Severe Case Mix Research Articles

Factors Associated with Acute Hospitalizations and Mortality of Older Adults in Long-Term Care Facilities and Long-Term Care Hospitals: A Population-Based, Pubic-Insurance Big-Data Analysis

Purpose: This study examined individual, institutional, and regional factors associated with 90-day acute hospitalizations and 1-year mortality among older people admitted to long-term care facilities (LTCFs) and long-term care hospitals (LTCH) in Korea.Methods: We analyzed the National Health Insurance Services (NHIS) Elderly Cohort Database linked with regional statistics. The sample included 13,839 LTCF residents and 23,962 LTCH patients. Multi-level logistic regression analyses were conducted.Results: The risk for 90-day acute hospital admission was positively associated with being male and having comorbidities among both LTCF residents and LTCH patients. Being 80+ years old and having a severe case-mix (LTCF grade 1/LTCH groups A1 & 2) were positively associated with acute hospitalizations among LTCF residents, but the relationships were negative among LTCH patients. People in urban LTCFs and/or those in facilities located in regions with a higher physician supply had lower acute hospitalizations. The risk for 1-year mortality after LTCF or LTCH admission was positively associated with being an old male, having a severe case-mix, and comorbidities. Among institutional factors, public ownership for LTCFs and being a larger size for LTCHs were negatively associated with mortality.Conclusion: This health and long-term care big data analysis showed various factors influenced adverse health outcomes among older Koreans receiving institutionalized long-term care, and the patterns of the relationships were different for LTCFs and LTCHs. Further investigations are needed into the mechanisms underlying the complex dynamics among the multi-level determinants of acute care utilization and mortality by institution type.

Abstract 13608: Center Variation in Home Time Following Acute Ischemic Stroke

Background: Stroke survivors have identified that home time is a high priority outcome, but there are limited data on factors associated with time at home following stroke as well as the degree to which home time varies among discharging hospitals. Methods: PROSPER is a PCORI-funded program designed with stroke survivors to evaluate post-stroke therapies and outcomes. We linked data for patients >65 years old who were enrolled in the GWTG-Stroke Registry to Medicare claims to ascertain home time, defined as time spent alive and out of a hospital or skilled nursing facility, at 90 days and 1 year after discharge for ischemic stroke. We used generalized mixed models with random effects to estimate adjusted mean home time for each hospital, accounting for patient characteristics. We then used linear regression to assess hospital factors associated with risk-adjusted home time. Results: From 2007-2011, 156,869 ischemic stroke patients at 1417 hospitals were linked to Medicare claims. Home time varied among hospitals, with overall unadjusted median home time (IQR) of 59.5 days (55.7-63.2) over the first 90 days and 270 days (256.0-281.1) over the first year. Hospital factors associated with more home time over 90 days included higher annual stroke volume; South, West, or Midwest geographic regions (vs. Northeast); and rural location (Table). Similar patterns were observed at 1 year. Compared with patients in the highest hospital home time quartile, patients in the lowest were older, more likely to be female, had more comorbidities, and had more severe strokes by NIHSS. Home time variation decreased after adjustment, with a median of 59.3 days (57.4-61.4) over 90 days and 270 days (266.3-274.2) over 1 year. Conclusions: In a population of older ischemic stroke survivors, home time after discharge varies by hospital stroke volume, severity case mix, and region. In adjusted analyses, hospital stroke volume and rural location were associated with more days at home following stroke.

Outcome of appendicectomy in children performed in paediatric surgery units compared with general surgery units

Appendicectomy for acute appendicitis in children may be performed in specialist centres by paediatric surgeons or in general surgery units. Service provision and outcome of appendicectomy in children may differ between such units. This multicentre observational study included all children (aged less than 16 years) who had an appendicectomy at either a paediatric surgery unit or general surgery unit. The primary outcome was normal appendicectomy rate (NAR). Secondary outcomes included 30-day adverse events, use of ultrasound imaging and laparoscopy, and consultant involvement in procedures. Appendicectomies performed in 19 paediatric surgery units (242 children) and 54 general surgery units (461 children) were included. Children treated in paediatric surgery units were younger and more likely to have a preoperative ultrasound examination, a laparoscopic procedure, a consultant present at the procedure, and histologically advanced appendicitis than children treated in general surgery units. The unadjusted NAR was significantly lower in paediatric surgery units (odds ratio (OR) 0.37, 95 per cent confidence interval 0.23 to 0.59; P < 0.001), and the difference persisted after adjusting for age, sex and use of preoperative ultrasound imaging (OR 0.34, 0.21 to 0.57; P < 0.001). Female sex and preoperative ultrasonography, but not age, were significantly associated with normal appendicectomy in general surgery units but not in paediatric surgery units in this adjusted model. The unadjusted 30-day adverse event rate was higher in paediatric surgery units than in general surgery units (OR 1.90, 1.18 to 3.06; P = 0.011). When adjusted for case mix and consultant presence at surgery, no statistically significant relationship between centre type and 30-day adverse event rate existed (OR 1.59, 0.93 to 2.73; P = 0.091). The NAR in general surgery units was over twice that in paediatric surgery units. Despite a more severe case mix, paediatric surgery units had a similar 30-day adverse event rate to general surgery units. Service provision differs between paediatric and general surgery units.

Rehospitalization in the First Year of Traumatic Spinal Cord Injury After Discharge From Medical Rehabilitation

ObjectiveTo determine rates of rehospitalization among discharged rehabilitation patients with traumatic spinal cord injury (SCI) in the first 12 months postinjury, and to identify factors associated with rehospitalization. DesignProspective observational cohort study. SettingSix geographically dispersed rehabilitation centers in the U.S. ParticipantsConsecutively enrolled individuals with new traumatic SCI (N=951), who were discharged from participating rehabilitation centers and participated in a 1-year follow-up survey. InterventionsNot applicable. Main Outcome MeasuresOccurrence of postrehabilitation rehospitalization within 1 year of injury, length of rehospitalization stays, and causes of rehospitalizations. ResultsMore than one third (36.2%) of participants were rehospitalized at least once in the 12-month follow-up period; 12.5% were rehospitalized at least twice. The average number of rehospitalizations among those rehospitalized at least once was 1.37 times, with an average length of stay (LOS) of 15.5 days across all rehospitalization episodes. The 3 most common health conditions associated with rehospitalization were those related to the genitourinary system (eg, urinary tract infection), respiratory system (eg, pneumonia), and skin and subcutaneous tissue (eg, pressure ulcer). Being a woman (95% confidence interval [CI], 1.034–2.279), having Medicaid as the main payer (95% CI, 1.303–2.936), and more severe case mix were associated with increased odds of rehospitalization. Those who had more intensive physical therapy (95% CI, .960–.981) had lower odds of rehospitalization. Some center-to-center variation in rehospitalization rates remained unexplained after case mix and practice differences were considered. The 6 SCI rehabilitation centers varied nearly 2-fold in rates at which their former SCI patients were rehospitalized—from 27.8% to 50%. Center-to-center variation diminished when patient case mix was considered. ConclusionsCompared with earlier studies, rehospitalization rates among individuals with SCI in the first postinjury year remain high and vary by level and completeness of injury. Rehospitalization risk was associated with younger age, being a woman, unemployment and retirement, and Medicaid coverage. Those who had more intensive physical therapy had lower odds of rehospitalization. Future studies should examine center-to-center variations in rehospitalization rates and availability of patient education and community resources.

819 The Effect of Neonatal Unit Care Level and Volume on Mortality, Discharge, and Transfer: Evidence from English Hospitals

Backgrounds/aims: In the US a low volume of admissions is associated with higher mortality in very low birth weight (VLBW) infants leading to recommendations for centralisation of neonatal services. We...

Progression of liver cirrhosis to HCC: an application of hidden Markov model

BackgroundHealth service databases of administrative type can be a useful tool for the study of progression of a disease, but the data reported in such sources could be affected by misclassifications of some patients' real disease states at the time. Aim of this work was to estimate the transition probabilities through the different degenerative phases of liver cirrhosis using health service databases.MethodsWe employed a hidden Markov model to determine the transition probabilities between two states, and of misclassification. The covariates inserted in the model were sex, age, the presence of comorbidities correlated with alcohol abuse, the presence of diagnosis codes indicating hepatitis C virus infection, and the Charlson Index. The analysis was conducted in patients presumed to have suffered the onset of cirrhosis in 2000, observing the disease evolution and, if applicable, death up to the end of the year 2006.ResultsThe incidence of hepatocellular carcinoma (HCC) in cirrhotic patients was 1.5% per year. The probability of developing HCC is higher in males (OR = 2.217) and patients over 65 (OR = 1.547); over 65-year-olds have a greater probability of death both while still suffering from cirrhosis (OR = 2.379) and if they have developed HCC (OR = 1.410). A more severe casemix affects the transition from HCC to death (OR = 1.714). The probability of misclassifying subjects with HCC as exclusively affected by liver cirrhosis is 14.08%.ConclusionsThe hidden Markov model allowing for misclassification is well suited to analyses of health service databases, since it is able to capture bias due to the fact that the quality and accuracy of the available information are not always optimal. The probability of evolution of a cirrhotic subject to HCC depends on sex and age class, while hepatitis C virus infection and comorbidities correlated with alcohol abuse do not seem to have an influence.

Modeling Probability-Based Injury Severity Scores in Logistic Regression Models: The Logit Transformation Should Be Used

The International Classification of Disease Injury Severity Score (ICISS) and the Trauma Registry Abbreviated Injury Scale Score (TRAIS) are trauma injury severity scores based on probabilities of survival. They are widely used in logistic regression models as raw probability scores to predict the logit of mortality. The aim of this study was to evaluate whether these severity indicators would offer a more accurate prediction of mortality if they were used with a logit transformation. Analyses were based on 25,111 patients from the trauma registries of the four Level I trauma centers in the province of Quebec, Canada, abstracted between 1998 and 2005. The ICISS and TRAIS were calculated using survival proportions from the National Trauma Data Bank. The performance of the ICISS and TRAIS in their widely used form, proportions varying from 0 to 1, was compared with a logit transformation of the scores in logistic regression models predicting in-hospital mortality. Calibration was assessed with the Hosmer-Lemeshow statistic. Neither the ICISS nor the TRAIS had a linear relation with the logit of mortality. A logit transformation of these scores led to a near-linear association and consequently improved model calibration. The Hosmer-Lemeshow statistic was 68 (35-192) and 69 (41-120) with the logit transformation compared with 272 (227-339) and 204 (166-266) with no transformation, for the ICISS and TRAIS, respectively. In logistic regression models predicting mortality, the ICISS and TRAIS should be used with a logit transformation. This study has direct implications for improving the validity of analyses requiring control for injury severity case mix.

Statistical Validation of the Revised Trauma Score

To validate the accuracy of the Revised Trauma Score (RTS) and its components for predicting in-hospital mortality. Analyses were based on 22,388 patients from the trauma registries of three urban Level I trauma centers in the province of Quebec, Canada. The accuracy of RTS coded variables for the Glasgow Coma Score (GCSc), Systolic Blood Pressure (SBPc), and Respiratory Rate (RRc) for predicting mortality was evaluated in logistic regression models with measures of discrimination and model fit and compared with Fractional Polynomial (FP) transformations of each component. RTS coded variables were associated with sparse data distributions and did not accurately represent the relation of GCS, SBP, and RR to mortality. FP models were always associated with significantly better discrimination (all p < 0.00001) and model fit. Survival probability estimates generated by the model with FP transformations were significantly different to those generated by the model with RTS-coded variables. The RTS in its present form does not accurately describe the relation of GCS, SBP, and RR to mortality. FP transformation would improve the accuracy of predicted survival probabilities used for performance evaluation and may improve control of confounding caused by of physiologic severity case mix in trauma research.

Admissions to intensive care units from emergency departments: a descriptive study

Objectives: To describe the case mix, activity, and outcome for admissions to intensive care units (ICUs) from emergency departments (EDs). Design: An observational study using data from a high quality...

Variations in the treatment culture of nursing homes and responses to regulations to reduce drug use.

The study examined the relationship between treatment cultures of nursing homes and their responses to regulations to reduce use of psychotropic drugs mandated by the 1987 Omnibus Budget Reconciliation ACT: The authors hypothesized that reduction in use of antipsychotic drugs was more likely to occur in homes with a resident-centered culture emphasizing psychosocial care, avoidance of psychotropic drugs, pharmacist feedback, and involvement of mental health workers. The authors also predicted greater reductions in drug use in facilities with a less severe case mix and better capacity for change. Data were collected in a stratified random sample of 16 skilled nursing facilities in Wisconsin. Participants included 1,181 residents in the baseline study and 1,650 residents in the follow-up study. Treatment culture was measured with a questionnaire for assessing nurses' beliefs and philosophies of care and their interactions with pharmacists and mental health workers. No significant change was observed in the use of benzodiazepines, antidepressants, or polymedicine (two or more psychotropic medications). However, use of antipsychotic drugs decreased significantly, from 24 percent to 16 percent. The change in use varied dramatically across facilities, from an 85 percent reduction to a 19 percent increase. Findings also revealed significant variability in treatment cultures. Greater reductions in use of antipsychotic drugs were found in facilities with a resident-centered culture, a less severe case mix, and a higher nurse-to-resident staffing ratio. Future policy and quality improvement efforts must address treatment cultures, staffing, and other organizational barriers to nursing home reform.

Inpatient treatment for substance abuse patients with psychiatric disorders: a national study of determinants of readmission.

This study examined the patient case mix and program determinants of 6-month readmission rates and early treatment dropout for 7,711 VA inpatients with both substance abuse and major psychiatric disorders treated in one of 104 substance abuse programs. Patients were treated in one of three types of inpatient programs: explicitly designed dual diagnosis specialty programs, substance abuse programs with a dual diagnosis psychotherapy group or standard substance abuse programs. Dual diagnosis specialty programs differed from regular substance abuse programs in that they had a more severe case mix, a higher 180-day readmission rate, greater dual diagnosis treatment orientation, used more psychotropic medication, had longer lengths of stay, had greater tolerance of relapse and medication noncompliance, and a higher rate of psychiatric aftercare in the 30 days after discharged. Programs with less severe case mix, longer intended and actual length of stay, lower 7-day dropout rates, greater tolerance of problem behavior, 12-step groups, and higher immediate postdischarge utilization of outpatient mental health treatment lower 180-day readmission rates. Programs with less severe patient case mix, more use of psychotropic medications but less of methadone and antabuse, less varied and diverse treatment activities, and low use of patient-led groups had lower dropout rates.

The impact of intra-DRG severity of illness on hospital profitability: implications for payment reform.

We examined the relationship between variations in intra-DRG severity of illness classifications and hospital profitability. Unlike in previous studies, we created a direct hospital-level measure of severity, formed from MedisGroup severity scores. We estimated separate regression equations for total margin, operating margin, net revenue per admission, and expense per admission. We examined data for 201 Pennsylvania hospitals and found that hospital profits were inversely related to the severity of illness index. Expense per admission was positively related to severity; however the relationship between severity and net revenue per admission was not significant. The results suggest that hospitals with a more severe case mix may not recover the full costs of providing services. Thus payment reform should include adjustments for severity of illness.