Infectious Disease Death Among Infants in the U.S
Infectious Disease Death Among Infants in the U.S
An estimated 3843 infant ID deaths occurred in the United States during 2008 and 2009, accounting for 8.3% of all infant deaths. Among these deaths, 2665 (69.5%) were LBW infants and 1170 (30.5%) were NBW infants ( Table 1 ). More than 60% of the infant ID deaths occurred during the neonatal period; this percentage was higher for LBW infants (72.7%) compared with NBW infants (34.3%, P < 0.01; Fig. 1). The overall median age of ID death among infants was 2 weeks (IQR: 0–8 weeks). LBW infants had a lower age of death (median: 1 week, IQR: 0–4 weeks) than NBW infants (median: 7 weeks, IQR: 2–20 weeks; P< 0.0001).
A large proportion of ID deaths were due to bacterial sepsis of newborn (28.3% overall, Table 2 ) with 96% of these deaths occurring in the neonatal period. The proportion of ID deaths due to bacterial sepsis of newborn was higher in LBW infants (34.1%) than NBW infants (15.3%; P < 0.01). Bacterial sepsis of newborn, unspecified was the most frequently listed UCOD among LBW (27.5%) and NBW (10.8%) infants. Among LBW infants, the other most frequently listed UCODs were newborn affected by chorioamnionitis (27.0%); septicemia, unspecified (9.2%); infection specific to the perinatal period, unspecified (3.1%) and congenital pneumonia, unspecified (2.1%). The top five UCODs represent 68.9% of LBW infant deaths; 84.7% of these were for neonates. The other most frequently listed UCODs among NBW infants were pneumonia, unspecified (7.4%); bronchopneumonia, unspecified (6.9%); septicemia, unspecified (5.8%) and congenital herpes viral (herpes simplex) infection (5.6%). Overall, 2294 (59.7%) of the infant ID deaths had prematurity (ICD-10 code P07) listed on their death record. Among LBW infant ID deaths, 84.8% had prematurity listed on their death record, whereas 2.3% of NBW infant ID deaths had prematurity listed on their death record.
The overall ID IMR was 47.5 deaths per 100,000 live births ( Table 1 ). The neonatal mortality rate was higher than the postneonatal mortality rate (RR: 19.7, 95% CI: 18.4–21.0). The IMR was higher for male infants, infants with a 5-minute Apgar score <7, infants with a gestational age <37 weeks, infants born to an unmarried mother, infants born to young mothers (<19 and 20–24 compared with 25–29 years), infants with a live birth order of first, third or fourth or more compared with second, infants of black race or of AI/AN race compared with white race and infants whose mothers had fewer prenatal visits (0, 1–2 and 3–5 compared with ≥6). The IMR for LBW infants was much higher (RR: 33.3, 95% CI: 31.1–35.7) than that for NBW infants and was highest for very low birth weight infants (RR: 160.3, 95% CI: 149.4–172.1). The IMR was lower for Hispanic infants and infants of A/PI race compared with white race.
(Enlarge Image)
Figure 1.
Number of infant ID deaths and cumulative percent by age at death in months, overall and by birth weight group*, United States, 2008–2009+. *LBW, low birth weight (<2500 g); NBW, normal birth weight (≥2500 g). +Infant ID deaths were restricted to singleton infants born in the United States to US residents and defined as an ID UCOD on the death record. Seven infant death records were missing birth weight and were not included in this analysis. There were no death records missing age at death in months.
The case-control study included infants whose 2008–2009 ID death record was linked to the corresponding birth certificate (2633 LBW and 1158 NBW infants; Table 3 ). In the univariate analyses, all characteristics were significantly associated with ID death in logistic regression for NBW infants, and all except for Hispanic origin were significant in logistic regression for LBW infants. Male sex, 5-minute Apgar score <7, young maternal age (≤19 and 20–24 years), black race, unmarried maternal marital status and live birth order of fourth or more were positively associated with ID death in both LBW and NBW infants ( Table 3 ). For NBW infants, AI/AN race was positively associated with ID death whereas having Hispanic origin and maternal age ≥30 years were negatively associated with ID death. For LBW infants, A/PI race was negatively associated with ID death compared with white race.
In the multivariable analyses, all characteristics that were included in the initial logistic regression models were significant except for maternal marital status in the model for LBW infants and maternal race in the model for NBW infants ( Table 4 ). Maternal race did not interact with any of the characteristics included in the initial LBW and NBW multivariable regression models. Male sex, live birth order of fourth or more, young maternal age (<19 and 20–24 years) and low 5-minute Apgar score were positively associated with ID death in both LBW and NBW infants ( Table 4 ); however, the effect of 5-minute Apgar score was greater for LBW infants than NBW infants. For LBW infants, black race was associated with increased odds of ID death. Among NBW infants, maternal age of ≥30 years, a live birth order of first and Hispanic origin were associated with decreased odds of ID death whereas being born to an unmarried mother was associated with increased odds of ID death.
Results
Infant ID Deaths and Mortality Rates
An estimated 3843 infant ID deaths occurred in the United States during 2008 and 2009, accounting for 8.3% of all infant deaths. Among these deaths, 2665 (69.5%) were LBW infants and 1170 (30.5%) were NBW infants ( Table 1 ). More than 60% of the infant ID deaths occurred during the neonatal period; this percentage was higher for LBW infants (72.7%) compared with NBW infants (34.3%, P < 0.01; Fig. 1). The overall median age of ID death among infants was 2 weeks (IQR: 0–8 weeks). LBW infants had a lower age of death (median: 1 week, IQR: 0–4 weeks) than NBW infants (median: 7 weeks, IQR: 2–20 weeks; P< 0.0001).
A large proportion of ID deaths were due to bacterial sepsis of newborn (28.3% overall, Table 2 ) with 96% of these deaths occurring in the neonatal period. The proportion of ID deaths due to bacterial sepsis of newborn was higher in LBW infants (34.1%) than NBW infants (15.3%; P < 0.01). Bacterial sepsis of newborn, unspecified was the most frequently listed UCOD among LBW (27.5%) and NBW (10.8%) infants. Among LBW infants, the other most frequently listed UCODs were newborn affected by chorioamnionitis (27.0%); septicemia, unspecified (9.2%); infection specific to the perinatal period, unspecified (3.1%) and congenital pneumonia, unspecified (2.1%). The top five UCODs represent 68.9% of LBW infant deaths; 84.7% of these were for neonates. The other most frequently listed UCODs among NBW infants were pneumonia, unspecified (7.4%); bronchopneumonia, unspecified (6.9%); septicemia, unspecified (5.8%) and congenital herpes viral (herpes simplex) infection (5.6%). Overall, 2294 (59.7%) of the infant ID deaths had prematurity (ICD-10 code P07) listed on their death record. Among LBW infant ID deaths, 84.8% had prematurity listed on their death record, whereas 2.3% of NBW infant ID deaths had prematurity listed on their death record.
The overall ID IMR was 47.5 deaths per 100,000 live births ( Table 1 ). The neonatal mortality rate was higher than the postneonatal mortality rate (RR: 19.7, 95% CI: 18.4–21.0). The IMR was higher for male infants, infants with a 5-minute Apgar score <7, infants with a gestational age <37 weeks, infants born to an unmarried mother, infants born to young mothers (<19 and 20–24 compared with 25–29 years), infants with a live birth order of first, third or fourth or more compared with second, infants of black race or of AI/AN race compared with white race and infants whose mothers had fewer prenatal visits (0, 1–2 and 3–5 compared with ≥6). The IMR for LBW infants was much higher (RR: 33.3, 95% CI: 31.1–35.7) than that for NBW infants and was highest for very low birth weight infants (RR: 160.3, 95% CI: 149.4–172.1). The IMR was lower for Hispanic infants and infants of A/PI race compared with white race.
(Enlarge Image)
Figure 1.
Number of infant ID deaths and cumulative percent by age at death in months, overall and by birth weight group*, United States, 2008–2009+. *LBW, low birth weight (<2500 g); NBW, normal birth weight (≥2500 g). +Infant ID deaths were restricted to singleton infants born in the United States to US residents and defined as an ID UCOD on the death record. Seven infant death records were missing birth weight and were not included in this analysis. There were no death records missing age at death in months.
Infant and Maternal Risk Factors for Infant ID Mortality
The case-control study included infants whose 2008–2009 ID death record was linked to the corresponding birth certificate (2633 LBW and 1158 NBW infants; Table 3 ). In the univariate analyses, all characteristics were significantly associated with ID death in logistic regression for NBW infants, and all except for Hispanic origin were significant in logistic regression for LBW infants. Male sex, 5-minute Apgar score <7, young maternal age (≤19 and 20–24 years), black race, unmarried maternal marital status and live birth order of fourth or more were positively associated with ID death in both LBW and NBW infants ( Table 3 ). For NBW infants, AI/AN race was positively associated with ID death whereas having Hispanic origin and maternal age ≥30 years were negatively associated with ID death. For LBW infants, A/PI race was negatively associated with ID death compared with white race.
In the multivariable analyses, all characteristics that were included in the initial logistic regression models were significant except for maternal marital status in the model for LBW infants and maternal race in the model for NBW infants ( Table 4 ). Maternal race did not interact with any of the characteristics included in the initial LBW and NBW multivariable regression models. Male sex, live birth order of fourth or more, young maternal age (<19 and 20–24 years) and low 5-minute Apgar score were positively associated with ID death in both LBW and NBW infants ( Table 4 ); however, the effect of 5-minute Apgar score was greater for LBW infants than NBW infants. For LBW infants, black race was associated with increased odds of ID death. Among NBW infants, maternal age of ≥30 years, a live birth order of first and Hispanic origin were associated with decreased odds of ID death whereas being born to an unmarried mother was associated with increased odds of ID death.
Source...