Length of Stay, Jaundice, and Hospital Readmission

DISCUSSION

Of all of the conditions found to account for readmission to the hospital within the first 14 days, only hyperbilirubinemia and dehydration/failure to thrive are susceptible to some kind of intervention that might prevent readmission. Only 5 of our 247 infants were readmitted because of dehydration/failure to thrive and we chose to examine more closely the issue of hyperbilirubinemia. As shown in Table 3, the effect of gestation was striking with odds ratios >7 for infants ≤38 weeks gestation (versus ≥40 weeks). The infant's birth weight did not enter into the model as a significant factor, however. The presence of jaundice in the nursery is, not surprisingly, an important risk factor.

A length of stay of <72 hours was also an important factor associated with the risk of readmission and, in particular, readmission for jaundice. However, although the American Academy of Pediatrics recommends closer follow-up for infants discharged <48 hours we found no increase in risk of readmission to hospital for those infants whose length of stay was <48 hours compared with ≥48 to <72 hours. These findings are similar to those of Soskolne et al⁵ and suggest that undue emphasis has been placed on the 48-hour time period. It seems that discharge at any time <72 hours significantly increases the risk for readmission with hyperbilirubinemia when compared with discharge after 72 hours.

Maternal smoking, rupture of membranes for ≥18 hours, and fetal passage of meconium were associated with a decreased risk of readmission to hospital. Rupture of membranes for ≥18 hours (but not maternal smoking) was also associated with a decreased risk of readmission for jaundice. An association between maternal smoking and lower neonatal serum bilirubin levels has been described previously,^6,7 although this has not been a consistent finding.⁸ It is plausible that maternal smoking and prolonged rupture of the membranes could stress the fetus sufficiently to increase the production of glucuronosyl transferase. On the other hand, it is also possible that these are chance associations. Early meconium passage is associated with lower bilirubin levels presumably as a result of a decrease in the enterohepatic circulation of bilirubin.⁹

As far as the jaundice is concerned, there is no inherent reason why infants discharged after 72 hours should be less likely to develop significant hyperbilirubinemia than those discharged before 72 hours, unless some intervention occurs in the first 72 hours that affects bilirubin levels. Such intervention might include lactation counseling for the mother and lead to more frequent and effective breastfeeding. Eighty-nine percent of the infants readmitted with jaundice were breastfed and increasing the frequency of nursing is associated with a reduced risk of later hyperbilirubinemia.¹⁰

There is also evidence that mothering competence may be affected by early discharge. Eidelman et al¹¹ have demonstrated that women on the first postpartum day score significantly lower than nonpregnant women on standardized tests of cognitive function. Although they did not find any significant decrease in cognitive function in parturient women on the 2nd or 3rd day after delivery, it is possible that mothers discharged early on the 2nd day may nevertheless manifest some degree of confusion and forgetfulness. Such mothers will not be able to reliably integrate information given to them by care givers and this could have an impact on the infant's well-being in the next several days. It is likely that the mothers of those infants discharged later have had a greater opportunity to establish good lactation under the guidance of nursing staff and lactation counselors.

To evaluate the possible effects of inadequate nursing, we observed the weight loss of infants readmitted for hyperbilirubinemia in the first 7 days. There were 121 such infants and we compared them with 57 infants who had been readmitted within 7 days for reasons other than jaundice, dehydration, or failure to thrive. The jaundiced babies had a mean weight loss (from birth weight) of 6.75 ± 4.36% versus 3.97 ± 4.74% in the nonjaundiced babies (a difference of 2.78%; 95% CL, 1.24, 4.15; P = .000534). Although the mean weight loss does not seem excessive, the difference between the two groups suggests less adequate fluid and caloric intake in the jaundiced infants which is consistent with previous observations.⁷

There can be no doubt, however, that whether they are discharged at 30 or 60 hours of life, those infants who are readmitted on days 4 to 6 with hyperbilirubinemia have not achieved their peak bilirubin level by the time they leave the hospital. Thus, if we want to be sure we do not miss very severe hyperbilirubinemia (that, even in a healthy term newborn can, on occasion, have disastrous consequences^12,13), then infants discharged <72 hours after birth should also be seen within 2 to 3 days of discharge. Perhaps current guidelines for the follow-up of infants should be reevaluated.

A weakness of this, and other similar studies, is that we do not have a true measure of morbidity in the early neonatal period. Because of the problem of ascertainment, we are forced to use hospital readmission as a surrogate for morbidity. As pointed out by Beebe et al,¹⁴the problems leading to admission such as jaundice, fever, or poor feeding often do not lead to a negative outcome even in the absence of intervention. Nevertheless, there is almost certainly a greater potential for morbidity in this population than in a control group. In addition, the criteria for readmission vary from institution to institution, making comparisons with other studies difficult. It is also possible that admission of some infants to other hospitals, or the use of home phototherapy, could lead us to underestimate the incidence of readmission. During the study period, home phototherapy was rarely used and the known admission patterns of the pediatricians involved indicate that, at most, these would account for a very small proportion of the population and would not affect the conclusions of the study.

We conclude that the major reason for readmission to hospital in the first 2 weeks of life is hyperbilirubinemia (incidence 4.2 per 1000 discharges). Significant jaundice, and dehydration/failure to thrive (0.2 per 1000 discharges) are the only causes of readmission that are potentially susceptible to intervention in the first few days of life. Attempts to decrease the risk of hyperbilirubinemia and dehydration/failure to thrive should be directed at the early establishment of effective lactation and closer surveillance for those infants who have risk factors for readmission such as gestation <38 weeks, jaundice in the nursery, length of stay <72 hours, male sex, and breastfeeding. The risk of readmission is similar for infants discharged <48 hours or ≥48 to <72 hours, suggesting that any infant discharged at <72 hours should be seen by a health care professional within 2 to 3 days of discharge.