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.

Effects of parental and household smoking on the risk of respiratory syncytial virus (RSV) hospitalisation in late-preterm infants and the potential impact of RSV prophylaxis.

OBJECTIVE: To assess the impact of household smoking and palivizumab prophylaxis on the risk of respiratory syncytial virus (RSV) hospitalisation in late-preterm (32-35 weeks' gestational age) infants. METHODS: Familial smoking and other RSV risk factor data from the FLIP, FLIP-2 and IMpact studies and datasets from France, Germany and Italy, together with palivizumab prophylaxis data from the FLIP-2 and IMpact studies, were analysed using cross-correlation and Bayesian meta-analytical modelling employing Markov Chain Monte Carlo sampling. RESULTS: There were 2.35 times (95% confidence interval [CI] 1.37-4.02) as many hospitalisations amongst infants from smoking compared with those from non-smoking families. Among non-prophylaxed infants, there were 2.53 times (95% CI 1.27-4.94) as many RSV hospitalisations from smoking than from non-smoking families and that excess hospitalisation was reduced to 1.03 times (95% CI 0.38-2.99) amongst prophylaxed infants. Familial smoking correlates significantly (p < 0.01) with other RSV risk factors: positive correlation with number of school-age siblings, history of family atopy, family wheeze and gestational age; negative correlation with birth weight and breast feeding. CONCLUSIONS: Late-preterm infants from smoking families appear to be at heightened risk for severe RSV infection requiring hospitalisation of which the risk may be reduced with RSV prophylaxis.

The risk of mortality among young children hospitalized for severe respiratory syncytial virus infection.

Respiratory syncytial virus (RSV) lower respiratory tract infection (LRTI) is the leading cause of childhood morbidity. Although also an important cause of childhood mortality worldwide, the impact of key risk factors has not been established. A systematic review of 34 articles reporting case fatality rates in young children hospitalized for severe RSV LRTI, according to the presence of underlying RSV risk factors, was conducted. The weighted mean case fatality rate was 1.2% (range, 0-8.3%; median, 0%; n = 10) among preterm infants; 5.2% (range, 2.0-37.0%; median, 5.9%; n = 7) among children with CHD; and 4.1% (range, 0-10.5%; median, 7.0%; n = 6) among children with BPD. Case fatality estimates among children not at high risk (n = 6) ranged from 0% to 1.5% (weighted mean, 0.2%; median, 0.0%). Fatality during hospitalization for severe RSV LRTI is rare among children not at high risk, but occurs more commonly among children at higher risk of RSV LRTI.

The evolution of risk factors for respiratory syncytial virus-related hospitalisation in infants born at 32-35 weeks' gestational age: time-based analysis using data from the FLIP-2 study.

AIM: The aim of this study was to examine whether the risk for respiratory syncytial virus (RSV)-related hospitalisation changes through the first year of life in infants of 32-35 weeks' gestational age (wGA). METHODS: Risk factors from the FLIP-2 study (190 cases/4566 age-matched controls) were included in a Cox regression analysis wherein time slices were taken at 1-month intervals from birth. RESULTS: Half of all RSV hospitalisations occurred in the first 68 days after birth, with 56% occurring within 90 days. The time taken for 50% of hospitalisations to occur was 148 days for those born outside the RSV season and 58 days for those born within the season. By 90 days old, 84% of infants born in the season and 20% of those born outside the season were hospitalised. In both groups, hospitalisations occurred ≥5 months after birth. Male sex, smoking whilst pregnant, month of birth, duration of breastfeeding, number of siblings at school, and number of smokers in household all contributed to the risk of RSV hospitalisation beyond the age of 90 days. CONCLUSIONS: The risk of RSV hospitalisation appears to persist to at least 5-6 months old in 32-35 wGA infants, which has implications for the optimal management of disease prevention.

The Alberta Hip and Knee Replacement Project: a model for health technology assessment based on comparative effectiveness of clinical pathways.

BACKGROUND: The Alberta Hip and Knee Replacement Project developed a new evidence-based clinical pathway (NCP) for total hip (THR) and knee (TKR) replacement. The aim was to facilitate the delivery of services in a timely and cost-effective manner while achieving the highest quality of care for the patient across the full continuum of care from patient referral to an orthopedic surgeon through surgery, recovery, and rehabilitation. The purpose of this article is to provide an overview of the study design, rationale, and execution of this project as a model for health technology assessment based on comparative effectiveness of alternative clinical pathways. METHODS: A pragmatic randomized controlled trial study design was used to evaluate the NCP compared with the standard of care (SOC) for these procedures. The pragmatic study design was selected as a rigorous approach to produce high quality evidence suitable for informing decisions between relevant interventions in real clinical practice. The NCP was evaluated in three of the nine regional health authorities (RHAs) in Alberta with dedicated central intake clinics offering multidisciplinary care teams, constituting 80 percent of THR and TKR surgeries performed annually in Alberta. Patients were identified in the offices of twenty orthopedic surgeons who routinely performed THR or TKR surgeries. Evaluation outcome measures were based on the six dimensions of the Alberta Quality Matrix for Health (AQMH): acceptability, accessibility, appropriateness, effectiveness, efficiency and safety. Data were collected prospectively through patient self-completed questionnaires at baseline and 3 and 12 months after surgery, ambulatory and inpatient chart reviews, and electronic administrative data. RESULTS: The trial design was successful in establishing similar groups for rigorous evaluation. Of the 4,985 patients invited to participate, 69 percent of patients consented. A total of 3,434 patients were randomized: 1,712 to SOC and 1,722 to the NCP. The baseline characteristics of patients in the two study arms, including demographics, comorbidity as measured by CDS and exposure to pain medications, and health-related quality of life, as measured by Western Ontario and McMaster Universities Osteoarthritis Index and Short Form-36, were similar. CONCLUSIONS: The Alberta Hip and Knee Replacement Project demonstrates the feasibility and advantages of applying a pragmatic randomized controlled trial to ascertain comparative effectiveness. This is a model for health technology assessment that incorporates how clinical pathways can be effectively evaluated.