Trends and Resource Utilization for Neonatal Jaundice Hospitalizations in the United States Free

Neonates with jaundice were identified from a serial cross sectional analysis of inpatient discharges between 2006 and 2016 using the Healthcare Cost and Utilization Project’s (HCUP) Kids’ Inpatient Database (KID). The KID is one of the largest publicly available all-payer inpatient care databases in the US. This database is part of a family of databases and software tools developed for the HCUP and sponsored by the Agency for Healthcare Research and Quality (AHRQ).⁹  Inpatient stay records in these databases include clinical and resource use information typically available from discharge abstracts created by hospitals for billing. The KID is available every 3 years and includes pediatric discharges (age 20 or less at admission) from community, nonrehabilitation hospitals in the US. KID is sampled at 10% of uncomplicated in-hospital births and 80% of other pediatric cases.¹⁰  The 2016 KID sample has 47 participating member states, 4200 hospitals with pediatric discharges, and almost 6 million weighted pediatric discharges. The HCUP databases have been used to study several newborn conditions.^6,11,12 

All neonatal hospitalizations (age at admission ≤28 days) were extracted using the ‘Neomat’ variable, which identifies discharges with neonatal and/or maternal diagnoses and procedures. To prevent double counting, all admission ≤28 days old that were transferred out to other facilities were excluded. Similar methodology has been applied before in other studies.^6,11  Neonatal hospitalizations with jaundice were identified using the International Classification of Diseases, Ninth/10th Revision, Clinical Modification (ICD-9/10-CM) codes in the primary or secondary fields (Supplemental Table 3). To reduce errors associated with polycythemia, we excluded those newborns who had both diagnosis code for polycythemia and a procedure code for ET while analyzing rates for ET.⁶  The Population derivation is shown in Fig 1.

We studied baseline characteristics of the study population for potential confounding assessment. Patient level characteristics such as gestational age, sex, race, median household income according to zip code (<$36 000, $36 000 to $44 999, or >$45 000), primary payer (Medicare or Medicaid, private insurance, self-pay, or no charge) and hospital-level characteristics such as hospital location (urban or rural), region (Northeast, Midwest, or North Central, South, and West), and teaching status were studied. Hospital Bed size (small, medium and large) based on hospital beds, and are specific to the hospital’s location and teaching status.¹³ 

Continuous variables were reported as medians with interquartile ranges and categorical variables were reported as proportions with SE. Outcomes of interest were the trends in the proportion of neonatal hospitalizations with jaundice, use of phototherapy and ET use in the management of neonatal jaundice. The use of exchange transfusion was expressed as number of procedures per year and phototherapy use was expressed as the proportion of neonatal hospitalizations with a diagnosis of jaundice that had a procedure code for phototherapy. For trend analysis, Cochran Armitage test for dichotomous dependent variables and Jonckheere-Terpstra test for continuous dependent variables were used. Since length of stay (LOS) was not normally distributed, log transformation was conducted, and survey regression was used.¹⁴  Statistical analyses were performed using SAS 9.4 (SAS Institute Inc. Cary, North Carolina). Two-sided P value <.05 was considered significant.

Among 16 094 653 weighted neonatal hospitalizations over the study period, 3 302 129 (20.5%) had a diagnosis of jaundice and 24.7% of those with a diagnosis of jaundice had a procedure code for phototherapy. The demographic and hospital level characteristics of the neonatal hospitalizations with and without diagnostic codes for jaundice are shown in Table 1. There were no significant differences between the 2 groups except that those with jaundice were more likely to be preterm (22.3% vs 4.4%) when compared with those without. As shown in Table 2, there was no significant change in the proportion of neonatal hospitalizations with a diagnosis of neonatal jaundice over time during the study period (20.9% in 2006% to 20.5% in 2016, P = .1).

During the study period, the proportion of neonatal hospitalizations with jaundice who had procedure codes for phototherapy increased significantly from 22.5% in 2006% to 27.0% in 2016 (P < .0001). The use of phototherapy for jaundice was significantly increased for all sex, races, geographic regions, and gestational ages as shown in Table 2. The median LOS for hospitalizations with jaundice that received phototherapy was 2.2 days (IQR, 1.5–4.1 days) and there was no significant change over time during the study period. Although, the absolute number of ET performed decreased from 188 to 171 per year among neonatal hospitalizations with jaundice, the rate of exchange transfusion per 100 000 neonatal hospitalizations (6.1 in 2006 to 6.0 in 2016, P = .82) did not change over time as shown in Fig 2.

Our results demonstrate that during the 11-year period following the release of the AAP guidelines on the management of hyperbilirubinemia from 2006 to 2016, the proportion of newborn hospitalizations diagnosed with jaundice remained stable, the use of phototherapy increased, and the use of ET remained stable. The findings from this study can inform future clinical practice guidelines in addition to the potential of positively impacting clinical practice.

In 2004, the AAP issued guidelines recommending a systematic assessment for the risk of severe hyperbilirubinemia on all infants before hospital discharge.⁴  One recommendation included measurement of bilirubin levels before discharging a newborn with appropriate follow-up. Our results indicate a stable trend in the diagnosis of neonatal jaundice from 2006 through 2016. Burke et al used the same databases to examine the trends in newborn hospitalizations with jaundice following the release of the 1994 and 2004 AAP guidelines on the management of hyperbilirubinemia. They found that the diagnosis of neonatal jaundice increased from 11.9% in 1994 to 1996, to 20.0% in 2003 to 2005.⁶  Interestingly, the current study has demonstrated that from 2006 through 2016, the proportion of newborn hospitalizations with jaundice stood at approximately 20%, unchanged since 2003 to 2005. This suggests that predischarge bilirubin screening has reached a saturation point and there have been no significant changes in the risk factors that will increase the occurrence of jaundice in newborns.

Phototherapy use for jaundice increased over the entire study period. This accords with the findings from several studies including population-based ones in the US and Canada that have demonstrated increased phototherapy use following the implementation of universal predischarge bilirubin screening.^7,15–17  The increased phototherapy use in the context of an unchanged proportion of newborn hospitalizations with neonatal jaundice may raise the possibility of the overuse of phototherapy, or varying interpretations and implementation of the AAP guidelines in the clinical setting.¹⁸  Indeed, Wickremasinghe et al have shown that in a large health care system in California, phototherapy was often prescribed in 19% of newborns with total serum bilirubin levels that were below the AAP threshold for initiating phototherapy from 2010 through 2014.¹⁹  This was ostensibly done to prevent hospital readmissions. This increased use of phototherapy may also be predicated on the idea that phototherapy is safe and harmless but it often interferes with the maternal-infant bonding process, in addition to reducing exclusive breastfeeding rates within the first 4 months.^20,21  Furthermore, clinicians should be concerned about the increasing use of phototherapy due to possibility of a link between phototherapy and childhood seizures.²²  We welcome the recent recommendation against the use of phototherapy at bilirubin levels below the AAP thresholds for phototherapy.²³ 

The increased use of phototherapy during the study period must also be interpreted within the overall context of the management of neonatal hyperbilirubinemia. Several large studies have shown that universal bilirubin screening led to a reduction in the incidence of bilirubin levels >25 mg/dL.^7,15,24  This might be the result of early and increased phototherapy use. Thus, it is not surprising that previous studies found a significant decline in the rate of ET for neonatal jaundice.^8,25–27  In contrast to these studies, we found no significant change in the rate of ET. These could be due to differences in patient population, study period and duration, and differences in database used. However, the large population-based study by Wolf et al which overlapped with the study period of the current study showed that the rate of exchange transfusion for neonatal jaundice remained stable between 2009 and 2016,²⁷  which accords with our findings. Further studies with databases containing granular clinical information may be needed to confirm the trend in ET practices for neonatal jaundice in the US.

A major strength of the current study is the use of a large, population-based database to examine neonatal hospitalizations with jaundice in the US since the year 2004. The limitations of this study, like others conducted using administrative databases, are well described.²⁸  Large databases such as the KID are susceptible to coding errors, omissions, and duplications. However, the HCUP has instituted mechanisms to ensure the validity of the data in these databases.²⁹  Additionally, phototherapy and ET are major procedures, and are more likely to be coded correctly since such coding is related to billing for inpatient hospital care. The HCUP database lacks clinical information as it relies on administrative coding without confirmation from patient level clinic data. This limited our ability to determine the bilirubin thresholds above which phototherapy and exchange transfusion were performed. Additionally, there is no ICD code for acute bilirubin encephalopathy and as a result, we could not determine the impact of the observed trends in phototherapy use and ET on the incidence of acute bilirubin encephalopathy. The hospitalization data in the KID makes no distinction between the initial birth hospitalization and subsequent readmission. Thus, some newborns are represented more than once in the databases due to readmissions following the initial birth hospitalization.

From 2006 through 2016, while neonatal hospitalizations for jaundice remained stable, there was a significant increase in the use of phototherapy but no significant change in the rate of ET for severe neonatal jaundice. The impact of these changes on the prevention of acute bilirubin encephalopathy needs further examination in future studies.

We thank the Healthcare Cost and Utilization Project (HCUP) sponsored by the Agency for Healthcare Research and Quality, Rockville, MD and its partner organizations that provide data to the HCUP. We also thank Paula Umscheid for proof-reading the manuscript.