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 Table of Contents  
ORIGINAL ARTICLE
Year : 2022  |  Volume : 11  |  Issue : 4  |  Page : 195-201

Prevalence and risk factors for admission hypothermia in neonates in a Tertiary Hospital in Jos, Nigeria


1 Department of Paediatrics, University of Jos; Department of Paediatrics, JOS University Teaching Hospital, Jos, Plateau State, Nigeria
2 Department of Paediatrics, JOS University Teaching Hospital, Jos, Plateau State, Nigeria

Date of Submission20-May-2022
Date of Decision16-Jun-2022
Date of Acceptance17-Jun-2022
Date of Web Publication04-Oct-2022

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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jcn.jcn_52_22

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  Abstract 


Background: Hypothermia on admission in neonatal units is a well-recognized contributor of neonatal mortality and morbidity. This study aimed to identify risk factors for hypothermia on admission in a resource-poor setting which will help provide targeted preventive interventions. Methods: A retrospective cross-sectional descriptive study was conducted from July 1, 2020 to January 31, 2022. A total of 567 neonates were included in the study, data were collected from the unit electronic database. The axillary temperature of each neonate was measured using a digital thermometer at the point of admission. Bivariate and multiple logistic regressions were used to assess associated risk factors. Results: The prevalence of admission hypothermia (AH) in the study population was 42.4% with mild and moderate hypothermia accounting for 46.3% and 53.7%, respectively. Maternal ages 20–29 years (adjusted odds ratio [aOR] 0.28, 95% confidence interval [CI] 0.09–0.93) and 30–39 years (aOR 0.27, 95% CI 0.08–0.88) and primary education (aOR 0.44, 95% CI 0.21–0.92) were associated with reduced risk of AH. Age <24 h (aOR 3.61, 95% CI 1.70–7.66), gestational age 28–32 weeks (aOR 3.90, 95% CI 1.41–10.79) and 33–36 weeks (aOR 2.835, 95% CI 1.52–5.28), admission weight <2.5 kg (aOR 2.01, 95% CI 1.18–3.43), and cold season (aOR 1.85, 95% CI 1.06–3.14) were associated with increased risk of AH. Mortality in those with AH was 3 folds (crude odds ratio 3.38, 95% CI 1.6–6.82). Conclusion: Hypothermia on admission is common in neonates in resource-poor settings. Training of newborn care-providers in maintaining thermoneutral environment and temperature at delivery and postnatal periods will be a cost-effective intervention in reducing neonatal mortality.

Keywords: Hypothermia, neonates, prevalence


How to cite this article:
Diala UM, Kanhu PU, Shwe DD, Toma BO. Prevalence and risk factors for admission hypothermia in neonates in a Tertiary Hospital in Jos, Nigeria. J Clin Neonatol 2022;11:195-201

How to cite this URL:
Diala UM, Kanhu PU, Shwe DD, Toma BO. Prevalence and risk factors for admission hypothermia in neonates in a Tertiary Hospital in Jos, Nigeria. J Clin Neonatol [serial online] 2022 [cited 2022 Nov 27];11:195-201. Available from: https://www.jcnonweb.com/text.asp?2022/11/4/195/357816




  Introduction Top


In spite of large strides made toward decreasing child deaths, there are still about 2.5 million neonatal deaths annually.[1] To achieve the global target of 12 neonatal deaths per 1000 births by 2030, it is imperative to identify neonates at risk of death. Admission hypothermia (AH) has been shown to predict neonatal deaths in hospitalized neonates as well as at the community level, especially in very low-birthweight (VLBW) infants.[2],[3],[4],[5]

The prevalence of AH in neonates varies widely from 19% to 75%.[6],[7],[8],[9],[10],[11] Study cut-off for defining hypothermia influences the prevalence values with studies using 36.0°C and lower generally reporting lower rates than those using 36.5C as defined by the World Health Organization (WHO).[12] Other factors that have contributed to the wide variation include the age of the neonates, prematurity, no skin–skin care within 1 h of birth, delayed initiation of breastfeeding, early bathing, and cold season.[10],[13],[14]

There is a paucity of data about the prevalence of AH among hospitalized neonates in Nigeria. Available studies include those by Ogunlesi et al. in Southwest Nigeria which reported prevalence rates of 67.6% in neonates aged <72 h and 62% in the whole neonatal population.[9],[10] However, both studies were limited by a small sample size. Furthermore, Jos is unique with a cold climate than most parts of Nigeria largely from her high altitude with mean minimum and maximum temperatures of 16°C and 26°C, respectively.[15] We postulate that the prevalence of AH will be higher than reported from other parts of the country. Therefore, we set out to determine the prevalence of and risk factors associated with AH in hospitalized neonates in a Tertiary Hospital in Jos, Nigeria.


  Methods Top


Study design and study period

This was a retrospective cross-sectional descriptive study carried out between July 1, 2020, and January 31, 2022 at the Special care baby unit of Jos University Teaching Hospital which is a 600 bed capacity public tertiary hospital located at Jos Plateau, North Central Nigeria.

Minimum sample size calculation

The minimum sample size of 359 was calculated using the Kish and Leslie formula for single proportions with power set at 80% and confidence level of 95% with the highest reference prevalence of AH of 62% for the whole neonatal population.[9]

Study population

The study involved all consecutive neonates admitted into the unit.

Inclusion criteria

All consecutive neonates admitted into the unit were included.

Exclusion criteria

Any neonate without temperature recording at admission was excluded.

Data collection

Data were collected from the unit electronic database. Axillary temperature was used for temperature and measured using a digital thermometer usually kept in place until it beeped (takes 1–3 min). Other variables of interest included the mother's age, educational level, and parity, infants' age at admission, sex, place of birth, weight on admission, gestational age at birth (by last menstrual period or Ballard score), and season.

Operational definition of variables

AH was defined as axillary temperature <36.5°C taken at admission. Hypothermia was further classified as mild (36.0°C–36.4°C), moderate (32°C–35.9°C), and severe (<32°C) as defined by the WHO.[16] Normothermia (36.5°C–37.5°C), hyperthermia (>37.5°C).

Inborn: Any neonate delivered in study hospital; outborn: Any neonate not delivered in study hospital including those delivered at home and in transit to a birth facility, usually admitted following a referral or self-referral.

A month was classified as cold if the mean monthly temperature was <21°C/70°F and included 6 months (July, August, September, November, December, and January) and hot if the average monthly temperature was above 21<°C/70°F (February, March, April, May, June, and October).[17]

Ethical considerations and permissions

Ethical clearance was obtained from the Ethical Review Board of the study hospital and permission to use unit data was obtained from the unit head. All data were de-identified before data analysis in line with relevant good clinical practice.

Data analysis

Data were entered into Microsoft Excel 2013 and analyzed using IBM SPSS Statistics for Windows, Version 25.0. (Armonk, NY, USA: IBM Corp.). Descriptive variables were presented in terms of proportions. The primary outcome variable was AH and presented in the percentage of total admission. Independent variables were categorical. Bivariate and multiple logistic regression was used to assess associated risk factors. For logistic regression, data form neonates with hyperthermia were excluded. Only variables with a P < 0.05 from the bivariate analysis were included in the multiple logistic regression. During the multiple logistic regression, gestational age and admission weight were analyzed separately because of their strong relationship to prevent overestimation of adjusted odds ratio (aOR) due to collinearity. Odds ratio was used to estimate effect size. When comparing admission outcomes, neonates admitted with temperature >37.5°C (122) and those who were discharged against medical advice (22) were excluded. Confidence level was set at 95% confidence interval (95% CI) and a P < 0.05% was considered statistically significant.


  Results Top


A total of 567 neonates were included in the study after excluding 40 for missing data about temperature reading at admission. About 48% of the studied neonates were admitted on their 1st day of life with 36.5% delivered preterm. Furthermore, 345 (60.8%) babies were admitted during the cold months. The modal age group of mothers was 30–39 years (47%). Forty-five percent of the mothers had at least secondary level of education and about half were multiparous (parity of 2–4) [Table 1]. In addition, (556/567) of the mothers were booked and only 14 (2.9%) of births were out-of-hospital.
Table 1: Sociodemographic characteristics of the studied neonates

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The prevalence of AH was 42.4% (240/567) with mild and moderate hypothermia accounting for 46.3% and 53.7% of the babies with AH, respectively. No baby had severe AH [Table 2]. Bivariate analysis identified maternal age, maternal education level, age, gestational age, admission weight, and cold season as associated risk factors of AH [Table 3]. Following multiple logistic regression, maternal ages 20–29 years (aOR 0.281, 95% CI 0.087–0.931), and 30–39 (aOR 0.272, 95% CI 0.084–0.880) years were significantly associated with 72% and 73% reduction in the odds of AH when compared to those aged ≥40 years, respectively. Furthermore, mothers with completed primary education had 57% reduced odds of AH when compared with those with tertiary education (aOR 0.437, 95% CI 0.206–0.921). Admission at age <24 h increased the odds of AH 3.6 folds when compared to those aged 8–28 days (aOR 3.607, 95% CI 1.698–7.663). Admission weight <2500 g increased the odds of AH two folds when compared with larger neonates (aOR 2.014, 95% CI 1.183–3.426). The odds of AH increased 3.9 folds in neonates at a gestational age of 28–32 weeks (aOR 3.902, 95% CI 1.411–10.794) and 2.8 folds in 33–36 weeks (aOR 2.835, 95% CI 1.522–5.282), respectively, when compared to term neonates. There was a two-fold increase in AH in those aged >28 weeks but was not statistically significant. Being admitted during the cold months also significantly increased the odds of AH by 85% (aOR 1.85, 95% CI 1.061–3.138) [Table 4].
Table 2: Distribution of temperature at admission of studied neonates

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Table 3: Bivariate analysis of factors associated with admission hypothermia

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Table 4: Multiple logistic regression of factors associated with admission hypothermia

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There was a 3-fold increase in the odds of mortality in neonates who had AH (crude odds ratio 3.38, 95% CI 1.67–6.82) with 38 (20.2%) and 11 (5.6%) mortality in neonates with and without AH, respectively [Table 5].
Table 5: Comparison of admission outcomes in neonates with or without admission hypothermia

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  Discussion Top


Neonatal hypothermia continues to affect a large proportion of newborns globally with an impact on health and survival. A combination of sociodemographic factors, as well as physiologic and environmental factors, play roles in perpetuating this silent epidemic across all birth weights. Our study showed that AH is common with a prevalence of 42.5% which is similar to reported in Ethiopia (50.3%) and Uganda (51%) studying whole neonatal populations.[5],[8] In contrast, a previous study in Tanzania reported a lower prevalence rate of 22% while higher prevalence rates were reported in South-west Nigeria (62%–67%).[3],[9],[10] One explanation for the lower prevalence rate in our study compared to the study from South-west Nigeria is the fact that our study included the whole neonatal population. In our study, the prevalence rate of AH was 70.8% in neonates admitted on the 1st day which is consistent with the high prevalence rates (66%–83%) reported studies using delivery room temperatures.[18],[19] Furthermore, by including the whole neonatal population, neonates admitted with hyperthermia (>37.5°C) constituted 21.5% of studied neonates and provided for a more realistic estimation of the prevalence of AH.

Looking at the severity distribution of AH in our study, about half of the neonates had mild and moderate AH. There were no reports of severe hypothermia (axillary temperature <32°C) in the studied neonates, a finding which is consistent with other studies and may be a reflection of a limitation of the WHO classification of hypothermia.[5],[20],[21] A review of neonatal hypothermia in low-resource settings criticized the WHO threshold for severe hypothermia as being impractical because of the unavailability of low-reading thermometers in many of these clinical settings and suggested increasing the threshold to <34.0°C.[12] This is important because the severity of hypothermia, especially moderate/severe hypothermia, has been shown to impact on short- and long-term outcomes.[11],[20] The risk of neonatal death increases by at least 30% with every degree Celsius decrease in body temperature from normal.[11],[12],[22]

In the current study, maternal aged 20–39 and surprisingly, having completed primary were associated with reduced risk of AH. These findings differ from studies that reported an increased risk of AH in adolescent mothers.[18] These sociodemographic factors attempt to describe a population of mothers whose babies are at increased risk of hypothermia as a result of a combination of behavioral factors from ignorance as well as environmental factors related to poverty. Mothers in the lower socioeconomic class are generally less likely to attend antenatal care (ANC), have delivery supervised by skilled birth attendants, and are more likely to engage in harmful cultural practices like early baths and delayed breastfeeding which have been associated with AH.[3],[5],[10],[12] Mothers in our study had near-universal uptake of ANC and hospital births among studied mothers which are higher than national averages of 67% and 39% for ANC attendance and delivery in a health facility, respectively (DHS, 2018) and could have dampened the effect of low educational attainment on AH.[23]

Physiologic factors associated with AH in our study were low admission weight and prematurity. These are consistent with most studies.[11],[20],[24] Low-birthweight and premature infants are more vulnerable to hypothermia due to inadequate brown fat, low tone, and higher surface area of skin.[12] Our study did not demonstrate a statistically significant association between AH and being delivered at <28 weeks gestation possibly because of the small number of neonates in the subgroup. Admission within 24 h of life was associated with AH in studied neonates. In a study in Brazil among referred neonates being admitted on the 1st day was also associated with AH.[24] Ogunlesi et al., in South West Nigeria, also reported an increased risk of AH in neonates admitted within 24 h of life.[9],[10] Clearly, neonates are at increased risk of hypothermia in the delivery room. Byaruhanga et al. measured rectal temperatures at 10, 30, 60, and 90 min after delivery and reported that the peak prevalence of hypothermia of 83% was obtained at 60 min.[18] No skin-to-skin contact, not wearing cap, inadequate clothing after delivery, and neonatal health problems such as respiratory distress, low APGAR scores, and congenital malformations contribute to hypothermia within the 1st day of life underscoring a combination of environmental and physiologic factors.[11],[19],[24]

Our study also demonstrated significantly higher proportions of AH during colder months. Other recent studies have highlighted that seasonality contributes significantly to the wide variability in the reported incidences of AH even in tropical countries.[8],[12] Mullany in a study in Nepal, demonstrated a 41.3% increase in the risk of moderate-to-severe hypothermia for every 5°C decrease in average ambient temperature.[25] As part of the intervention to prevent neonatal hypothermia, guidelines in temperate countries recommend that ambient temperature in delivery rooms be set at a lower threshold of 25°C.[26]

Another finding from our study is the increased risk of mortality in neonates with AH which echoes findings from several studies. A 3-fold increase in the risk of mortality was reported among hospitalized Tanzanian neonates.[3] In another study among outborn neonates, moderate AH was associated with a 3-fold increase in the risk of mortality.[24] In Kenya, there were 20 folds decreased risk of survival on the 1st day of life in neonates with AH.[14] A meta-analysis which included 18 studies reported an 89% increased odds of mortality in VLBW preterm neonates with AH.[27]

Our study highlights the high prevalence of neonatal hypothermia and has identified subpopulations of neonates at risk to facilitate tailored preventive interventions. A study in the USA reported sustained elimination of AH in a neonatal intensive care unit (NICU) by the use of a standardized protocol that managed thermoregulation from predelivery through admission to the NICU of VLBW infants by a multi-disciplinary team and the use of control feedback.[28] More recently, AH rates were reduced from 39.8% to 10% by a program that involved health workforce education, and improved use of clinical heat mattresses and polythene bags in VLBW infants. These interventions had higher effects in those born between 33 and 36 weeks.[29] In a tertiary hospital in India, AH was significantly reduced among inborn babies by introducing educational programs among health workers that reinforced the use of caps, cling wraps, warm linen and Ziploc bags, and use of transport incubators.[30]

One of our study limitations is the unavailability of data about the ambient temperature of the delivery room and the unit. Considering the association of AH to cold weather and the high prevalence of hospital births in our setting, it will be important to institute measure to ensure delivery rooms and the neonatal unit have optimum temperatures, especially during cold months. Furthermore, we did not evaluate the impact of home delivery on AH because of the small number of mothers that delivered at home. This is particularly important because of the unavailability of transport incubators due to resource constraints.


  Conclusion Top


Hypothermia is common in hospitalized neonates in low-resource settings. Infants of mothers with younger age groups and completed primary education have decreased odds of hypothermia whereas being admitted on the 1st day of life, low admission weight and low gestational age and cold season were physiological and environmental factors associated with AH. It is, therefore, pertinent to institute targeted measures to maintain the warm chain in line with the WHO recommendations.

Acknowledgment

We appreciate all the members of staff of the neonatology unit of JUTH for their passionate service. Special thanks to Mercy Okor and Dorathy Dagba for assistance with data entry.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]



 

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