Objective. It is standard practice to defer discharge of premature infants until they have achieved a set number of days without experiencing apnea. The duration of this period, however, is highly variable across institutions, and there is scant literature on its effectiveness or value-for-money. Our objective was to establish the economic impact of varying durations of predischarge observation for apnea of prematurity.
Methods. Using computer simulation, we compared the alternatives of hospital monitoring for 1 to 10 days, after apparent cessation of apnea, with no monitoring and with the next longest period of monitoring. The daily probability of apnea requiring stimulation after a given number of apnea-free days was obtained from chart review of 216 infants, beginning on the day they attained both full feeds and temperature stability in an open crib. Baseline rates of survival or impairment, utilities for calculation of quality-adjusted life years (QALYs), outcomes for respiratory arrest at home, and long-run costs for neurodevelopmental impairment were derived from the literature. Hospital expenditures were obtained from itemized billing records for infants on each of the final 10 days of hospitalization and converted to costs using Medicare cost-to-charge ratios. Costs are reported in 2000 US dollars.
Results. For infants born at 24 to 26 weeks’ gestation, each additional day of monitoring cost from $41000 per QALY saved for the first day to >$130000 per additional QALY gained for the tenth day. Cost-effectiveness was poorer for infants who were born at gestational ages >30 weeks. Results were sensitive to the proportion of charted apneas requiring stimulation that would actually progress, without intervention, to respiratory arrest.
Conclusions. In this model, the cost-effectiveness of predischarge monitoring for apnea of prematurity declined significantly as the duration of monitoring was increased. Consideration should be given to alternative uses for resources in formulating neonatal discharge guidelines.
Sirs:
Zupancic, Richardson, O'Brien, Eichenwald and Weinstein are to be commended for addressing the difficult issue of pre-discharge, hospital monitoring of preterm infants. Not surprisingly, they found that when babies are kept in the hospital for increasing periods free of symptoms, the "cost" of each quality-adjusted life year (QALY) preserved goes up, as fewer QALYs are added to the benefits column while the costs increase. This can be attributed to either a decreasing likelihood of an apparrent life threatening event (ALTE) happening after an increasing period without an ALTE or to an increased maturity at the time of discharge. They conclude that "monitoring lower gestation infants for a longer period and higher gestation infants for a shorter period may result in better outcomes and decreased costs compared with the status quo."
First, the authors do not make clear what is the "status quo." I interpolate that it is 7 symptom free days of monitoring for all infants born before 35 weeks of gestation who have reached thermal and nutritional stability. This may not be true for more mature infants. Second, and more importantly, while the results may be helpful to policy makers and insurance companies, they are really not useful at the bedside. Should a regulatory agency some day have the fortitude to say that only treatment that yields QALYs at less than "X" amount of dollars will be funded, then the results will be useful at the bedside. I am concerned that insurance companies will use the data to justify the speedy discharge of infants from the hospital without concern for the social and legal fallout.
What the practitioner needs are the data for risk of ALTE that the authors used to calculate lost QALYs. We can discuss with parents the likelihood of a significant event happening after each day of symptom free observation. It would be nice to know if the likelihood becomes asymptotic to the baseline after either a certain number of days or post menstrual age (PMA = gestational age plus postnatal age.) At that point, hospitalization is of no further benefit. Using PMA may be a better way of looking at safe discharge across wide ranges of gestational age. We could then help parents weigh the benefits of continued hospital stay versus discharge home.
I doubt that many parents can grasp the significance of cost of a QALY. In fact, if I were a parent, I would ask that my baby stay in the hospital long enough to be sure he will be safe at home, or provide a way to protect him at home. The day or PMA at which the risk at home equals the risk in the hospital could/should be the day of discharge. I would consider the cost irrelevant if there were a safe way to attempt protect my child. (Hence the (? excess) use of home monitors.)
I agree with the authors that equipoise does exist about the duration of in-hospital monitoring. In such a situation, the safest (for the practioner) approach is a clinical trial with fully informed, consenting parents. My dilema in designing such a study would be our inability to predict ALTE's at home, and even to define a "significant" event in the hospital or at home. It may in fact turn out that in-hospital monitoring does not actually improve QALYs. Furthermore, while home care is certainly better in the long run than hospital care for a "well" child, I do not know the benefits of discharge that is one week earlier than otherwise planned. Thus a risk-benefit analysis for parents (as is required for all research consent forms) is currently difficult to do.
Kenneth Harkavy, MD