Assessing the ability of comorbidity indexes to capture comorbid disease in the inpatient rehabilitation burn injury population

Long term mortality in burn injury survivors: A matched cohort study

BACKGROUND

Survivors of burn injuries may be at risk of early death. This study describes the mortality of burn survivors in comparison with two matched cohorts.

METHODS

This retrospective cohort study compared adults admitted with a burn injury from 2009 to 2019 with two matched cohorts; one from the general population and one with a diagnosis of acute pancreatitis. Patients were excluded from analysis if they died during hospital admission or within 90 days of hospital discharge. Cox proportional hazards models were used to explore differences between cohorts and variables associated with mortality.

RESULTS

7,147 burns patients were matched with 6,810 pancreatitis patients and 28,184 individuals from the general population. Patients with a burn injury had an increased risk of death when compared to the general population (HR 2.46, 95 % CI 2.28,2.66, p < 0.001) and those with acute pancreatitis (HR 1.28, 95 % CI 1.17,1.40, p < 0.001). Socioeconomic deprivation, increasing comorbidity and specific comorbidities such as alcohol, drug abuse and depression were also associated with increased mortality.

CONCLUSION

Survivors of burn injury are at increased risk of mortality compared to individuals matched on sex, age and socioeconomic deprivation in both the general population and with a hospital admission due to acute pancreatitis.

Capture rates of comorbidity measures at inpatient rehabilitation facilities after a stroke or brain injury

BACKGROUND

Comorbidity indices have been used to represent the overall medical complexity of patient populations in clinical research; however, it is not known how well they capture the comorbidities of patients with a stroke or brain injury admitted to inpatient rehabilitation facilities (IRFs).

OBJECTIVE

To determine how well commonly used comorbidity indices capture the comorbidities of patients admitted to IRFs after a stroke or brain injury.

DESIGN

Cross-sectional, retrospective study.

SETTING

IRFs nationwide.

PARTICIPANTS

Adults from four impairment groups: (1) hemorrhagic stroke, (2) ischemic stroke, (3) nontraumatic brain injury (NTBI), and (4) traumatic brain injury (TBI).

MAIN OUTCOME MEASURES

International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes were extracted from the Uniform Data System for Medical Rehabilitation (UDSMR) for IRF discharges from October 1, 2015 to December 31, 2017. The percentage of discharges captured by Deyo-Charlson, Elixhauser, and Centers for Medicare and Medicaid Services (CMS) tiers was determined, as was the percentage of comorbidities captured. These measures were also compared with respect to their ability to capture chronic medical complexity by examining the percentage of codes captured after removal of codes deemed to represent hospital complications or sequela of the admission diagnosis.

RESULTS

The percentage of discharges without at least one ICD-10-CM code captured by any index ranged from 0.3%-3.8%. The percentage of comorbidities with a prevalence exceeding 1% captured by at least one index ranged from 37.1%-43.6%. Chronic comorbidities were most likely to be captured by Elixhauser (40.7%-44.4%), followed by Deyo-Charlson (7.8%-9.6%), then CMS tiers (4.5%-6.9%). Existing comorbidity measures capture most IRF discharges related to a brain injury or stroke, whereas most medical comorbidities escape representation. Several common, functionally relevant diagnoses were not captured.

CONCLUSION

The use of comorbidity indices in the IRF neurologic injury population should account for the fact that these measures miss several common, important comorbidities.

Assessing the Ability of Comorbidity Indexes to Capture Comorbid Disease in the Inpatient Rehabilitation Spinal Cord Injury Population

OBJECTIVE

To examine whether commonly used comorbidity indexes (Deyo-Charlson comorbidity index, Elixhauser comorbidity index, the Centers for Medicare and Medicaid Services [CMS] comorbidity tiers) capture comorbidities in the acute traumatic and nontraumatic SCI inpatient rehabilitation population.

DESIGN

Retrospective cross-sectional study.

PARTICIPANTS

Data were obtained from the Uniform Data System for Medical Rehabilitation from October 1, 2015 to December 31, 2017 for adults with spinal cord injury (SCI) (Medicare-established Impairment Group Codes 04.110-04.230, 14.1, 14.3). This study included SCI discharges (N=66,235) from 833 inpatient rehabilitation facilities.

MAIN OUTCOME MEASURES

International Classification of Diseases-10th Revision-Clinical Modifications (ICD-10-CM) codes were used to assess 3 comorbidity indexes (Deyo-Charlson comorbidity index, Elixhauser comorbidity index, CMS comorbidity tiers). The comorbidity codes that occurred with >1% frequency were reported. The percentages of discharges for which no comorbidities were captured by each comorbidity index were calculated.

RESULTS

Of the total study population, 39,285 (59.3%) were men and 11,476 (17.3%) were tetraplegic. The mean number of comorbidities was 14.7. There were 13,939 distinct ICD-10-CM comorbidity codes. There were 237 comorbidities that occurred with >1% frequency. The Deyo-Charlson comorbidity index, Elixhauser comorbidity index, and the CMS tiers did not capture comorbidities of 58.4% (95% confidence interval, 58.08%-58.84%), 29.4% (29.07%-29.76%), and 66.1% (65.73%-66.46%) of the discharges in our study, respectively, and 28.8% (28.42%-29.11%) of the discharges did not have any comorbidities captured by any of the comorbidity indexes.

CONCLUSION

Commonly used comorbidity indexes do not reflect the extent of comorbid disease in the SCI rehabilitation population. This work suggests that alternative measures may be needed to capture the complexity of this population.

Functional status predicts acute care readmission in the traumatic spinal cord injury population

CONTEXT/OBJECTIVE

Acute care readmission has been identified as an important marker of healthcare quality. Most previous models assessing risk prediction of readmission incorporate variables for medical comorbidity. We hypothesized that functional status is a more robust predictor of readmission in the spinal cord injury population than medical comorbidities.

DESIGN

Retrospective cross-sectional analysis.

SETTING

Inpatient rehabilitation facilities, Uniform Data System for Medical Rehabilitation data from 2002 to 2012.

PARTICIPANTS

traumatic spinal cord injury patients.

OUTCOME MEASURES

A logistic regression model for predicting acute care readmission based on demographic variables and functional status (Functional Model) was compared with models incorporating demographics, functional status, and medical comorbidities (Functional-Plus) or models including demographics and medical comorbidities (Demographic-Comorbidity). The primary outcomes were 3- and 30-day readmission, and the primary measure of model performance was the c-statistic.

RESULTS

There were a total of 68,395 patients with 1,469 (2.15%) readmitted at 3 days and 7,081 (10.35%) readmitted at 30 days. The c-statistics for the Functional Model were 0.703 and 0.654 for 3 and 30 days. The Functional Model outperformed Demographic-Comorbidity models at 3 days (c-statistic difference: 0.066-0.096) and outperformed two of the three Demographic-Comorbidity models at 30 days (c-statistic difference: 0.029-0.056). The Functional-Plus models exhibited negligible improvements (0.002-0.010) in model performance compared to the Functional models.

CONCLUSION

Readmissions are used as a marker of hospital performance. Function-based readmission models in the spinal cord injury population outperform models incorporating medical comorbidities. Readmission risk models for this population would benefit from the inclusion of functional status.

Burn Injuries and Their Impact on Cognitive-Communication Skills in the Inpatient Rehabilitation Setting

The prevalence and extent of cognitive-communication disorders and factors that have impact on outcomes are examined in the burn population within an inpatient rehabilitation facility. A retrospective data analysis was conducted on adults diagnosed with burn injury (n = 144). Descriptive statistics were used to identify the prevalence of cognitive-communication deficits on admission and discharge. The main outcomes were cognitive-communication ratings on discharge from inpatient rehabilitation as measured by the memory and problem-solving domains of the Functional Independence Measure (FIM) and composite score of the Functional Communication Measure (FCM). Medical, demographic and rehabilitation predictors of the main outcomes were assessed using regression analyses. On admission to inpatient rehabilitation, 79% of the total population presented with cognitive-communication impairments, and of them, 27% presented with persistent deficits on discharge. Admission FIM memory score, marital status, and age were significant predictors of discharge FIM memory score. Admission FIM problem-solving score, age, marital status, and prehospital living-with were significant predictors of discharge FIM problem-solving score. Admission FCM score and age were significant predictors of discharge FCM cognitive score. Persons with burn injuries are at risk for cognitive-communication impairments, which may persist after inpatient rehabilitation. FIM data obtained on admission can be used as a screening tool to identify these at-risk patients. Future work is needed to assess the efficacy of speech-language pathologist intervention for cognitive-communication deficits within the burn injury population.

Acute Kidney Injury in Burn Patients: Clinically Significant Over the Initial Hospitalization and 1 Year After Injury: An Original Retrospective Cohort Study

OBJECTIVE

To examine the development of acute kidney injury (AKI) after burn injury as an independent risk factor for increased morbidity and mortality over initial hospitalization and 1-year follow-up.

BACKGROUND

Variability in fluid resuscitation and difficulty recognizing early sepsis are major barriers to preventing AKI after burn injury. Expanding our understanding of the burden AKI has on the clinical course of burn patients would highlight the need for standardized protocols.

METHODS

We queried the Healthcare Cost and Utilization Project State Inpatient Databases in the states of Florida and New York during the years 2009 to 2013 for patients over age 18 hospitalized with a primary diagnosis of burn injury using ICD-9 codes. We identified and grouped 18,155 patients, including 1476 with burns >20% total body surface area, by presence of AKI. Outcomes were compared in these cohorts via univariate analysis and multivariate logistic regression models.

RESULTS

During initial hospitalization, AKI was associated with increased pulmonary failure, mechanical ventilation, pneumonia, myocardial infarction, length of stay, cost, and mortality, and also a lower likelihood of being discharged home. One year after injury, AKI was associated with development of chronic kidney disease, conversion to chronic dialysis, hospital readmission, and long-term mortality.

CONCLUSIONS

AKI is associated with a profound and severe increase in morbidity and mortality in burn patients during initial hospitalization and up to 1 year after injury. Consensus protocols for initial burn resuscitation and early sepsis recognition and treatment are crucial to avoid the consequences of AKI after burn injury.

Comparing Comorbidity Indices to Predict Post-Acute Rehabilitation Outcomes in Older Adults

OBJECTIVE

Compare 5 comorbidity indices to predict community discharge and functional status following post-acute rehabilitation.

DESIGN

This was a retrospective study of Medicare beneficiaries with stroke, lower-extremity fracture, and joint replacement discharged from inpatient rehabilitation in 2011 (N = 105,275). Community discharge and self-care, mobility, and cognitive function were compared using the Charlson, Elixhauser, Tier, Functional Comorbidity, and Hierarchical Condition Category comorbidity indices.

RESULTS

Of the patients, 64.4% were female, and 84.6% were non-Hispanic white. Mean age was 79.3 (SD, 7.5) years. Base regression models including sociodemographic and clinical variables explained 56.6%, 42.2%, and 23.0% of the variance (R) for discharge self-care; 47.4%, 30.9%, and 18.6% for mobility; and 62.0%, 55.3%, and 37.3% for cognition across the 3 impairment groups. R values for self-care, mobility, and cognition increased by 0.2% to 3.3% when the comorbidity indices were added to the models. The base model C statistics for community discharge were 0.58 (stroke), 0.61 (fracture), and 0.62 (joint replacement). The C statistics increased more than 25% with the addition of discharge functional status to the base model. Adding the comorbidity indices individually to the base model resulted in C-statistic increases of 1% to 2%.

CONCLUSION

Comorbidity indices were poor predictors of community discharge and functional status in Medicare beneficiaries receiving inpatient rehabilitation.