Effect of comorbidity on injury outcomes: a review of existing indices

Decline in Explanatory Power of Trauma Mortality Models With Age: Varying Contribution of Glasgow Coma Scale, Injury Severity Score, Comorbidities, and Frailty

INTRODUCTION

Adjusting for confounding variables is critical for objective comparison of outcomes. The explanatory power of variables used in adjusted models for injury and their relative utility across age groups has not been well-defined. This study aimed to assess the explanatory power of covariates commonly adjusted in injury research and their relative performance across age groups.

METHODS

Inpatients 18-100 y (2017-2022) were selected from 90 hospital trauma registries. Patients were grouped into sequential 5-y age blocks. Mortality was defined as the proportion of patients "expired + hospice". Dominance analysis was used to determine the average contribution (McFadden's R2) for covariates commonly included in multivariable logistic regressions.

RESULTS

Three hundred seventeen-thousand one hundred thirty-six patients were included (51.1% male, mean age: 63, mean injury severity score [ISS]: 9.8, mean Glasgow Coma Scale: 14.3, 93.5% blunt). Total explanatory power (McFadden's R2) for mortality was highest in youngest age group (52.7% in 18-24 group) and decreased with age, with the lowest R2 (19.6%) in 95-100 group. Regardless of age, the Glasgow Coma Scale was the most important covariate (R2 ranging from 9.0% to 20.4%). At age 18-24 y, ISS was a more dominant contributor than Elixhauser Score, but beyond 55 y, Elixhauser Score became more dominant than ISS.

CONCLUSIONS

The explanatory power of adjustment models including common covariates is limited and varies significantly across age groups, decreasing linearly with age. Adjusting for outcomes using these covariates may limit objective comparisons especially for older adults. Additional research is needed to identify covariates that enhance the explanatory power of adjustment models to allow for more objective comparisons across all ages.

Impact of pre-existing medical conditions on mortality in geriatric trauma: a nationwide study in Japan

PURPOSE

To investigate the relationship between pre-existing medical conditions and outcomes in elderly trauma patients in Japan.

METHODS

This multicenter observational study utilized data from the Japan Trauma Data Bank (JTDB) from 2019 to 2020. The primary outcome was in-hospital mortality. Factors associated with in-hospital mortality were identified using multivariate logistic regression analysis, from which adjusted odds ratios (AOR) and 95% confidence intervals (CI) were determined.

RESULTS

Of the participants during the study period, 19,598 patients were included in the analysis. Among the pre-existing medical conditions, moderate or severe liver disease showed the strongest positive association with in-hospital mortality (AOR: 7.087, 95% CI: 3.194-15.722), followed by multiple malignancies (AOR: 3.490, 95% CI: 1.046-11.641), congestive heart failure (AOR: 2.572, 95% CI: 1.920-3.445), and moderate or severe renal disease (AOR: 2.256, 95% CI: 1.584-3.215).

CONCLUSION

Data from JTDB suggests that pre-existing conditions like moderate or severe liver disease, congestive heart failure, and moderate or severe renal disease in elderly trauma patients are positively correlated with in-hospital mortality.

Regional Variation in Outpatient Antibiotic Prescribing for Acute Respiratory Tract Infections in a Commercially Insured Population, United States, 2017

Background

Studies have shown that the Southern United States has higher rates of outpatient antibiotic prescribing rates compared with other regions in the country, but the reasons for this variation are unclear. We aimed to determine whether the regional variability in outpatient antibiotic prescribing for respiratory diagnoses can be explained by differences in prescriber clinical factors found in a commercially insured population.

Methods

We analyzed the 2017 IBM MarketScan Commercial Database of commercially insured individuals aged <65 years. We included visits with acute respiratory tract infection (ARTI) diagnoses from retail clinics, urgent care centers, emergency departments, and physician offices. ARTI diagnoses were categorized based on antibiotic indication. We calculated risk ratios and 95% CIs stratified by ARTI tier and region using log-binomial models controlling for patient age, comorbidities, care setting, prescriber type, and diagnosis.

Results

Of the 14.9 million ARTI visits, 40% received an antibiotic. The South had the highest proportion of visits with an antibiotic prescription (43%), and the West the lowest (34%). ARTI visits in the South are 34% more likely receive an antibiotic for rarely antibiotic-appropriate ARTI visits when compared with the West in multivariable modeling (relative risk, 1.34; 95% CI, 1.33-1.34).

Conclusions

It is likely that higher antibiotic prescribing in the South is in part due to nonclinical factors such as regional differences in clinicians' prescribing habits and patient expectations. There is a need for future studies to define and characterize these factors to better inform regional and local stewardship interventions and achieve greater health equity in antibiotic prescribing.

A Novel Comorbidity Risk Score for Predicting Post-Operative 30-day Complications in Total Shoulder Arthroplasty & Elucidation of Potential Racial Disparities

Background

Efficient and effective preoperative identification of those patients with elevated risk may allow for more cost-effective interventions, accurate bundled payment adjustments, and overall improved patient care. Few comorbidity indices have provided clinical utility and adequate discriminative ability in the setting of complications after shoulder arthroplasty (SA).

Methods

The American College of Surgeons National Surgical Quality Improvement Program database was queried for anatomic and/or reverse SA procedures between 2010 and 2019. A subset of comorbidities were utilized including end-stage renal disease, history of hypertension, chronic obstructive pulmonary disease, functional status, history of bleeding disorder, and disseminated cancer.

Results

A total of 25,927 patients with an average age of 69.2 (standard deviation ±9.5) years were included in the study. Patients with a comorbidity risk score (CRS) at or above 2 were indicated to have at least a 29.6% 30-day postoperative complication rate after undergoing total shoulder arthroplasty, significantly higher than the described average of approximately 15%. The area under receiver operator curve for the novel CRS scoring system was 0.595, indicating fair discriminative ability to predict 30-day postoperative complications after SA. This illustrates a discriminative ability similar to that of the American Society of Anesthesiologists classification (0.584, confidence interval [CI] 0.578-0.589), modified Charlson Comorbidity Index (0.567, CI 0.561-0.573), and modified Frailty Index (0.534, CI 0.529-0.539), each of which are common comorbidity indices used for the National Surgical Quality Improvement Program database. The average CRS for the population was 0.8537 (CI 0.8011-0.8150; P < .05) while that for the Black demographic was 1.08 (CI 1.03-1.13; P < .001). Our results suggest that if the disparity in CRS among races was corrected, the average complication rate would be decreased by 2.0%.

Discussion and Conclusion

A higher CRS score resulted in higher rates of 30-day postoperative complications following SA. Black patients had a higher average CRS than all other races illustrating a racial disparity in comorbidity risk. Although the average complication rate of each race would still be unequal, this could mitigate some of the racial disparities observed and decrease the overall 30-day complication rate in SA. With the rise of bundled payments further increasing the need to preoperatively identify patients at high risk for costly complications, the CRS is based on easily identified, relevant comorbidities that may be an advantageous tool to identify patients at increased risk of complications following SA.

Pharmacists as accessible health care providers: quantifying the opportunity

BACKGROUND: Community pharmacists are well positioned to improve patient access to care, which may assist value-based care programs in reaching patients. While pharmacy accessibility is broadly acknowledged, much of the research supporting accessibility claims is poor quality. OBJECTIVE: To quantify the accessibility of pharmacists in comparison with physicians or qualified health care professionals (QHP) in a commercially insured population. METHODS: IBM MarketScan claims data from 2018 were used for this cross-sectional study. Beneficiaries included in the primary analysis were aged 18-64 years, enrolled with pharmacy benefits in 2018 for 12 months, and had at least 1 valid prescription drug claim or evaluation and management (E&M) code in 2018. Unique pharmacy visits were defined using a 6-day fill window for prescription fill dates, while visits to physicians or other QHP were defined as unique service dates tied to an E&M code. We assessed differences in visit frequency for the full sample, those with multiple chronic conditions (MCC), and "superutilizers" (top 5% based on total cost of care). Our statistical approach included descriptive statistics and the Wilcoxon sign rank test. RESULTS: After applying the inclusion criteria, 11,720,958 beneficiaries were included in the full sample. The MCC cohort contained 13.8% of the total sample (mean [SD] age: 50.8 [10.8]; 908,880 [56.1%] female). Finally, the superutilizers were 57.3% female with an average age of 48.4 years and comprised 5.3% of the total sample. The median number of pharmacy and physician or QHP visits for the full sample were 5 and 3 (P < 0.0001), yielding a pharmacy to physician or QHP visit ratio of 1.7:1. The MCC cohort had a median of 13 pharmacy visits and 7 physician or QHP visits (ratio 1.9:1; P < 0.0001), and the superutilizers had a median of 14 pharmacy visits and 9 physician or QHP visits (ratio 1.6:1; P < 0.0001). CONCLUSIONS: This study found that patients visit their community pharmacies almost twice as often as they visit their physicians or other QHP. Study findings emphasize the accessibility of community pharmacists and highlight the role of community pharmacists in improving patient engagement in all care programs, including value-based care programs. DISCLOSURES: The database infrastructure used for this project was funded by the Department of Epidemiology, University of North Carolina (UNC) Gillings School of Global Public Health; the Cecil G. Sheps Center for Health Services Research, UNC; the CER Strategic Initiative of UNC's Clinical Translational Science Award (UL1TR001111); and the UNC School of Medicine. All authors are employed by the UNC School of Pharmacy. Urick declares consulting fees from Cardinal Health. The other authors have no conflicts of interest to disclose. Portions of this work were previously presented at the AMCP 2021 Virtual, April 12-16, 2021.

Crohn's Disease Increases In-Hospital Lengths of Stay, Medical Complications, and Costs of Care following Primary Total Knee Arthroplasty

The literature has shown an increase in prevalence of Crohn's disease (CD) within the United States alongside a concomitant rise in primary total knee arthroplasty (TKA) procedures. As such, with these parallel increases, orthopaedic surgeons will invariably encounter CD patients requiring TKA. Limited studies exist evaluating the impact of this disease on patients undergoing the procedure; therefore, this study endeavors to determine whether CD patients undergoing primary TKA have higher rates of (1) in-hospital lengths of stay (LOS), (2) medical complications, and (3) episode of care (EOC) costs. To accomplish this, a nationwide database was queried from January 1, 2005 to March 31, 2014 to identify patients undergoing TKA. The study group, patients with CD, was randomly matched to the controls, patients without CD, in a 1:5 ratio after accounting for age, sex, and medical comorbidities associated with CD. Patients consuming corticosteroids were excluded, as they are at risk of higher rates of adverse events following TKA. This query ultimately yielded a total of 96,213 patients, with 16,037 in the study cohort and 80,176 in the control one. The study compared in-hospital (LOS), 90-day medical complications, and day of surgery and total global 90-day EOC costs between CD and non-CD patients undergoing primary TKA. The results found CD patients undergoing primary TKA had significantly longer in-hospital LOS (4- vs. 3 days, p < 0.0001) compared with non-CD patients. CD patients were also found to have significantly higher incidence and odds of 90-day medical complications (25.31 vs. 10.75; odds ratio: 2.05, p < 0.0001) compared with their counterparts. Furthermore, CD patients were found to have significantly higher 90-day EOC costs ($15,401.63 vs. 14,241.15, p < 0.0001) compared with controls. This study demonstrated that, after adjusting for age, sex, and medical comorbidities, patients with CD have prolonged in-hospital LOS, increased medical complications, and higher EOC costs following primary TKA. Therefore, it establishes the importance for orthopaedists to adequately counsel CD patients of the potential complications and outcomes following their procedure.

Australian Injury Comorbidity Indices (AICIs) to predict burden and readmission among hospital-admitted injury patients

BACKGROUND

Existing comorbidity measures predict mortality among general patient populations. Due to the lack of outcome specific and patient-group specific measures, the existing indices are also applied to non-mortality outcomes in injury epidemiology. This study derived indices to capture the association between comorbidity, and burden and readmission outcomes for injury populations.

METHODS

Injury-related hospital admissions data from July 2012 to June 2014 (161,334 patients) for the state of Victoria, Australia were analyzed. Various multivariable regression models were run and results used to derive both binary and weighted indices that quantify the association between comorbidities and length of stay (LOS), hospital costs and readmissions. The new and existing indices were validated internally among patient subgroups, and externally using data from the states of New South Wales and Western Australia.

RESULTS

Twenty-four comorbidities were significantly associated with overnight stay, twenty-seven with LOS, twenty-eight with costs, ten with all-cause and eleven with non-planned 30-day readmissions. The number of and types of comorbidities, and their relative impact were different to the associations established with the existing Charlson Comorbidity Index (CCI) and Elixhauser Comorbidity Measure (ECM). The new indices performed equally well to the long-listed ECM and in certain instances outperformed the CCI.

CONCLUSIONS

The more parsimonious, up to date, outcome and patient-specific indices presented in this study are better suited for use in present injury epidemiology. Their use can be trialed by hospital administrations in resource allocation models and patient classification models in clinical settings.

Developing an Index of Medical Conditions Associated with Outcomes after Moderate-to-Severe Traumatic Brain Injury

Medical conditions co-occurring with traumatic brain injury (TBI) are associated with outcomes, and comorbidity indices such as Charlson and Elixhauser are used in TBI research, but they are not TBI specific. The purpose of this research was to develop an index or indices of medical conditions, identified in acute care after moderate to severe TBI, that are associated with outcomes at rehabilitation discharge. Using the TBI Model Systems National Database, the International Classification of Diseases, Ninth Revision (ICD-9) and Tenth Revision (ICD-10) codes of 8988 participants were converted to Healthcare Cost and Utilization Project (HCUP) diagnostic categories. Poisson regression models were built predicting Disability Rating Scale and Functional Independence Measure Cognitive and Motor subscale scores from HCUP categories after controlling for demographic and injury characteristics. Unweighted, weighted, and anchored indices based on the outcome models predicted 7.5-14.3% of the variance in the observed outcomes. When the indices were applied to a new validation sample of 1613 cases, however, only 2.6-6.6% of the observed outcomes were predicted. Therefore, no models or indices were recommended for future use, but several study findings are highlighted suggesting the importance and the potential for future research in this area.

Risk Factors of Redo Surgery After Unilateral Focused Parathyroidectomy: Conclusions From a Comprehensive Nationwide Database of 13,247 Interventions Over 6 Years

BACKGROUND

Surgical removal of hyperfunctional parathyroid gland is the definitive treatment for primary hyperparathyroidism (pHPT). Postoperative follow-up shows variability in persistent/recurrent disease rate throughout different centers.

OBJECTIVE

To evaluate the incidence of redo surgery after targeted parathyroidectomy for pHPT.

METHODS

We performed a nationwide retrospective cohort study on the "Programme de Medicalisation des Systemes d'Information," the French administrative database that collects information on all healthcare facilities' discharges. We extracted data from 2009 to 2018 for all patients who underwent parathyroidectomy for pHPT between January 2011 to December 2016. The primary outcome was the reoperation rate within 2 years since first surgery. Patients who had a first attempt of surgery within the previous 24 months, familial hyperparathyroidism, multiglandular disease, and renal failure were excluded. Results were adjusted according to sex and the Elixhauser Comorbidity Index. Operative volume thresholds to define high-volume centers were achieved by the Chi-Squared Automatic Interaction Detector method.

RESULTS

In the study period, 13,247 patients (median age 63, F/M=3.6) had a focused parathyroidectomy by open (88.7%) or endoscopic approach. Need of remedial surgery was 2.8% at 2 years. In multivariate analysis, factors predicting redo surgery were: cardiac history (P=0.008), obesity (P=0.048), endoscopic approach (P=0.005), and low-volume center (P<0.001). We evaluated that an annual caseload of 31 parathyroidectomies was the best threshold to discriminate high-volume centers and carries the lowest morbidity/failure rate.

CONCLUSION

Although focused parathyroidectomy represents a standardized operation, cure rate is strongly associated with annual hospital caseload, type of procedure (endoscopic), and patients' features (obesity, cardiac history). Patients with risk factors for redo surgery should be considered for an open surgery in a high-volume center.

The Australian Injury Comorbidity Indices (AICIs) to predict in-hospital complications: A population-based data linkage study

Background

Hospital-admitted patients are at risk of experiencing certain adverse outcomes during their hospital-stay. Patients may need to be admitted to the intensive care unit or be placed on the ventilator while there is also a possibility for complications to develop. Pre-existing comorbidity could increase the risk of these outcomes. The Charlson Comorbidity Index (CCI) and the Elixhauser Comorbidity Measure (ECM), originally derived for mortality outcomes among general medical populations, are widely used for assessing these in-hospital complications even among specific injury populations. This study derived indices to specifically capture the effect of comorbidity on intensive care unit and ventilator use as well as hospital-acquired complications for injury patients.

Methods

Retrospective data on injury hospital-admissions from July 2012 to June 2014 (161,334 patients) for the state of Victoria, Australia was analysed. Results from multivariable regression analysis were used to derive the Australian Injury Comorbidity Indices (AICIs) for intensive care unit and ventilator hours and hospital-acquired complications. The AICIs, CCI and ECM were validated on data from Victoria and two other Australian states.

Results

Five comorbidities were significantly associated with intensive care unit hours, two with ventilator hours and fifteen with hospital-acquired complications for hospitalised injury patients. Not all diseases listed in the CCI or ECM were found to be associated with these outcomes. The AICIs performed equally well in terms of predictive ability to the long-listed ECM and in most instances outperformed the CCI.

Conclusions

Associations between outcomes and comorbidities vary based on the type of outcome measure. The new comorbidity indices developed in this study provide a relevant, parsimonious and up-to-date method to capture the effect of comorbidity on in-hospital complications among admitted injury patients and is better suited for use in that context compared to the CCI and ECM.

Personalized and typical concurrent risk of limitations in social activity and mobility in older persons with multiple chronic conditions and polypharmacy

PURPOSE

We define personalized concurrent risk (PCR) as the subject-specific probability of an index outcome within a defined interval of time, while currently at risk for a separate outcome, where the outcomes are not mutually exclusive and can be jointly modeled with a shared random intercept. We further define typical concurrent risk as the risk obtained by setting the random intercept to null.

METHODS

Drawing data from the Medical Expenditure Panel Survey (cohorts 2008-2013), we jointly model limitations in social activity and mobility over two years among older community-dwelling persons with both hypertension and chronic obstructive pulmonary disease. The joint model uses inverse probability of treatment weighting based on each participant's baseline propensity of polypharmacy (≥5 classes of medication).

RESULTS

Even among participants with the same covariates, older persons with multiple chronic conditions exhibit wide-ranging heterogeneity of the treatment effect from polypharmacy, a risk factor for negative health outcomes among older persons. The magnitude of the PCRs is dominated by the value of the subject-specific random effect.

CONCLUSIONS

Estimates of PCR and typical concurrent risk can be calculated from national or institutional data sets and may facilitate the practice of personalized care for older patients with multiple chronic conditions.