Journal of Marine Medical Society

ORIGINAL ARTICLE
Year
: 2019  |  Volume : 21  |  Issue : 1  |  Page : 55--58

Comparison between 1st and 2nd day serum bilirubin levels in relation to the prediction of requirement of phototherapy in neonates of ≥35 weeks of gestation


Ashok Bhandari1, Shankar Narayan2,  
1 Department of Pediatrics, INHS Asvini, Mumbai, Maharashtra, India
2 Professor, Department of Paediatrics, Office of DGMS Navy, New Delhi, India

Correspondence Address:
Surg Capt Ashok Bhandari
Department of Pediatrics, INHS Asvini, Colaba, Mumbai - 400 005, Maharashtra
India

Abstract

Background: Follow-up of neonates discharged early is essential to identify neonates at risk of hyperbilirubinemia. The present study was conducted to evaluate and compare 20 ± 4 and 44 ± 4 h serum bilirubin level for predicting significant hyperbilirubinemia and requirement of follow-up after discharge. Materials and Methods: This study was a hospital-based prospective study. A total of 300 healthy newborns were included with gestational age of ≥35 weeks. Serum bilirubin levels on the 1st day and 2nd day were measured by microbilirubinometer at 20 ± 4 h of life and 44 ± 4 h of life, respectively. Results: In our study, we found that, for bilirubin level of >6 mg/dl for neonates at 20 ± 4 h of age requiring phototherapy for hyperbilirubinemia, sensitivity was 79.3%, specificity was 60.9%, positive predictive value (PPV) was 17.8%, and negative predictive value (NPV) was 96.4%. At 44 ± 4 h of life, for bilirubin level of >9 mg/dl requiring phototherapy for hyperbilirubinemia, sensitivity was 89.7%, specificity was 64.2%, PPV was 21.1%, and NPV was 98.3%. Conclusion: Babies with total serum bilirubin values below 6 mg/dl at 20 ± 4 h and 9 mg/dl at 44 ± 4 h can well be discharged early with proper discharge advice. Babies with serum bilirubin levels above the cutoff value (6 mg/dl at 20 ± 4 h and 9 mg/dl at 44 ± 4 h) can be discharged after 24 h or 48 h, but requires frequent follow-ups in the 1st week of life.



How to cite this article:
Bhandari A, Narayan S. Comparison between 1st and 2nd day serum bilirubin levels in relation to the prediction of requirement of phototherapy in neonates of ≥35 weeks of gestation.J Mar Med Soc 2019;21:55-58


How to cite this URL:
Bhandari A, Narayan S. Comparison between 1st and 2nd day serum bilirubin levels in relation to the prediction of requirement of phototherapy in neonates of ≥35 weeks of gestation. J Mar Med Soc [serial online] 2019 [cited 2020 Mar 29 ];21:55-58
Available from: http://www.marinemedicalsociety.in/text.asp?2019/21/1/55/260678


Full Text



 Introduction



Healthy term newborns are usually discharged within the first 48 h after delivery due to various socioeconomic reasons.[1],[2],[3],[4] Due to early discharge, there is increased incidence of readmission to the hospital. Neonatal jaundice is one of the most common causes of admission of infant <1 month of age.[5],[6],[7]

Follow-up of neonates discharged early is essential to identify neonates at risk of hyperbilirubinemia which is also recommended by the American Academy of Pediatrics.[8] As universal follow-up is not possible, it is essential to reliably predict and identify risk factors for neonates for the development of severe hyperbilirubinemia.

Various methods were studied to identify significant hyperbilirubinemia by many investigators to accurately identify at-risk neonates.[9],[10],[11] There is a paucity of studies regarding the prediction of hyperbilirubinemia requiring intervention in the form of phototherapy in India.[12]

The primary objective of this study was to estimate the prevalence of newborns developing significant hyperbilirubinemia and requiring phototherapy in the study population. The secondary objective was to compare the predictability of 20 ± 4 h and 44 ± 4 h serum bilirubin levels in relation to the requirement of phototherapy in neonates of ≥35 weeks' gestation. In this way, we can decide about the timing of serum bilirubin levels of neonates before routine discharge.

 Materials and Methods



This study was a hospital-based prospective study to compare the predictive ability of bilirubin at 20 ± 4 h and 44 ± 4 h of age for subsequent hyperbilirubinemia requiring phototherapy in healthy neonates >35 weeks' gestation. A total of 300 healthy newborns delivered at zonal hospital were included with a gestational age of ≥35 weeks. Sample size was based on an average of 7% newborns developing significant neonatal jaundice out of 1000 newborns being delivered annually at this center (95% confidence interval and 3% deviation). A systemic random sampling procedure was used, and we selected every 3rd newborn baby after considering the inclusion and exclusion criteria. The study was approved by the ethical committee of the hospital. Neonates with sepsis, birth asphyxia, intrauterine growth restriction, gross congenital anomalies, Rh and ABO blood group incompatibility, conjugated hyperbilirubinemia, congenital malformation, birth injury, or any illness other than neonatal jaundice were excluded from this study.

Serum bilirubin levels on the 1st day and 2nd day were measured at 20 ± 4 h of life and 44 ± 4 h of life, respectively by One Beam microbilirubinometer manufactured by GINEVRI srl from Rome, Italy. At the time of discharge, all parents were educated about how to look for yellow discoloration of the face and body and visit pediatric outpatient department (OPD) as soon as the face or body looks yellow. They were also asked to visit pediatric OPD at least twice within the first 7 days of life after discharge even if there was no problem. After taking informed consent, newborn babies details were filled up in the standard proforma within 24 h of birth. Detailed clinical examination was carried out to identify any neonates satisfying the exclusion criteria as mentioned above. Phototherapy was given according to the standard guidelines in relation to the start of phototherapy in infants of ≥35 weeks of gestation (adapted from the American Academy of Pediatrics Subcommittee on hyperbilirubinemia). The data were analyzed at 95% confidence level to find out the critical total serum bilirubin (TSB) value at 20 ± 4 h and 44 ± 4 h of life which predicts the neonates at risk of developing significant hyperbilirubinemia. Receiver operating characteristic (ROC) curve analysis was done to determine the best cutoff value of total serum bilirubin value at 20 ± 4 h and 44 ± 4 h of life which would predict neonates likely to require phototherapy. Ultimate comparison between these two groups is in relation to the requirement of phototherapy at various assumed cutoff values at 20 ± 4 h and 44 ± 4 h of life. Results of this study were based on statistical analysis using descriptive analysis, independent sample t-test, and Chi-square test.

 Results



There were 147 (49%) male neonates and 153 (51%) female neonates. Twenty-nine newborns (9.66%) developed significant hyperbilirubinemia and required phototherapy. The gestational age of 295 neonates (98.6%) was ≥37 weeks. Only five neonates (1.6%) were <37 weeks of gestation. A total of 269 newborns (89.7%) weighed >2.5 kg and 31 (10.3%) were between 2.0 and 2.5 kg.

Out of 29 neonates with significant hyperbilirubinemia, two (6.9%) neonates required phototherapy to be started on day 2 of life, 15 (51.7%) neonates required phototherapy to be started on day 3 of life, and 8 (27.6%) neonates were put under phototherapy from day 4 of life. In this way, it was found that 86.3% of neonates developed significant hyperbilirubinemia within 96 h of life. The remaining four (13.7%) babies were started under phototherapy after 96 h of life.

As shown in [Table 1], mean serum bilirubin level of newborn babies at 20 ± 4 h and 44 ± 4 h of life was 5.89 and 8.52 mg%, respectively. At 20 ± 4–44 ± 4 h of age, serum bilirubin levels of 6 and 9 mg%, respectively, were found to be the cutoff value by ROC curves [Figure 1] and [Figure 2] to predict the newborns who develop significant hyperbilirubinemia.{Table 1}{Figure 1}{Figure 2}

In this study, using 20 ± 4 h serum bilirubin level of >6 mg/dl, significant hyperbilirubinemia could be predicted with a sensitivity of 79.3%, a specificity of 60.9%, a positive predictive value (PPV) of 17.8%, and a negative predictive value (NPV) of 96.4% [Table 2]. Using 44 ± 4 h serum bilirubin level of >9 mg/dl, significant hyperbilirubinemia could be predicted with a sensitivity of 89.7%, a specificity of 64.2%, a PPV of 21.1%, and a NPV of 98.3%. Area under the ROC curve for 44 ± 4 h bilirubin was more than 20 ± 4 h which indicates that 44 ± 4 h value is better than 20 ± 4 h in relation to the prediction of significant hyperbilirubinemia later on requiring phototherapy.{Table 2}

Serum bilirubin value of higher- and lower-than-cutoff values (6 mg%) at 20 ± 4 h of age was compared in relation to the requirement of phototherapy. There was a statistically significant difference in the requirement of phototherapy, with P < 0.0001. Similar statistically significant difference was found for cutoff value of serum bilirubin (9 mg%) at 44 ± 4 h, with P < 0.0001 [Table 3] and [Table 4].{Table 3}{Table 4}

 Discussion



Parents and health-care workers are always concerned of neonatal jaundice due to its unpredictable nature. In our study, we found that 3.5% of neonates having serum bilirubin level <6 mg/dl at 20 ± 4 h of life required phototherapy and 17.8% required phototherapy with serum bilirubin level of >6 mg/dl. Similarly, we found that 1.7% of neonates having serum bilirubin level <9 mg/dl at 44 ± 4 h of life required phototherapy and 21.1% required phototherapy with serum bilirubin level of >9 mg/dl. Serum bilirubin level of higher- and lower-than-cutoff values (6 mg%) at 20 ± 4 h of life was compared in relation to the requirement of phototherapy. There was a significant difference in the requirement of phototherapy, with P < 0.0001. Similar significant difference was found for cutoff value of serum bilirubin (9 mg%) at 44 ± 4 h of life.

Bhutani et al. found cutoff value of bilirubin level of 5 mg/dL at 20–28 h of life to predict significant hyperbilirubinemia[13] Seidman et al. also found similar cutoff value of 5 mg/dl with a high specificity (91.9%), a low sensitivity (45.5%), and a high NPV (99%).[14] Agarwal and Deorari evaluated the predictive efficacy of TSB >6 mg/dl at 24 ± 6 h and found to have a high sensitivity (95%) and a high NPV (93.5%).[15] Randhev et al.'s study revealed cutoff value of serum bilirubin value of 6.4 mg/dl on the 1st day of life.[16]

In another study, Alpay et al. found bilirubin level of >6 mg/dL during the first 24 h of life, and 26.21% of patients developed significant hyperbilirubinemia with a sensitivity of 90% and a NPV of 97.9%.[17] This finding is similar to our study, in which 17.8% of neonates required phototherapy when serum bilirubin was found >6 mg% in the first 24 h of life.

In our study, we found that for bilirubin level of >6 mg/dl for neonates at 20 ± 4 h of age requiring phototherapy for hyperbilirubinemia, the sensitivity was 79.3%, specificity was 60.9%, PPV was 17.8%, and NPV was 96.4%. For neonates at 44 ± 4 h of life, for bilirubin level of >9 mg/dl requiring phototherapy for hyperbilirubinemia, the sensitivity was 89.7%, specificity was 64.2%, PPV was 21.1%, and NPV was 98.3%. Studies by Alpay et al., Agarwal et al., and Patra also found serum bilirubin level of 6 mg% on the 1st day of life as cutoff value for the prediction of significant hyperbilirubinemia later on.[18],[19]

One of the most important aims of our study was to compare the cutoff value of bilirubin in relation to the prediction of requirement of phototherapy. Serum bilirubin cutoff value of >9 mg% for neonates at 44 ± 4 h had better sensitivity, specificity, and NPV than that of the cutoff value of >6 mg% at 20 ± 4 h of life.

 Conclusion



Newborn babies with serum bilirubin values below 6 mg/dl at 20 ± 4 h and 9 mg/dl at 44 ± 4 h of life can well be discharged early with proper discharge advice and health education regarding common neonatal problem identification. Babies with serum bilirubin levels above the cutoff value (6 mg/dl at 20 ± 4 h and 9 mg/dl at 44 ± 4 h) can be discharged after 24 h or 48 h, but requires frequent follow-ups in the 1st week of life. Serum bilirubin levels at 44 ± 4 h should be preferred over serum bilirubin levels of 20 ± 4 h of life to decide about further follow-up in hospitals where newborns are routinely discharged after 48 h of life.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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