Longitudinal Healthcare Utilization Research Articles

Machine Learning-based Characterization of Longitudinal Health Care Utilization Among Patients With Inflammatory Bowel Diseases.

Inflammatory bowel disease (IBD) is associated with increased health care utilization. Forecasting of high resource utilizers could improve resource allocation. In this study, we aimed to develop machine learning models (1) to cluster patients according to clinical utilization patterns and (2) to predict longitudinal utilization patterns based on readily available baseline clinical characteristics. We conducted a retrospective study of adults with IBD at 2 academic centers between 2015 and 2021. Outcomes included different clinical encounters, new prescriptions of corticosteroids, and initiation of biologic therapy. Machine learning models were developed to characterize health care utilization. Poisson regression compared frequencies of clinical encounters. A total of 1174 IBD patients were followed for more than 5673 12-month observational windows. The clustering method separated patients according to low, medium, and high resource utilizers. In Poisson regression models, compared with low resource utilizers, moderate and high resource utilizers had significantly higher rates of each encounter type. Comparing moderate and high resource utilizers, the latter had greater utilization of each encounter type, except for telephone encounters and biologic therapy initiation. Machine learning models predicted longitudinal health care utilization with 81% to 85% accuracy (area under the receiver operating characteristic curve 0.84-0.90); these were superior to ordinal regression and random choice methods. Machine learning models were able to cluster individuals according to relative health care resource utilization and to accurately predict longitudinal resource utilization using baseline clinical factors. Integration of such models into the electronic medical records could provide a powerful semiautomated tool to guide patient risk assessment, targeted care coordination, and more efficient resource allocation.

Spotlight in Plastic Surgery: April 2023.

Spotlight in Plastic Surgery: April 2023.

Healthcare utilization among children with a history of neonatal opioid withdrawal syndrome: A matched cohort study

ObjectivesCompare longitudinal healthcare utilization patterns in children with and without a history of neonatal opioid withdrawal syndrome (NOWS). Study designA retrospective matched cohort study was conducted using billing data extracted from between 2003 and 2016 in North Texas hospitals. The sample included 595 pediatric patients diagnosed with NOWS (i.e. exposed). The unexposed were patients not diagnosed with NOWS and matched 4:1 on sex, age at first encounter, and ethnicity to the exposed who received care during the same period. Multi-level regression models (accounting for clustered data structure of multiple visits per patient) compared number of hospitalizations, number of outpatient visits, number of emergency department (ED) visits, average length of stay, and healthcare expenditures across patients with and without NOWS. ResultsHospitalizations were significantly lower among exposed (Incidence Rate Ratio [IRR] = 0.58, 95 % Confidence Interval [CI] = 0.44–0.77) compared to unexposed. Outpatient visits, ED visits, and average length of stay was significantly higher among exposed compared to unexposed (IRR = 1.19, 95 % CI = 1.04–1.36; IRR = 1.22, 95 % CI = 1.04–1.42; IRR = 2.21, 95 % CI = 2.03–2.42, respectively). Overall healthcare expenditure was greater among exposed, as well as for patients with neurologic, endocrine, cardiac, mental disorders, respiratory, perinatal, infectious disease, eye, ear, digestive, congenital anomaly, and skin diagnoses. ConclusionsChildren with a diagnosis of NOWS have significantly higher healthcare expenditures, and with the exception of hospitalizations, higher healthcare utilization beyond the newborn visit. These findings suggest the needs for interventions for children with NOWS beyond the immediate neonatal period.

Reoperation Through a Prosthetic-Reinforced Abdominal Wall and Its Association With Postoperative Outcomes and Longitudinal Health Care Utilization

Prosthetic reinforcement of critically sized incisional hernias is necessary to decrease hernia recurrence, but long-term prosthetic-mesh footprint may increase complication risk during subsequent abdominal operations. To investigate the association of prior incisional hernia repair with mesh (IHRWM) with postoperative outcomes and health care utilization after common abdominal operations. This was a population-based, retrospective cohort study of patients undergoing inpatient abdominal surgical procedures during the period of January 2009 to December 2016, with at least 1 year of follow-up within 5 geographically diverse statewide inpatient/ambulatory databases (Florida, Iowa, Nebraska, New York, Utah). History of an abdominal operation was ascertained within the 3-year period preceding the index operation. Patients admitted to the hospital with a history of an abdominal operation (ie, bariatric, cholecystectomy, small- or large-bowel resection, prostatectomy, gynecologic) were identified using the International Classification of Diseases, Ninth Revision and Tenth Revision, Clinical Modification procedure codes. Patients with prior IHRWM were propensity score matched (1:1) to controls both with and without a history of an abdominal surgical procedure based on clinical and operative characteristics. Data analysis was conducted from March 1 to November 27, 2021. The primary outcome was a composite of adverse postoperative outcomes (surgical and nonsurgical). Secondary outcomes included health care utilization determined by length of hospital stay, hospital charges, and 1-year readmissions. Logistic and Cox regression determined the association of prior IHRWM with the outcomes of interest. Additional subanalyses matched and compared patients with prior IHR without mesh (IHRWOM) to those with a history of an abdominal operation. Of the 914 105 patients undergoing common abdominal surgical procedures (81 123 bariatric [8.9%], 284 450 small- or large-bowel resection [31.1%], 223 768 cholecystectomy [24.5%], 33 183 prostatectomy [3.6%], and 291 581 gynecologic [31.9%]), all 3517 patients (age group: 46-55 years, 1547 [44.0%]; 2396 majority sex [68.1%]) with prior IHRWM were matched to patients without a history of abdominal surgical procedures. After matching, prior IHRWM was associated with increased overall complications (odds ratio [OR], 1.43; 95% CI, 1.27-1.60), surgical complications (OR, 1.51; 95% CI, 1.34-1.70), length of hospital stay (mean increase of 1.03 days; 95% CI, 0.56-1.49 days; P < .001), index admission charges (predicted mean difference of $11 896.10; 95% CI, $6096.80-$17 695.40; P < .001), and 1-year unplanned readmissions (hazard ratio, 1.14; 95% CI, 1.05-1.25; P = .002). This trend persisted even when comparing matched patients with prior IHRWM to patients with a history of abdominal surgical procedures, and the treatment outcome disappeared when comparing patients with prior IHRWOM to those without a previous abdominal operation. Reoperation through a previously prosthetic-reinforced abdominal wall was associated with increased surgical complications and health care utilization. This risk appeared to be independent of a history of abdominal surgical procedures and was magnified by the presence of a prosthetic-mesh footprint in the abdominal wall.

Demographic and Clinical Differences Between Applied Definitions of Medical Complexity.

To identify the degree of concordance and characterize demographic and clinical differences between commonly used definitions of multisystem medical complexity in children hospitalized in children's hospitals. We conducted a retrospective, cross-sectional cohort study of children <21 years of age hospitalized at 47 US Pediatric Health Information System-participating children's hospitals between January 2017 to December 2019. We classified patients as having multisystem complexity when using 3 definitions of medical complexity (pediatric complex chronic conditions, pediatric medical complexity algorithm, and pediatric chronic critical illness) and assessed their overlap. We compared demographic, clinical, outcome, cost characteristics, and longitudinal healthcare utilization for each grouping. Nearly one-fourth (23.5%) of children hospitalized at Pediatric Health Information System-participating institutions were identified as meeting at least 1 definition of multisystem complexity. Children with multisystem complexity ranged from 1.0% to 22.1% of hospitalized children, depending on the definition, with 31.2% to 95.9% requiring an ICU stay during their index admission. Differences were seen in demographic, clinical, and resource utilization patterns across the definitions. Definitions of multisystem complexity demonstrated poor agreement (Fleiss' κ 0.21), with 3.5% of identified children meeting all 3. Three definitions of multisystem complexity identified varied populations of children with complex medical needs, with poor overall agreement. Careful consideration is required when applying definitions of medical complexity in health services research, and their lack of concordance should result in caution in the interpretation of research using differing definitions of medical complexity.

Longitudinal Healthcare Utilization and Costs in Parkinson’s Disease: Pre-Diagnosis to 9 Years After

There is currently insufficient long-term data on costs of treatment in patients with Parkinson's disease (PD), which is chronic and progressive, and associated with substantial healthcare costs. Identifying patterns in healthcare utilization and cost may illuminate further discussion on early intervention. To characterize long-term healthcare utilization and costs of PD in newly diagnosed patients managed by movement disorder specialists. Using a longitudinal matched-cohort study of linked data from the National Neuroscience Institute Parkinson's disease and Movement Disorder and healthcare administrative databases in Singapore from 2008-2017, we compared healthcare utilization and costs between patients and controls matched on age, sex, race, and Charlson Comorbidity Index score. 1,162 patients met study inclusion criteria and 1,157 matched controls were identified. The total mean annual healthcare cost (at 2017 costs) was significantly increased in patients compared to controls from years 1-9 post-diagnosis. The increased cost was observed 2 years before diagnosis (USD2322 vs. 2052; p < 0.001). Mean annual cost attributable to PD increased from USD1854 at 1-year post-diagnosis to USD2652 at 9 years. Over 9 years, average costs were significantly higher across all domains of healthcare utilization except primary care-cost of intermediate and long-term care was increased by a factor of 2.5, specialist care by 2.3, emergency department visits by 1.6, and hospital admissions by 1.3. PD results in higher healthcare utilization and costs. Pre-diagnosis increase in healthcare utilization observed in patients supports the presence of prodromal PD symptoms and may present an opportunity for early diagnosis.

Longitudinal Health Care Utilization of Medicaid-Insured Children with a History of Neonatal Abstinence Syndrome

To describe longitudinal health care utilization of Medicaid-insured children with a history of neonatal abstinence syndrome (NAS) compared with similar children without NAS. Retrospective, longitudinal cohort study. Data were extracted from the Medicaid Analytic eXtract files for all available states and DC from 2003-2013. Subjects were followed up to 11years. In total, 17 229 children with NAS were identified using the International Classification of Diseases, Ninth Revision code 779.5. Children without NAS, matched on demographic and health variables, served as the comparison group. Outcomes were number of claims for inpatient, outpatient, and emergency department encounters, numbers of prescription claims, and costs associated with these services. Linked claims were identified for each subject using a unique, within-state ID. Children with NAS had increased claims for inpatient admissions (marginal effect [ME] 0.49; SE 0.01) and emergency department visits (ME 0.30; SE 0.04) through year 1; increased prescriptions (ME 1.45; SE 0.08, age 0) (ME 0.69; SE 0.11, age 1year) through year 2; and increased outpatient encounters (ME 20.13; SE 0.54, age 0) (ME 3.95; SE 0.62, age 1year) (ME 2.90; SE 1.11, age 2years) through year 3 after adjusting for potential confounders (P<.01 for all). Beyond the third year, health care utilization was similar between those with and without NAS. Children with a diagnosis of NAS have greater health care utilization through the third year of life. These differences resolve by the fourth year. Our results suggest resolution of disparities may be due to shifts in developmental health management in school-age children and inability to track relevant diagnoses in a health care database.

Impact of Idiopathic Pulmonary Fibrosis on Longitudinal Health-care Utilization in a Community-Based Cohort of Patients

Idiopathic pulmonary fibrosis (IPF) is a rare, chronic lung disease associated with substantial symptom burden, morbidity, and cost. Delivery of high-quality effective care in IPF requires understanding health-care resource utilization (HRU) patterns; however, longitudinal data from real-world populations are limited. This study aimed to define HRU attributable to IPF by evaluating a longitudinal cohort of community patients with IPF compared with matched control subjects. Incident IPF cases were identified in the Kaiser Permanente Northern California electronic health records (2000-2015) using case-validated code-based algorithms. IPF cases were compared with matched control subjects by age, sex, and length of enrollment. Annual rates of HRU measures were assessed during the 5 years pre- and postdiagnosis. Poisson generalized estimating equations were used to estimate adjusted case-control differences in HRU. IPF treatment trends were assessed before and after the availability of IPF-specific medications. A total of 691 IPF cases were identified and matched with 3,452 control subjects. Adjusted rates of all diagnostic procedures were significantly increased (P< .001) for IPF cases compared with control subjects in both the pre- and postindex periods, including chest CT scans (pre-relative risk [RR], 80.35; post-RR, 32.79), 6-min walk tests (pre-RR, 20.81; post-RR, 34.49), and pulmonary function tests (pre-RR, 9.50; post-RR, 13.24). All-cause hospitalizations (pre-RR, 1.42; post-RR, 2.33) and outpatient visits (pre-RR, 1.22; post-RR, 1.80) were significantly higher among cases compared with control subjects during both the preindex (P< .05) and postindex (P< .001) periods. We observed use of immunosuppressive and IPF-specific therapies prior to diagnosis, and high rates of corticosteroid use before and after diagnosis. This study defines a marked increase in HRU in patients with IPF compared with control subjects, with accelerated use beginning at least 1 year prediagnosis and elevated use sustained over the following 5 years. To our knowledge, this is the first study to evaluate longitudinal medication trends in IPF. Collectively, this information is foundational to advancing IPF care delivery models and supporting clinical decision-making.

Characteristics and health care utilization among patients with chronic heart failure: a longitudinal claim database analysis.

AimsThis study aimed to determine the characteristics of patients with heart failure and high costs (top 1% and top 2–5% highest costs in perspective of the general population) and to explore the longitudinal health care utilization and persistency of high costs.Methods and resultsLongitudinal observational study using claims data from 2006 to 2014 in the Netherlands. We identified all patients that received a hospital treatment for chronic heart failure between 1 January 2008 and 31 December 2010. Of each selected patient, all claims from the Dutch curative health system and with a starting date between 1 January 2006 and 31 December 2014 were extracted. Pharmaceutical and hospital claims were used to establish characteristics and indicators for health care utilization. Descriptive analyses and generalized estimating equation models were used to analyse characteristics, longitudinal health care utilization and to identify factors associated with high costs. Our findings revealed that the difference in costs between top 1%, top 2–5%, and bottom 95% patients with heart failure was mainly driven by hospital costs; and the top 1% group experienced a remarkable increase of mental health costs. Top 1% and top 2–5% patients with heart failure differed from lower cost patients in their higher rate of chronic conditions, excessive polypharmacy, hospital admissions, and heart‐related surgeries. Heart‐related surgeries contributed to the incidental high costs in 54% of top 1% patients, and the costs of the remaining top 1% patients were driven by mental health and pharmaceuticals use and rates of chronic conditions and multimorbidity. Top 1% patients were relatively young. Anaemia, dementia, diseases of arteries, veins and lymphatic vessels, influenza, and kidney failure were significantly associated with high costs. The end‐of‐life period was predictive of top 1% and top 5% costs. More than 90% of the population incurred at least one top 5% year during follow‐up, and 31.8% incurred at least one top 1% year. Fifty‐seven per cent incurred multiple top 5% years whereas only 8.6% incurred multiple top 1% years. Top 5% years were more frequently consecutive than top 1% years.ConclusionsTop 1% utilization occurs predominantly incidentally and among less than a third of patients with heart failure, whereas almost all patients with heart failure experience at least one top 5% year, and more than half experience two or more top 5% years. Both medical and psychiatric/psychosocial needs contribute to high costs in heart failure patients. Comprehensive and integrated efforts are needed to further improve quality of care and reduce unnecessary costs.

Predictive ability of an expert-defined population segmentation framework for healthcare utilization and mortality - a retrospective cohort study

BackgroundPopulation segmentation of patients into parsimonious and relatively homogenous subgroups or segments based on healthcare requirements can aid healthcare resource planning and the development of targeted intervention programs. In this study, we evaluated the predictive ability of a previously described expert-defined segmentation approach on 3-year hospital utilization and mortality.MethodsWe segmented all adult patients who had a healthcare encounter with Singapore Health Services (SingHealth) in 2012 using the SingHealth Electronic Health Records (SingHealth EHRs). Patients were divided into non-overlapping segments defined as Mostly Healthy, Stable Chronic, Serious Acute, Complex Chronic without Frequent Hospital Admissions, Complex Chronic with Frequent Hospital Admissions, and End of Life, using a previously described expert-defined segmentation approach. Hospital admissions, emergency department attendances (ED), specialist outpatient clinic attendances (SOC) and mortality in different patient subgroups were analyzed from 2013 to 2015.Results819,993 patients were included in this study. Patients in Complex Chronic with Frequent Hospital Admissions segment were most likely to have a hospital admission (IRR 22.7; p < 0.001) and ED visit (IRR 14.5; p < 0.001) in the follow-on 3 years compared to other segments. Patients in the End of Life and Complex Chronic with Frequent Hospital Admissions segments had the lowest three-year survival rates of 58.2 and 62.6% respectively whereas other segments had survival rates of above 90% after 3 years.ConclusionIn this study, we demonstrated the predictive ability of an expert-driven segmentation framework on longitudinal healthcare utilization and mortality.

Assessing the validity of a data driven segmentation approach: A 4 year longitudinal study of healthcare utilization and mortality.

BackgroundSegmentation of heterogeneous patient populations into parsimonious and relatively homogenous groups with similar healthcare needs can facilitate healthcare resource planning and development of effective integrated healthcare interventions for each segment. We aimed to apply a data-driven, healthcare utilization-based clustering analysis to segment a regional health system patient population and validate its discriminative ability on 4-year longitudinal healthcare utilization and mortality data.MethodsWe extracted data from the Singapore Health Services Electronic Health Intelligence System, an electronic medical record database that included healthcare utilization (inpatient admissions, specialist outpatient clinic visits, emergency department visits, and primary care clinic visits), mortality, diseases, and demographics for all adult Singapore residents who resided in and had a healthcare encounter with our regional health system in 2012. Hierarchical clustering analysis (Ward’s linkage) and K-means cluster analysis using age and healthcare utilization data in 2012 were applied to segment the selected population. These segments were compared using their demographics (other than age) and morbidities in 2012, and longitudinal healthcare utilization and mortality from 2013–2016.ResultsAmong 146,999 subjects, five distinct patient segments “Young, healthy”; “Middle age, healthy”; “Stable, chronic disease”; “Complicated chronic disease” and “Frequent admitters” were identified. Healthcare utilization patterns in 2012, morbidity patterns and demographics differed significantly across all segments. The “Frequent admitters” segment had the smallest number of patients (1.79% of the population) but consumed 69% of inpatient admissions, 77% of specialist outpatient visits, 54% of emergency department visits, and 23% of primary care clinic visits in 2012. 11.5% and 31.2% of this segment has end stage renal failure and malignancy respectively. The validity of cluster-analysis derived segments is supported by discriminative ability for longitudinal healthcare utilization and mortality from 2013–2016. Incident rate ratios for healthcare utilization and Cox hazards ratio for mortality increased as patient segments increased in complexity. Patients in the “Frequent admitters” segment accounted for a disproportionate healthcare utilization and 8.16 times higher mortality rate.ConclusionOur data-driven clustering analysis on a general patient population in Singapore identified five patient segments with distinct longitudinal healthcare utilization patterns and mortality risk to provide an evidence-based segmentation of a regional health system’s healthcare needs.

Healthcare utilization in older patients using personal emergency response systems: an analysis of electronic health records and medical alert data

BackgroundPersonal Emergency Response Systems (PERS) are traditionally used as fall alert systems for older adults, a population that contributes an overwhelming proportion of healthcare costs in the United States. Previous studies focused mainly on qualitative evaluations of PERS without a longitudinal quantitative evaluation of healthcare utilization in users. To address this gap and better understand the needs of older patients on PERS, we analyzed longitudinal healthcare utilization trends in patients using PERS through the home care management service of a large healthcare organization.MethodsRetrospective, longitudinal analyses of healthcare and PERS utilization records of older patients over a 5-years period from 2011–2015. The primary outcome was to characterize the healthcare utilization of PERS patients. This outcome was assessed by 30-, 90-, and 180-day readmission rates, frequency of principal admitting diagnoses, and prevalence of conditions leading to potentially avoidable admissions based on Centers for Medicare and Medicaid Services classification criteria.ResultsThe overall 30-day readmission rate was 14.2%, 90-days readmission rate was 34.4%, and 180-days readmission rate was 42.2%. While 30-day readmission rates did not increase significantly (p = 0.16) over the study period, 90-days (p = 0.03) and 180-days (p = 0.04) readmission rates did increase significantly. The top 5 most frequent principal diagnoses for inpatient admissions included congestive heart failure (5.7%), chronic obstructive pulmonary disease (4.6%), dysrhythmias (4.3%), septicemia (4.1%), and pneumonia (4.1%). Additionally, 21% of all admissions were due to conditions leading to potentially avoidable admissions in either institutional or non-institutional settings (16% in institutional settings only).ConclusionsChronic medical conditions account for the majority of healthcare utilization in older patients using PERS. Results suggest that PERS data combined with electronic medical records data can provide useful insights that can be used to improve health outcomes in older patients.

Assessing Adverse Events of Postprostatectomy Radiation Therapy for Prostate Cancer: Evaluation of Outcomes in the Regione Emilia-Romagna, Italy

Although the likelihood of radiation-related adverse events influences treatment decisions regarding radiation therapy after prostatectomy for eligible patients, the data available to inform decisions are limited. This study was designed to evaluate the genitourinary, gastrointestinal, and sexual adverse events associated with postprostatectomy radiation therapy and to assess the influence of radiation timing on the risk of adverse events. The Regione Emilia-Romagna Italian Longitudinal Health Care Utilization Database was queried to identify a cohort of men who received radical prostatectomy for prostate cancer during 2003 to 2009, including patients who received postprostatectomy radiation therapy. Patients with prior radiation therapy were excluded. Outcome measures were genitourinary, gastrointestinal, and sexual adverse events after prostatectomy. Rates of adverse events were compared between the cohorts who did and did not receive postoperative radiation therapy. Multivariable Cox proportional hazards models were developed for each class of adverse events, including models with radiation therapy as a time-varying covariate. A total of 9876 men were included in the analyses: 2176 (22%) who received radiation therapy and 7700 (78%) treated with prostatectomy alone. In multivariable Cox proportional hazards models, the additional exposure to radiation therapy after prostatectomy was associated with increased rates of gastrointestinal (rate ratio [RR] 1.81; 95% confidence interval [CI] 1.44-2.27; P<.001) and urinary nonincontinence events (RR 1.83; 95% CI 1.83-2.80; P<.001) but not urinary incontinence events or erectile dysfunction. The addition of the time from prostatectomy to radiation therapy interaction term was not significant for any of the adverse event outcomes (P>.1 for all outcomes). Radiation therapy after prostatectomy is associated with an increase in gastrointestinal and genitourinary adverse events. However, the timing of radiation therapy did not influence the risk of radiation therapy-associated adverse events in this cohort, which contradicts the commonly held clinical tenet that delaying radiation therapy reduces the risk of adverse events.

Partner violence and health among HIV-infected jail detainees.

Little is known about the association of intimate partner violence (IPV) with specific HIV-treatment outcomes, especially among criminal justice (CJ) populations who are disproportionately affected by IPV, HIV, mental, and substance use disorders (SUDs) and are at high risk of poor post-release continuity of care. Mixed methods were used to describe the prevalence, severity, and correlates of lifetime IPV exposure among HIV-infected jail detainees enrolled in a novel jail-release demonstration project in Connecticut. Additionally, the effect of IPV on HIV treatment outcomes and longitudinal healthcare utilization was examined. Structured baseline surveys defined 49 percent of 84 participants as having significant IPV exposure, which was associated with female gender, longer duration since HIV diagnosis, suicidal ideation, having higher alcohol use severity, having experienced other forms of childhood and adulthood abuse, and homo/bisexual orientation. IPV was not directly correlated with HIV healthcare utilization or treatment outcomes. In-depth qualitative interviews with 20 surveyed participants, however, confirmed that IPV was associated with disengagement from HIV care especially in the context of overlapping vulnerabilities, including transitioning from CJ to community settings, having untreated mental disorders, and actively using drugs or alcohol at the time of incarceration. Post-release interventions for HIV-infected CJ populations should minimally integrate HIV secondary prevention with violence reduction and treatment for SUDs.

Complications of Postprostatectomy Radiation Therapy for Prostate Cancer: Outcomes From Longitudinal Health Care Utilization Database of the Regione Emilia-Romagna, Italy

Complications of Postprostatectomy Radiation Therapy for Prostate Cancer: Outcomes From Longitudinal Health Care Utilization Database of the Regione Emilia-Romagna, Italy

Long term healthcare costs of infants who survived neonatal necrotizing enterocolitis: a retrospective longitudinal study among infants enrolled in Texas Medicaid.

BackgroundInfants who survive advanced necrotizing enterocolitis (NEC) at the time of birth are at increased risk of having poor long term physiological and neurodevelopmental growth. The economic implications of the long term morbidity in these children have not been studied to date. This paper compares the long term healthcare costs beyond the initial hospitalization period incurred by medical and surgical NEC survivors with that of matched controls without a diagnosis of NEC during birth hospitalization.MethodsThe longitudinal healthcare utilization claim files of infants born between January 2002 and December 2003 and enrolled in the Texas Medicaid fee-for-service program were used for this research. Propensity scoring was used to match infants diagnosed with NEC during birth hospitalization to infants without a diagnosis of NEC on the basis of gender, race, prematurity, extremely low birth weight status and presence of any major birth defects. The Medicaid paid all-inclusive healthcare costs for the period from 6 months to 3 years of age among children in the medical NEC, surgical NEC and matched control groups were evaluated descriptively, and in a generalized linear regression framework in order to model the impact of NEC over time and by birth weight.ResultsTwo hundred fifty NEC survivors (73 with surgical NEC) and 2,909 matched controls were available for follow-up. Medical NEC infants incurred significantly higher healthcare costs than matched controls between 6–12 months of age (mean incremental cost = US$ 5,112 per infant). No significant difference in healthcare costs between medical NEC infants and matched controls was seen after 12 months. Surgical NEC survivors incurred healthcare costs that were consistently higher than that of matched controls through 36 months of age. The mean incremental healthcare costs of surgical NEC infants compared to matched controls between 6–12, 12–24 and 24–36 months of age were US$ 18,274, 14,067 (p < 0.01) and 8,501 (p = 0.06) per infant per six month period, respectively. These incremental costs were found to vary between sub-groups of infants born with birth weight < 1,000g versus ≥ 1,000g (p < 0.05).ConclusionsThe all-inclusive healthcare costs of surgical NEC survivors continued to be substantially higher than that of matched controls through the early childhood development period. These results can have important treatment and policy implications. Further research in this topic is needed.

Understanding secondary databases: a commentary on “Sources of bias for health state characteristics in secondary databases”

Understanding secondary databases: a commentary on “Sources of bias for health state characteristics in secondary databases”

Log-Linear Modeling with the Negative Multinomial Distribution

We develop a negative multinomial sampling plan in which observed cell counts are positively correlated. We show that maximum likelihood estimates of cell means are the same as those found under independent Poisson sampling. There is no maximum likelihood estimate for the shape parameter in general. We propose an estimate of the shape parameter based on the mean and quantiles of Pearson's chi-squared statistic. These techniques are applied to models of cancer incidence for three cities in Ohio and longitudinal health care utilization by a group of senior citizens.