Dana B. Mukamel

Association between Intraoperative Blood Transfusion and Mortality and Morbidity in Patients Undergoing Noncardiac Surgery

Background:The impact of intraoperative erythrocyte transfusion on outcomes of anemic patients undergoing noncardiac surgery has not been well characterized. The objective of this study was to examine the association between blood transfusion and mortality and morbidity in patients with severe anemia (hematocrit less than 30%) who are exposed to one or two units of erythrocytes intraoperatively. Methods:This was a retrospective analysis of the association of blood transfusion and 30-day mortality and 30-day morbidity in 10,100 patients undergoing general, vascular, or orthopedic surgery. We estimated separate multivariate logistic regression models for 30-day mortality and for 30-day complications. Results:Intraoperative blood transfusion was associated with an increased risk of death (odds ratio [OR], 1.29; 95% CI, 1.03–1.62). Patients receiving an intraoperative transfusion were more likely to have pulmonary, septic, wound, or thromboembolic complications, compared with patients not receiving an intraoperative transfusion. Compared with patients who were not transfused, patients receiving one or two units of erythrocytes were more likely to have pulmonary complications (OR, 1.76; 95% CI, 1.48–2.09), sepsis (OR, 1.43; 95% CI, 1.21–1.68), thromboembolic complications (OR, 1.77; 95% CI, 1.32–2.38), and wound complications (OR, 1.87; 95% CI, 1.47–2.37). Conclusions:Intraoperative blood transfusion is associated with a higher risk of mortality and morbidity in surgical patients with severe anemia. It is unknown whether this association is due to the adverse effects of blood transfusion or is, instead, the result of increased blood loss in the patients receiving blood.

The Surgical Mortality Probability Model: derivation and validation of a simple risk prediction rule for noncardiac surgery.

Objective:To develop a 30-day mortality risk index for noncardiac surgery that can be used to communicate risk information to patients and guide clinical management at the “point-of-care,” and that can be used by surgeons and hospitals to internally audit their quality of care. Background:Clinicians rely on the Revised Cardiac Risk Index to quantify the risk of cardiac complications in patients undergoing noncardiac surgery. Because mortality from noncardiac causes accounts for many perioperative deaths, there is also a need for a simple bedside risk index to predict 30-day all-cause mortality after noncardiac surgery. Methods:Retrospective cohort study of 298,772 patients undergoing noncardiac surgery during 2005 to 2007 using the American College of Surgeons National Surgical Quality Improvement Program database. Results:The 9-point S-MPM (Surgical Mortality Probability Model) 30-day mortality risk index was derived empirically and includes three risk factors: ASA (American Society of Anesthesiologists) physical status, emergency status, and surgery risk class. Patients with ASA physical status I, II, III, IV or V were assigned either 0, 2, 4, 5, or 6 points, respectively; intermediate- or high-risk procedures were assigned 1 or 2 points, respectively; and emergency procedures were assigned 1 point. Patients with risk scores less than 5 had a predicted risk of mortality less than 0.50%, whereas patients with a risk score of 5 to 6 had a risk of mortality between 1.5% and 4.0%. Patients with a risk score greater than 6 had risk of mortality more than 10%. S-MPM exhibited excellent discrimination (C statistic, 0.897) and acceptable calibration (Hosmer-Lemeshow statistic 13.0, P = 0.023) in the validation data set. Conclusions:Thirty-day mortality after noncardiac surgery can be accurately predicted using a simple and accurate risk score based on information readily available at the bedside. This risk index may play a useful role in facilitating shared decision making, developing and implementing risk-reduction strategies, and guiding quality improvement efforts.

A screening approach to the surveillance of patients with diabetes for the presence of vision-threatening retinopathy

OBJECTIVE To provide scientifically based screening rules for the primary care setting designed to identify, through evaluation of a prescribed and limited portion of the posterior fundus, those patients with diabetes who have retinopathy severe enough to need referral to eye care specialists. DESIGN Retrospective analysis of the Early Treatment Diabetic Retinopathy Study (ETDRS) photographic data base. PARTICIPANTS The fundus photographic grading data from 3711 patients with diabetes enrolled in the ETDRS. METHODS Multivariate regression techniques were used to identify retinopathy lesions in photographic fields 1, 2, 3, or a combination thereof that predict proliferative diabetic retinopathy (PDR) or clinically significant macular edema (CSME) within the seven standard fields. These were used to construct a family of screening rules with optimal combined sensitivity and specificity on which to base referrals to eye care specialists. MAIN OUTCOME MEASURES Presence of moderate to severe nonproliferative diabetic retinopathy (NPDR), PDR, or CSME in graded fundus photographs. RESULTS Hemorrhages and microaneurysms (h/ma) temporal to the macula (photographic field 3), as severe as or more severe than ETDRS standard photograph 1 (h/ma 3 > or = 3), identified 87% to 89% of eyes with PDR and 92% to 93% of eyes with moderately severe to severe NPDR, which are at high risk for developing PDR. Extrapolating the results using retinopathy prevalence data from epidemiologic studies for the general older onset diabetic population, the calculated sensitivity for detecting PDR on a single examination is 87%, the specificity 80%; for moderate NPDR or worse, the sensitivity is 81 %, specificity 93%. Applying the presence of h/ma 3 > or = 3 as a screening rule to the older onset population, 26.5% of patients would be referred and 73.5% would not be referred. Any hard exudate within one disc diameter of the macular center detects CSME with sensitivity 94%, specificity 54%. Hard exudate of moderate or worse severity anywhere in the macular region (field 2) predicts CSME with sensitivity 89%, specificity 58%. CONCLUSIONS Screening protocols based on assessing retinopathy lesion severity in the posterior fundus have the potential to identify most diabetic patients with vision-threatening retinopathy. If the protocols can be implemented effectively in a primary care setting, patients requiring referral for specialty care could be reliably identified, and the total number of patients needing specialty referral could be substantially reduced from current guidelines.

Measuring interdisciplinary team performance in a long-term care setting.

Objectives:The objectives of this study were to test the reliability and the validity of a survey instrument for assessing interdisciplinary team performance in long-term care settings and to measure team performance in the Program of All-Inclusive Care for the Elderly (PACE). Research Design and Methods:The analysis is based on 1220 surveys completed by team members of 26 PACE programs. Cronbachs alphas, analysis of variance, and regression models were used to assess the reliability and the validity of the instrument. Multivariate regression analysis was used to examine factors associated with team performance in PACE. Results:Cronbachs alphas ranging from 0.76 to 0.89 demonstrate good-to-high reliability for all domains of the team process and performance (effectiveness). Construct validity is demonstrated through the results of the regression analysis showing that leadership, communication, coordination, and conflict management are positive and significant (P <0.001) predictors of team cohesion and team effectiveness. The data also support the appropriateness of aggregating individual-level responses to the unit level. Perceived team effectiveness significantly (P <0.05) increases with: age of the respondents; longer length of the teams professional work experience; shorter duration of the teams PACE experience; more ethnically diverse composition of the team; greater ethnic concordance between team members and the participants; and greater perceived resource availability. Conclusions:Several of the factors influencing team effectiveness in PACE are potentially modifiable and, therefore, could offer insights for improving team practice.

TMPM-ICD9: a trauma mortality prediction model based on ICD-9-CM codes.

Objective:To develop and validate a new ICD-9 injury model that uses regression modeling, as opposed to a simple ratio measurement, to estimate empiric injury severities for each of the injuries in the ICD-9-CM lexicon. Background:The American College of Surgeons now requires International Classification of diseases ninth Edition (ICD-9-CM) codes for injury coding in the National Trauma Databank. International Classification of diseases ninth Edition Injury Severity Score (ICISS) is the best-known risk-adjustment model when injuries are recorded using ICD-9-CM coding, and would likely be used to risk-adjust outcome measures for hospital trauma report cards. ICISS, however, has been criticized for its poor calibration. Methods:We developed and validated a new ICD-9 injury model using data on 749,374 patients admitted to 359 hospitals in the National Trauma Databank (version 7.0). Empiric measures of injury severity for each of the trauma ICD-9-CM codes were estimated using a regression-based approach, and then used as the basis for a new Trauma Mortality Prediction Model (TMPM-ICD9). ICISS and the Single-Worst Injury (SWI) model were also re-estimated. The performance of each of these models was compared using the area under the receiver operating characteristic (ROC), the Hosmer-Lemeshow statistic, and the Akaike information criterion statistic. Results:TMPM-ICD9 exhibits significantly better discrimination (ROCTMPM = 0.880 [0.876–0.883]; ROCICISS = 0.850 [0.846–0.855]; ROCSWI = 0.862 [0.858–0.867]) and calibration (HLTMPM = 29.3 [12.1–44.1]; HLICISS = 231 [176–279]; HLSWI = 462 [380–548]) compared with both ICISS and the Single Worst Injury model. All models were improved with the addition of age, gender, and mechanism of injury, but TMPM-ICD9 continued to demonstrate superior model performance. Conclusions:Because TMPM-ICD9 uniformly out-performs ICISS and the SWI model, it should be used in preference to ICISS for risk-adjusting trauma outcomes when injuries are recorded using ICD9-CM codes.

Impact of patient volume on the mortality rate of adult intensive care unit patients.

Objective:Expert task forces have proposed that adult critical care medicine services should be regionalized in order to improve outcomes. However, it is currently unknown if high intensive care unit (ICU) patient volumes are associated with reduced mortality rate. The objective was to investigate whether high-volume ICUs have better mortality outcomes than low-volume ICUs. Design:Retrospective cohort study analyzing the association between ICU volume and in-hospital mortality using Project IMPACT (a clinical outcomes database created by the Society of Critical Care Medicine). Patients:The analyses were based on 70,757 patients admitted to 92 ICUs between 2001 and 2003. Interventions:None. Measurements and Main Results:The main outcome measure was in-hospital mortality. Hierarchical logistic regression modeling was used to examine the volume-outcome association. The median (interquartile range) ICU volume was 827 (631–1,234) patient admissions per year. The overall mortality rate was 14.6%. After controlling for patient risk factors and ICU characteristics, and clustering, there was evidence that patients admitted to high-volume ICUs had improved outcomes (p = .025). However, this mortality benefit was seen only in high-risk patients treated at ICUs treating high volumes of high-risk patients. Conclusions:There is evidence that high ICU patient volumes are associated with lower mortality rates in high-risk critically ill adults.

Increases in Mortality, Length of Stay, and Cost Associated With Hospital-Acquired Infections in Trauma Patients

OBJECTIVE To explore the clinical impact and economic burden of hospital-acquired infections (HAIs) in trauma patients using a nationally representative database. DESIGN Retrospective study. SETTING The Healthcare Cost and Utilization Project Nationwide Inpatient Sample. PATIENTS Trauma patients. MAIN OUTCOME MEASURES We examined the association between HAIs (sepsis, pneumonia, Staphylococcus infections, and Clostridium difficile- associated disease) and in-hospital mortality, length of stay, and inpatient costs using logistic regression and generalized linear models. RESULTS After controlling for patient demographics, mechanism of injury, injury type, injury severity, and comorbidities, we found that mortality, cost, and length of stay were significantly higher in patients with HAIs compared with patients without HAIs. Patients with sepsis had a nearly 6-fold higher odds of death compared with patients without an HAI (odds ratio, 5.78; 95% confidence interval, 5.03-6.64; P < .001). Patients with other HAIs had a 1.5- to 1.9-fold higher odds of mortality compared with controls (P < .005). Patients with HAIs had costs that were approximately 2- to 2.5-fold higher compared with patients without HAIs (P < .001). The median length of stay was approximately 2-fold higher in patients with HAIs compared with patients without HAIs (P < .001). CONCLUSIONS Trauma patients with HAIs are at increased risk for mortality, have longer lengths of stay, and incur higher inpatient costs. In light of the preventability of many HAIs and the magnitude of the clinical and economic burden associated with HAIs, policies aiming to decrease the incidence of HAIs may have a potentially large impact on outcomes in injured patients.

Perioperative outcomes among patients with the modified metabolic syndrome who are undergoing noncardiac surgery.

Background:Previous studies have demonstrated that obesity is paradoxically associated with a lower risk of mortality after noncardiac surgery. This study will determine the impact of the modified metabolic syndrome (defined as the presence of obesity, hypertension, and diabetes) on perioperative outcomes. Methods:This study is based on data from 310,208 patients in the American College of Surgeons National Surgical Quality Improvement Program database. We estimated separate multivariate logistic regression models for 30-day mortality and for 30-day complications. Results:Patients with the modified metabolic syndrome who are super obese had a 2-fold increased risk of death (adjusted odds ratio [AOR] 1.99; 95% CI 1.41–2.80). As stratified by body mass index, patients with the modified metabolic syndrome had a 2- to 2.5-fold higher risk of cardiac adverse events (CAE) compared with normal-weight patients: obese (AOR 1.70; 95% CI 1.40–2.07), morbidly obese (AOR 2.01; 95% CI 1.48–2.73), and super obese (AOR 2.66; 95% CI 1.68–4.19). In addition, the risk of acute kidney injury (AKI) was 3- to 7-fold higher in these patients: obese (AOR 3.30; 95% CI 2.75–3.94), morbidly obese (AOR 5.01; 95% CI 3.87–6.49), and super obese (AOR 7.29; 95% CI 5.27–10.1). Conclusion:Patients with the modified metabolic syndrome undergoing noncardiac surgery are at substantially higher risk of complications compared with patients of normal weight.

Nursing home costs and risk-adjusted outcome measures of quality.

BACKGROUND The inadequacy of quality of care in nursing homes has been and continues to be a focus of public concerns. Understanding the relationship between quality and costs can offer guidance to policies designed to encourage high quality. OBJECTIVES To investigate the relationship between costs and quality of care in nursing homes, and to test the hypothesis that higher quality may be associated with lower costs. RESEARCH DESIGN Statistical regression techniques were used to estimate nursing home variable-cost functions that included three risk-adjusted outcome measures of quality. Quality measures were based on decline in functional status, worsening pressure ulcers, and mortality. The study hypothesis was tested by an F test for the exclusion of nonlinear quality variables in the cost functions. SUBJECTS The study included 525 free-standing private and public nursing homes in New York State, or 84% of all nursing homes in the state during 1991. RESULTS F tests rejected the hypotheses that the three quality measures could be excluded from the cost function and that the association between costs and quality was linear. An inverted U-shaped relationship between quality and costs suggests that there are quality regimens in which higher quality is associated with lower costs. CONCLUSIONS Policies that encourage research to identify care protocols and management strategies leading to better outcomes and lower costs, as well as policies that encourage dissemination of such practices, may prevent decline in quality despite the continued financial constraints faced by nursing homes.

Quality Report Cards, Selection of Cardiac Surgeons, and Racial Disparities: A Study of the Publication of the New York State Cardiac Surgery Reports

Quality report cards have become common in many health care markets. This study evaluates their effectiveness by examining the impact of the New York State (NYS) Cardiac Surgery Reports on selection of cardiac surgeons. The analyses compares selection of surgeons in 1991 (pre-report publication) and 1992 (post-report publication). We find that the information about a surgeons quality published in the reports influences selection directly and diminishes the importance of surgeon experience and price as signals for quality. Furthermore, selection of surgeons for black patients is as sensitive to the published information as is the selection for white patients.