Cleft lip and/or palate mortality trends in the USA: a retrospective population-based study (2024)

WHAT IS ALREADY KNOWN ON THIS TOPIC

• Racial variations in prevalence of cleft lip and/or palate (CL/P) births have been reported, but few studies have examined racial differences in mortality of individuals with CL/P.

WHAT THIS STUDY ADDS

• We found a greater risk of mortality in female, black, Hispanic and American Indian individuals. There was a significant increase in the mortality rate of Hispanic and American Indian individuals with CL/P from 2000 to 2019.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY

• It highlights the importance of cleft birth and mortality surveillance in black, Hispanic and American Indian populations.

Data sources

We conducted a retrospective population-based cross-sectional study using 20 years of birth and mortality records collected for the Centers for Disease Control and Prevention (CDC) by the National Center for Health Statistics (NCHS). Data on all births and deaths for all residents and non-residents in the USA were derived from vital statistics offices in each state, and then compiled into national data. For birth data, the NCHS collected data from birth certificates for all births occurring in the USA, including demographic information and health status of the newborn, before amalgamating these data to form the Birth Data files. Mortality data were ascertained from medically certified death certificates filled out by physicians or medical examiners,9 and merged to form the Mortality Multiple Cause data files. Recorded data pertaining to death include the underlying cause of death and any additional contributing causes.

Study cohort creation

To create the study cohort, the Birth Data files and Mortality Multiple Cause data files were linked for the period from 2000 to 2019.10 11 All births in the USA with a reporting flag of CL/P were extracted from the Birth Data files to capture all CL/P births. Subsequently, all deaths occurring in the USA within the specified period with a medically confirmed CL/P diagnosis at the time of death were extracted from the Mortality Multiple Cause data files. All cause-of-death information in the USA has been recorded using International Classification of Diseases (ICD)-10 codes since 1999.11 12 To identify deaths with CL/P for our study cohort, we used the ICD-10 codes Q35–Q37, which encompass the codes for cleft lip, cleft palate, as well as cleft lip and cleft palate. In the Mortality Multiple Cause data files, all contributing causes of death are described in the record axis conditions, where the underlying cause of death and up to 20 additional contributing causes of death are recorded. We included all cases where a CL/P diagnosis was made as 1 of 20 contributing causes of death. To classify race, we used the Race Recode variable reported by the CDC, which categorised race as white, black, American Indian or Asian/Pacific Islander. To identify individuals of Hispanic ethnicity, we integrated the Race Recode variable with the Hispanic Origin variable retrieved from the same dataset. This allowed us to distinguish between non-Hispanic and Hispanic individuals across the aforementioned racial categories. Our study thus categorised participants into five groups: white (non-Hispanic), black (non-Hispanic), Hispanic, American Indian (non-Hispanic) or Asian/Pacific Islander (non-Hispanic), aligning with federal guidelines. Race and ethnicity data were primarily derived from self-reporting on birth and death certificates; however, in cases where self-reported data were not available, race was classified based on observation by the reporting entity, such as hospital staff. Race data were missing in 0.6% (n=500 918 of 80 710 348) of births.

Data analysis

First, the total number of births with CL/P was enumerated annually from 2000 to 2019. Next, the overall number of deaths in individuals with CL/P, as well as the number of deaths resulting directly from CL/P, were calculated. These numbers were used to compute the overall CL/P mortality rate per 1000 cleft births as well as a direct cause-of-death mortality rate for deaths with CL/P listed as the underlying cause of death. The strata-specific rates were then calculated by age, sex and race. Multivariable logistic regression models adjusted for sex, race and age were used to describe associations between sex and race with risk of CL/P mortality. Separate linear regression models were used to calculate the annual change in CL/P mortality rates and assess the significance of the upward or downward trend from 2000 to 2019. All statistical analyses were conducted using SAS V.9.4 statistical software and p values of <0.05 were considered statistically significant.

Patient and public involvement

Patients and/or the public were not involved in this research’s design, conduct, reporting or dissemination plans.

Mortality

Based on medically certified birth and death certificate information, we found a mortality rate in individuals with CL/P of 20.3 deaths per 1000 births with CL/P. This is substantially higher than the US general population mortality rate of 8.4 deaths per 1000 live births.9 In other developed countries, individuals with CL/P have also been reported as having higher IMRs and overall mortality rates compared with the general population.11 13–15 In particular, a study of Dutch infants with CL/P from 1997 to 2011 found an elevated IMR of 21 per 1000 cleft births, which was significantly higher than the general population IMR of 4.5 per 1000 births.11 15 The high mortality rate in individuals with CL/P could possibly be explained by the presence of additional congenital anomalies. A meta-analysis conducted in 2013 suggested that the presence of chromosomal or congenital anomalies was associated with a higher rate of mortality in children with CL/P.6 Our study showed that Patau syndrome was the leading cause of death in individuals with CL/P in the USA, with other genetic conditions such as Edwards syndrome also contributing significantly. In individuals with Patau syndrome, CL/P incidence has been reported to be between 43% and 80% and shown to adversely affect the survival of the individual.16 17 The combined burden of additional malformations often presenting in cases of Patau syndrome such as cardiac anomalies and nervous system malformations causes over 90% of individuals to die within the first year of life.11 18 Genetic disorders and congenital malformations have also been in shown to be large contributors to death in individuals with CL/P in another study reported by the East of England Cleft Network. Their study of 639 children found that 61% of deaths in individuals with cleft were caused by associated anomalies and another 17% by infections.11 19 The high mortality rates in individuals with CL/P indicate the need for thorough medical examination for associated anomalies that can have fatal consequences on health outcomes.

Sex

Our study found most cleft births (58.3%) occurred in males, which is consistent with previous studies.11 20 A study in Singapore found the distribution by gender to be a ratio 1.1:1.0 male to female, which is comparable with our findings in the USA.13 Differences in cleft births have been postulated to be the cause of timing differences in embryological development.21 However, there is a paucity of literature examining differences in mortality between males and females with CL/P. Despite a higher rate of cleft births in males, our study revealed a higher mortality rate in females with CL/P. Since genetic disorders such as Patau syndrome were shown to be the underlying cause of death in a large portion of deaths with CL/P, the increased risk of mortality in females can possibly be explained by an increased risk of Patau syndrome and additional congenital anomalies.22 Therefore, thorough investigations for associated congenital anomalies in females with CL/P are necessary to properly facilitate appropriate care.

Race

From 2000 to 2019, we found most cleft births to be in the white group. However, we found American Indian individuals had a higher number of births with CL/P per 1000 live births, which complements previous findings of a 70% increase in CL/P prevalence in Native Americans.23 Contrary to previous studies reporting a higher risk of CL/P in Asian individuals,24 25 we did not find an elevated CL/P birth rate in the Asian/Pacific Islander group in the USA.

Although white individuals comprised of most cleft births, they had a lower mortality rate per 1000 births compared with black, Hispanic and American Indian individuals. The highest mortality rate in individuals with CL/P was found in the black group with a near twofold increase in mortality rate per 1000 births compared with the white group. Previous studies have shown a lower prevalence of cleft births in black patients compared with white26 27; however, there is a paucity of data investigating racial differences in the CL/P mortality. We also found that Patau syndrome was the leading cause of death in black patients with CL/P; however, it has been shown that black newborns have a lower risk of genetic conditions and cardiac, genitourinary and craniofacial malformations.28 Instead, it is possible that socioeconomic factors such as education, income and occupation may hinder black individuals in the USA from accessing proper care for CL/P or other congenital anomalies.29 An ideal care team for patients with cleft would consist of a multidisciplinary team of healthcare practitioners throughout infancy and childhood, yet it is likely to be at a high cost for healthcare users and therefore inaccessible to certain sociodemographic groups.30 An increased risk of mortality in individuals with CL/P was also observed in Hispanic and American Indian groups, where both groups saw a significant increasing trend in CL/P mortality during 2000–2019. We also found the leading cause of death in American Indian patients with CL/P to be holoprosencephaly. Patients with holoprosencephaly present additional challenges to cleft management and require more specialised care due to the presentation of a wide variety of clinical outcomes.31 The high prevalence of American Indian residences in rural areas in the USA presents additional challenges in accessing proper cleft care and may result in poorer health outcomes and increased mortality.32 Public health initiatives aimed at improving access to multidisciplinary care teams are required for patients with CL/P in the USA to address the racial disparities and increasing trend in CL/P mortality.

Strengths and limitations

Our study had some notable limitations. One limitation pertains to surveillance concerns in the misclassification of race data. In cases where self-reported data were not available, race was classified based on observation from hospital staff, which could potentially introduce bias, given that racial classification can be influenced by the observer’s personal perceptions. A previous study showed that few misclassifications occurred in Hispanic, white and black individuals, but Asian or Pacific Islanders and American Indian individuals were more often misclassified.33 However, we found that reporting practices outside of self-report rarely occurred in our dataset (<1% cases), and therefore are unlikely to have significantly influenced the overall effects observed. The broad ICD-10 coding system also did not allow for analysis of differences in CL/P cases such as severity, and syndromic/non-syndromic forms and the limited list of demographic variables in the dataset prevented us from analysing additional socioeconomic variables. Nevertheless, certified medical professionals confirmed the information on each birth and death certificate, and we maintained consistency in our use of the same ICD-10 codes throughout the entire period of 2000–2019. Historically, there has been variable and unreliable reporting of congenital anomalies on birth certificates; hence, a proportion of CL/P births in the USA from 2000 to 2019 were likely not captured by our analysis.34 35 Despite limitations, our study has several strengths. To our knowledge, this is the largest population-based study capturing 80 million live births in the USA to calculate the annual mortality rate and risk of patients with CL/P stratified by sex and race. The large sample size and population-based nature of our study provided sufficient power to examine associations of sex and race with CL/P mortality and allow for generalisation of study findings to the greater American population. Moreover, our study encourages keen reporting of congenital anomalies such as CL/P on birth certificates moving forward.

CL/P surveillance is essential in healthcare and prevention planning. Our findings showed that significant racial disparities in mortality of patients with CL/P exist in the USA and raise awareness for the urgent need to address the increasing rate of CL/P-related mortality in American Indian and Hispanic populations. Future in-depth studies focusing on these populations are required to understand the increase in CL/P mortality rates.

Patient consent for publication

Not required.

Ethics approval

This study involves human participants, but institutional ethics approval was exempted by the University of Toronto Research Ethics Board, since it is not required in accord with the Tri-Council Policy of 2018, as all data used were obtained from publicly available databases. Participants gave informed consent to participate in the study before taking part.