Rehospitalization for respiratory syncytial virus among premature infants

Does Duration Off Respiratory Support Prior to Discharge from NICU Predict Hospital Readmission among Extremely Low Gestational Age Neonates?

OBJECTIVE

Our objective was to determine if the duration off respiratory support prior to discharge home from the neonatal intensive care unit (NICU) would impact hospital readmission rates among extremely low gestational age neonates (ELGAN).

STUDY DESIGN

In this retrospective chart review, we examined readmission rates for ELGAN admitted to the Montefiore-Weiler NICU between 2013 and 2015.

RESULTS

Of 140 infants born at <29 weeks' gestational age, 30 (21%) of these infants were subsequently readmitted within 90 days, primarily for respiratory complaints. Readmitted infants were born at an earlier gestational age (median = 26 weeks; interquartile range [IQR]: 24-27 weeks) compared to infants who did not require readmission (median = 27 weeks; IQR: 25-28 weeks), p = 0.03. Birth weights were smaller among infants who required readmission, 800 ± 248 g compared to 910 ± 214 g (p = 0.02). Infants with Hispanic ethnicity and those discharged during the spring season were likely to be readmitted. Duration off respiratory support prior to discharge did not predict 90-day readmission rates. Lower gestational age and birth weight were associated with higher rates of readmissions after NICU discharge.

CONCLUSION

Duration off and invasiveness of respiratory support prior to discharge did not predict risk of 90-day readmission nor did discharge during months with traditionally higher prevalence of respiratory viruses.

Effectiveness of Palivizumab Against Respiratory Syncytial Virus Hospitalization Among Preterm Infants in a Setting With Year-Round Circulation

BACKGROUND

The year-round respiratory syncytial virus (RSV) circulation in tropical regions leads to different transmission patterns and burden of disease among infants born very preterm.

METHODS

We conducted a retrospective cohort study to estimate the effectiveness of palivizumab in preventing RSV hospitalization at 6 and 12 months after discharge, among infants born at <32 weeks' gestation in our tropical setting.

RESULTS

A total of 109 infants (26.3%) received palivizumab at discharge, of 415 who were eligible. All patients received ≥4 doses, with 105 infants (96.3%) completing 5 doses. Within 1 year after discharge, there were 35 RSV-associated admissions (3 [2.8%] in the palivizumab vs 32 [10.5%] in the nonpalivizumab group; P = .02). After adjustment for confounders, the effectiveness of palivizumab against RSV hospitalization was estimated to be 90% (95% confidence interval, 10%-99%) up to 6 months after discharge. The median time to RSV hospitalization was shorter in the nonpalivizumab than in the palivizumab group (median [range], 155 [15-358] vs 287 [145-359] days, respectively; P = .11). Five infants (14.3%), all from the nonpalivizumab group, required admission to the intensive care unit.

CONCLUSIONS

In our setting with year-round RSV circulation, palivizumab prophylaxis was effective in reducing RSV hospitalization among high-risk preterm infants of <32 weeks' gestation within the initial 6 months after discharge.

Respiratory syncytial virus acute respiratory infection-associated hospitalizations in preterm Mexican infants: A cohort study

Background

Respiratory syncytial virus (RSV) is the leading cause of severe acute respiratory infections (ARI) in preterm infants. The incidence of RSV‐associated hospitalizations has not been defined in Mexico.

Objectives

To determine the incidence of ARI‐ and RSV‐associated hospitalizations in preterm infants during the first year of life.

Methods

Prospective cohort study of 294 preterm infants followed up through monthly telephone calls and routine outpatient visits. Hospitalized children were identified through daily visits to pediatric wards of participating hospitals and through telephone calls. Respiratory samples were tested for RSV by RT‐PCR.

Results

Mean gestational age of participating infants was 33 weeks. Ninety‐six infants were diagnosed with bronchopulmonary dysplasia (BPD) and 17 with congenital heart disease (CHD); 11 had both conditions. There were 71 hospitalization episodes in 53 infants. Respiratory samples for RSV detection were available in 44 hospitalization episodes, and the result was positive in 16 (36.3%). At least one hospitalization for ARI was recorded in 33 of 96 participants with BPD, in seven of 17 with CHD, and 18 of 192 infants without these diagnoses. Five (71.4%) of CHD infants who required admission also had BPD. RSV‐confirmed hospitalization rates were 9.4%, 5.9%, and 2.6% for infants with BPD, CHD, and otherwise healthy preterm infants, respectively. Attributable RSV admission frequencies were estimated to be 13.6%, 16.5%, and 4.1%, respectively.

Conclusions

Mexican preterm infants, particularly those with BPD, have high rates of ARI‐ and RSVassociated hospitalizations. Specific interventions to reduce the incidence of severe infections in this highrisk group are required.

Retrospective Review of Clinical and Chest X-Ray Findings in Children Admitted to a Community Hospital for Respiratory Syncytial Virus Infection

INTRODUCTION

We performed a retrospective study to evaluate demographics, clinical course, outcome, and radiological findings of children with respiratory syncytial virus (RSV) infection.

METHODS

Four hundred patients admitted between October 2013 and May 2016 were enrolled. Clinical and radiographic trends were evaluated for association with severity of RSV presentation. Severity was defined as hospitalization >2 days, pediatric intensive care unit admission, or need for mechanical ventilation.

RESULTS

Common clinical findings included fever (78.5%), coughing (97%), rhinorrhea/congestion (93%), and hypoxia (44.8%). Hypoxia was seen in 64.7% of the severe group compared with 32.0% in the nonsevere group ( P < .001). Airspace opacification was seen in 49.2% of chest X-rays of the severe group compared with 26.4% in the nonsevere group ( P < .001).

CONCLUSION

Higher incidence of hypoxia or airspace opacification on chest X-ray may be predictors of poorer outcomes for patients with RSV infection.

Predictors and incidence of hospitalization due to respiratory syncytial virus (RSV)-associated lower respiratory tract infection (LRTI) in non-prophylaxed moderate-to-late preterm infants in Bosnia and Herzegovina

Prematurity is a risk factor for respiratory syncytial virus (RSV)-associated lower respiratory tract infections (LRTIs), due to immature humoral and cell-mediated immune system in preterm newborns, as well as their incomplete lung development. Palivizumab, a humanized monoclonal antibody against the F glycoprotein of RSV, is licensed for the prevention of severe RSV LRTI in children at high risk for the disease. This study is a part of a larger observational, retrospective-prospective epidemiological study (PONI) conducted at 72 sites across 23 countries in the northern temperate zone. The aim of our non-interventional study was to identify common predictors and factors associated with RSV LRTI hospitalization in non-prophylaxed, moderate-to-late preterm infants, born between 33 weeks and 0 days and 35 weeks and 6 days of gestation, and less than 6 months prior to or during the RSV season in Bosnia and Herzegovina (B&H). A total of 160 moderate-to-late preterm infants were included from four sites in B&H (Sarajevo, Tuzla, Mostar, and Banja Luka). We identified several significant intrinsic and extrinsic factors to be associated with the risk of RSV LRTI hospitalization in the preterm infants, including: comorbidities after birth, shorter hospital stay, admission to NICU/PICU while in the maternity ward, household smoking, low maternal age, breast feeding, number of family members, and history of family/paternal atopy. Overall, our results indicated that the risk of RSV LRTI in preterm newborns can be associated with different environmental and social/cultural factors, and further research is needed to comprehensively evaluate these associations.

Apnea, bradycardia and desaturation spells in premature infants: impact of a protocol for the duration of 'spell-free' observation on interprovider variability and readmission rates

OBJECTIVE

To study the impact of implementing a protocol to standardize the duration of observation in preterm infants with apnea/bradycardia/desaturation spells before hospital discharge on length of stay (LOS) and readmission rates.

STUDY DESIGN

A protocol to standardize the duration of in-hospital observation for preterm infants with apnea, bradycardia and desaturation spells who were otherwise ready for discharge was implemented in December 2013. We evaluated the impact of this protocol on the LOS and readmission rates of very low birth weight infants (VLBW). Data on readmission for apnea and an apparent life-threatening event (ALTE) within 30 days of discharge were collected. The pre-implementation epoch (2011 to 2013) was compared to the post-implementation period (2014 to 2016).

RESULTS

There were 426 and 368 VLBW discharges before and after initiation of the protocol during 2011 to 2013 and 2014 to 2016, respectively. The LOS did not change with protocol implementation (66±42 vs 64±42 days before and after implementation of the protocol, respectively). Interprovider variability on the duration of observation for apneic spells (F-8.8, P=0.04) and bradycardia spells (F-17.4, P<0.001) decreased after implementation of the protocol. The readmission rate for apnea/ALTE after the protocol decreased from 12.1 to 3.4% (P=0.01).

CONCLUSION

Implementing an institutional protocol for VLBW infants to determine the duration of apnea/bradycardia/ desaturation spell-free observation period as recommended by the American Academy of Pediatrics clinical report did not prolong the LOS but effectively reduced interprovider variability and readmission rates.

Pediatric Readmissions After Hospitalizations for Lower Respiratory Infections

BACKGROUND AND OBJECTIVE

Lower respiratory infections (LRIs) are among the most common reasons for pediatric hospitalization and among the diagnoses with the highest number of readmissions. Characterizing LRI readmissions would help guide efforts to prevent them. We assessed variation in pediatric LRI readmission rates, risk factors for readmission, and readmission diagnoses.

METHODS

We analyzed 2008-2009 Medicaid Analytic eXtract data for patients <18 years of age in 26 states. We identified LRI hospitalizations based on a primary diagnosis of bronchiolitis, influenza, or community-acquired pneumonia or a secondary diagnosis of one of these LRIs plus a primary diagnosis of asthma, respiratory failure, or sepsis/bacteremia. Readmission rates were calculated as the proportion of hospitalizations followed by ≥1 unplanned readmission within 30 days. We used logistic regression with fixed effects for patient characteristics and a hospital random intercept to case-mix adjust rates and assess risk factors.

RESULTS

Of 150 590 LRI hospitalizations, 8233 (5.5%) were followed by ≥1 readmission. The median adjusted hospital readmission rate was 5.2% (interquartile range: 5.1%-5.4%), and rates varied across hospitals (P < .0001). Infants (patients <1 year of age), boys, and children with chronic conditions were more likely to be readmitted. The most common primary diagnoses on readmission were LRIs (48.2%), asthma (10.0%), fluid/electrolyte disorders (3.4%), respiratory failure (3.3%), and upper respiratory infections (2.7%).

CONCLUSIONS

LRI readmissions are common and vary across hospitals. Multiple risk factors are associated with readmission, indicating potential targets for strategies to reduce readmissions. Readmission diagnoses sometimes seem related to the original LRI.

The impact of preterm birth <37 weeks on parents and families: a cross-sectional study in the 2 years after discharge from the neonatal intensive care unit

BACKGROUND

Little is known about the quality of life of parents and families of preterm infants after discharge from the neonatal intensive care unit (NICU). Our aims were (1) to describe the impact of preterm birth on parents and families and (2) and to identify potentially modifiable determinants of parent and family impact.

METHODS

We surveyed 196 parents of preterm infants <24 months corrected age in 3 specialty clinics (82% response rate). Primary outcomes were: (1) the Impact on Family Scale total score; and (2) the Infant Toddler Quality of Life parent emotion and (3) time limitations scores. Potentially modifiable factors were use of community-based services, financial burdens, and health-related social problems. We estimated associations of potentially modifiable factors with outcomes, adjusting for socio-demographic and infant characteristics using linear regression.

RESULTS

Median (inter-quartile range) infant gestational age was 28 (26-31) weeks. Higher Impact on Family scores (indicating worse effects on family functioning) were associated with taking ≥3 unpaid hours/week off from work, increased debt, financial worry, unsafe home environment and social isolation. Lower parent emotion scores (indicating greater impact on the parent) were also associated with social isolation and unpaid time off from work. Lower parent time limitations scores were associated with social isolation, unpaid time off from work, financial worry, and an unsafe home environment. In contrast, higher parent time limitations scores (indicating less impact) were associated with enrollment in early intervention and Medicaid.

CONCLUSIONS

Interventions to reduce social isolation, lessen financial burden, improve home safety, and increase enrollment in early intervention and Medicaid all have the potential to lessen the impact of preterm birth on parents and families.

Defining the Risk and Associated Morbidity and Mortality of Severe Respiratory Syncytial Virus Infection Among Infants with Chronic Lung Disease

INTRODUCTION

The REGAL (RSV evidence-a geographical archive of the literature) series provide a comprehensive review of the published evidence in the field of respiratory syncytial virus (RSV) in Western countries over the last 20 years. This third publication covers the risk and burden of RSV infection in infants with chronic lung disease (CLD), formerly called bronchopulmonary dysplasia (BPD).

METHODS

A systematic review was undertaken of publications between January 1, 1995 and December 31, 2015 across PubMed, Embase, The Cochrane Library, and Clinicaltrials.gov. Studies reporting data for hospital visits/admissions for RSV infection among infants with CLD/BPD who were not prophylaxed, as well as studies reporting RSV-associated morbidity, mortality, and healthcare costs, were included. Burdens of disease data were compared with preterm infants without CLD/BPD, other high-risk groups and term infants. Study quality and strength of evidence (SOE) were graded using recognized criteria.

RESULTS

A total of 1837 studies were identified and 39 were included. CLD/BPD is a significant independent risk factor for RSV hospitalization [RSVH (odds ratio 2.2-7.2); high SOE]. Infants and young children with CLD/BPD had high RSVH rates which were generally similar in Europe, the United States, and Canada, mostly varying between 12 and 21%. Infants with CLD also had a longer length of hospital stay than other high-risk groups and term infants (high SOE). On average, infants spent 4-11 days in hospital (moderate SOE). Once hospitalized for RSV, affected children were at risk for a more severe course of disease than children with no RSVH (moderate SOE).

CONCLUSION

Severe RSV infection in infants and young children with CLD/BPD poses a significant health burden in Western countries. Further studies focussing on the burden of RSV infection in this well-recognized population at high risk for severe disease are needed to help improve outcomes and plan allocation of healthcare resources.

FUNDING

AbbVie.

Defining the Risk and Associated Morbidity and Mortality of Severe Respiratory Syncytial Virus Infection Among Preterm Infants Without Chronic Lung Disease or Congenital Heart Disease

INTRODUCTION

The REGAL (RSV Evidence-a Geographical Archive of the Literature) series provide a comprehensive review of the published evidence in the field of respiratory syncytial virus (RSV) in Western countries over the last 20 years. This second publication covers the risk and burden of RSV infection in preterm infants born at <37 weeks' gestational age (wGA) without chronic lung disease or congenital heart disease.

METHODS

A systematic review was undertaken for articles published between January 1, 1995 and December 31, 2015. Studies reporting data for hospital visits/admissions for RSV infection among preterm infants 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.

RESULTS

2469 studies were identified of which 85 were included. Preterm infants, particularly those born at lower wGA, tended to have higher RSV hospitalization (RSVH) rates compared with otherwise healthy term infants (high SOE). RSVH rates ranged from ~5 per 1000 children to >100 per 1000 children with the highest rates shown in the lowest gestational age infants (high SOE). Independent risk factors associated with RSVH include: proximity of birth to the RSV season, living with school-age siblings, smoking of mother during pregnancy or infant exposure to environmental smoking, reduced breast feeding, male sex, and familial atopy (asthma) (high SOE). Predictive models can identify 32/33-35 wGA infants at risk of RSVH (high SOE).

CONCLUSION

RSV infection remains a major burden on Western healthcare systems and is associated with significant morbidity. Further studies focusing on the prevalence and burden of RSV in different gestational age cohorts, the changing risk of RSVH during the first year of life, and on RSV-related mortality in preterm infants are needed to determine the true burden of disease.

FUNDING

AbbVie.

A population study of respiratory rehospitalisation in very preterm infants in the first 3 years of life

AIM

Very premature infants consume healthcare resources following discharge from neonatal intensive care units (NICU). This study aimed to evaluate the burden of respiratory related rehospitalisation within the first 3 years post discharge in very premature infants in an Australian population.

METHODS

Rehospitalisation of a 4-year cohort of NICU survivors, born less than 32 weeks gestation, was derived from data linkage of three state-wide databases including NSW Neonatal Intensive Care Units' Data Collection, Admitted Patient Data Collection and the Death Registry. Rehospitalisation diagnoses were determined by ICD-10 AM codes.

RESULTS

Of the 2939 survivors, 525 (18%) had bronchopulmonary dysplasia (BPD) and 261 BPD infants (50%) were discharged on home oxygen. Almost two-third (1860, 63%) of the survivors are required rehospitalisation, respiratory causes, including 394 respiratory syncytial virus (RSV)-related, accounted for 2668 (48%) of the 5599 rehospitalisations. Significantly more home oxygen BPD survivors had respiratory (70%) and RSV-related (22%) rehospitalisations than the BPD infants not needing home oxygen (58% and 18%, respectively), and the survivors without BPD had the lowest rates (32% and 10%, P < 0.001). Most respiratory (61%) and RSV-related (74%) rehospitalisations occurred during the first 12 months post discharge. No RSV-related fatality occurred. Amongst the total 17 562 hospital days, respiratory and RSV-related admissions accounted for 10 905 (62%) and 3031 (17.2%) days. In multivariable logistic analyses, home oxygen and maternal indigenous status were independently associated with high (3 or more) respiratory and RSV rehospitalisation rates.

CONCLUSIONS

Respiratory rehospitalisations are common in very premature survivors. Home oxygen and indigenous status are significant risk factors for respiratory and RSV-related rehospitalisations.

Respiratory Syncytial Virus Hospitalizations in Healthy Preterm Infants: Systematic Review

BACKGROUND

Studies have explored the risk for and impact of respiratory syncytial virus (RSV) infection requiring hospitalization among healthy preterm infants born at 29-35 weeks of gestational age not given RSV immunoprophylaxis. We performed a systematic review and qualitative synthesis of these studies.

METHODS

Two experienced reviewers used prespecified inclusion/exclusion criteria to screen titles/abstracts and full-text studies using MEDLINE, Embase, BIOSIS and Cochrane Library (January 1, 1985, to November 6, 2014). We abstracted data on risk factors for RSV hospitalization, incidence and short- and long-term outcomes of RSV hospitalization. Using standard procedures, we assessed study risk of bias and graded strength of evidence (SOE).

RESULTS

We identified 4754 records and reviewed 27. Important risk factors for RSV hospitalization included young age during the RSV season, having school-age siblings and day-care attendance, with odds ratios >2.5 in at least one study (high SOE). Incidence rates for RSV hospitalizations ranged from 2.3% to 10% (low SOE). Length of hospital stays ranged from 3.8 to 6.1 days (low SOE). Recurrent wheezing rates ranged from 20.7% to 42.8% 1 to 2 years after RSV hospitalization (low SOE).

CONCLUSIONS

Young chronological age and some environmental risk factors are important clinical indicators of an increased risk of RSV hospitalization in healthy preterm infants 32 to 35 weeks of gestational age. SOE was low for estimates of incidence of RSV hospitalizations, in-hospital resource use and recurrent wheezing in this population. Studies were inconsistent in study characteristics, including weeks of gestational age, age during RSV season and control for confounding factors.

Evaluation of recent New Vaccine Surveillance Network data regarding respiratory syncytial virus hospitalization rates in US preterm infants

In July 2014, the Committee on Infectious Diseases (COID) updated their guidance on the use of palivizumab, recommending against use in preterm infants 29 to 35 weeks' gestational age (wGA). A primary data source cited to support this significant change was the low respiratory syncytial virus (RSV) hospitalization rate observed in the subpopulation of preterm (<37 wGA) infants evaluated from 2000 to 2005 through the New Vaccine Surveillance Network (NVSN). Here we critically appraise the preterm infant data from the NVSN in the context of data regarding the use of palivizumab in this same time period. Data from the NVSN, an analysis of Florida Medicaid data, and a national survey of US in-hospital palivizumab administration demonstrated that during 2001 to 2007, palivizumab was administered to 59% to 83% of preterm infants born at <32 wGA and 21% to 27% of all preterm infants (<37 wGA). When the NVSN data regarding incidence of RSV hospitalization in preterm infant subgroups were evaluated as a function of chronologic age, preterm infants <32 wGA showed a paradoxical increase in RSV hospitalization with older age, with the highest risk of RSV hospitalization occurring at 18 to 23 months of age. This pattern is most consistent with a reduction in RSV hospitalizations in <32 wGA infants in the first 12 to 18 months of life due to high palivizumab use at these young ages. The NVSN data were not designed to and cannot accurately describe RSV disease burden in preterm infants given the small size of the analyzed subpopulation and the high use of palivizumab during the study period.

Prematurity and the burden of influenza and respiratory syncytial virus disease

BACKGROUND

Respiratory morbidity of former preterm infants and especially those with bronchopulmonary dysplasia (BPD) is high during infancy and early childhood.

DATA SOURCES

We performed a review based on a literature search including EMBASE, MEDLINE, and CINAHL databases to identify all relevant papers published in the English and German literature on influenza and respiratory syncytial virus infection associated with preterm infant, prematurity, and BPD between 1980 and 2014.

RESULTS

Recurrent respiratory symptoms remain common at preschool age, school age and even into young adulthood. Acute viral respiratory tract infections due to different pathogens cause significant morbidity and necessitate rehospitalizations during the first years of life. Influenza virus infection plays a minor role compared to respiratory syncytial virus (RSV) associated respiratory tract infection during infancy and early childhood. Nevertheless, particular morbidity to both viruses is high.

CONCLUSIONS

The particular burden of both viral diseases in preterm infants is dominated by RSV and its associated rehospitalizations during the first two years of life. Prophylactic measures include vaccination against influenza virus of family members and caregivers and active immunization starting at the age of 6 months, and monthly injections of palivizumab during the cold season to avoid severe RSV disease and its sequelae.

Tracheal Infections

Infectious processes of the trachea represent a distinct clinical entity with an evolving landscape owing to advances in airway management and vaccination practices. Untreated inflammatory processes of the trachea may present in the form of acute airway obstruction, potentially resulting in significant morbidity and even mortality. Therefore it is important to recognize the cardinal features of some of the common tracheal infectious processes to differentiate them from non-infectious pathology, as the latter is associated with a more indolent course.

As with most other infectious processes of the airway, pathogens causing tracheal infection can be bacterial, viral or fungal in nature. Viral etiology represents the most common cause of laryngotracheal infection in a child. Bacterial infections of the trachea are responsible for more significant morbidity, including prolonged hospitalization, need for endotracheal intubation and even an occasional tracheostomy. The current chapter describes the clinical features and microbiology of tracheal infections at large, explores the utility of diagnostic tests, and provides an algorithm for management.

Use of Medical Resources by Preterm Infants Born at Less than 33 Weeks' Gestation Following Discharge from the Neonatal Intensive Care Unit in Korea

This study was aimed to provide data on the use of medical resources by preterm infants following discharge from the neonatal intensive care unit (NICU). The cohort included preterm infants (n=2,351) born at 22-32 weeks' gestation who were discharged from the NICUs of 44 Korean hospitals between April 2009 to March 2010. Mean duration of post-discharge follow-up was 425±237 days. After discharge from the NICU, 94.5% of total infants visited a pediatric outpatient clinic (11.5±9.8 mean visits), 42.9% visited a pediatric clinic for respiratory problems irregularly (4.9±6.6 mean visits), and 31.1% utilized emergency center at least once. Among all visits to the emergency center, 24.7% resulted in readmission and 50.8% of those visits were due to respiratory problems. At least one episode of readmission was required by 33.6% (788/2,346) of total infants, and 18.4% (431/2,346) of total infants were readmitted with respiratory problems at least once. Among all infants readmitted for respiratory problems, 16.2% (70/341) were diagnosed with respiratory syncytial virus infection which accounted for 30.3% of viral etiologies confirmed by laboratory testing. Infants born at <30 weeks' gestation had more frequent total readmission and respiratory readmission than those ≥30 weeks' gestation (2±1.7 vs. 1.7±1.2, P=0.009, 1.8±1.2 vs. 1.5±1.1, 0.027, respectively). Overall, use of medical resources is common, and respiratory problems are the leading cause of use of medical resources. Total readmissions and respiratory readmissions are more frequent in more immature infants.

Respiratory Syncytial Virus Related Readmission in Preterm Infants Less than 34 weeks' Gestation Following Discharge from a Neonatal Intensive Care Unit in Korea

This study was done to evaluate respiratory syncytial virus (RSV) related readmission (RRR) and risk factors of RRR in preterm infants < 34 weeks gestational age (GA) within 1 yr following discharge from the neonatal intensive care unit (NICU). Infants (n = 1,140) who were born and admitted to the NICUs of 46 hospitals in Korea from April to September 2012, and followed up for > 1 yr after discharge from the NICU, were enrolled. The average GA and birth weight of the infants was 30(+5) ± 2(+5) weeks and 1,502 ± 474 g, respectively. The RRR rate of enrolled infants was 8.4% (96/1,140), and RSV accounted for 58.2% of respiratory readmissions of infants who had laboratory tests confirming etiological viruses. Living with elder siblings (odd ratio [OR], 2.68; 95% confidence interval [CI], 1.68-4.28; P < 0.001), and bronchopulmonary dysplasia (BPD) (OR, 2.95; 95% CI, 1.44-6.04; P = 0.003, BPD vs. none) increased the risk of RRR. Palivizumab prophylaxis (OR, 0.06; 95% CI, 0.03-0.13; P < 0.001) decreased the risk of RRR. The risk of RRR of infants of 32-33 weeks' gestation was lower than that of infants < 26 weeks' gestation (OR, 0.11; 95% CI, 0.02-0.53; P = 0.006). This was a nationwide study that evaluated the rate and associated risk factors of RRR in Korean preterm infants. Preterm infants with BPD or living with siblings should be supervised, and administration of palivizumab to prevent RRR should be considered.

Epidemiology and virology of acute respiratory infections during the first year of life: a birth cohort study in Vietnam

BACKGROUND

Understanding viral etiology and age-specific incidence of acute respiratory infections in infants can help identify risk groups and inform vaccine delivery, but community-based data is lacking from tropical settings.

METHODS

One thousand four hundred and seventy-eight infants in urban Ho Chi Minh City and 981 infants in a semi-rural district in southern Vietnam were enrolled at birth and followed to 1 year of age. Acute respiratory infection (ARI) episodes were identified through clinic-based illness surveillance, hospital admissions and self-reports. Nasopharyngeal swabs were collected from infants with respiratory symptoms and tested for 14 respiratory pathogens using multiplex reverse transcription-polymerase chain reaction.

RESULTS

Estimated incidence of ARI was 542 and 2691 per 1000 infant-years, and hospitalization rates for ARI were 81 and 138 per 1000 infant-years, in urban and semi-rural cohorts, respectively, from clinic- and hospital-based surveillance. However self-reported ARI episodes were just 1.5-fold higher in the semi-rural versus urban cohort, indicating that part of the urban-rural difference was explained by under-ascertainment in the urban cohort. Incidence was higher in infants ≥6 months of age than <6 months, but this was pathogen-specific. One or more viruses were detected in 53% (urban) and 64% (semi-rural) of samples from outpatients with ARI and in 78% and 66% of samples from hospitalized ARI patients, respectively. The most frequently detected viruses were rhinovirus, respiratory syncytial virus, influenza virus A and bocavirus. ARI-associated hospitalizations were associated with longer stays and more frequent ICU admission than other infections.

CONCLUSIONS

ARI is a significant cause of morbidity in Vietnamese infants and influenza virus A is an under-appreciated cause of vaccine-preventable disease and hospitalizations in this tropical setting. Public health strategies to reduce infant ARI incidence and hospitalization rates are needed.

Prolonged seasonality of respiratory syncytial virus infection among preterm infants in a subtropical climate

Objective

There is limited epidemiological data on the seasonality of respiratory syncytial virus (RSV) infection in subtropical climates, such as in Taiwan. This study aimed to assess RSV seasonality among children ≤24 months of age in Taiwan. We also assessed factors (gestational age [GA], chronologic age [CA], and bronchopulmonary dysplasia [BPD]) associated with RSV-associated hospitalization in preterm infants to confirm the appropriateness of the novel Taiwanese RSV prophylactic policy.

Study Design

From January 2000 to August 2010, 3572 children aged ≤24-months were admitted to Taipei Mackay Memorial Hospital due to RSV infection. The monthly RSV-associated hospitalization rate among children aged ≤24 months was retrospectively reviewed. Among these children, 378 were born preterm. The associations between GA, CA, and BPD and the incidence of RSV-associated hospitalization in the preterm infants were assessed.

Results

In children aged ≤24 months, the monthly distribution of RSV-associated hospitalization rates revealed a prolonged RSV season with a duration of 10 months. Infants with GAs ≤32 weeks and those who had BPD had the highest rates of RSV hospitalization (P<0.001). Preterm infants were most vulnerable to RSV infection within CA 9 months.

Conclusions

Given that Taiwan has a prolonged (10-month) RSV season, the American Academy of Pediatrics' recommendations for RSV prophylaxis are not directly applicable. The current Taiwanese guidelines for RSV prophylaxis, which specify palivizumab injection (a total six doses until CA 8–9 months) for preterm infants (those born before 28^6/7 weeks GA or before 35^6/7 weeks GA with BPD), are appropriate. This prophylaxis strategy may be applicable to other countries/regions with subtropical climates.

Can we improve the targeting of respiratory syncytial virus (RSV) prophylaxis in infants born 32-35 weeks' gestational age with more informed use of risk factors?

OBJECTIVE

To evaluate the key risk factors for respiratory syncytial virus (RSV) hospitalisation in 32-35 weeks' gestational age (wGA) infants.

METHODS

Published risk factors were assessed for predictive accuracy (area under the receiver operating characteristic curve [ROC AUC]) and for number needed to treat (NNT).

RESULTS

Key risk factors included: proximity of birth to the RSV season; having siblings; crowding at home; day care; smoking; breast feeding; small for GA; male gender; and familial wheezing/eczema. Proximity of birth to the RSV season appeared the most predictive. Risk factors models from Europe and Canada were found to have a high level of predictive accuracy (ROC AUC both > 0.75; NNT for European model 9.5). A model optimised for three risk factors (birth ± 10 weeks from start of RSV season, number of siblings ≥ 2 years and breast feeding for ≤ 2 months) had a similar level of prediction (ROC AUC: 0.776; NNT: 10.2). An example two-risk factor model (day care attendance and living with ≥ 2 siblings < 5 years old) had a lower level of predictive accuracy (ROC AUC: 0.55; NNT: 26).

CONCLUSIONS

An optimised combination of risk factors has the potential to improve the identification of 32-35 wGA infants at heightened risk of RSV hospitalisation.

A systematic review of predictive modeling for bronchiolitis

PURPOSE

Bronchiolitis is the most common cause of illness leading to hospitalization in young children. At present, many bronchiolitis management decisions are made subjectively, leading to significant practice variation among hospitals and physicians caring for children with bronchiolitis. To standardize care for bronchiolitis, researchers have proposed various models to predict the disease course to help determine a proper management plan. This paper reviews the existing state of the art of predictive modeling for bronchiolitis. Predictive modeling for respiratory syncytial virus (RSV) infection is covered whenever appropriate, as RSV accounts for about 70% of bronchiolitis cases.

METHODS

A systematic review was conducted through a PubMed search up to April 25, 2014. The literature on predictive modeling for bronchiolitis was retrieved using a comprehensive search query, which was developed through an iterative process. Search results were limited to human subjects, the English language, and children (birth to 18 years).

RESULTS

The literature search returned 2312 references in total. After manual review, 168 of these references were determined to be relevant and are discussed in this paper. We identify several limitations and open problems in predictive modeling for bronchiolitis, and provide some preliminary thoughts on how to address them, with the hope to stimulate future research in this domain.

CONCLUSIONS

Many problems remain open in predictive modeling for bronchiolitis. Future studies will need to address them to achieve optimal predictive models.

A novel six consecutive monthly doses of palivizumab prophylaxis protocol for the prevention of respiratory syncytial virus infection in high-risk preterm infants in Taiwan

BACKGROUND

Respiratory syncytial virus (RSV) circulates year round in Taiwan. A novel six consecutive monthly doses of palivizumab for RSV prevention protocol has been approved for high risk preterm infants since December 2010. This study aimed to determine the clinical effectiveness and safety of this novel protocol for the prevention of RSV infection.

METHODS

From April 2011 to March 2013, we enrolled infants born at ≤28 weeks gestation and infants born at ≤35 weeks gestation with chronic lung disease (CLD) who received palivizumab prophylaxis as study group and followed up for 12 months. Historic control, those who were born and followed up between July 2000 and June 2008, were retrieved for propensity score matching. Primary endpoint was RSV-related hospitalization, and secondary endpoints included the length of hospital stay and intensive care unit (ICU) care.

RESULTS

We enrolled 127 infants (108 infants born at ≤28 weeks and 19 infants born at 29-35 weeks with CLD). They completed 6-dose palivizumab as scheduled. Among the study group, the RSV-related hospitalizations were 2 (1.6%) within 6 months and 5 (3.9%) within 12 months after discharge. We matched 127 infants in the control group with 127 infants in the study group by propensity score matching. The reduction of RSV-related hospitalization rates were 86% (10.2% vs 1.6%, p = 0.002) within 6 months after discharge and 78% (15.7% vs 3.9%, p = 0.004) within 12 months after discharge. Compared to the control group, the rate of ICU care significantly decreased from 7.1% to 0.8% (p = 0.024) within 6 months after discharge and from 7.9% to 0.8% (p = 0.014) within 12 months after discharge. Adverse events were recorded in 6.4% injections.

CONCLUSIONS

Six monthly intramuscular administration of palivizumab is effective for prevention of RSV hospitalization in regions with no single seasonal peak of RSV infection such as Taiwan.

Identifying and ensuring optimal care for all children at risk of developing serious respiratory syncytial virus disease: a Canadian nurses' perspective

Globally, respiratory syncytial virus (RSV) infection causes substantial morbidity in infants and young children, particularly those with specific risk factors (e.g., prematurity, chronic lung and congenital heart disease). Supportive measures are the mainstay of care for RSV-related disease. In the absence of medical treatments, RSV prophylaxis (RSVP) with palivizumab is recommended for high-risk patients to help reduce the risk of developing serious disease. Geographic distances, language and cultural barriers, and other factors can impede effective education of caregivers regarding the potential impact of RSV disease and benefits of RSVP compliance. We present our experiences developing successful Canadian RSVP programs, organized through a dedicated coordinator or small group of health care staff. These programs focus on identifying all infants and young children eligible for RSVP, effectively educating health care staff and family caregivers, developing educational tools that consider language and cultural factors, and interdisciplinary collaboration and networking throughout the health care system.

Adherence to Immunoprophylaxis Regimens for Respiratory Syncytial Virus Infection in Insured and Medicaid Populations

BACKGROUND

Immunoprophylaxis is the only pharmaceutical intervention for mitigating respiratory syncytial virus (RSV) infection. Patient level data on adherence to American Academy of Pediatrics (AAP) immunoprophylaxis recommendations are limited. This study characterizes adherence to AAP guidelines in privately insured and Medicaid populations.

METHODS

We performed a retrospective birth cohort study of 211 174 privately insured children in Northern California; and 458 837 publicly insured children in Tennessee born between January 1, 1996 and December 31, 2008. Adherence to the AAP guideline was defined for eligible infants as the number of doses of RSV immunoprophylaxis administered over the number recommended for 4 mutually exclusive eligibility groups: chronic lung disease, prematurity <29 weeks, prematurity <32 weeks, and other eligibility.

RESULTS

We identified 3456 California (Kaiser Permanente Northern California [KPNC]) and 12 251 Tennessee (Tennessee Medicaid [TennCare]) infants meeting AAP eligibility criteria. Immunoprophylaxis administration increased over the study period, from 15% for all eligible groups in 1998 to 54% in 2007. Adherence was highest among babies with chronic lung disease (KPNC 67% and TennCare 55%). Nonadherence (0% adherence) was greatest among infants of African American mothers (adjusted odds ratio [AOR] = 1.32; 95% confidence interval [CI] = .98-1.78); those with mothers with less than a high school education (AOR = 1.58; CI = 1.09-2.30) in KPNC; and in infants of Hispanic mothers in TennCare (AOR = 1.65; CI = 1.24-2.20). In KPNC, 0.11% of ineligible term infants and 5% of ineligible premature infants received immunoprophylaxis; the corresponding proportions in TennCare were 1% and 11%.

CONCLUSIONS

Overall adherence with AAP guidelines has increased over time. Considerable overuse and underuse of immunoprophylaxis are evident with identifiable risk groups to target for improvement.

Persistent recurring wheezing in the fifth year of life after laboratory-confirmed, medically attended respiratory syncytial virus infection in infancy

Background

Respiratory syncytial virus (RSV) infection in infancy is associated with subsequent recurrent wheezing.

Methods

A retrospective cohort study examined children born at ≥32 weeks gestation between 1996–2004. All children were enrolled in an integrated health care delivery system in Northern California and were followed through the fifth year of life. The primary endpoint was recurrent wheezing in the fifth year of life and its association with laboratory-confirmed, medically-attended RSV infection during the first year, prematurity, and supplemental oxygen during birth hospitalization. Other outcomes measured were recurrent wheezing quantified through outpatient visits, inpatient hospital stays, and asthma prescriptions.

Results

The study sample included 72,602 children. The rate of recurrent wheezing in the second year was 5.6% and fell to 4.7% by the fifth year. Recurrent wheezing rates varied by risk status: the rate was 12.5% among infants with RSV hospitalization, 8% among infants 32–33 weeks gestation, and 18% in infants with bronchopulmonary dysplasia. In multivariate analyses, increasing severity of respiratory syncytial virus infection was significantly associated with recurrent wheezing in year 5; compared with children without RSV infection in infancy, children who only had an outpatient RSV encounter had an adjusted odds ratio of 1.38 (95% CI,1.03–1.85), while children with a prolonged RSV hospitalization had an adjusted odds ratio of 2.59 (95% CI, 1.49–4.50).

Conclusions

Laboratory-confirmed, medically attended RSV infection, prematurity, and neonatal exposure to supplemental oxygen have independent associations with development of recurrent wheezing in the fifth year of life.

Should respiratory care in preterm infants include prophylaxis against respiratory syncytial virus infection? The case in favour

Respiratory syncytial virus (RSV) is the most significant cause of acute respiratory tract infections (RTI) in infants and young children throughout the world. Preterm infants are at increased risk for severe RSV lower respiratory tract infection due to small lung volumes, a reduced lung surface area, small airways and an increased air space wall thickness. Additionally, the airways of preterm infants have been ventilated mechanically and suctioned and potentially damaged by many microtraumas with disruption of endothelial surfaces enabling pathogens to invade more easily. The immune system of preterm infants is immature resulting in low antibody titers (incomplete transplacental transfer of maternal antibodies) and a reduced cellular immunity with reduced viral clearance. Rehospitalization rates of preterm compared to term infants due to RSV infection are increased as are total morbidity and mortality associated with RSV disease. Palivizumab effectively reduces RSV related rehospitalisation in this high-risk population.

Value of Chest Radiographic Pattern in RSV Disease of the Newborn: A Multicenter Retrospective Cohort Study

Respiratory syncytial virus (RSV) lower respiratory tract infection is the most common viral respiratory infection in infants. Several authors have sought to determine which risk factors are the best predictors for severe RSV disease. Our aim was to evaluate if a specific chest radiographic pattern in RSV disease can predict the disease severity. We conducted a multicenter retrospective cohort study in term and preterm neonates with confirmed lower respiratory tract RSV infection, admitted to neonatal intensive care units (NICU) from 2000 to 2010. To determine which factors independently predicted the outcomes, multivariate logistic regression analysis was performed. A total of 259 term and preterm neonates were enrolled. Patients with a consolidation pattern on the chest radiograph at admission (n = 101) had greater need for invasive mechanical ventilation (OR: 2.5; P = .015), respiratory support (OR: 2.3; P = .005), supplemental oxygen (OR: 3.0; P = .008), and prolonged stay in the NICU (>7 days) (OR: 1.8; P = .025). Newborns with a consolidation pattern on admission chest radiograph had a more severe disease course, with greater risk of invasive mechanical ventilation, respiratory support, supplemental oxygen, and prolonged hospitalization.

Hospitalizations for respiratory syncytial virus bronchiolitis in preterm infants at <33 weeks gestation without bronchopulmonary dysplasia: the CASTOR study

This study was conducted during the 2008–2009 respiratory syncytial virus (RSV) season in France to compare hospitalization rates for bronchiolitis (RSV-confirmed and all types) between very preterm infants (<33 weeks' gestational age, WGA) without bronchopulmonary dysplasia and full-term infants (39–41 WGA) matched for date of birth, gender and birth location, and to evaluate the country-specific risk factors for bronchiolitis hospitalization. Data on hospitalizations were collected both retrospectively and prospectively for 498 matched infants (249 per group) aged <6 months at the beginning of the RSV season. Compared to full-term infants, preterm infants had a fourfold [95% confidence interval (CI) 1·36–11·80] and a sevenfold (95% CI 2·79–17·57) higher risk of being hospitalized for bronchiolitis, RSV-confirmed and all types, respectively. Prematurity was the only factor that significantly increased the risk of being hospitalized for bronchiolitis. The risk of multiple hospitalizations for bronchiolitis in the same infant significantly increased with male gender and the presence of siblings aged ⩾2 years.

Epidemiology of respiratory syncytial virus infection in preterm infants

This review focuses on the burden of respiratory syncytial virus (RSV) infection in preterm infants with and without chronic lung disease (bronchopulmonary dysplasia, BPD). The year-to-year and seasonal variations in RSV activity are key aspects of RSV epidemiology, and knowledge/monitoring of local RSV activity is mandatory for guidance of prophylaxis with the monoclonal antibodies palivizumab and in the near future motavizumab. Morbidity expressed in rates of hospitalizations attributable to RSV illness revealed a mean of 10 percent in preterm infants without and 19 percent (p=0.016) with BPD. Mortality rates diverged widely, and case fatality rates have been reported to range from 0 to 12 percent. The typical clinical picture of lower respiratory tract infection is not different in term and preterm infants, but rates of apnoeas are significantly increased in preterms, ranging from 4.9 to 37.5 percent with decreasing rates observed in more recent studies. Until a RSV vaccine is developed and will be available, prophylaxis with palivizumab is the only preventative strategy other than hand hygiene and contact measures that significantly reduces RSV hospitalization rates in preterm infants both with and without BPD.

Epidemiology and prevention of respiratory syncytial virus infections among infants and young children

Since its discovery in 1956, respiratory syncytial virus (RSV) has been recognized as one of the most common causes of serious lower respiratory tract infections in young children worldwide. While considered a high priority, development of a safe and effective vaccine has remained elusive. Prevention of RSV disease relies on infection control and hygiene measures, as well as providing immunoprophylaxis in select infants. The prophylaxis, however, is costly, and so targeting the recipient population and timing of administration is important for optimal effectiveness and judicious use of limited health care resources. This article reviews the epidemiology of RSV infections in infants and young children, including risk factors for severe disease, so as to inform decisions about prevention efforts.

Factors predicting prolonged hospital stay for infants with bronchiolitis

BACKGROUND

Prior prediction models for length of stay (LOS) in bronchiolitis have focused more on birth- and disease-related risk factors than on early hospital course factors, particularly common clinical markers including respiratory status and caloric intake.

OBJECTIVES

1) Study the associations of various clinical markers and LOS; and 2) develop a LOS prediction model.

DESIGN

Retrospective cohort study.

SETTING

Children's Hospital of Wisconsin.

PATIENTS

Inclusion criteria were: age < 365 days old; admission between November 1, 2004 and April 15, 2005; final diagnosis of bronchiolitis; placement on the bronchiolitis treatment protocol; and lack of concurrent condition impacting LOS.

RESULTS

During the study period, 272/347 infants admitted with bronchiolitis met inclusion criteria. On hospital day 2, infants in the prolonged LOS group (≥ 108 hours) had a significantly greater number of hours on supplemental oxygen, maximum supplemental oxygen use, minimum supplemental oxygen use, maximum respiratory rate, mean respiratory score, and number of times suctioned. They had significantly lower minimum oxygen saturation and caloric intake. Recursive partitioning demonstrated five variables (hours of supplemental oxygen, maximum respiratory rate, minimum supplemental oxygen use, gestation, and caloric intake) to predict short or prolonged LOS with an area under the receiver-operator characteristic curve of 0.89/0.72 in the learning/test trees; sensitivity, 0.85; and specificity, 0.82.

CONCLUSIONS

There are important differences between infants with bronchiolitis having short and prolonged hospital stays, including several clinical markers identifiable on hospital day 2. This model may be a useful prediction tool for targeting early interventions for high-risk infants.

Antibiotic use in premature infants after discharge from the neonatal intensive care unit

Using a retrospective cohort of premature infants, we constructed multivariable Poisson models to determine factors associated with the receipt of antibiotics during the first year after discharge, N = 891. Black race (incidence rate ratio 1.80 compared with White infants, P = .008), male gender (incidence rate ratio 1.44; P = .007), bronchopulmonary dysplasia (incidence rate ratio 1.47; P = .04), and each additional child at home (incidence rate ratio 1.21, P = .002) increased the receipt of antibiotics for any reason. Male gender and additional children at home increased the receipt of non-recommended antibiotics, while Black infants received care at facilities that prescribed more non-recommended antibiotics. Even in a high-risk population of children, factors other than the medical history and presentation of the child may alter antibiotic prescription patterns and result in variations in care.

The role of outpatient facilities in explaining variations in risk-adjusted readmission rates between hospitals

OBJECTIVE

Validate risk-adjusted readmission rates as a measure of inpatient quality of care after accounting for outpatient facilities, using premature infants as a test case.

STUDY SETTING

Surviving infants born between January 1, 1998 and December 12, 2001 at five Northern California Kaiser Permanente neonatal intensive care units (NICU) with 1-year follow-up at 32 outpatient facilities.

STUDY DESIGN

Using a retrospective cohort of premature infants (N=898), Poisson's regression models determined the risk-adjusted variation in unplanned readmissions between 0-1 month, 0-3 months, 3-6 months, and 3-12 months after discharge attributable to patient factors, NICUs, and outpatient facilities.

DATA COLLECTION

Prospectively collected maternal and infant hospital data were linked to inpatient, outpatient, and pharmacy databases.

PRINCIPAL RESULTS

Medical and sociodemographic factors explained the largest amount of variation in risk-adjusted readmission rates. NICU facilities were significantly associated with readmission rates up to 1 year after discharge, but the outpatient facility where patients received outpatient care can explain much of this variation. Characteristics of outpatient facilities, not the NICUs, were associated with variations in readmission rates.

CONCLUSION

Ignoring outpatient facilities leads to an overstatement of the effect of NICUs on readmissions and ignores a significant cause of variations in readmissions.

[Bronchopulmonary dysplasia and prematurity. Short-and long-term respiratory changes]

Bronchopulmonary dysplasia (BPD) is the most frequent chronic lung disease in premature children. With the inclusion of antenatal steroid therapy, surfactant use and novel mechanical ventilation strategies, survival of premature newborns has increased, whereupon the incidence of BPD has not only decreased but has also risen in extremely premature newborns. This has led to a high respiratory morbidity in the first 2-3 years of life, with numerous admissions to hospital and respiratory exacerbations mostly due to viral infections. Although there is a trend towards improvement, during school age and adolescence, respiratory symptoms may persist, due to changes in pulmonary function often showing a lower exercise capacity. Although BPD symptoms are similar to those of asthma, as there is limitation in airflow and bronchial hyperresponsiveness (BHR), pathophysiological mechanisms could be different in both diseases. On the other hand, isolated prematurity plays an important role in the child's respiratory pathology, proving that pulmonary function alterations in preterm children are present since the first months of life. A higher respiratory morbidity has also been observed in these children when compared to full-term newborns, not only during the first years of life but also subsequently. In this study, different aspects of chronic respiratory disease associated with prematurity will be analysed, drawing special attention to clinical symptoms, respiratory function changes, BHR and exercise capacity. All these aspects will be reviewed from early childhood until adolescence and young adult age. Similarities and differences between BPD and asthma will also be discussed.

[Usefulness of different risk factor associations in predicting admissions due to respiratory syncytial virus in premature newborns of 32 to 35 weeks gestation in Spain]

AIM

The aim of the study was to evaluate the risk factor associations for respiratory syncytial virus (RSV) hospitalization in preterm infants from 32 to 35 weeks gestation, treated during two consecutive RSV seasons in Spain.

PATIENTS AND METHODS

A database (FLIP-2) was used after excluding the infants who received prophylactic palivizumab. A total of 193 RSV+ admissions and 4568 non-hospitalized children were studied. The risk factors analyzed were: chronological age <=10 weeks at start of RSV season or to be born during the first 10 weeks of the season; school-age siblings or daycare attendance; mother smoking during pregnancy; male gender; breastfeeding <=2 months; >=4 adults at home; history of wheezing; small for gestational age; >=2 smokers at home.

RESULTS

Logistic regression model included the first four previously mentioned risk factors as independently significant variables, with R(2) of 0.062 and area under curve of 0.687 (P<0.001). Predictive values for a child with the four risk factors were: sensitivity 6.2%, specificity 98.6%, predictive positive value 16.2%, negative predictive value 96.1%, accuracy 94.9%, positive likelihood ratio 4.581, and negative likelihood ratio 0.951. Positive likelihood ratio for a child with the two major risk factors is 2.657.

CONCLUSIONS

Usefulness of different risk factor associations to predict hospitalization for respiratory syncytial virus infection in preterm infants 32 to 35 weeks gestation in Spain is low, although similar to other models.

Infant functional status: the timing of physiologic maturation of premature infants

OBJECTIVE

To describe the maturation of physiologic milestones in preterm infants born between 24 and 32 weeks' gestational age.

METHODS

We abstracted daily physiologic maturity information on 865 infants born at < or =32 weeks' gestation in the Northern California Kaiser Permanente Medical Care Program between 1998 and 2001. Data included ventilator and incubator settings, body temperature, apnea and bradycardia spells, use of methylxanthines, feeding method, and requirements for intravenous fluids. Multivariable quantile regression models identified risk factors associated with longer postmenstrual age to achieve various physiologic milestones, including time to full oral feeding, time to wean from supplemental heat, the last day with an apnea or bradycardia episode, the last day on methylxanthine medications, and the last day on supplemental oxygen.

RESULTS

Most milestones were achieved between 34 and 36 weeks' postmenstrual age, although there were wide variations between patients. In most cases, feeding and oxygen milestones were achieved last. For each milestone there was a monotonic relationship between birth gestational age and the median achievement postmenstrual age. However, bronchopulmonary dysplasia and necrotizing enterocolitis strongly influenced these results in infants of younger gestational age.

CONCLUSIONS

This study provides epidemiologic data describing the achievement of basic physiologic milestones that influence the discharge of a premature infant. This work serves as an additional contribution in the development of algorithms to monitor the progress of neonates through their initial hospitalization and provides a reference population for future interventions to improve the physiologic maturation of prematurely born infants.

Time to send the preemie home? Additional maturity at discharge and subsequent health care costs and outcomes

OBJECTIVE

To determine whether longer stays of premature infants allowing for increased physical maturity result in subsequent postdischarge cost savings that help counterbalance increased inpatient costs.

DATA SOURCES

One thousand four hundred and two premature infants born in the Northern California Kaiser Permanente Medical Care Program between 1998 and 2002.

STUDY DESIGN/METHODS

Using multivariate matching with a time-dependent propensity score we matched 701 "Early" babies to 701 "Late" babies (developmentally similar at the time the earlier baby was sent home but who were discharged on average 3 days later) and assessed subsequent costs and clinical outcomes.

PRINCIPAL FINDINGS

Late babies accrued inpatient costs after the Early baby was already home, yet costs after discharge through 6 months were virtually identical across groups, as were clinical outcomes. Overall, after the Early baby went home, the Late-Early cost difference was $5,016 (p<.0001). A sensitivity analysis suggests our conclusions would not easily be altered by failure to match on some unmeasured covariate.

CONCLUSIONS

In a large integrated health care system, if a baby is ready for discharge (as defined by the typical criteria), staying longer increased inpatient costs but did not reduce postdischarge costs nor improve postdischarge clinical outcomes.

Pediatric care for preterm infants after NICU discharge: high number of office visits and prescription medications

OBJECTIVE

To determine the frequency and risk factors for clinic and pharmacy use in preterm infants during the first year after neonatal intensive care unit (NICU) discharge.

STUDY DESIGN

We analyzed clinic visits and prescriptions in a cohort of 23 to 32 weeks infants. We constructed multivariable regression models to determine risk factors for high use.

RESULT

The 892 preterm infants experienced 18 346 pediatric visits (mean 20 visits per infant per year) and filled 2100 prescriptions (mean 5.5 prescriptions per year among infants taking medications). Most visits were non-well child care visits to pediatric primary care providers. Prematurity and bronchopulmonary dysplasia (BPD) are important risk factors: infants at 23 to 26 weeks gestation or infants with BPD had an average 29 visits per year and 9 prescriptions per year among infants taking medication. However, half of the highest using infants were relatively healthy infants at 27 to 32 weeks gestation who escaped BPD, NEC or grade 3 to 4 intraventricular hemorrhage.

CONCLUSION

Premature infants had frequent pediatric visits and prescription medications. Extreme prematurity and neonatal morbidities are important risk factors; however, half of the highest using infants are moderately preterm without neonatal morbidities.

FLIP-2 Study: risk factors linked to respiratory syncytial virus infection requiring hospitalization in premature infants born in Spain at a gestational age of 32 to 35 weeks

BACKGROUND

Ex-premature infants are more predisposed to complicated primary respiratory syncytial virus (RSV) infection. The aim of the present study was to validate the risk factors found in a previous epidemiologic case-control study regarding hospitalization as a result of RSV infection in premature infants born at 32-35 weeks of gestational age (WGA) in Spain.

METHODS

A prospective 2-cohort study was conducted during the 2005-2006 (October 2005 to April 2006) and 2006-2007 (October 2006 to April 2007) RSV seasons, respectively. Cases were premature infants hospitalized for RSV infection whereas controls were premature infants of the same age who did not require any hospitalization for respiratory causes.

RESULTS

During the study period 5441 children from 37 Spanish hospitals were included in the risk factor analysis. Two hundred two (3.7%) were cases and the rest controls. Of the cases, 17.8% were admitted to the intensive care unit and 7.4% required mechanical ventilation. None of the patients died. Logistic regression analysis demonstrated that the risk of RSV-related respiratory infection requiring hospital admission in preterm infants (32-35 WGA) was associated with the following factors: absolute chronologic age of < or = 10 weeks at the onset of RSV season [odds ratio (OR): 2.99; 95% confidence interval (CI): 2.23-4.01]; presence of school-age siblings or day care attendance (OR: 2.04; 95% CI: 1.53-2.74); and smoking during pregnancy (OR: 1.61; 95% CI: 1.16-2.25).

CONCLUSIONS

In premature infants (32-35 WGA), only 3 independent risk factors were found to significantly increase the risk of RSV-related respiratory infection and hospitalization.

Development and Validation of a Risk Scoring Tool to Predict Respiratory Syncytial Virus Hospitalization in Premature Infants Born at 33 through 35 Completed Weeks of Gestation

Objective. The purpose of the study was to develop and validate a clinical instrument predicting the risk of respiratory syncytial virus (RSV)-associated hospitalization (RSV-H) in premature infants born at 33 through 35 completed weeks of gestation (33— 35GA). Design. An RSV risk scoring tool (RSV-RS) was developed by entering risk factors for RSV-H, determined in a Canadian prospective study, into a multiple logistic regression model. The scoring tool was then validated externally with data from a Spanish case-control study (FLIP). The Canadian cohort comprised 1758 RSV-positive infants born 33— 35GA, of whom 66 (3.7%) had confirmed RSV-H. The FLIP data set comprised 186 (33.4%) RSV-H cases and 371 (66.7%) controls. Method. The primary outcome measure was RSV-H. The RSV-RS score was the sum of the weighted probabilities for each included risk factor multiplied by 100 and ranged from 0 to 100. Receiver operator characteristic curve analyses determined cutoff points to predict subjects at low, moderate, or high RSV-H risk. Results. The RSV-RS included 7 risk factors and cutoff scores of 0— 48, 49— 64, and 65— 100 for low-, moderate-, and high-risk subjects, respectively. For the Canadian cohort, RSV-RS sensitivity in predicting RSV-H cases was 68.2%, with 71.9% specificity. With the FLIP data set, the RSV-RS had lower accuracy (61.3% sensitivity; 65.8% specificity) but showed significant positive association with increased risk for RSV-H. Conclusion. The RSV-RS accurately identified 33— 35GA infants at increased risk for RSV-H in a Canadian cohort. External validation with Spanish case-control study data further confirmed that the scoring tool is appropriate for the estimation of RSV-H risk.

An overview of mortality and sequelae of preterm birth from infancy to adulthood

Survival rates have greatly improved in recent years for infants of borderline viability; however, these infants remain at risk of developing a wide array of complications, not only in the neonatal unit, but also in the long term. Morbidity is inversely related to gestational age; however, there is no gestational age, including term, that is wholly exempt. Neurodevelopmental disabilities and recurrent health problems take a toll in early childhood. Subsequently hidden disabilities such as school difficulties and behavioural problems become apparent and persist into adolescence. Reassuringly, however, most children born very preterm adjust remarkably well during their transition into adulthood. Because mortality rates have fallen, the focus for perinatal interventions is to develop strategies to reduce long-term morbidity, especially the prevention of brain injury and abnormal brain development. In addition, follow-up to middle age and beyond is warranted to identify the risks, especially for cardiovascular and metabolic disorders that are likely to be experienced by preterm survivors.

Risk factors for severe RSV-induced lower respiratory tract infection over four consecutive epidemics

Variability in severity among different respiratory syncytial virus (RSV) seasons may influence hospital admission rates for RSV-induced lower respiratory tract infection (LRTI) in young children. The aim of the present study was to identify through logistic regression analysis, risk factors associated with higher likelihood to acquire RSV-induced LRTI, in children with symptoms severe enough to lead to hospital admission. Over four consecutive RSV seasons (2000-2004), records from children <4 years of age admitted for RSV-induced LRTI ("cases") were compared with those from children with LRTI not due to RSV and not requiring hospitalization ("controls"). 145 "case-patients" and 295 "control-patients" were evaluated. Independent from the severity of the four epidemic seasons, seven predictors for hospitalization for RSV infection were found in the bivariate analysis: number of children in the family, chronological age at the onset of RSV season, birth weight and gestational age, birth order, daycare attendance, previous RSV infections. In the logistic regression analysis, only three predictors were detected: chronological age at the beginning of RSV season [aOR =8.46; 95% CI:3.09-23.18]; birth weight category [aOR =7.70; 95% CI:1.29-45.91]; birth order (aOR =1.92; 95% CI:1.21-3.06).

CONCLUSIONS

Independent from the RSV seasonality, specific host/environmental factors can be used to identify children at greatest risk for hospitalization for RSV infection.

Lung function in prematurely born infants after viral lower respiratory tract infections

BACKGROUND

Chronic respiratory morbidity has been reported in prematurely born infants after respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) lower respiratory tract infections (LRTIs). The aim of this study was to determine the impact of viral LRTI on lung function at follow-up of prematurely born infants.

METHODS

Fifty-nine infants born before 32 weeks of gestational age were prospectively followed after neonatal unit discharge. Nasopharyngeal aspirates were obtained when the infants developed LRTIs in hospital or the community. RSV was identified by immunofluorescence and/or culture. In addition, RSV and other viral infections were identified by real time reverse transcription polymerase chain reaction. At a corrected age of 1 year, measurements of lung volume [functional residual capacity (FRC)pleth] and airway resistance (R(aw)) were made by plethysmography, and lung volume was also assessed by helium gas dilution (FRC(He)). Before the measurements, parents completed diary cards for 1 month documenting on a daily basis whether their infant wheezed, coughed, or required bronchodilator therapy.

RESULTS

Twenty-five infants had at least 1 proven RSV LRTI (RSV-positive group). The RSV-positive group compared with the rest of the cohort had similar lung volumes, but significantly higher R(aw) (P = 0.002), more days of wheeze (P < 0.001), and bronchodilator requirement (P = 0.027). Regression analysis also identified that hMPV LRTI was associated with elevated airways resistance at follow-up.

CONCLUSION

RSV and hMPV LRTIs in prematurely born infants are associated with abnormal lung function at follow-up.

Risk factors for hospitalization due to respiratory syncytial virus infection among infants in the Basque Country, Spain

This study analysed the role of several risk factors for hospitalization due to community-acquired, respiratory syncytial virus (RSV) infection. The risk factors detected in infants hospitalized for RSV infection in the first 24 months of life were compared with those in the general infant population in our region. There were 361 episodes of hospitalization in 357 infants. Eighty per cent of the infants did not present underlying conditions for severe RSV infection and only 10 (3%) were candidates for palivizumab prophylaxis. In multivariate analysis, birthweight of <2500 g was independently associated with hospitalization for RSV infection and was the most commonly detected medical risk factor. Other risk factors were maternal age at delivery <25 years, birth in the second half of the year, prematurity, suburban residence and congenital heart disease. In conclusion, together with well-known risk factors, we found that low birthweight was an independent factor for severe RSV infection.

Diminished lung function, RSV infection, and respiratory morbidity in prematurely born infants

BACKGROUND

Diminished lung function appears to be a risk factor for respiratory syncytial virus (RSV) infection/bronchiolitis in term born infants.

AIMS

To determine if diminished lung function prior to neonatal unit discharge was associated with subsequent symptomatic RSV lower respiratory tract infection (LRTI) and respiratory morbidity in prematurely born infants.

METHODS

Of 39 infants in a tertiary neonatal intensive care unit (median gestational age 28 weeks, range 23-31), 20 had bronchopulmonary dysplasia. Lung function (compliance and resistance of the respiratory system (C(rs) and R(rs)) and functional residual capacity (FRC)) was measured on the neonatal unit at 36 weeks postmenstrual age (PMA). Following neonatal unit discharge, nasopharyngeal aspirates were obtained on every occasion, at home or in hospital, an infant had an LRTI. RSV was identified by immunofluorescence and/or culture.

RESULTS

The 15 infants who suffered a symptomatic RSV LRTI had a higher mean R(rs) and suffered more wheeze at follow up than the rest of the cohort. Regression analysis showed that a high R(rs) was significantly associated with a symptomatic RSV LRTI; significant factors for cough were a high R(rs) and a symptomatic RSV LRTI, and for wheeze were a high R(rs).

CONCLUSION

Prematurely born infants, who had a symptomatic RSV LRTI and/or respiratory morbidity at follow up, had worse lung function prior to neonatal unit discharge.

Prospective study of healthcare utilisation and respiratory morbidity due to RSV infection in prematurely born infants

BACKGROUND

A study was undertaken to determine the impact of respiratory syncytial virus (RSV) infection, both in hospital and the community, on healthcare utilisation and respiratory morbidity in prematurely born infants and to identify risk factors for symptomatic RSV infection.

METHODS

A hospital and community follow up study was undertaken of 126 infants born before 32 weeks of gestational age. Healthcare utilisation (hospital admissions and general practitioner attendances) in the first year, respiratory morbidity at follow up (wheeze and cough documented by parent completed diary cards), and RSV positive lower respiratory tract infections (LRTIs) were documented. Nasopharyngeal aspirates were obtained for immunofluorescence and culture for RSV whenever the infants had an LRTI, either in the community or in hospital.

RESULTS

Forty two infants had an RSV positive LRTI (RSV group), 50 had an RSV negative LRTI (RSV negative LRTI group), and 32 infants had no LRTI (no LRTI group). Compared with the RSV negative LRTI and the no LRTI groups, the RSV group required more admissions (p=0.392, p<0.001) and days in hospital (p=0.049, p=0.006) and had more cough (p=0.05, p=0.038) and wheeze (p=0.003, p=0.003) at follow up. Significant risk factors for symptomatic RSV LRTI were number of siblings (p=0.035) and maternal smoking in pregnancy (p=0.005), for cough were number of siblings (p=0.002) and RSV LRTI (p=0.02), and for wheeze was RSV LRTI (p=0.019).

CONCLUSION

RSV infection, even if hospital admission is not required, is associated with increased subsequent respiratory morbidity in prematurely born infants.