Association of neurocognitive disorders with morbidity and mortality in older adults undergoing major surgery in the USA: a retrospective, population-based, cohort study.

BACKGROUND: Neurocognitive disorders become increasingly common as patients age, and increasing numbers of surgical interventions are done on older patients. The aim of this study was to understand the clinical characteristics and outcomes of surgical patients with neurocognitive disorders in the USA in order to guide future targeted interventions for better care. METHODS: This retrospective cohort study used claims data for US Medicare beneficiaries aged 65 years and older with a record of inpatient admission for a major diagnostic or therapeutic surgical procedure between Jan 1, 2017, and Dec 31, 2018. Data were retrieved through a data use agreement between Dartmouth Hitchcock Medical Center and US Centers for Medicare and Medicaid Services via the Research Data Assistance Center. The exposure of interest was the presence of a pre-existing neurocognitive disorder as defined by diagnostic code within 3 years of index hospital admission. The primary outcome was mortality at 30 days, 90 days, and 365 days from date of surgery among all patients with available data. FINDINGS: Among 5 263 264 Medicare patients who underwent a major surgical procedure, 767 830 (14·59%) had a pre-existing neurocognitive disorder and 4 495 434 (85·41%) had no pre-existing neurocognitive disorder. Adjusting for demographic factors and comorbidities, patients with a neurocognitive disorder had higher 30-day (hazard ratio 1·24 [95% CI 1·23-1·25]; p<0·0001), 90-day (1·25 [1·24-1·26]; p<0·0001), and 365-day mortality (1·25 [1·25-1·26]; p<0·0001) compared with patients without a neurocognitive disorder. INTERPRETATION: Our findings suggest that the presence of a neurocognitive disorder is independently associated with an increased risk of mortality. Identification of a neurocognitive disorder before surgery can help clinicians to better disclose risks and plan for patient care after hospital discharge. FUNDING: Department of Anesthesiology and Perioperative Medicine at Dartmouth Hitchcock Medical Center.

Validation of the All Patient Refined Diagnosis Related Group (APR-DRG) Risk of Mortality and Severity of Illness Modifiers as a Measure of Perioperative Risk.

The All Patient Refined Diagnosis Related Group (APR-DRG) is an inpatient visit classification system that assigns a diagnostic related group, a Risk of Mortality (ROM) subclass and a Severity of Illness (SOI) subclass. While extensively used for cost adjustment, no study has compared the APR-DRG subclass modifiers to the popular Charlson Comorbidity Index as a measure of comorbidity severity in models for perioperative in-hospital mortality. In this study we attempt to validate the use of these subclasses to predict mortality in a cohort of surgical patients. We analyzed all adult (age over 18 years) inpatient non-cardiac surgery at our institution between December 2005 and July 2013. After exclusions, we split the cohort into training and validation sets. We created prediction models of inpatient mortality using the Charlson Comorbidity Index, ROM only, SOI only, and ROM with SOI. Models were compared by receiver-operator characteristic (ROC) curve, area under the ROC curve (AUC), and Brier score. After exclusions, we analyzed 63,681 patient-visits. Overall in-hospital mortality was 1.3%. The median number of ICD-9-CM diagnosis codes was 6 (Q1-Q3 4-10). The median Charlson Comorbidity Index was 0 (Q1-Q3 0-2). When the model was applied to the validation set, the c-statistic for Charlson was 0.865, c-statistic for ROM was 0.975, and for ROM and SOI combined the c-statistic was 0.977. The scaled Brier score for Charlson was 0.044, Brier for ROM only was 0.230, and Brier for ROM and SOI was 0.257. The APR-DRG ROM or SOI subclasses are better predictors than the Charlson Comorbidity Index of in-hospital mortality among surgical patients.

Patient characteristics and anesthetic technique are additive but not synergistic predictors of successful motor evoked potential monitoring.

BACKGROUND: Spinal cord monitoring is associated with a significantly lower rate of neurologic deficits after deformity surgery, and has been shown to have predictive value in cervical, thoracic, and lumbar surgery. Lower extremity motor evoked potentials (MEPs) are particularly sensitive to anesthetics and physiologic change, and can be difficult to obtain at baseline. The anesthesiologist is often required to modify the maintenance anesthetic to facilitate signal attainment. Although intuitive, the predictive significance of increasing age, body mass index (BMI), presence of diabetes and/or hypertension, surgical procedure, and anesthetic technique has not been well delineated. METHODS: We conducted a retrospective chart review of the anesthetic records of all patients who underwent spine surgery and MEP monitoring of the lower extremities from August 1, 2001 to December 31, 2005. Patients with preexisting paralysis of the lower extremities were excluded. Univariate analysis was performed to examine the distribution of diabetes, hypertension, anesthesia technique, age, gender, BMI, and surgical procedure. The chi(2) test and the 2-sample t test were used to test associations between MEP status and potential risk factors. Cochran-Armitage test was used to analyze trends in BMI and age by quartile. The effects of diabetes and hypertension, compared with patients with neither, were presented for each anesthetic technique. Bivariate analysis of the data was performed to analyze a potentially synergistic deleterious effect of diabetes, hypertension, and anesthetic technique using the Breslow-Day test for homogeneity of the odds ratios. Logistic regression analysis through stepwise selection was performed to form a model of the data. RESULTS: Two hundred fifty-six charts were reviewed. The univariate analysis showed that diabetes, hypertension, anesthesia technique, age, and BMI were significantly associated with failure to obtain MEP signals. None of the variables were found to have a synergistic effect on MEP signal attainment in the bivariate analysis. Hypertension, diabetes, and anesthetic technique were independent factors for MEP failure and their joint effects were additive not synergistic. CONCLUSIONS: Diabetes, hypertension, and anesthetic technique were the most important patient risk factors associated with failure to obtain lower extremity MEP signals. These results will improve anesthesiologists' ability to tailor anesthetic regimen to patient comorbidity when MEP monitoring is planned.