Hemalkumar B. Mehta

Relative contributions of complications and failure to rescue on mortality in older patients undergoing pancreatectomy

Background:For pancreatectomy patients, mortality increases with increasing age. Our study evaluated the relative contribution of overall postoperative complications and failure to rescue rates on the observed increased mortality in older patients undergoing pancreatic resection at specialized centers. Methods:We identified 2694 patients who underwent pancreatic resection from the American College of Surgeons’ National Surgical Quality Improvement Pancreatectomy Demonstration Project at 37 high-volume centers. Overall morbidity and in-hospital mortality were determined in patients younger than 80 years (N = 2496) and 80 years or older (N = 198). Failure to rescue was the number of deaths in patients with complications divided by the total number of patients with postoperative complications. Results:No significant differences were observed between patients younger than 80 years and those 80 years or older in the rates of overall complications (41.4% vs 39.4%, P = 0.58). In-hospital mortality increased in patients 80 years or older compared to patients younger than 80 years (3.0% vs 1.1%, P = 0.02). Failures to rescue rates were higher in patients 80 years or older (7.7% vs 2.7%, P = 0.01). Across 37 high-volume centers, unadjusted complication rates ranged from 25.0% to 72.2% and failure to rescue rates ranged from 0.0% to 25.0%. Among patients with postoperative complications, comorbidities associated with failure to rescue were ascites, chronic obstructive pulmonary disease, and diabetes. Complications associated with failure to rescue included acute renal failure, septic shock, and postoperative pulmonary complications. Conclusions:In experienced hands, the rates of complications after pancreatectomy in patients 80 years or older compared to patients younger than 80 years were similar. However, when complications occurred, older patients were more likely to die. Interventions to identify and aggressively treat complications are necessary to decrease mortality in vulnerable older patients.

Comparison of Comorbidity Scores in Predicting Surgical Outcomes.

Introduction:The optimal methodology for assessing comorbidity to predict various surgical outcomes such as mortality, readmissions, complications, and failure to rescue (FTR) using claims data has not been established. Objective:Compare diagnosis-based and prescription-based comorbidity scores for predicting surgical outcomes. Methods:We used 100% Texas Medicare data (2006–2011) and included patients undergoing coronary artery bypass grafting, pulmonary lobectomy, endovascular repair of abdominal aortic aneurysm, open repair of abdominal aortic aneurysm, colectomy, and hip replacement (N=39,616). The ability of diagnosis-based [Charlson comorbidity score, Elixhauser comorbidity score, Combined Comorbidity Score, Centers for Medicare and Medicaid Services-Hierarchical Condition Categories (CMS-HCC)] versus prescription-based Chronic disease score in predicting 30-day mortality, 1-year mortality, 30-day readmission, complications, and FTR were compared using c-statistics (c) and integrated discrimination improvement (IDI). Results:The overall 30-day mortality was 5.8%, 1-year mortality was 17.7%, 30-day readmission was 14.1%, complication rate was 39.7%, and FTR was 14.5%. CMS-HCC performed the best in predicting surgical outcomes (30-d mortality, c=0.797, IDI=4.59%; 1-y mortality, c=0.798, IDI=9.60%; 30-d readmission, c=0.630, IDI=1.27%; complications, c=0.766, IDI=9.37%; FTR, c=0.811, IDI=5.24%) followed by Elixhauser comorbidity index/disease categories (30-d mortality, c=0.750, IDI=2.37%; 1-y mortality, c=0.755, IDI=5.82%; 30-d readmission, c=0.629, IDI=1.43%; complications, c=0.730, IDI=3.99%; FTR, c=0.749, IDI=2.17%). Addition of prescription-based scores to diagnosis-based scores did not improve performance. Conclusions:The CMS-HCC had superior performance in predicting surgical outcomes. Prescription-based scores, alone or in addition to diagnosis-based scores, were not better than any diagnosis-based scoring system.

Development and Validation of the RxDx- Dementia Risk Index to Predict Dementia in Patients with Type 2 Diabetes and Hypertension

BACKGROUND Elderly patients with type 2 diabetes mellitus and hypertension are at high risk for developing dementia. In addition to comorbid disease conditions (Dx), prescription drugs (Rx) are important risk factors for dementia. OBJECTIVE Develop and validate the RxDx-Dementia risk index by combining diagnosis and prescription information in a single risk index to predict incident dementia, and compare its performance with diagnosis-based Charlson comorbidity score (CCS) and prescription-based chronic disease score (CDS). METHODS Elderly patients diagnosed with type 2 diabetes mellitus and hypertension, and without prior dementia were identified from the Clinical Practice Research Datalink (2003-2012). A Cox proportional hazard model was constructed to model the time to dementia by incorporating age, gender, and 31 RxDx disease conditions as independent variables. Points were assigned to risk factors to obtain summary risk score. Discrimination and calibration of the risk index were evaluated. Different risk indices were compared against RxDx-Dementia risk index using c-statistic, net reclassification improvement (NRI) and integrated discrimination improvement (IDI). RESULTS Of 133,176 patients with type 2 diabetes mellitus and hypertension, 3.42% patients developed dementia.The c-statistics value for RxDx-Dementia risk index was 0.806 (95% CI, 0.799-0.812). Based on the c-statistics, NRI and IDI values, the RxDx-Dementia risk index performed better compared to CCS, CDS, and their combinations. CONCLUSION The RxDx-Dementia risk index can be a useful tool to identify hypertensive and diabetic patients who are at high risk of developing dementia. This has implications for clinical management of patients with multiple comorbid conditions as well as risk adjustment for database studies.

Comparative effectiveness of individual angiotensin receptor blockers on risk of mortality in patients with chronic heart failure.

There is little evidence on comparative effectiveness of individual angiotensin receptor blockers (ARBs) in patients with chronic heart failure (CHF). This study compared four ARBs in reducing risk of mortality in clinical practice.

Regression coefficient-based scoring system should be used to assign weights to the risk index

OBJECTIVE Some previously developed risk scores contained a mathematical error in their construction: risk ratios were added to derive weights to construct a summary risk score. This study demonstrates the mathematical error and derived different versions of the Charlson comorbidity score (CCS) using regression coefficient-based and risk ratio-based scoring systems to further demonstrate the effects of incorrect weighting on performance in predicting mortality. STUDY DESIGN AND SETTING This retrospective cohort study included elderly people from the Clinical Practice Research Datalink. Cox proportional hazards regression models were constructed for time to 1-year mortality. Weights were assigned to 17 comorbidities using regression coefficient-based and risk ratio-based scoring systems. Different versions of CCS were compared using Akaike information criteria (AIC), McFaddens adjusted R2, and net reclassification improvement (NRI). RESULTS Regression coefficient-based models (Beta, Beta10/integer, Beta/Schneeweiss, Beta/Sullivan) had lower AIC and higher R2 compared to risk ratio-based models (HR/Charlson, HR/Johnson). Regression coefficient-based CCS reclassified more number of people into the correct strata (NRI range, 9.02-10.04) compared to risk ratio-based CCS (NRI range, 8.14-8.22). CONCLUSION Previously developed risk scores contained an error in their construction adding ratios instead of multiplying them. Furthermore, as demonstrated here, adding ratios fail to even work adequately from a practical standpoint. CCS derived using regression coefficients performed slightly better than in fitting the data compared to risk ratio-based scoring systems. Researchers should use a regression coefficient-based scoring system to develop a risk index, which is theoretically correct.

Relative impact of surgeon and hospital volume on operative mortality and complications following pancreatic resection in Medicare patients

BACKGROUND Surgeon and hospital volume are both known to affect outcomes for patients undergoing pancreatic resection. The objective was to evaluate the relative effects of surgeon and hospital volume on 30-d mortality and 30-d complications after pancreatic resection among older patients. MATERIALS AND METHODS The study used Texas Medicare data (2000-2012), identifying high-volume surgeons as those performing ≥4 pancreatic resections/year, and high-volume hospitals as those performing ≥11 pancreatic resections/year, on Medicare patients. Three-level hierarchical logistic regression models were used to evaluate the relative effects of surgeon and hospital volumes on mortality and complications, after adjusting for case mix differences. RESULTS There were 2453 pancreatic resections performed by 490 surgeons operating in 138 hospitals. Of the total, 4.5% of surgeons and 6.5% of hospitals were high volume. The overall 30-d mortality was 9.0%, and the 30-d complication rate was 40.6%. Overall, 8.9% of the variance in 30-d mortality was attributed to surgeon factors and 9.8% to hospital factors. For 30-d complications, 4.7% of the variance was attributed to surgeon factors and 1.2% to hospital factors. After adjusting for patient, surgeon, and hospital characteristics, high surgeon volume (odds ratio [OR] = 0.54, 95% confidence interval [CI], 0.33-0.87) and high hospital volume (OR = 0.52; 95% CI, 0.30-0.92) were associated with lower risk of mortality; high surgeon volume (OR = 0.71, 95% CI, 0.55-0.93) was also associated lower risk of 30-d complications. CONCLUSIONS Both hospital and surgeon factors contributed significantly to the observed variance in mortality, but only surgeon factors impacted complications.

Application of the nonlinear Blinder-Oaxaca decomposition to study racial/ethnic disparities in antiobesity medication use in the United States

BACKGROUND The nonlinear Blinder-Oaxaca (BO) decomposition method is gaining popularity in health services research because of its ability to explain disparity issues. The present study demonstrates the use of this method for categorical variables by addressing antiobesity medication use disparity. OBJECTIVE To examine racial/ethnic disparity in antiobesity medication use and to quantify the observed factor contribution behind the disparity using the nonlinear BO decomposition. METHODS Medical Expenditure Panel Survey data, 2002-2007, were used in this retrospective cross-sectional study. Adults with body mass index (BMI) >30, or BMI ≥27 and comorbidities such as hypertension, cardiovascular diseases, diabetes, or hyperlipidemia were included in the cohort (N=65,886,625). Multivariable logistic regression was performed to examine racial/ethnic disparity in antiobesity medication use controlling for predisposing, enabling, and need factors. The nonlinear BO decomposition was used to identify the contribution of each predisposing, enabling, and need factors in explaining the racial/ethnic disparity and to estimate the residual unexplained disparity. RESULTS Non-Hispanic Blacks were 46% (odds ratio [OR]: 0.54; 95% confidence interval [CI]: 0.35-0.83) less likely to use antiobesity drugs compared with non-Hispanic Whites, whereas no difference was observed between Hispanics and non-Hispanic Whites. A 0.22 percentage point of disparity existed between non-Hispanic Whites and Blacks. The nonlinear BO decomposition estimated a decomposition coefficient of -0.0013 indicating that the observed disparity would have been 58% higher (-0.0013/0.0022) if non-Hispanic Blacks had similar observed characteristics as non-Hispanic Whites. Age, gender, marital status, region, and BMI were significant factors in the decomposition model; only marital status explained the racial/ethnic disparity among all observed characteristics. CONCLUSIONS The study revealed that differences in the predisposing, enabling, and need characteristics (except marital status) did not successfully explain the racial/ethnic disparity in antiobesity medication use. Further studies examining racial/ethnic differences in individual beliefs, behavioral patterns, and provider prescription patterns are vital to understand these disparities.

Association of Hypoglycemia With Subsequent Dementia in Older Patients With Type 2 Diabetes Mellitus

Background Studies have found conflicting evidence regarding the association of hypoglycemia with dementia. We evaluated an association of hypoglycemia with subsequent dementia in patients with type 2 diabetes. Methods This retrospective longitudinal cohort study used the Clinical Practice Research Datalink, an electronic medical records data from the United Kingdom, from 2003 to 2012. We included patients aged >65 years diagnosed with type 2 diabetes, with no prior diagnosis of dementia. Dementia was defined using diagnosis codes from medical records. All patients were followed from the date of initial diabetes diagnosis. To account for competing risk of death, we used Fine and Grays competing risk model to determine the association of hypoglycemia with dementia while adjusting for potential confounders. Hypoglycemia was modeled as a time-dependent covariate. Results Of 53,055 patients, 5.7% (n = 3,018) had at least one hypoglycemia episodes. The overall incidence rate of dementia was 12.7 per 1,000 person-years. In the fully adjusted model that controlled for all confounders, the occurrence of at least one hypoglycemia episode was associated with 27% higher odds of subsequent dementia (hazard ratio = 1.27; 95% confidence interval = 1.06-1.51). The risk increased with the number of hypoglycemia episodes: one episode (hazard ratio = 1.26; 95% confidence interval = 1.03-1.54); two or more episodes (hazard ratio = 1.50; 95% confidence interval = 1.09-2.08). Conclusions Hypoglycemia is associated with a higher risk of dementia and may be responsible in part for the higher risk of dementia in patients with diabetes. Alternatively, hypoglycemia may be a marker for undiagnosed cognitive impairment, and we cannot rule out the possibility of reverse causation between hypoglycemia and dementia.

Race and outcomes in gastroschisis repair: a nationwide analysis☆☆☆★★★☆☆☆

BACKGROUND The incidence of gastroschisis has increased 30% between the periods 1995-2005 and 2006-2012, with the largest increase in Black neonates born to Black mothers younger than 20years old. OBJECTIVE Racial disparities in peri- and post-operative outcomes have been previously identified in several types of adult and pediatric surgical patients. Is there an association between race and clinical outcomes and healthcare resource utilization in neonates with gastroschisis? METHODS Retrospective study using national administrative data from the Kids Inpatient Database (KID) from 2006, 2009, and 2012 for neonates (age<28days) with gastroschisis. Multivariable logistic regression was constructed to determine the association of race and socioeconomic characteristics with complications and mortality; linear regression was used for length of stay and hospital charges. RESULTS We identified 3846 neonates with gastroschisis that underwent surgical repair, including 676 patients with complex gastroschisis. When controlling for birth weight, payer status, socioeconomic status, and hospital characteristics, Black neonates had increased odds of having complex gastroschisis and associated atresias. Mortality was higher in patients with complex gastroschisis, patients from the lowest income quartiles, and patients with Medicaid as primary payer (compared to those with private insurance). Length of stay (LOS) was increased in patients with complex gastroschisis, birth weight <2500g, and Medicaid patients. Hospital charges were higher in complex gastroschisis, Black and Hispanic neonates (as compared to Whites), males, birth weight <2500g, and Medicaid patients. CONCLUSIONS There is an association between race and complex gastroschisis, associated intestinal atresias, and total charges in neonates with gastroschisis. In addition, income status is associated with mortality and hospital charges while payer status is associated with complications, mortality, LOS, and hospital charges. Public health and prenatal interventions should target at-risk populations to improve clinical outcomes. PROGNOSIS STUDY Level of Evidence: II.

Cost‐related medication nonadherence among adolescent and young adult cancer survivors

This study investigated cost‐related medication nonadherence among survivors of adolescent and young adult cancer and a comparison group in the United States.