmission greatly varies with age. In this work, we propose a multivariate age-structured stochastic model to understand bronchiolitis dynamics in children younger than 2 years of age considering high-quality data from the Valencia health system integrated database. Our modeling approach combines ideas from compartmental models and Bayesian hierarchical Poisson models in a novel way. Finally, we develop an extension of the model that simulates the effect of potential newborn immunization scenarios on the burden of disease. We provide an app tool that estimates the expected reduction in bronchiolitis episodes for a range of different values of uptake and effectiveness.

[An initiative to reduce the use of unnecessary medication in infants with bronchiolitis in primary care]

INTRODUCTION AND OBJECTIVE

Although evidence-based guidelines for acute bronchiolitis recommend primarily supportive care unnecessary treatments remain well documented. The objective of this study was to analyse a quality improvement initiative to reduce overuse of unnecessary treatments in infants with acute bronchiolitis in primary care settings.

METHOD

To determine the number of unnecessary treatments we reviewed the charts corresponding to infants aged <24 months of age diagnosed with acute bronchiolitis in two Primary Care areas during two bronchiolitis seasons [October-Mars of 2015-2016 (pre-intervention period) and 2016-2017 (post-intervention period)]. Between those seasons we distributed an evidence-based management protocol and developed interactive sessions with on-line data collection and feed-back. Outcomes were the rate of infants receiving salbutamol, steroids or antibiotics.

RESULTS

Twenty outpatient clinics contributed with 1,277 chart reviews (619 in the pre-intervention period and 658 in the post-intervention period). Overall, the use of any medication was reduced from 72.5% (95% CI, 68.8-75.9) to 52.1% (95% CI, 48.3-55.9) (p<0.01): salbutamol from 56.0% (95% CI, 52.1-59.9) to 38.3% (95% CI, 34.6-42.0) (p<0.01), corticosteroids from 23.7% (95% CI, 20.5-27.2) to 12.9% (95% CI, 10.5-15.7) (p<0.01) and antibiotics from 36.1% (95% CI; 32.5-40.0) to 29.6% (95% CI; 26.2-33.2) (p<0.05). The number of medications per patient decreased from a mean of 1.81 (SD: 0.86) to 1.62 (SD: 0.81) (p<0.01).

CONCLUSIONS

We significantly decreased the use of unnecessary treatments in infants with acute bronchiolitis. This quality improvement initiative may be applied to the settings where the majority of infants with acute bronchiolitis are attended in western countries.

Defining the Epidemiology and Burden of Severe Respiratory Syncytial Virus Infection Among Infants and Children in Western Countries

INTRODUCTION

The REGAL (RSV [respiratory syncytial virus] Evidence-a Geographical Archive of the Literature) series provides a comprehensive review of the published evidence in the field of RSV in Western countries over the last 20 years. This first of seven publications covers the epidemiology and burden of RSV infection.

METHODS

A systematic review was undertaken for articles published between Jan 1, 1995 and Dec 31, 2015 across PubMed, Embase, The Cochrane Library, and Clinicaltrials.gov. Studies reporting data for hospital visits/admissions for RSV infection among children (≤18 years of age), as well as studies reporting RSV-associated morbidity, mortality, and risk factors were included. Study quality and strength of evidence (SOE) were graded using recognized criteria.

RESULT

2315 studies were identified of which 98 were included. RSV was associated with 12-63% of all acute respiratory infections (ARIs) and 19-81% of all viral ARIs causing hospitalizations in children (high SOE). Annual RSV hospitalization (RSVH) rates increased with decreasing age and varied by a factor of 2-3 across seasons (high SOE). Studies were conflicting on whether the incidence of RSVH has increased, decreased, or remained stable over the last 20 years (moderate SOE). Length of hospital stay ranged from 2 to 11 days, with 2-12% of cases requiring intensive care unit admission (moderate SOE). Case-fatality rates were <0.5% (moderate SOE). Risk factors associated with RSVH included: male sex; age <6 months; birth during the first half of the RSV season; crowding/siblings; and day-care exposure (high SOE).

CONCLUSION

RSV infection remains a major burden on Western healthcare systems and has been associated with significant morbidity. Further studies focusing on the epidemiology of RSV infection (particularly in the outpatient setting), the impact of co-infection, better estimates of case-fatality rates and associated risk factors (all currently moderate/low SOE) are needed to determine the true burden of disease.

FUNDING

Abbvie.

[High flow nasal cannula oxygen therapy in the treatment of acute bronchiolitis in neonates]

OBJECTIVE

To determine whether the availability of heated humidified high-flow nasal cannula (HFNC) therapy was associated with a decrease in need for mechanical ventilation in neonates hospitalised with acute bronchiolitis.

METHODS

A combined retrospective and prospective (ambispective) cohort study was performed in a type II-B Neonatal Unit, including hospitalised neonates with acute bronchiolitis after the introduction of HFNC (HFNC-period; October 2011-April 2015). They were compared with a historical cohort prior to the availability of this technique (pre-HFNC; January 2008-May 2011). The need for mechanical ventilation between the two study groups was analysed. Clinical parameters and technique-related complications were evaluated in neonates treated with HFNC.

RESULTS

A total of 112 neonates were included, 56 after the introduction of HFNC and 56 from the period before the introduction of HFNC. None of patients in the HFNC-period required intubation, compared with 3.6% of the patients in the pre-HFNC group. The availability of HFNC resulted in a significant decrease in the need for non-invasive mechanical ventilation (30.4% vs 10.7%; P=.01), with a relative risk (RR) of .353 (95% CI; .150-.829), an absolute risk reduction (ARR) of 19.6% (95% CI; 5.13 - 34.2), yielding a NNT of 5. In the HFNC-period, 22 patients received high flow therapy, and 22.7% (95% CI; 7.8 to 45.4) required non-invasive ventilation. Treatment with HFNC was associated with a significant decrease in heart rate (P=.03), respiratory rate (P=.01), and an improvement in the Wood-Downes Férres score (P=.00). No adverse effects were observed.

CONCLUSIONS

The availability of HFNC reduces the need for non-invasive mechanical ventilation, allowing a safe and effective medical management of neonates with acute bronchiolitis.

Population-based Analysis of Bronchiolitis Epidemiology in Valencia, Spain

BACKGROUND

There is a lack of European epidemiologic population-based studies on bronchiolitis and respiratory syncytial virus (RSV) bronchiolitis including both hospitalizations and primary care attendance.

METHODS

A retrospective cohort of all children born between 2009 and 2012 was followed from birth to 2 years of age using population and health databases. We searched for global bronchiolitis (International Classification of Diseases, 9th revision, Clinical Modification codes 466.1, 466.11 and 466.19) and RSV bronchiolitis (code 466.11 and code 466.19 with positive RSV test) in the first appearance either in primary care or in hospitalization databases. A preterm subcohort (International Classification of Diseases, 9th revision, Clinical Modification codes 765) was also analyzed.

RESULTS

The cohort consisted of 198,223 children of whom 41,479 were diagnosed of bronchiolitis (incidence rate 16.4/100 children <2 years per year). Of those, 5390 were hospitalized with the majority of hospitalizations occurring at <6 months of age (incidence rate of 5.2/100 children <6 months per year) and 3106 of the hospitalizations were RSV positive (incidence rate 3.2/100 children <6 months per year). RSV hospitalizations were 26% longer than non-RSV. In preterm infants, hospitalization incidence was more than double, and the mean length of hospitalization was 29% longer.

CONCLUSIONS

Most (87%) bronchiolitis cases are managed in primary care offices. Approximately 2 out of every 10 children <2 are diagnosed of bronchiolitis, 3 out of every 100 are hospitalized and 1.6 out of every 100 are hospitalized with RSV bronchiolitis in our cohort. Infants between 2 and 10 weeks constitute a risk group for severe bronchiolitis.

Respiratory Syncytial Virus Bronchiolitis in Children up to 5 Years of Age in Spain: Epidemiology and Comorbidities: An Observational Study

This epidemiological survey in Spain estimates the burden of respiratory syncytial virus (RSV) infection in children up to 5 year of age during a 15-year period (1997-2011). Observational retrospective survey was conducted by reviewing data of the National Surveillance System for Hospital Data, including >98% of Spanish hospitals. All hospitalizations related to RSV infection for children up to 5 years, reported during 1997-2011 period, were analyzed. Codes were selected by using the International Classification of Diseases 9th Clinical Modification 466.0-466.19, 480.1, and 079.6. A total of 326,175 and 286,007 hospital discharges for children up to 5 and 2 years of age were reported during the study period. The annual incidence was 1072 and 2413 patients per 100,000, respectively. The average length of hospital stay was 5.7 (standard deviation 8.2) days. Four hundred forty-six deaths were reported; of those, 403 occurred in children <2 years and 355 (80%) occurred in children <12 months of age. Hospitalization and mortality rates were significantly higher in boys and decrease significantly with age. The higher rate of hospitalization and mortality rates were found in the first year of life. Annual average cost for National Health Care System was € 47 M with a mean hospitalization cost of €2162. The average length of hospitalization and costs were significantly higher in high-risk children. RSV infections in children up to 5 year of age still pose a significant health threat in Spain, especially in the infants. The development of preventive, diagnostic, and therapeutic guidelines focused in children with comorbidities may help reduce the hospital and economic burden of the disease.

Bronchiolite del lattante

La bronchiolite è un’infezione virale stagionale delle vie respiratorie basse del lattante. Il suo agente causale principale è il virus respiratorio sinciziale. La comparsa di un distress respiratorio è legata all’intensità della risposta infiammatoria delle vie aeree. Benché si tratti di una malattia frequente, le cause della suscettibilità dei lattanti a questa infezione non sono conosciute. La diagnosi è clinica. Il trattamento è sintomatico in assenza di misure specifiche. I rapporti a medio e a lungo termine di un primo episodio di bronchiolite con le recidive e con l’asma non sono spiegati. Essi potrebbero dipendere dalla natura del virus in causa al momento del primo episodio e da fattori genetici individuali.

Fatality rates in published reports of RSV hospitalizations among high-risk and otherwise healthy children

OBJECTIVE

To review the fatalities among children hospitalized with respiratory syncytial virus (RSV) infection, and identify factors leading to a fatal outcome.

RESEARCH DESIGN AND METHODS

Review of literature identified from a structured search of PubMed (1966-2009) using the following Medical Subject Headings: respiratory syncytial virus infection; hospitalized; infants; and risk factors. Publications were restricted to: English language; full papers; inclusion of > or =10 subjects; children aged < or =18 years, hospitalization for RSV infection; and deaths reported. Case fatality rates were defined as number of deaths divided by number of children hospitalized for RSV and were calculated for each study.

RESULTS

Thirty-six studies met the inclusion and exclusion criteria. Case fatality rates among children hospitalized for RSV ranged from 0 to 33%. In general, studies showed that subgroups of high-risk children (chronic lung disease [CLD] 3.5-23%, congenital heart disease [CHD] 2-37%, and prematurity 0-6.1%) had higher fatality rates than older or otherwise healthy children (consistently <1%). Presence of severe underlying comorbidities such as neuromuscular disease, immunosuppression, and malignancies was associated with death among term and/or older (>1 year) children. Higher fatality rates were reported for infants receiving intensive unit care (1.1-8.6%), extracorporeal life support (33%) or for those who acquired nosocomial RSV infection (0-12.2%). The majority of studies did not report cause of death and clinical details of the fatal cases were often not provided. Other limitations of this review include our search limits, the possibility of inherent bias in our methodology that could result in an under or over estimation of case-fatality rates, and potential publication bias.

CONCLUSIONS

Children at high risk for RSV (CLD, CHD and prematurity), those with severe underlying comorbidities, or those with nosocomial RSV appear to be at increased risk for death after RSV hospitalization. More data are needed on cause of death and how much is directly attributable to RSV.

Burden of paediatric Rotavirus Gastroenteritis (RVGE) and potential benefits of a universal Rotavirus vaccination programme with a pentavalent vaccine in Spain

BACKGROUND

Rotavirus is the most common cause of gastroenteritis in young children worldwide. The aim of the study was to assess the health outcomes and the economic impact of a universal rotavirus vaccination programme with RotaTeq, the pentavalent rotavirus vaccine, versus no vaccination programme in Spain.

METHODS

A birth cohort was followed up to the age of 5 using a cohort model. Epidemiological parameters were taken from the REVEAL study (a prospective epidemiological study conducted in Spain, 2004-2005) and from the literature. Direct and indirect costs were assessed from the national healthcare payer and societal perspectives by combining health care resource utilisation collected in REVEAL study and unit costs from official sources. RotaTeq per protocol efficacy data was taken from a large worldwide rotavirus clinical trial (70,000 children). Health outcomes included home care cases, General Practioner (GP)/Paediatrician, emergency department visits, hospitalisations and nosocomial infections.

RESULTS

The model estimates that the introduction of a universal rotavirus vaccination programme with RotaTeq (90% coverage rate) would reduce the rotavirus gastroenteritis (RVGE) burden by 75% in Spain; 53,692 home care cases, 35,187 GP/Paediatrician visits, 34,287 emergency department visits, 10,987 hospitalisations and 2,053 nosocomial infections would be avoided. The introduction of RotaTeq would avoid about 76% of RVGE-related costs from both perspectives: euro22 million from the national health system perspective and euro38 million from the societal perspective.

CONCLUSIONS

A rotavirus vaccination programme with RotaTeq would reduce significantly the important medical and economic burden of RVGE in Spain.

[Consensus conference on acute bronchiolitis (II): epidemiology of acute bronchiolitis. Review of the scientific evidence]

A review of the evidence on epidemiology, risk factors, etiology and clinical-etiological profile of acute bronchiolitis is presented. The frequency estimates are very heterogeneous; in the population under two years the frequency of admission for bronchiolitis is between 1 and 3.5%, primary care consultations between 4 and 20% and emergency visits between 1 and 2%. The frequency of admissions for respiratory infection by respiratory syncytial virus in the risk population is: in premature infants < or =32 weeks of gestation between 4.4 and 18%, in patients with bronchopulmonary dysplasia between 7.3 and 42%, and in infants with congenital heart disease between 1.6 and 9.8%. The main risk factors are: prematurity, chronic lung disease or bronchopulmonary dysplasia, congenital heart disease and age less than 3-6 months at onset of the epidemic. Other factors are: older siblings or day care attendance, male gender, exposure to smoking, breastfeeding for less than 1-2 months and variables associated with lower socioeconomic status. Respiratory syncytial virus is the dominant etiological agent, constituting just over half the cases (median 56%; interval 27% to 73%). Other viruses implicated, in descending order of frequency, are rhinovirus, adenovirus, metapneumovirus, influenza viruses, parainfluenza, enterovirus and bocavirus. In studies with genomic detection techniques, between 20 and 25% of cases the virus involved is not identified and between 9% and 27% of cases have viral co-infection. Although respiratory syncytial virus bronchiolitis shows more wheezing and retractions, longer duration of respiratory symptoms and oxygen therapy and are associated with lower use of antibiotics. This pattern is associated with the younger age of the patients and does not help us to predict the etiology. In general, the etiological identification is not useful for the management of patients. However, in young infants (<3 months) with febrile bronchiolitis in the hospital environment, conservative management may help these patients and avoid diagnostic and therapeutic procedures.

Nosocomial rotavirus gastroenteritis in Spain: a multicenter prospective study

BACKGROUND

The objective of this study was to assess the incidence of nosocomial rotavirus gastroenteritis among children <2 years of age.

METHODS

We conducted a prospective active surveillance for acute gastroenteritis (AGE) in the pediatric wards of 3 representative hospitals in Valencia (Spain) from October 2006 to March 2007, among children between 1 and 23 months of age with acute diarrhea. Children were followed up for 3 days after discharge. We obtained clinical and demographic information from participants and tested their stool specimens for rotavirus.

RESULTS

A total of 1576 children were hospitalized at the 3 hospitals and 1300 (82.5%) were followed up as the study cohort. In 69 children, AGE started 48 hours after admission and were considered nosocomial infections. In 35 of the 59 cases where stool samples were obtained, rotavirus (RV) was present (59%), and in 12 of them symptoms started after discharge. The accumulated incidence of nosocomial rotavirus disease during the study period was 2.8 cases per 100 inpatients (95% CI: 1.9-3.8), and the incidence rate was 4.8 cases per 1000 hospital days (95% CI: 3.2-6.5). The most commonly found genotype in nosocomial infection was G9P[8], in 23 cases (66%), followed by G1P[8] in 4 cases (11%). The total economic cost was 883 euro per case.

CONCLUSION

Active surveillance demonstrated that the burden of nosocomial rotavirus disease is substantial, and G9P [8] was the genotype found most frequently. Following up children after discharge from hospital allowed the discovery of cases of nosocomial RVAGE which are missed in most other studies.

Mathematical modelling of respiratory syncytial virus (RSV): vaccination strategies and budget applications

We propose an age-structured mathematical model for respiratory syncytial virus in which children aged <1 year are especially considered. Real data on hospitalized children in the Spanish region of Valencia were used in order to determine some seasonal parameters of the model. Weekly predictions of the number of children aged <1 year that will be hospitalized in the following years in Valencia are presented using this model. Results are applied to estimate the regional cost of paediatric hospitalizations and to perform a cost-effectiveness analysis of possible vaccination strategies.

Stochastic modeling of the transmission of respiratory syncytial virus (RSV) in the region of Valencia, Spain

In this paper, we study the dynamics of the transmission of respiratory syncytial virus (RSV) in the population using stochastic models. The stochastic models are developed introducing stochastic perturbations on the demographic parameter as well as on the transmission rate of the RSV. Numerical simulations of the deterministic and stochastic models are performed in order to understand the effect of fluctuating birth rate and transmission rate of the RSV on the population dynamics. The numerical solutions of stochastic models are calculated using Euler-Maruyama and Milstein schemes, and confidence intervals for stochastic solutions are given using Monte-Carlo method. Analysis of the numerical results reveals that perturbations on the transmission rate are more decisive in the dynamics of RSV than perturbations on demographic parameters. In addition, the stochastic models show the advantage of reproducing more effectively the noisy RSV hospitalization data. It is concluded that these stochastic models are a viable option to provide a realistic modeling of the RSV dynamics on the population.

[Success and failure predictors of non-invasive ventilation in acute bronchiolitis]

INTRODUCTION

The objective was to identify predictive factors for non-invasive ventilation (NIV) failure and to describe its use in bronchiolitis.

PATIENTS AND METHODS

Prospective observational study that included patients diagnosed with bronchiolitis with a modified Wood's Clinical Asthma Score 5, or oxygen saturation <92%, or venous CO(2) partial pressure (PCO(2)) 60 mm Hg, with no response to medical treatment, who received NIV from December 2005 to May 2008. We collected clinical data before NIV began and at 1, 6, 12, 24 and 48 h. Need for intubation was considered as NIV failure.

RESULTS

NIV was successful in 83% of 47 cases included. Patients in whom NIV failed had lower weight (5.2+/-2.2 vs. 3.5+/-0.8 kg, P=.011), lower age [1.8 (0.3-12.3) vs. 0.8 (0.4-4.3) months, P=.038)], lower heart rate (HR) before NIV began (176.3+/-19.1 vs. 160.4+/-9.7 beats/minute, P=.010), lower HR decrease at hours 1 (-16.0+/-17.3 vs.+1.1+/-11.6, P=.005) and 12 (-31.5+/-19.7 vs. -0.75+/-12.2, P=.002), presence of apnoeas (23.1% vs. 75%; P=.004) and of a predisposing condition (84.6% vs. 50%; P=.029). Multivariate analysis identified the absence of a predisposing condition, and a greater HR decrease during the first hour as success-associated independent factors (OR 0.004; 95% CI 0.000-0.664 and OR 0.896; 95% CI: 0.809-0.993, respectively).

CONCLUSIONS

NIV has a high success rate in bronchiolitis. The main parameters which can predict NIV success are the absence of a predisposing condition and a higher HR decrease in the first hour.