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Of MCV4, ADHD and ECGs
Recent guidelines reinforce the need to do thorough evaluations of our patients.
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Although the meningococcal conjugate vaccine was approved by the FDA for children as young as 2 years in Oct. 17, 2007, the Advisory Committee on Immunization Practices decided to maintain its current policy of routine immunization at 11 years of age and catch up for older teenagers (MMWR; 2008;57(17);462-465).
It did not recommend routine immunization of those for whom the vaccine was recently approved. The group did recommend that those at increased risk in this age group receive meningococcal conjugate vaccine (MCV4, Menactra, Sanofi Pasteur) rather than the previously recommended polysaccharide vaccine (MPSV). Those who have received MPSV three or more years previously should be reimmunized with MCV4. Although the duration of protection is unknown at this time, experience with other conjugate vaccines has been that immunologic memory is durable, yielding protection longer than with comparable polysaccharide vaccines. Antibody titers were greater following the conjugate vaccine in this age group.
The decision was based on the cost of the program weighed against the benefits to be gained.
In children aged 2 to 11, there were 160 cases and 13 deaths by strains included in the vaccine compared with 250 and 15 in the second decade. The vaccine protects against groups A, C, Y and W-135.
Group B, which is not included in the vaccine, causes about 50% of the cases in the 2- to 4-year-old age group and fewer in older people. The other factor to be taken into consideration is that the carrier rate does not seem to rise until the teen years. Thus, in contrast to influenza, immunization of those people younger than 11 years is not likely to affect older individuals. In addition, the acceptance of hepatitis A vaccine, which also is recommended for 2-year-olds, has been about 50%. Finally, it is uncertain how long protection will last following a single dose of MCV4 given at 2 years of age.
New AHA guidelines
In 1999, the American Heart Association (AHA) warned about the cardiac risk of stimulant drugs used to treat ADHD. Between 1999 and 2004, 19 deaths and 26 severe cardiac events were reported in these children.
In a new document, AHA officials make a recommendation that it is reasonable to consider screening children and particularly those with heart disease who also have a higher risk of ADHD (see related story). In 2005, the FDA made a labeling change indicating that Adderall-XR should generally not be used in children with structural heart lesions and also warned about the danger of amphetamine drugs in general in this group. The evidence for methylphenidate was less clear. The FDA has issued warnings about the risk of these drugs in children with cardiac disease or hypertension.
Some categories of children with cardiac disease have an estimated risk of ADHD of close to 50%, while the frequency in the general population is estimated to be between 4% and 12%. That is a lot of children. There are several thousands of deaths annually in children and mainly from children with underlying heart disease. How to recognize the children at risk has been the challenge. The ECG has generally been more sensitive for screening than history and physical examinations in several studies and has become routine for screening athletes and in all newborns in Italy.
The recommendation of the AHA’s initial report can be summarized as follows:
- All children who are considered for therapy should have a complete personal and family history, including the use of other medications, and cardiovascular events in personal and family history and a thorough physical examination including blood pressure.
- An ECG can be considered. Those patients with known cardiovascular disease should be referred to a pediatric cardiologist for evaluation if possible. The details are included in the AHA report including recommendations for each drug that might be considered for patients with ADHD.
The AAP responded with the following qualification: The recommendation for universal ECG testing may not be practicable because of the shortage of pediatric cardiologists in some areas. Shortly thereafter, the AHA revised its statement emphasizing “acquiring an ECG is a ‘class IIa recommendation,’ meaning that it is reasonable for a physician to consider obtaining an ECG as part of the evaluation of children being considered for stimulant drug therapy, but this should be at the physician’s judgment, and it is not mandatory to obtain one.”
The AAP and AHA go on to state that the inability to obtain an ECG should not result in a child not receiving therapy for ADHD. It also is uncertain whether children already on therapy need to have an ECG.
In comparing the cost-effectiveness of MCV4 and ECG assessment, it would appear that the former would not meet the test whereas ECG testing would, although the methods of assessing cost are not comparable and much is still to be learned about the effectiveness of ECG testing. The AHA statement reinforces the need to do thorough evaluations of our patients.