Infant Mortality Trends in Duval County, Florida

Saju Joy, M.D. and Mark L. Hudak, M.D.

 

Background

There are numerous factors that predispose the United States to having one of the highest infant mortality rates (IMR) in the industrialized world. However, we are constantly reminded of the big picture - infant mortality - and we constantly look at the small picture - how we save low birth weight babies. We know the ultimate key to success is going to be in finding a way to reduce the large number of low birth weight (LBW) babies in this country.1

Since 1980, the IMR in the United States has declined by greater than 40%; however, this fall has been attributable to reductions in birth weight-specific IMRs, and not to a decrease in the percentage of LBW infants. Since 1990, the IMRs decreased more than 20% for infants weighing greater than 500 grams yet declined only 4% for those weighing less. The United States has been unsuccessful in reducing the number of preterm and LBW deliveries in recent years even though prevention efforts have the potential to save many more infant lives and reduce subsequent morbidity than do further improvements in neonatal care. Most of the reduction in the IMR in the 1990s can be attributed to the introduction of surfactant replacement therapy and to the success of the "back-to-sleep" recommendations in decreasing the number of sudden infant death syndrome (SIDS) fatalities. However, the disproportionately high percentage of LBW infants that has only increased through the 1990s is undisputedly the primary reason why the U.S. IMR exceeds that of other industrialized countries.

International trends

Internationally, socioeconomic status correlates best with infant mortality. 4-8 In Quebec, Denmark and Italy, the level of maternal education has been shown to be an important factor in infant mortality rates. 4-6 Specifically, IMR's have decreased most in those who are more educated but remain higher in those least educated. Some of the decrease in total IMR can be attributed to the widening of the social gap between different educational groups during the last decade. This may partly be explained by the decreasing number of women in the lowest educational group.5,7 One might speculate that less well-educated women may have less appreciation of the importance of prenatal care, less understanding of the risks of antepartum infections, and a lower recognition of the signs and symptoms of preterm labor.

National trends

The 1999 national statistics were not available at time of publications and thus the 1998 IMR statistics are discussed. The national IMR for 1997 and 1998 has plateaued at its lowest ever recorded level (7.2 infant deaths per 1000 live births). In these years, the ratio of the IMR among black infants to that for white infants was 2.4. The absolute difference between black and white IMR has actually decreased since 1990, from 10.4 to 8.1 deaths per 1000 live births in 1998.2 Although progress in reducing infant mortality has been encouraging, racial disparities in infant mortality continue to be a major challenge. A higher incidence of LBW babies born to black mothers accounts for a substantial portion of the excess black infant mortality rate.

Differences in LBW and IMR by state reflect, in part, differences in the racial, ethnic, and socioeconomic composition of their populations. For example, the comparatively low IMR for New Hampshire (4.3) primarily reflects a lower percentage of LBW births. In contrast, the District of Columbia has a high IMR reflecting a higher percent of LBW births to black mothers who constitute the majority of mothers in D.C.2,3

Causes of mortality

Figure 1 and 2 list risk factors and patient characteristics associated with infant mortality.



Congenital anomalies, preterm birth and low birth weight, and SIDS are the most likely causes of infant deaths. Figure 3 lists percentages of the most common diagnoses reported in the literature including Duval county findings. Other important etiologies of infant mortality include perinatal asphyxia and neonatal and infant infections.9-12

Morbidity

While emphasis is placed on infant mortality as a primary indicator of the health status of a community, state, or country, it should be remembered that survival does not in all cases confer a potential for normal neurodevelopmental outcome. As the number of survivors of extreme prematurity increase, there is an increased burden of morbidity that families and communities are too-often ill-equipped and inadequately funded to address. Preterm infants may have special medical needs with respect to pulmonary, nutritional, and ophthalmologic issues and require intensive occupational/physical/speech therapy as well as developmental enrichment. Cerebral palsy, mental retardation, and learning disabilities may result from specific or non-specific neurologic injury sustained as a consequence of preterm birth.

Local Outcomes

In 1998, Florida had an IMR of 7.1 per 1000 that was similar to the national average of 7.2 per 1000. However, Florida's IMR was much lower than neighboring states of Alabama and Georgia that had IMR's of 9.5 and 8.6, respectively.2 Unfortunately, the Duval county IMR has not followed the Florida or the national trend. On the contrary, from 1996 to 1999, the Duval county IMR has steadily increased from 8 per 1000 to 10.2 per 1000 live births. Furthermore, the 1999 non-white IMR is more than twice that of the white IMR, 15.3 vs. 7.0 respectively. 12-13 As a result of these worrisome findings, the Northeast Florida Healthy Start Coalition undertook a multidisciplinary review. Their earliest finding identified a target area of five zip codes with the highest black infant mortality rates (see Figures 4 and 5).

 

Black vs. White Disparities

Statistics show that IMR for black infants in the United States is two times that of white infants. Is race the major difference or are there other factors to consider? It has been shown that the incidence of infant mortality is unrelated to race/ethnicity, after controlling for prematurity and low birth weight, underscoring the importance of intervention efforts aimed at their prevention.16 When comparing black foreign-born mothers among the black U.S.-born mothers, mortality risk was more than 20% lower with the black foreign-born mother group.17 When comparing college-educated parents, exclusion of low-birth-weight or preterm births correlates to no difference in black and white infant mortality rates.18 In this sub-group of college-educated parents, black race is not identified as a significant predictor of infant mortality.19

Potential interventions

Infant Mortality Reviews

In the field of maternal and child health, there has been a debated tradition of using regional mortality reviews as a tool for understanding maternal and perinatal deaths and identifying preventative measures. Similarly, the fetal and infant mortality reviews (FIMR) were instituted as part of the Healthy Start Initiative to understand and reduce infant mortality rates in high-risk communities. As with other urban IMRs, the Boston IMR began with a multi-tiered method of review. FIMR's start by identifying cases, reviewing the medical records, interviewing family members, and then having an interdisciplinary provider review panel identify clinical and social risk conditions. These findings from the data analysis and provider panel reviews are shared with the community working groups (community leaders, policy makers, health and social services providers) to involve them in developing recommendations for policy and practice. Once recommendations are generated, these are communicated to the community for implementation. Project Impact, initiated in 1995, is the FIMR project in Northeast Florida.

Duval County Conclusions

There are numerous factors that contribute to the elevated IMR of Duval County. Identifying the target area of 5 zip codes revealed several findings. The most important finding echoes the original statement of reducing the number of preterm births and low birth weight babies. If the Duval county VLBW rate could have been reduced by 25% (from 4.1% à 3.1%), there could have been as much as a 40% reduction in IMR (from 19.6 à 13.9).12 Currently, the extremely premature infant has an improved likelihood of survival compared to years past, secondary to advances in neonatal intensive care. However, the prognosis is poor for these infants with regards to morbidity and both the financial and social demands.

A second finding is that the Duval county statistics may be misrepresented secondary to the inclusion of non-viable infants (<500 grams and/or <24 weeks gestational age). Thirty-five percent of the mortality cases reviewed for the IMR calculation represented these non-viable infants. For most of these non-viable infants, no resuscitative efforts were undertaken at the request of the mother. Although these "live births" were included in the Duval county IMR, other counties in Florida and the United States might not always classify these infants as liveborn. This would in fact establish lower rates in other counties resulting from an undercount of these non-viable infants.

Another important factor is educating the community and specifically those at risk. The Table summarizes recommendations from the work of Northeast Florida and other FIMR groups directed toward reducing infant mortality.

Summary

Infant mortality results from a combination of medical, social, economic, organizational, and political factors. Intervention to reduce infant mortality can only be expected to be effective if all of these factors are addressed.11 Race, birth weight and nativity are just a few factors associated with higher infant mortality. Although certain populations may have preferential maternal sociodemographic and prenatal care risk characteristics, these alone do not explain the higher U.S. IMR compared to other industrialized countries.21 Among the heterogeneity of determinants include preterm labor, sexually transmitted diseases, prenatal care and social services follow-up. Some state that more prenatal care is better than none or a little -- for example, a woman who starts prenatal care in the first trimester has a four time greater chance of having a normal child than a woman who receives no prenatal care.1 However, in-depth evaluation reveals that availability of prenatal care alone is inadequate, mothers must access quality care! Poma reported that only 56% of women received recommended procedures during the first two visits and only 32% received recommended counseling during the pregnancy. Surprisingly, this study found that private offices were significantly less likely to provide adequate care compared with state-funded clinics.10

These infant mortality reviews, in time, should have a similar impact, as did the maternal mortality reviews of the 1930's and 1940's. Improvements in technology and medical care, including transition to hospital-based births, have resulted in a 50-fold reduction in maternal mortality and a 10-fold decline in infant mortality.1,3 By addressing local problems and challenges in these FIMRs, community members have the opportunity to devise and implement local solutions particular to their city, county or state. Furthermore, this forum educates providers about specific changes needed in the health care system and involves them in the process of change.11

Premature birth continues to be the leading cause of infant mortality. It is undeniable that success in reducing the IMR begins with reducing premature births. Attention should therefore begin with education for both patients and providers. Maternal education should focus on educating mothers about high risk behavior that might lead to preterm birth. Family planning should also focus on increasing the interpregnancy interval. Health care provider education requires community effort to identify those at risk and to integrate them into an easily accessible, quality health care system. The health care team should provide close follow-up, especially to those with a history of preterm birth and poor prenatal follow-up. Although the social and economic circumstances of patients' lives are not within the capability of physicians to solve, they are the context in which clinical outcomes occur!1 It is also possible that disparities in IMR may not be completely eliminated until the average level of maternal health and education is equivalent amongst different populations.

The method most likely to bear short term positive results is to increase community awareness and involvement. This requires participation in patient education programs as well as optimizing use of both medical and social service resources. And although low birth weight correlates with infant mortality, its predictiveness may be modified by other factors. For instance, although the average birth weight and gestational age of Japanese-American infants born in Hawaii are significantly less than those in white infants, the IMR of these two populations are equal.21 In the short-term, there is hope that focusing on high-risk groups, regardless of race, might provide the potential for a substantial reduction in the prevailing infant mortality rate. 6,17

References

  1. Davidson EC. A strategy to reduce infant mortality. Obstet Gynecol 1991:77(1):1-5.
  2. Guyer B, Hoyert DL, Martin JA, Ventura SJ, MacDorman MF and Strobino DM. Annual summary of Vital Statistics _ 1998. Pediatrics 1999:104:1229-46.
  3. Guyer B, Freedman MA, Strobino DM, Sondik EJ. Annual summary of vital statistics: Trends in the health of Americans during the 20th century. Pediatrics 2000:106(6):1307-17.
  4. Parazzini F, Pirotta N, La Vecchia C, Bocciolone L, Fedele L. Determinants of perinatal and infant mortality in Italy. Rev Epidemiol Sante Publique. 1992;40(1):15-24.
  5. Olsen O, Madsen M. Effects of maternal education on infant mortality and stillbirths in Denmark. Scand J Public Health. 1999 Jun;27(2):128-36.
  6. Chen J, Fair M, Wilkins R, Cyr M. Maternal education and fetal and infant mortality in Quebec. Fetal and Infant Mortality Study Group of the Canadian Perinatal Surveillance System. Health Rep. 1998 Autumn;10(2):53-64 (Eng); 57-70 (Fre). English; French.
  7. Piekkala P, Kero P, Tenovuo A, Sillanpaa M, Erkkola R. Infant mortality in a region of Finland, 1968-1982. Eur J Pediatr. 1986 Dec;145(6):467-70.
  8. Knudsen LB, Bengt Kallen AJ. Infant mortality in Denmark and Sweden. A comparison based on data in two national registries. Eur J Obstet Gynecol Reprod Biol. 1997 Dec;75(1):85-90.
  9. McCloskey L, Plough AL, Power KL, Higgins CA, Cruz AN and Brown ER. A community-wide infant mortality review: findings and implications. Public Health Reports 1999:114:165-77.
  10. Poma PA. Effect of prenatal care on infant mortality rates according to birth-death certificate files. J Natl Med Assoc. 1999;91:515-20.
  11. Garber RM , Carroll-Pankhurst C, Woods-Erwin K and Mortimer EA. The university/public health link in reducing infant mortality in a high-risk population. Am J Prev Med 1995; 11(suppl 1):34-8.
  12. Black infant mortality in Duval County: identifying causes, taking action. Infant Mortality Work Group Northeast Florida Healthy Start Coalition; January 2001
  13. Huddleston K and Brady C. Racial Diaparities in Birth Outcomes: Insights from Project Impact. Jacksonville Medicine 2001 Jan:12-13.
  14. Sanders-Phillips K and Davis S. Improved prenatal care services for low-income African American women and infants. J Health Care Poor & Underserved 1998;9(1):14-29.
  15. Keely DF, McElwee YF, Bale CS, Gates AD, Melvin CL and Sappenfield WM. Infant death review: a new way to understand your county's infant mortality. J South Carolina Med Assoc 1991;Feb:90-93.
  16. DuPlessis HM, Bell R, Richards T. Adolescent pregnancy: understanding the impact of age and race on outcomes. J Adolesc Health. 1997 Mar;20(3):187-97.
  17. Kleinman JC, Fingerhut LA, Prager K. Differences in infant mortality by race, nativity status, and other maternal characteristics. Am J Dis Child. 1991 Feb;145(2):194-9.
  18. Schoendorf KC, Hogue CJ, Kleinman JC, Rowley D. Mortality among infants of black as compared with white college-educated parents. N Engl J Med. 1992 Jun 4;326(23):1522-6.
  19. Scott-Wright AO, Wrona RM, Flanagan TM. Predictors of infant mortality among college-educated black and white women, Davidson County, Tennessee, 1990-1994.
  20. Din-Dzietham R, Hertz-Picciotto I. Infant mortality differences between whites and African Americans: the effect of maternal education. Am J Public Health. 1998 Apr;88(4):651-6.
  21. Mor JM, Alexander GR, Kogan MD, Kieffer EC, Ichiho HM. Similarities and disparities in maternal risk and birth outcomes of white and Japanese-American mothers. Paediatr Perinat Epidemiol. 1995 Jan;9(1):59-73.
  22. Sharma RK. Causal pathways to infant mortality: linking social variables to infant mortality through intermediate variables. J Health Soc Policy. 1998;9(3):15-28.
Jacksonville Medicine / December, 2001

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