A systematic review of compliance with palivizumab administration for RSV immunoprophylaxis

Abstract

Background: Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection (LRTI) in infants and young children, accounting for approximately 75,000-125,000 hospitalizations per year. It is estimated that in 2000, RSV infection accounted for 1.7 million office visits, 402,000 emergency room visits, and 236,000 hospital outpatient visits per year for children younger than 5 years of age. Palivizumab, a humanized monoclonal antibody directed against RSV, is the only immunoprophylaxis therapy approved by the FDA for prevention of serious lower respiratory tract disease caused by RSV in infants (up to 2 years of age) who meet 1 or more of the following criteria for high risk: (a) gestational age up to 35 weeks;(b) diagnosis of chronic lung disease (CLD, formerly bronchopulmonary dysplasia [BPD]); or (c) diagnosis of cyanotic or complex congenital heart disease. The RSV season typically occurs between November and March but may vary by region. During the period of our review, depending on local duration of the RSV season, infants usually required 5 monthly (every 28-30 days) intramuscular injections of palivizumab. Infants born in the middle of the season received their palivizumab doses from the time of birth to the end of the season and, therefore, may have required less than 5 doses.It is unclear if compliance with monthly doses is a problem and whether noncompliance increases the risk of RSV hospitalizations in routine clinical practice.

Objectives: To (a) identify and describe compliance rates and the factors that influence parental compliance with immunoprophylaxis regimens, (b)review intervention programs and describe those that have been associated with increased compliance, and (c) summarize the association of compliance with RSV hospitalization rates.

Methods: An electronic literature search was conducted using journal databases, including Ovid, Current Contents, Embase, Medline In-Process & Other Non-Indexed Citations; Ovid Medline, PubMed, and Web of Science;and an abstract database, Medical Intelligence Solution, for citations through April 2008. Specific search terms used were palivizumab with patient compliance, patient adherence, or patient persistence.

Results: Twenty-five articles and abstracts met the inclusion criteria. Available studies were mostly retrospective or observational prospective.Compliance, defined in various ways across the studies, varied between 25% and 100%, and 12 studies identified some of the factors related to noncompliance. Compliance generally was lower among Medicaid patients,African American patients, and other minorities. Ten studies (3 manuscripts and 7 abstracts) investigated the association of administration of prophylaxis through monthly home visits by a health professional with parental compliance with therapy. Most of the home-based programs were associated with higher compliance rates compared with clinic or office programs.Rates as high as 94% and 64% were achieved when Medicaid infants and infants of minority descent, respectively, received their doses through a home health program. When these infants received their doses at a clinic or office, depending on the definition of compliance, rates were 61%-100% for Medicaid infants and 44% for infants of minority descent. Reminder telephone calls to parents or caregivers, comprehensive multidisciplinary programs that included extensive counseling of parents, calendars with sticker reminders, and education in the language native to parents also were associated with increased compliance, although statistical significance was reported in only 1 study. Several studies recommended educating parents on the benefits of RSV prophylaxis, alleviating transportation and language difficulties, recognizing cultural differences and biases, and clarifying misperception of RSV illness severity. Home health programs had lower rates of RSV hospitalizations than office-based programs in 3 analyses conducted in 2 studies. In 4 other abstracts, the rates of RSV hospitalization for home health programs and office-based administration did not significantly differ. In a large, 4-season, prospective outcome study, compliant infants had lower RSV hospitalization rates than those who were not compliant under one definition of compliance (doses within 35-day intervals). RSV hospitalization rates were not significantly different using another definition of compliance (receipt of anticipated doses, expected vs. observed rates).In a large survey of 10,390 infants identified from pharmacy dispensing records, RSV hospitalization rates were 1.4% in the compliant group versus 3.1% in the noncompliant group (OR = 2.2, 95% CI = 1.4-3.5, P < 0.001).Adjustment for confounding was not reported in these studies.

Conclusion: Medicaid and minority infants were less likely to receive scheduled palivizumab doses. Home-based programs for the administration of palivizumab have been investigated more than other interventions and are associated with improved compliance compared with office-based administration. Compliance with dosing, in general, was associated with lower RSV hospitalization rates. However, these strategies should be further investigated using well-designed studies.