The cost-effectiveness of palivizumab for respiratory syncytial virus prophylaxis in premature infants with a gestational age of 32-35 weeks: a Canadian-based analysis

BACKGROUND

Prophylactic therapy with palivizumab, a humanized monoclonal antibody, has been shown to reduce the number of respiratory syncytial virus (RSV)-related hospitalizations in preterm infants, including those in the 32-35 weeks' gestational age (GA) subgroup. The cost-effectiveness of this therapy in Canada is unknown.

OBJECTIVES

To evaluate the cost-effectiveness of palivizumab as respiratory syncytial virus prophylaxis in premature infants born at 32-35 weeks' GA.

DESIGN

A decision analytic model was designed to compare both direct and indirect medical costs and benefits of prophylaxis in this subgroup of premature infants. Sensitivity analyses were performed to ascertain the robustness of the model for five point estimates: mortality rate, discounting rates, health-utility values, degree of vial-sharing and administration costs. A probabilistic sensitivity analysis (PSA) was also conducted.

SETTING

Canadian publicly funded health-care system (Ministry of Health payer perspective) for base-case analysis. Societal perspective, accounting for future lost productivity, was adopted for a secondary analysis.

PARTICIPANTS

Canadian infants born at 32-35 weeks' GA without chronic lung disease.

INTERVENTIONS

Palivizumab prophylaxis versus no prophylaxis.

MAIN OUTCOME MEASURES

Expected costs and incremental cost-effectiveness ratio expressed as cost per life-year gained (LYG) and quality-adjusted life-year (QALY) using 2007 Canadian dollars.

RESULTS

The expected costs were higher for palivizumab prophylaxis as compared with no prophylaxis. The incremental cost-effectiveness ratio (ICER) for the base-case scenario was $20 924 per QALY after discounting, which is considered cost-effective in Canada. When the uncertainty of the input parameter assumptions was tested through sensitivity analyses assessing several data sources for five key parameters, no substantial differences were found from the base-case results. The PSA indicated a 0.99 probability that the ICER for palivizumab was less than $50 000/QALY. Sub-analyses that varied the number of risk factors found that for infants with two or more risk factors, or at least moderate risk, palivizumab had incremental costs per QALY that indicated moderate-to-strong evidence for adoption (range: $808-81 331, per QALY).

CONCLUSIONS

Palivizumab was cost-effective and the authors' model supports prophylaxis for infants born at 32-35 weeks' GA, particularly those with more than two risk factors or at least a moderate level of risk according to a risk scoring tool.

Current strategies in the prevention of respiratory syncytial virus disease

Infants infected with respiratory syncytial virus (RSV) develop both upper and lower respiratory tract infections resulting in laryngotracheobronchitis, bronchiolitis and pneumonia. Premature infants of less than 32 weeks' gestation and those with underlying chronic lung disease are particularly susceptible and incur significant morbidity and mortality following hospitalisation. Conservative RSV prevention strategies focus on the interruption of transmission by proper hand-washing techniques and reducing exposure to potential environmental risk factors. Major challenges have impeded the development of an RSV vaccine but a licensed product may be expected in the near future. Prophylaxis with a humanised mouse monoclonal antibody (palivizumab) has been effective in reducing the rate of RSV hospitalisation in high-risk premature infants in phase II-IV trials and is available for use within internationally approved guidelines. Experimental studies evaluating the use of palivizumab in patients with congenital heart disease, those with cystic fibrosis and immunosuppressed bone marrow transplant recipients are well underway, the results of which are eagerly awaited.

Case report and review of the perinatal implications of maternal lithium use

The purpose of this study was to review the use of lithium in pregnancy and its effects on the neonate. This was a case study and review of the published literature. Lithium is commonly used in the treatment of psychiatric disorders, specifically bipolar depression. Bipolar disorders that require treatment with lithium demand special consideration when the woman becomes pregnant. Reported neonatal problems with maternal lithium therapy include Ebstein's anomaly, poor respiratory effort and cyanosis, rhythm disturbances, nephrogenic diabetes insipidus, thyroid dysfunction, hypoglycemia, hypotonia and lethargy, hyperbilirubinemia, and large-for-gestational-age infants. Lithium can have adverse effects on the fetus and newborn infant, but data suggest normal behavioral patterns in childhood.

Late-onset left diaphragmatic hernia after group B streptococcal sepsis: An unusual presentation

There are several reported cases of late presentations of right diaphragmatic hernia with early- as well as late-onset group B streptococcal (GBS) infections. The authors describe the first case of late-onset left diaphragmatic hernia with late onset GBS infection in a preterm infant. The diagnosis was prompted by a dramatic clinical deterioration during the recovery phase of GBS sepsis.

Palivizumab prophylaxis for respiratory syncytial virus in Canada: utilization and outcomes

OBJECTIVE

To provide information on the use and outcomes of palivizumab prophylaxis in children at high risk of serious respiratory syncytial virus (RSV) infection.

DESIGN

Observational, prospective, longitudinal, multicenter study.

SETTING

Eighteen hospitals and pediatric clinics located in six provinces across Canada.

PATIENTS

Infants enrolled in the palivizumab Special Access Programme of Canada's Therapeutic Products Programme throughout the 1999 to 2000 RSV season. Most were premature infants born at < or = 32 weeks of gestation and/or had bronchopulmonary dysplasia.

METHODS AND MAIN OUTCOME MEASURES

Neonatal and demographic data were recorded for each subject. The parent/caregiver was contacted on a monthly basis until the end of the RSV season to obtain information on palivizumab utilization and compliance as well as incidence and severity of respiratory infections.

RESULTS

There were 444 evaluable subjects who each received 1 to 7 injections of palivizumab for a total of 1702 doses from September 1999 to April 2000. Most subjects received 5 injections with high compliance. Prophylaxis was discontinued in 2% of children. There were 116 clinical events or hospitalizations involving respiratory tract infections reported in 91 children. Eighty-six of these were managed in an outpatient setting, and 30 required hospitalization. The estimated incidence of hospitalization for RSV-positive lower respiratory tract infections (LRTIs) was 2.4%. Hospitalization for RSV LRTI occurred more often in children with bronchopulmonary dysplasia (6.0%) than in those with prematurity only (1.6%).

CONCLUSIONS

This study demonstrates that prophylaxis with palivizumab during the RSV season was associated with a low rate of hospitalization for RSV-positive LRTIs. Palivizumab was well-tolerated, and compliance was high. The findings confirm the results of the major randomized clinical trial of palivizumab and demonstrate the safety and effectiveness of RSV prophylaxis.

Ovarian cyst in a premature infant treated with spironolactone

We describe the late occurrence of an ovarian cyst in a premature infant, the second of a set of monochorionic diamnionic twins, during treatment with spironolactone. Spironolactone is commonly used in the management of neonatal chronic lung disease in combination with other diuretics because of its potassium-sparing effect. It has progestational activity and has been reported to cause gynecomastia. It is used widely for its antiandrogenic properties in the treatment of female hirsutism and hyperandrogenism and it has a role in the management of familial male-limited precocious puberty. However, the estrogenic influence induced during therapy may significantly alter the hormonal milieu in newborn females, resulting in the formation of ovarian cysts. Simple ovarian lesions <5 cm merit close ultrasonographic surveillance for resolution while larger complex masses may warrant surgical intervention.

Group B streptococcus. Is it time for a screening program?

Group B streptococcal infection often causes perinatal sepsis. Early diagnosis is based on a high index of suspicion and laboratory tests. Proposed interventions targeted at the antepartum, intrapartum, and postpartum periods have met with limited success. Screening has not been widely adopted.

Discordant fibular aplasia in twins

A male infant, one of monozygotic twins, was born with absence of fibulae, ectrodactyly of the right hand and both feet, with accompanying deficiencies. This second case report of a discordant fibular aplasia developmental field defect occurring in monozygotic twins, although likely sporadic, is interesting because of the similar pattern of anomalies.

Changing physicians' behavior using combined strategies and an evidence-based protocol

OBJECTIVES

To review the number of superficial cultures performed in the evaluation of neonatal sepsis and to validate physicians' compliance with an established protocol.

DESIGN

Before-and-after-comparison using medical audit.

SETTING

Intensive care nursery in a secondary level perinatal facility.

PARTICIPANTS

One hundred seventy-five consecutive newborns admitted during a 6-month period for the assessment and potential treatment of sepsis. Eligible patients met the entrance criteria of having a superficial culture performed in conjunction with at least one deep culture, which included cerebrospinal fluid, blood, or urine. This cohort was compared with 205 patients before the introduction of the protocol.

INTERVENTIONS

A second audit of physician practice 9 months following the introduction of an evidence-based hospital protocol to discontinue the use of superficial cultures in the diagnostic assessment of neonatal infection. Evidence-based medicine, an opinion leader, continuing medical education rounds, immediate feedback through direct encounters with physicians, and barriers in accessing microbiological tests were used to alter physician behavior.

MEASUREMENTS/RESULTS

A significant reduction from 50.5% to 6.9% was achieved in the proportion of superficial cultures performed and a substantial cost savings of $4454.84 was realized without incurring patient morbidity.

CONCLUSIONS

A methodologically rigorous reaudit process with planned, interventional strategies may be used as part of a continuous quality improvement program to affect change in physicians' practices. Existing hospital practice standards should be reevaluated against emerging scientific evidence.

Congenital hypothyroidism: diagnosis and management

Every newborn infant should be screened for congenital hypothyroidism before discharge from the nursery. Neonatal screening for hypothyroidism was introduced to North America in 1972 and has been demonstrated to be cost effective in the prevention of neurological damage in children. Interpretation of diagnostic test results from such programs is based on understanding the physiology of the thyroid gland and recognition that neonatal hypothyroidism primarily stems from an embryological disorder of thyroid development rather than central causes involving the hypothalamic-pituitary axis. Early diagnosis of hypothyroidism is dependent on proper timing and collection of blood samples and an efficient screening program reporting accurate results. A thorough maternal and family history in conjunction with clinical signs and symptoms of hypothyroidism, biochemical tests, and radiological findings should be used to rapidly establish the diagnosis. Early detection and treatment with thyroxine normalizes skeletal maturation, physical growth, cognitive functioning, and motor development of affected newborns. Nurses play an important role in identification, management, and supportive care of infants with hypothyroidism so that maximal potential is achieved.

Cloacal exstrophy: prenatal diagnosis before rupture of the cloacal membrane

Embryologically, cloacal exstrophy is thought to result from persistence and subsequent rupture of the infraumbilical cloacal membrane during the fifth embryonic week. We report a case of cloacal exstrophy in which a prenatal diagnosis was made prior to rupture of the cloacal membrane. A routine ultrasound at 17 weeks' gestation demonstrated monoamniotic twins. One twin was normal, but the other was found to have a sacral myelomeningocele, "rocker-bottom" feet, splaying of the pubic rami, and a large cystic mass protruding from the infraumbilical anterior abdominal wall. A repeat ultrasound was performed at 22 weeks, with the same findings. At 26 weeks, further examination showed disappearance of the abdominal cyst, a small omphalocele, no demonstrable bladder, and the suggestion of prolapsed bowel inferior to the umbilical cord insertion. After delivery at 34 weeks, the abnormal twin was found to have the typical findings of cloacal exstrophy, myelomeningocele, bilateral lower limb anomalies, and extremely foreshortened small bowel. Rupture of the presumed cloacal membrane after 22 weeks in this case is inconsistent with our current understanding of the embryology of this anomaly, and should stimulate a reexamination of the current concepts. If the characteristic features are recognized, cloacal exstrophy can be diagnosed by prenatal ultrasound, permitting prenatal counseling and appropriate perinatal management.

Appraisal of Meconium at Delivery: A look at intervention strategies

A critical appraisal of the scientific literature on managing mesconium in labor identified 15 studies which were used to evaluate intervention strategies. Only four were randomized trials: two on the use of amnioinfusion in labor, one on the technique of bulb versus DeLee catheter suction of the newborn, and one on the need for endotracheal intubation and suction in meconium-stained neonates. Current practice is dictated by the most favorable tradeoff between benefit and risk because of limited scientific evidence.

Suctioning Newborns: A practical guide to when and how

All medical personnel involved in perinatal care are responsible for stabilizing the newborn at delivery. The initial step in resuscitation both in the delivery room and in the neonatal unit is ensuring patency of the airway through proper, efficient suctioning. This article outlines a systematic approach to the procedure.

Value of Superficial Cultures: Diagnosing neonatal sepsis in a community hospital

In a study of babies younger than 2 weeks who were admitted to a community neonatal facility with suspected sepsis, pathogenic organisms grown from superficial swab samples were compared with those from deep cultures to meet the gold standard definition of true sepsis. We conclude that superficial cultures have limited value in the diagnosis of neonatal sepsis in a community setting.

Management of prenatally diagnosed tracheal obstruction: access to the airway in utero prior to delivery

A fetus of 23-weeks gestation presented with polyhydramnios, and was found on sonography to have a large anterior cervical teratoma. At 26 weeks the mother went into premature labor and the membranes ruptured; at this time the uterus was of 32-weeks size secondary to polyhydramnios. A cesarean section was performed through a low transverse uterine incision, and the fetal head and shoulders were delivered with the cord intact. An endotracheal tube was placed, and the cord was then divided. The baby was taken to the neonatal intensive care unit for stabilization prior to planned resection, but suffered pharyngeal hemorrhage followed by endotracheal tube dislodgement several hours after birth, and expired. Despite an unfortunate outcome, this case illustrates the feasibility and potential value of in utero airway access in cases of prenatally diagnosed tracheal obstruction.

Baller-Gerold syndrome associated with congenital hydrocephalus

We present a new case of the Baller-Gerold syndrome (BGS) in an infant with prenatally apparent severe hydrocephalus, growth retardation, and cardiac and limb abnormalities detected by ultrasound at 26 weeks of gestational age. Subsequent survival to term and neonatal examination confirmed an unsuspected diagnosis of BGS.

Subcutaneous fat necrosis with hypercalcemia

We report the case of an infant with diffuse subcutaneous fat necrosis following birth asphyxia who had hypercalcemia and the rare complication of venous calcification. The clinical and radiologic findings resolved over 5 months. The disease is characterized by the presence of painless subcutaneous nodules, mainly over bony prominences, possibly associated with hypercalcemia and calcification. Early identification of hypercalcemia will avert its serious sequelae.

Neonatal Cardio-pulmonary Arrest: Emergency Catheterization of Umbilical Vein

In an emergency, the physician responsible for neonatal care must be skilled in umbilical catheterization. Several drugs can be given through an endotracheal tube, but some require intravenous administration. The umbilical vein is a better route of administration than peripheral veins because it is easily located and can be entered readily. It allows immediate access to the central circulation, enhancing drug distribution. The authors outline the procedure in a step-by-step description. This pictorial article can be used as a handy reference by physicians needing to administer fluids and drugs during cardio-pulmonary arrest in neonates.

Intravenous infusion by superficial vein in the neonate

State-of-the-art equipment, such as extremly-low-volume controlled infusion pumps and Teflon catheters, has simplified the management of intravenous therapy in the newborn. This article details the proper I.V. insertion procedure for neonates. It also reviews indications for neonatal infusion, preferred insertion sites, types of catheters currently in use, and potential complications relevant to neonatal intravenous care.

Neonatal resuscitation: a pictorial review

All medical personnel participating in obstetrical deliveries have the obligation to anticipate potential neonatal problems and to maintain competence in newborn resuscitation. This step-by-step demonstration of neonatal resuscitation is applicable to both community and teaching hospitals.

Birth asphyxia: does the Apgar score have diagnostic value?

The current literature was reviewed to evaluate the Apgar score as a diagnostic test for the presence of asphyxia. Several studies were examined and the sensitivity, specificity, and predictive values of the Apgar scores calculated. Using an umbilical cord arterial pH below 7.2 as evidence of asphyxia, the one-minute Apgar score showed poor sensitivity as a marker of asphyxia. Therefore, we discourage reference to the term "asphyxia" when Apgar scores alone are used as supportive evidence.