© 2002 American Public Health Association
At the time of this study, Embry M. Howell and Barbara Foot were with Mathematica Policy Research Inc, Washington, DC. Douglas Richardson is with the Harvard Program in Newborn Medicine (Beth Israel Deaconess Medical Center, Children's Hospital, Brigham and Women's Hospital, and Harvard Medical School) and the Department of Maternal and Child Health, Harvard School of Public Health, Boston, Mass. Paul Ginsburg is with the Center for Studying Health System Change, Washington, DC. Correspondence: Requests for reprints should be sent to Embry M. Howell, PhD, The Urban Institute, Health Policy Center, 2100 M St, NW, Washington, DC 20037 (e-mail: ehowell{at}ui.urban.org).
Objectives. This report describes the extent of deregionalization of neonatal intensive care in urban areas of the United States in the 1980s and 1990s and the factors associated with it. Methods. We conducted a 15-year retrospective analysis of secondary data from US metropolitan statistical areas. Primary outcome measures are number of neonatal intensive care unit (NICU) beds, number of NICU hospitals, and number of small NICUs. Results. Growth in the supply of NICU care has outpaced the need. During the study period (19801995), the number of hospitals grew by 99%, the number of NICU beds by 138%, and the number of neonatologists by 268%. In contrast, the growth in needed bed days was only 84%. Of greater concern, the number of beds in small NICU facilities continues to grow. Local regulatory and practice characteristics are important in explaining this growth. Conclusions. Local policymakers should examine the factors that facilitate the proliferation of services, especially the development of small NICUs. Policies that encourage cooperative efforts by hospitals should be developed. Eliminating small NICUs would not restrict the NICU bed supply in most metropolitan statistical areas.
Care for high-risk newborns is provided in neonatal intensive care units (NICUs) in hospitals with obstetric services or in children's hospitals. According to the American Academy of Pediatrics, services in NICUs include "constant nursing and continuous cardiopulmonary and other support for severely ill infants" as well as other specialty services and technology.1 Generally, this care is provided under the supervision of neonatologists. Not all birth hospitals have NICUs; infants who are born outside of NICU hospitals and who need such services are usually transferred to the nearest NICU facility. Research has shown that infants who are cared for in NICUs have better rates of survival than those who are not, after infant size and gestation are controlled for (see McCormick and Richardson2 for an extensive review of this literature). Another body of research has generally shown that infants born in higher-volume NICUs have better survival than those born in lower-volume facilities,3,4 although results are not completely consistent.5 To achieve the goal of optimum care for sick newborns, perinatal regionalization programs were set up around the country beginning in the early 1970s.68 Under a regionalized perinatal system, each facility with an obstetric service is designated as being 1 of 3 levels. Level 1 hospitals are obstetric hospitals without specialized care for newborns. Level 2 facilities, often called "intermediate care facilities," are defined by the American Academy of Pediatrics as being for "sick newborns who do not require intensive care but require 612 hours of nursing time each day." Level 3 facilities have NICUs. The criteria for these levels of care vary from state to state. In some states, there is a certification process for level of care, but in others there is none. Thus, the designation may not be a legal one; rather, it may be based on formal or informal agreements among hospitals, or it may be simply a hospital's self-designation. Schwartz9 documented the growth in numbers of both intermediate and NICU beds in the 1980s, and anecdotal evidence suggests that patterns in regionalization may have changed. For example, recent case studies by Richardson et al.10 in Hartford, Conn, Menard et al.11 in South Carolina, and Yeast et al.12 in Missouri illustrate the challenges to regionalization as community hospitals add NICUs to compete for obstetric and neonatal patients. In this study, we develop a concept of "deregionalization" associated with both the amount of NICU services and the concentration of those services. We first examine whether the proliferation of NICU facilities, beds, and physician specialists (neonatologists) is due to increased need for such services. After establishing that the rate of growth exceeds the likely need, we further explore geographic and hospital characteristics associated with growth, placing particular emphasis on whether expansions in services have occurred in smaller-than-optimal NICUs. Where the number of beds in small NICUs continues to grow, we provide evidence of a pattern of deregionalization in which hospitals establish (or maintain) their own small NICU rather than transfer infants to larger NICUs. By describing these patterns, we hope to assist policymakers in understanding the proliferation of neonatal intensive care and the deregionalization of NICU services.
In this study we used data for 1980, 1990, and 1995 from the annual survey of hospitals conducted by the American Hospital Association (AHA).13 Each hospital reports its number of total beds, obstetrical beds, NICU beds, intermediate care beds, and births, as well as (through 1990) the occupancy rate for each unit. The AHA provides a definition of NICU beds and intermediate beds for purposes of collecting data for the annual survey, a definition that has varied somewhat over time and that is also subject to considerable interpretation. For example, the AHA definition of a NICU in 1980 was as follows: "This unit provides intermediate, recovery, and intensive care." By 1995, the definition had become more specific: "A unit that must be separate from the newborn nursery providing intensive care to all sick infants including those with the very lowest birthweights (<1500 g). A NICU has the potential for providing mechanical ventilation, neonatal surgery, and special care for the sickest infants born in the hospital or transferred from another institution. A fulltime neonatologist serves as director of the NICU" (M. Janko, AHA, written communication, February 4, 1997). Since the AHA definition of NICU has become more specific over time, some beds that would have been classified as NICU beds in 1980 may have been excluded by hospitals from their NICU bed count later, possibly being reclassified as intermediate-care beds. Since the AHA survey does not specifically ask the hospital about obstetric level of care, we were led to define a "NICU hospital" (most level 3 hospitals in most states are probably included under our definition). For this report, we restricted NICU hospitals to those with at least 1 NICU bed, but we also included both reported intermediate care beds and NICU beds in such hospitals. Hospitals reporting only intermediate care beds, probably classified as level 2 hospitals in most states, were excluded from the study, although our definition may include some level 2 hospitals when they report NICU beds. We excluded level 2 hospitals because they are not clearly identified in the AHA data and the definition of level 2 is more variable from state to state than the definition of level 3. We further defined "small" NICUs, building on the study by Phibbs et al.4 showing that fragile infants had lower mortality rates in facilities with an average daily census of at least 15. Assuming an average occupancy rate of about 75%, we defined small NICUs as those with 20 beds or fewer. The AHA survey provides data on certain other hospital characteristics that could affect the hospital's decision to operate a NICU, such as for-profit status, teaching status, and geographic location (zip code and county code). We used Atlas Select software14 to calculate the proximity of each birth hospital to its nearest NICU hospital. The distance is zero for NICU hospitals. Metropolitan statistical areas (MSAs) are clusters of counties that are considered to be economic markets by the US Census Bureau. MSAs contained over 85% of all NICU beds in 1995. To examine market characteristics such as managed care penetration, we included only hospitals in MSAs in this study. Thus, while the findings presented here reflect the dominant pattern of NICU growth nationwide, they are not necessarily reflective of the pattern in largely rural areas. MSA boundaries are revised periodically, usually as new counties are added. For this study, we included all hospitals in any county in an MSA in 1995, whether or not the hospital was in an MSA earlier. MSA characteristics include population size, the percentage of people with household income below the poverty level, and the proportion of the MSA population enrolled in health maintenance organizations (HMOs) in 1995 as reported by InterStudy.15 (InterStudy does not maintain consistent information for earlier years.) We included the state and census region (Northeast, South, Midwest, and West) for each hospital and MSA. The number of neonatologists was obtained from the American Board of Medical Specialties.16 Data were summarized from individual physician records to the zip code and county level. Those who practice as neonatologists but are not board certified were excluded.
There was dramatic growth nationwide in technology and manpower associated with caring for high-risk infants in the 1980s and 1990s. As shown in Table 1
Occupancy rates in NICUs remained essentially stable between 1980 and 1990, despite the dramatic increase in the number of NICU hospitals and beds. This could be due to various factors, such as use of such beds by lower-risk infants or increased need for such beds because of increased survival of infants needing NICUs.
During the period of this study, mortality rates for very-low-birthweight infants declined, and the survivors tended to stay in NICUs for a prolonged period following birth.17,18 Table 2
Some might argue that much of the growth in NICUs in small MSAs may be justified, since each distinct market "deserves" at least 1 NICU to improve geographic access to needed services. Table 3
Whereas the smallest MSAs had an average of only a single NICU in 1995, medium-sized MSAs had an average of 2.9 NICU hospitals and the largest MSAs had an average of 9.9 such hospitals. We investigated whether deregionalization, represented by growth in the number of small NICUs, occurred during the period. Table 3
To try to explain why deregionalization has occurred, we conducted a multivariate logistic analysis to control for some of the multiple factors that could explain the decision of a hospital to open and maintain a small NICU. As shown in Table 4, 3
We sought a possible explanation for why hospitals in the Northeast are more prone to establish small NICUs. Table 5
Our data show rapid and continued growth in neonatal intensive care in urban areas of the United States in the 1980s and 1990s. This expansion of services has increased geographic access, especially in smaller MSAs. We have shown that much of this growth occurred in NICUs that are smaller than optimal, rather than in further expansion of optimally sized NICUs, and that such a process continued through the mid-1990s. In excluding hospitals with only intermediate-care beds (i.e., level 2 hospitals) from this study, we may have underestimated the size and scope of this proliferation. Deregionalization of perinatal services is indicated by the existence of small NICUs in relatively geographically compact areas, such as in small states (e.g., Connecticut and New Jersey) and in large cities such as Philadelphia, where effective transfer programs should be able to ensure geographic access. Market-level factors, such as HMO enrollment rates, do not explain these patterns, as determined by the rather crude measures that are readily available, although more subtle market competition factors that cannot be measured with existing data may still be important. State-specific regulatory approaches could have influenced this marked state pattern. For example, in mid-1997, 37 states maintained some form of certificate-of-need program whereby health care providers are required to apply for permission to build or expand facilities. Twenty-four of those programs require certificates of need specifically for neonatal intensive care services.19 Although certificate-of-need and other regulatory approaches do not offer a panacea for ensuring regionalization of services, it is notable that Pennsylvania is the only Northeast region state with no certificate-of-need program. (The New Hampshire program does not apply specifically to NICU services, but it does apply to medical equipment purchases of more than $400 000.) The effects of state regulatory practices are illustrated by a recent case study in Massachusetts, a state with strict certificate-of-need regulation of perinatal services. Flaherty showed that the proportion of very-low-birthweight births in NICU hospitals rose from 35% to 86% between 1975 and 1994, with a net change of only 3 new NICUs. This was accompanied by a progressive fall in neonatal mortality,20 and currently Massachusetts has the lowest infant mortality rate in the United States.21 Investigating the myriad local factors that could lead to a proliferation of small NICUs, and consequently to the deregionalization of perinatal services, is beyond the scope of this study. These are likely to include local politics, citizen pressures, hospital ownership, the history of cooperation among health care providers, the current competitive environment, and a desire by the expanding pool of neonatologists to have appropriate practice environments. Further case studies such as the one cited earlier for Hartford10 and the multicity case studies by Allison-Cook et al.22 will be needed at the local level to tease out these various factors. In particular, a study of the factors leading to a fragmentation of perinatal services in Philadelphia might lend insights for other communities. It is possible that such forces also affect, in a similar manner, other important specialty services, such as cardiac care, that benefit from regionalization.23 Currently, policymakers are undergoing an intense process of considering ways to regulate fairly the quality of health care. As part of this process, the issues surrounding regionalization are an important area for examination and possible intervention. The results of this study suggest that health officials should examine why the number of small NICUs has expanded in some cities, counter to the long-standing professional acceptance of the value of regionalization.
The research was supported by the Robert Wood Johnson Foundation through its grant to the Center for Studying Health System Change. The authors acknowledge the help of Mei-Ling Mason and Royston McNeil, who constructed the data files and prepared the tables.
E. M. Howell designed the study and directed the research, including overseeing the data analysis and writing parts of the manuscript. D. Richardson assisted in synthesizing the literature, interpreting results, suggesting analyses, and writing sections of the manuscript. P. Ginsburg played a substantive review role, providing suggestions about data, methods, and the direction of the analysis. B. Foot performed much of the data analysis and wrote sections of the manuscript. Accepted for publication December 13, 2000.
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