Time to send the preemie home? Additional maturity at discharge and subsequent health care costs and outcomes

Predicting Feeding Conditions of Premature InfantsThrough Non-Nutritive Sucking Skills Using a Sensitized Pacifier

Due to the lack of enough physical or suck central pattern generator (SCPG) development, premature infants require assistance in improving their sucking skills as one of the first coordinated muscular activities in infants. Hence, we need to quantitatively measure their sucking abilities for future studies on their sucking interventions. Here, we present a new device that can measure both intraoral pressure (IP) and expression pressure (EP) as ororhithmic behavior parameters of non-nutritive sucking skills in infants. Our device is low-cost, easy-to-use, and accurate, which makes it appropriate for extensive studies. To showcase one of the applications of our device, we collected weekly data from 137 premature infants from 29 week-old to 36 week-old. Around half of the infants in our study needed intensive care even after they were 36 week-old. We call them full attainment of oral feeding (FAOF) infants. We then used the Non-nutritive sucking (NNS) features of EP and IP signals of infants recorded by our device to predict FAOF infants' sucking conditions. We found that our pipeline can predict FAOF infants several weeks before discharge from the hospital. Thus, this application of our device presents a robust and inexpensive alternative to monitor oral feeding ability in premature infants.

Discharge Age and Weight for Very Preterm Infants: 2005-2018

BACKGROUND

A complex set of medical, social, and financial factors underlie decisions to discharge very preterm infants. As care practices change, whether postmenstrual age and weight at discharge have changed is unknown.

METHODS

Between 2005 and 2018, 824 US Vermont Oxford Network member hospitals reported 314 811 infants 24 to 29 weeks' gestational age at birth without major congenital abnormalities who survived to discharge from the hospital. Using quantile regression, adjusting for infant characteristics and complexity of hospital course, we estimated differences in median age, weight, and discharge weight z score at discharge stratified by gestational age at birth and by NICU type.

RESULTS

From 2005 to 2018, postmenstrual age at discharge increased an estimated 8 (compatibility interval [CI]: 8 to 9) days for all infants. For infants initially discharged from the hospital, discharge weight increased an estimated 316 (CI: 308 to 324) grams, and median discharge weight z score increased an estimated 0.19 (CI: 0.18 to 0.20) standard units. Increases occurred within all birth gestational ages and across all NICU types. The proportion of infants discharged home from the hospital on human milk increased, and the proportions of infants discharged home from the hospital on oxygen or a cardiorespiratory monitor decreased.

CONCLUSIONS

Gestational age and weight at discharge increased steadily from 2005 to 2018 for survivors 24 to 29 weeks' gestation with undetermined causes, benefits, and costs.

Evaluating the Costs and Outcomes of Hospital Nursing Resources: a Matched Cohort Study of Patients with Common Medical Conditions

BACKGROUND

Nursing resources, such as staffing ratios and skill mix, vary across hospitals. Better nursing resources have been linked to better patient outcomes but are assumed to increase costs. The value of investments in nursing resources, in terms of clinical benefits relative to costs, is unclear.

OBJECTIVE

To determine whether there are differential clinical outcomes, costs, and value among medical patients at hospitals characterized by better or worse nursing resources.

DESIGN

Matched cohort study of patients in 306 acute care hospitals.

PATIENTS

A total of 74,045 matched pairs of fee-for-service Medicare beneficiaries admitted for common medical conditions (25,446 sepsis pairs; 16,332 congestive heart failure pairs; 12,811 pneumonia pairs; 10,598 stroke pairs; 8858 acute myocardial infarction pairs). Patients were also matched on hospital size, technology, and teaching status.

MAIN MEASURES

Better (n = 76) and worse (n = 230) nursing resourced hospitals were defined by patient-to-nurse ratios, skill mix, proportions of bachelors-degree nurses, and nurse work environments. Outcomes included 30-day mortality, readmission, and resource utilization-based costs.

KEY RESULTS

Patients in hospitals with better nursing resources had significantly lower 30-day mortality (16.1% vs 17.1%, p < 0.0001) and fewer readmissions (32.3% vs 33.6%, p < 0.0001) yet costs were not significantly different ($18,848 vs 18,671, p = 0.133). The greatest outcomes and cost advantage of better nursing resourced hospitals were in patients with sepsis who had lower mortality (25.3% vs 27.6%, p < 0.0001). Overall, patients with the highest risk of mortality on admission experienced the greatest reductions in mortality and readmission from better nursing at no difference in cost.

CONCLUSIONS

Medicare beneficiaries with common medical conditions admitted to hospitals with better nursing resources experienced more favorable outcomes at almost no difference in cost.

Metabolic Acidosis in Preterm Infants is Associated with a Longer Length of Stay in the Neonatal Intensive Care Unit

INTRODUCTION

Preterm births account for disproportionately high healthcare costs, in large part due to expenses related to length of stay in the hospital neonatal intensive care unit (NICU). It is common for preterm infants to receive human milk fortifier (HMF) while in the NICU. Liquid HMF is available in both acidified and non-acidified formulations. A recent randomized clinical trial found that acidified HMF is associated with an increased incidence of metabolic acidosis, which may contribute to increased costs and longer NICU length of stay.

OBJECTIVE

The present study is a secondary analysis of these data, seeking to determine whether additional factors contribute to metabolic acidosis, whether metabolic acidosis is associated with longer hospital length of stay, and whether these associations contribute to the burden of hospital costs.

METHODS

The study sample consisted of 152 infants who were hospitalized in US NICUs. Multiple logistic regression was used to model the NICU length of stay. Data from the 2012 Healthcare Cost and Utilization Project (HCUP) Kids' Inpatient Database (KID) were used to calculate the average cost (charge) per day in a NICU. Costs (charges) were adjusted to $US, year 2018 values, using the health Consumer Price Index.

RESULT

Results indicated that acidified HMF was a strong predictor of metabolic acidosis, more so than gestational age or birth weight. Furthermore, metabolic acidosis was associated with incremental NICU costs (charges) of $US19,002 ($US65,462) per infant and longer NICU LOS.

CONCLUSION

Future studies should further investigate factors that contribute to NICU length of stay and associated costs of care.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02307760.

Matching with time-dependent treatments: A review and look forward

Observational studies of treatment effects attempt to mimic a randomized experiment by balancing the covariate distribution in treated and control groups, thus removing biases related to measured confounders. Methods such as weighting, matching, and stratification, with or without a propensity score, are common in cross‐sectional data. When treatments are initiated over longitudinal follow‐up, a target pragmatic trial can be emulated using appropriate matching methods. The ideal experiment of interest is simple; patients would be enrolled sequentially, randomized to one or more treatments and followed subsequently. This tutorial defines a class of longitudinal matching methods that emulate this experiment and provides a review of existing variations, with guidance regarding study design, execution, and analysis. These principles are illustrated in application to the study of statins on cardiovascular outcomes in the Framingham Offspring cohort. We identify avenues for future research and highlight the relevance of this methodology to high‐quality comparative effectiveness studies in the era of big data.

Valuing hospital investments in nursing: multistate matched-cohort study of surgical patients

BACKGROUND

There are known clinical benefits associated with investments in nursing. Less is known about their value.

AIMS

To compare surgical patient outcomes and costs in hospitals with better versus worse nursing resources and to determine if value differs across these hospitals for patients with different mortality risks.

METHODS

Retrospective matched-cohort design of patient outcomes at hospitals with better versus worse nursing resources, defined by patient-to-nurse ratios, skill mix, proportions of bachelors-degree nurses and nurse work environments. The sample included 62 715 pairs of surgical patients in 76 better nursing resourced hospitals and 230 worse nursing resourced hospitals from 2013 to 2015. Patients were exactly matched on principal procedures and their hospital's size category, teaching and technology status, and were closely matched on comorbidities and other risk factors.

RESULTS

Patients in hospitals with better nursing resources had lower 30-day mortality: 2.7% vs 3.1% (p<0.001), lower failure-to-rescue: 5.4% vs 6.2% (p<0.001), lower readmissions: 12.6% vs 13.5% (p<0.001), shorter lengths of stay: 4.70 days vs 4.76 days (p<0.001), more intensive care unit admissions: 17.2% vs 15.4% (p<0.001) and marginally higher nurse-adjusted costs (which account for the costs of better nursing resources): $20 096 vs $19 358 (p<0.001), as compared with patients in worse nursing resourced hospitals. The nurse-adjusted cost associated with a 1% improvement in mortality at better nursing hospitals was $2035. Patients with the highest mortality risk realised the greatest value from nursing resources.

CONCLUSION

Hospitals with better nursing resources provided better clinical outcomes for surgical patients at a small additional cost. Generally, the sicker the patient, the greater the value at better nursing resourced hospitals.

Examining the Trade-off Between NICU Length of Stay and Postdischarge Monitoring: An Instrumental Variables Approach

EXECUTIVE SUMMARY

Treatment of very low birth weight infants in a neonatal intensive care unit (NICU) can be expensive, particularly in rural areas, but may potentially reduce long-term treatment costs and improve short- and long-term health outcomes. Few studies look at this trade-off. We employed an instrumental variables approach (fuzzy discontinuity) based on changes in practice for the treatment of very low birth weight infants in a perinatal referral center's NICU in 2000-2001. The strategy of keeping infants in a NICU longer reduced the likelihood of discharge with an apnea/cardio monitor. The primary instrumental variables specification estimated that every additional 100 g of discharge weight reduced the likelihood of discharge with an apnea/cardio monitor by 4.8%. Extending an infant's length of stay (LOS) thus has important benefits. Greater expenses on days in the NICU are partially compensated by reduced monitoring post discharge. In contexts where postdischarge monitoring is particularly difficult or expensive, extending LOS may be cost effective and potentially improve outcomes.

Usefulness of the Infant Driven Scale in the early identification of preterm infants at risk for delayed oral feeding independency

BACKGROUND

Very preterm infants frequently experience difficulties in achieving feeding independency. The availability of feeding assessment instruments has been recommended to evaluate an infant's readiness for oral feeding and enable preterm infants' caregivers to document each infant's feeding readiness and advancements.

AIMS

To investigate the implementation of the Infant Driven Scale in neonatal intensive care units and to identify a cut off value associated with delayed feeding independency.

STUDY DESIGN

Prospective, observational, single-centre study.

SUBJECTS

A total of 47 infants born at a gestational age≤32weeks, consecutively admitted to a tertiary neonatal unit between July 2015 and March 2016.

OUTCOMES MEASURES

The infant's feeding readiness and the postmenstrual age at achievement of feeding independency.

RESULTS

Mean postmenstrual age at feeding independency was 35.6±1.34weeks. A linear regression analysis showed that a score≤8 at 32weeks of postmenstrual age was associated with a delay of 1.8weeks in achieving feeding independency.

CONCLUSION

The Infant Driven Scale appears to be a useful additional instrument for the assessment of preterm infants' oral feeding readiness and the early identification of the infants at risk for delayed feeding independency.

Osteopathic manipulative treatment showed reduction of length of stay and costs in preterm infants: A systematic review and meta-analysis

BACKGROUND

Osteopathic medicine is an emerging and complementary method used in neonatology.

METHODS

Outcomes were the mean difference in length of stay (LOS) and costs between osteopathy and alternative treatment group. A comprehensive literature search of (quasi)- randomized controlled trials (RCTs), was conducted from journal inception to May, 2015. Eligible studies must have treated preterm infants directly in the crib or bed and Osteopathic Manipulative Treatment (OMT) must have been performed by osteopaths. A rigorous Cochrane-like method was used for study screening and selection, risk of bias assessment and data reporting. Fixed effect meta-analysis was performed to synthesize data.

RESULTS

5 trials enrolling 1306 infants met our inclusion criteria. Although the heterogeneity was moderate (I = 61%, P = 0.03), meta-analysis of all five studies showed that preterm infants treated with OMT had a significant reduction of LOS by 2.71 days (95% CI -3.99, -1.43; P < 0.001). Considering costs, meta-analysis showed reduction in the OMT group (-1,545.66&OV0556;, -1,888.03&OV0556;, -1,203.29&OV0556;, P < 0.0001). All studies reported no adverse events associated to OMT. Subgroup analysis showed that the benefit of OMT is inversely associated to gestational age.

CONCLUSIONS

The present systematic review showed the clinical effectiveness of OMT on the reduction of LOS and costs in a large population of preterm infants.

Cost comparison of mechanically ventilated patients across the age span

OBJECTIVE

To compare the use of mechanical ventilation and hospital costs across ventilated patients of all ages, preterm through adults, in a nationally representative sample.

STUDY DESIGN

Secondary analysis of the 2009 Agency for Healthcare Research and Quality National Inpatient Sample.

RESULTS

A total of 1 107 563 (2.8%) patients received mechanical ventilation. For surviving ventilated patients, median costs for infants ⩽32 weeks' gestation were $51000 to $209 000, whereas median costs for older patients were lower from $17 000 to $25 000. For non-surviving ventilated patients, median costs were $27 000 to $39 000 except at the extremes of age; the median cost was $10 000 for <24 week newborns and $14 000 for 91+ year adults. Newborns of all gestational ages had a disproportionate share of hospital costs relative to their total volume.

CONCLUSION

Most intensive care unit resources at the extremes of age are not directed toward non-surviving patients. From a perinatal perspective, attention should be directed toward improving outcomes and reducing costs for all infants, not just at the earliest gestational ages.

A multicenter, randomized, controlled trial of osteopathic manipulative treatment on preterms

Background

Despite some preliminary evidence, it is still largely unknown whether osteopathic manipulative treatment improves preterm clinical outcomes.

Materials and Methods

The present multi-center randomized single blind parallel group clinical trial enrolled newborns who met the criteria for gestational age between 29 and 37 weeks, without any congenital complication from 3 different public neonatal intensive care units. Preterm infants were randomly assigned to usual prenatal care (control group) or osteopathic manipulative treatment (study group). The primary outcome was the mean difference in length of hospital stay between groups.

Results

A total of 695 newborns were randomly assigned to either the study group (n= 352) or the control group (n=343). A statistical significant difference was observed between the two groups for the primary outcome (13.8 and 17.5 days for the study and control group respectively, p<0.001, effect size: 0.31). Multivariate analysis showed a reduction of the length of stay of 3.9 days (95% CI -5.5 to -2.3, p<0.001). Furthermore, there were significant reductions with treatment as compared to usual care in cost (difference between study and control group: 1,586.01€; 95% CI 1,087.18 to 6,277.28; p<0.001) but not in daily weight gain. There were no complications associated to the intervention.

Conclusions

Osteopathic treatment reduced significantly the number of days of hospitalization and is cost-effective on a large cohort of preterm infants.

Age and weight at final discharge from an early discharge programme for stable but tube-fed preterm infants

AIM

Preterm birth is often associated with prolonged hospitalisation, complicating the parent-child relationship and breastfeeding rates. As a result, an early discharge programme was implemented in the department of neonatology at Rigshospitalet. The infants were stable, but required tube feeding, and during the programme, they received home visits by neonatal nurses. We evaluated the programme, focusing on the infants' well-being, using weight gain, breastfeeding rates and total duration of hospitalisation as outcomes.

METHODS

Over an 11-year period, 500 infants participated in the programme and they constituted the early discharge group. They were compared with 400 infants discharged from the Naestved and Nykoebing Falster hospitals.

RESULTS

The early discharge group's length of hospitalisation was only three days shorter than the comparison group, but they were eight days younger when they joined the programme (p < 0.0001). Total admission was 21 days longer (p < 0.0001). There was no difference in weight-for-age at discharge (p = 0.15), but infants in the early discharge group were more frequently fully or partly breastfed (88% versus 80%, p < 0.005).

CONCLUSION

While recognising the limited comparability of the two groups, weight-for-age at discharge was similar, but the programme appeared to allow better breastfeeding success at the expense of a later final discharge.

Incident Diabetes and Mobility Limitations: Reducing Bias Through Risk-set Matching

BACKGROUND

Increased prevalence of diabetes in the U.S. population could contribute substantially to increases in disability at older ages. Previous studies have examined the association between prevalent diabetes and various impairments and disabilities. Methods considering incident, rather than prevalent, diabetes as the exposure of interest can reduce bias in estimates of these associations.

METHODS

Risk-set matching, a type of propensity score matching meant to handle time-varying exposures, was used to estimate the relationship between incident diabetes and mobility limitations among adults in the Health and Retirement Study. This approach ensures that covariates precede diabetes onset rather than follow it.

RESULTS

Individuals who were diagnosed with diabetes during the study period accumulated more subsequent mobility limitations than were accumulated by matched controls. Among observationally similar pairs of individuals, those who developed diabetes reported an average of 24.9% more mobility limitations at study exit than those who did not.

CONCLUSIONS

The magnitude of the relationship between diabetes and limitations estimated in this article is smaller than that presented in previous studies, but the method presented here is likely to provide a less-biased estimate of the association between diabetes and accumulation of mobility limitations.

Bronchopulmonary dysplasia - trends over three decades

OBJECTIVES

To describe the characteristics of bronchopulmonary dysplasia (BPD) and respiratory distress syndrome subjects, along with the trends in severity and mortality associated with BPD over the past three decades.

METHODS

Retrospective study of BPD and respiratory distress syndrome subjects born between 1980 and 2008, and admitted to Montreal Children's Hospital (Montreal, Quebec). Data were abstracted from hospital records.

RESULTS

Gestational age and birth weight were correlated with the occurrence of BPD with each additional week of gestation and 100 g in birth weight being associated with an OR of developing BPD of 0.77 and 0.89, respectively. BPD severity was associated with male sex, Apgar score and the occurrence of neonatal pneumonia. Significant trends were observed for lower mortality despite lower gestational age and birth weight, greater maternal age and multiple gestations.

CONCLUSION

Mortality from BPD has improved over the past three decades despite significant trends toward more pronounced prematurity and lower birth weights.

Longer interdialytic interval and cause-specific hospitalization in children receiving chronic dialysis

BACKGROUND

Previous studies have demonstrated a relationship between longer interdialytic intervals and hospitalization for cardiovascular causes in adults maintained on hemodialysis (HD). This association has not been previously demonstrated in children. We hypothesized that the risk of hospitalization for hypertension (HTN), fluid overload or electrolyte abnormalities would be increased on the days following a longer interdialytic interval in children.

METHODS

We queried the Pediatric Hospital Information System for all admissions of patients with chronic kidney disease stage V or V-D who received dialysis during the hospitalization. Admissions were divided into two categories: admissions for HTN, fluid overload or electrolyte abnormalities and admissions for all other causes. We assumed that HD patients did not receive dialysis on weekends, and therefore any admission on Monday occurred following a longer interval from the last dialysis. We assumed that all peritoneal dialysis (PD) patients received dialysis on a daily basis. We used mixed effects logistic regression, clustering by patient within each hospital, to assess the increased odds for cause-specific admission on Monday versus other days of the week. We stratified the analysis by dialysis modality, HD or PD.

RESULTS

Among HD patients, the odds ratio of admission for HTN, fluid overload or electrolyte abnormalities was 2.6 (95% CI = 1.4-4.7, P = 0.003) if the admission occurred on a Monday versus other days of the week. The odds of cause-specific admission among PD patients was not significantly different on Monday compared with other days of the week (95% CI =0.5-1.3, P = 0.8).

CONCLUSION

Children receiving chronic HD are more likely to be hospitalized for HTN, fluid overload or electrolyte abnormalities following a longer interdialytic interval. Changes to the frequency of outpatient dialysis treatments may decrease admissions in this population and decrease resource utilization in this high-risk population.

Medical and financial risks associated with surgery in the elderly obese

OBJECTIVE

To study the medical and financial outcomes associated with surgery in elderly obese patients and to ask if obesity itself influences outcomes above and beyond the effects from comorbidities that are known to be associated with obesity.

BACKGROUND

Obesity is a surgical risk factor not present in Medicare's risk adjustment or payment algorithms, as BMI is not collected in administrative claims.

METHODS

A total of 2045 severely or morbidly obese patients (BMI ≥ 35 kg/m, aged between 65 and 80 years) selected from 15,914 elderly patients in 47 hospitals undergoing hip and knee surgery, colectomy, and thoracotomy were matched to 2 sets of 2045 nonobese patients (BMI = 20-30 kg/m). A "limited match" controlled for age, sex, race, procedure, and hospital. A "complete match" also controlled for 30 additional factors such as diabetes and admission clinical data from chart abstraction.

RESULTS

Mean BMI in the obese patients was 40 kg/m compared with 26 kg/m in the nonobese. In the complete match, obese patients displayed increased odds of wound infection: OR (odds ratio) = 1.64 (95% CI: 1.21, 2.21); renal dysfunction: OR = 2.05 (1.39, 3.05); urinary tract infection: OR = 1.55 (1.24, 1.94); hypotension: OR = 1.38 (1.07, 1.80); respiratory events: OR = 1.44 (1.19, 1.75); 30-day readmission: OR = 1.38 (1.08, 1.77); and a 12% longer length of stay (8%, 17%). Provider costs were 10% (7%, 12%) greater in obese than in nonobese patients, whereas Medicare payments increased only 3% (2%, 5%). Findings were similar in the limited match.

CONCLUSIONS

Obesity increases the risks and costs of surgery. Better approaches are needed to reduce these risks. Furthermore, to avoid incentives to underserve this population, Medicare should consider incorporating incremental costs of caring for obese patients into payment policy and include obesity in severity adjustment models.

Neonatal intensive care unit discharge preparedness: primary care implications

OBJECTIVE

To investigate specific post-neonatal intensive care unit (NICU) discharge outcomes and issues for families.

STUDY DESIGN

The authors prospectively surveyed family's discharge preparedness at the infant's NICU discharge. In the weeks after the infant was discharged, families were interviewed by telephone for self-reported utilization of health services as well as any infant-associated problems or issues.

RESULTS

At discharge, 35 of 287 (12%) families were "unprepared" as defined by a Likert response of less than 7 by either the family member or nursing assessment. Unprepared families were more likely to report that their pediatrician could not access the infant's NICU hospital discharge summary, problems with the infant's milk/formula, and an inability to obtain needed feeding supplies.

CONCLUSIONS

Although most of the families are "prepared" for discharge at the time of discharge, this study highlights several issues that primary care providers accepting care and NICU staff discharging infants/families should be aware.

Optimal Nonbipartite Matching and Its Statistical Applications

Matching is a powerful statistical tool in design and analysis. Conventional two-group, or bipartite, matching has been widely used in practice. However, its utility is limited to simpler designs. In contrast, nonbipartite matching is not limited to the two-group case, handling multiparty matching situations. It can be used to find the set of matches that minimize the sum of distances based on a given distance matrix. It brings greater flexibility to the matching design, such as multigroup comparisons. Thanks to improvements in computing power and freely available algorithms to solve nonbipartite problems, the cost in terms of computation time and complexity is low. This article reviews the optimal nonbipartite matching algorithm and its statistical applications, including observational studies with complex designs and an exact distribution-free test comparing two multivariate distributions. We also introduce an R package that performs optimal nonbipartite matching. We present an easily accessible web application to make nonbipartite matching freely available to general researchers.

Epidemiology of apnea and bradycardia resolution in premature infants

BACKGROUND

There is little epidemiologic evidence to assess the maturation of respiratory control in premature infants.

OBJECTIVE

To measure the success rate or the percentage of infants who have no additional events of various apnea- or bradycardia-free intervals after correcting for gestational age, postmenstrual age of the last apnea or bradycardia event, and the severity of the event.

METHODS

This was a retrospective cohort study of infants born at 34 weeks' gestational age or earlier at 1 of 5 Kaiser Permanente Medical Care Program hospitals between 1998 and 2001. The success rates of various apnea- or bradycardia-free intervals were calculated after stratifying according to gestational age, postmenstrual age of the last event, or event severity.

RESULTS

Among the 1403 infants identified in this study, 84.2% did not have an apnea event and 78.5% did not have a bradycardia event after they were otherwise ready for discharge. For the entire cohort, a 95% success rate was statistically reached, with a 7-day apnea- or bradycardia-free interval. Infants with a gestational age of 30 weeks or less had a 5% to 15% lower success rate than infants with a gestational age more than 30 weeks for any given apnea- or bradycardia-free interval. The success rate was reduced by an additional 5% to 10% if the last apnea or bradycardia event occurred at a postmenstrual age of more than 36 weeks. Including only the most severe events slightly improved the success rate of a given interval.

CONCLUSIONS

The risk of recurrence for apnea or bradycardia differs depending on the gestational age of the infant and the postmenstrual age of the last apnea or bradycardia event.

Costs and quality of hospitals in different health care systems: a multi-level approach with propensity score matching

Cross-country comparisons of costs and quality between hospitals are often made at the macro level. The goal of this study was to explore methods to compare micro-level data from hospitals in different health care systems. To do so, we developed a multi-level framework in combination with a propensity score matching technique using similarly structured data for patients receiving treatment for acute myocardial infarction in German and US Veterans Health Administration hospitals. Our case study shows important differences in results between multi-level regressions based on matched and unmatched samples. We conclude that propensity score matching techniques are an appropriate way to deal with the usual baseline imbalances across the samples from different countries. Multi-level models are recommendable to consider the clustered structure of the data when patient-level data from different hospitals and health care systems are compared. The results provide an important justification for exploring new ways in performing health system comparisons.

Premature infants born to adolescent mothers: health care utilization after initial discharge

OBJECTIVE

Premature infants have increased health care utilization after initial discharge compared with term infants. Young maternal age has been shown to impact health care utilization among term infants, but little is known about the impact of maternal age on health care utilization among premature infants. We compared health care utilization among premature infants of adolescent (aged < or = 19 years) and young adult (aged 20-29 years) mothers, hypothesizing that premature infants of adolescent mothers would have increased acute care utilization, while having decreased preventive care utilization.

METHODS

In this retrospective cohort study, we analyzed health care utilization of premature infants born to adolescent mothers (n = 76) compared with premature infants born to young adult mothers (n = 587) within a cohort of premature infants born between 1998 and 2001 in an integrated health care delivery system.

RESULTS

After controlling for illness severity, premature infants born to adolescent mothers had significantly increased odds of medical rehospitalizations (odds ratio 3.57, 95% confidence interval, 1.81-7.05) and emergency department visits (odds ratio 3.67, 95% confidence interval, 2.11-6.39) during the first year after initial discharge compared with premature infants born to young adult mothers. Differences in rehospitalization rates were significant within the first 3 months after discharge (P < .001). Frequency of preventive care visits was not significantly different between the two groups.

CONCLUSIONS

Despite similar severity of chronic illness and similar preventive care utilization, premature infants born to adolescent mothers had significantly increased rates of rehospitalizations and emergency department visits compared with premature infants born to young adult mothers.

The role of outpatient facilities in explaining variations in risk-adjusted readmission rates between hospitals

OBJECTIVE

Validate risk-adjusted readmission rates as a measure of inpatient quality of care after accounting for outpatient facilities, using premature infants as a test case.

STUDY SETTING

Surviving infants born between January 1, 1998 and December 12, 2001 at five Northern California Kaiser Permanente neonatal intensive care units (NICU) with 1-year follow-up at 32 outpatient facilities.

STUDY DESIGN

Using a retrospective cohort of premature infants (N=898), Poisson's regression models determined the risk-adjusted variation in unplanned readmissions between 0-1 month, 0-3 months, 3-6 months, and 3-12 months after discharge attributable to patient factors, NICUs, and outpatient facilities.

DATA COLLECTION

Prospectively collected maternal and infant hospital data were linked to inpatient, outpatient, and pharmacy databases.

PRINCIPAL RESULTS

Medical and sociodemographic factors explained the largest amount of variation in risk-adjusted readmission rates. NICU facilities were significantly associated with readmission rates up to 1 year after discharge, but the outpatient facility where patients received outpatient care can explain much of this variation. Characteristics of outpatient facilities, not the NICUs, were associated with variations in readmission rates.

CONCLUSION

Ignoring outpatient facilities leads to an overstatement of the effect of NICUs on readmissions and ignores a significant cause of variations in readmissions.