Ruth Hall

Searching for an improved clinical comorbidity index for use with ICD-9-CM administrative data

We studied approaches to comorbidity risk adjustment by comparing two ICD-9-CM adaptations (Deyo, Dartmouth-Manitoba) of the Charlson comorbidity index applied to Massachusetts coronary artery bypass surgery data. We also developed a new comorbidity index by assigning study-specific weights to the original Charlson comorbidity variables. The 2 ICD-9-CM coding adaptations assigned identical Charlson comorbidity scores to 90% of cases, and specific comorbidities were largely found in the same cases (kappa values of 0.72-1.0 for 15 of 16 comorbidities). Meanwhile, the study-specific comorbidity index identified a 10% subset of patients with 15% mortality, whereas the 5% highest-risk patients according to the Charlson index had only 8% mortality (p = 0.01). A model using the new index to predict mortality had better validated performance than a model based on the original Charlson index (c = 0.74 vs. 0.70). Thus, in our population, the ICD-9-CM adaptation used to create the Charlson score mattered little, but using study-specific weights with the Charlson variables substantially improved the power of these data to predict mortality.

IScore A Risk Score to Predict Death Early After Hospitalization for an Acute Ischemic Stroke

Background— A predictive model of stroke mortality may be useful for clinicians to improve communication with and care of hospitalized patients. Our aim was to identify predictors of mortality and to develop and validate a risk score model using information available at hospital presentation. Methods and Results— This retrospective study included 12 262 community-based patients presenting with an acute ischemic stroke at multiple hospitals in Ontario, Canada, between 2003 and 2008 who had been identified from the Registry of the Canadian Stroke Network (8223 patients in the derivation cohort, 4039 in the internal validation cohort) and the Ontario Stroke Audit (3720 for the external validation cohort). The mortality rates for the derivation and internal validation cohorts were 12.2% and 12.6%, respectively, at 30 days and 22.5% and 22.9% at 1 year. Multivariable predictors of 30-day and 1-year mortality included older age, male sex, severe stroke, nonlacunar stroke subtype, glucose ≥7.5 mmol/L (135 mg/dL), history of atrial fibrillation, coronary artery disease, congestive heart failure, cancer, dementia, kidney disease on dialysis, and dependency before the stroke. A risk score index stratified the risk of death and identified low- and high- risk individuals. The c statistic was 0.850 for 30-day mortality and 0.823 for 1-year mortality for the derivation cohort, 0.851 for the 30-day model and 0.840 for the 1-year mortality model in the internal validation set, and 0.790 for the 30-day model and 0.782 for the 1-year model in the external validation set. Conclusion— Among patients with ischemic stroke, factors identifiable within hours of hospital presentation predicted mortality risk at 30 days and 1 year. The predictive score may assist clinicians in estimating stroke mortality risk and policymakers in providing a quantitative tool to compare facilities.

Risk factors, inpatient care, and outcomes of pneumonia after ischemic stroke

Objectives: Pneumonia is the most common medical complication after stroke. Although several risk factors have been reported, the role of common comorbidities in the development of pneumonia is not well established. Moreover, there is discrepancy in the literature regarding the impact of pneumonia on stroke outcomes. Methods: This is a multicenter retrospective cohort study including consecutive patients with ischemic stroke admitted to Regional Stroke Centers participating in the Registry of Canadian Stroke Network in July 2003–March 2007. Pneumonia was defined as a complication that occurred within the first 30 days of the stroke and was confirmed radiographically. The main outcome measure was adjusted 30-day mortality. Secondary outcomes were adjusted 7- and 365-day mortality, institutionalization, length of stay, and modified Rankin score on discharge. We also assessed the impact of organized stroke care on pneumonia development and mortality. Results: Overall, 8,251 patients were included in the study. Stroke-associated pneumonia was observed in 587 patients (7.1*). Pneumonia increased 30-day (odds ratio [OR] 2.2 [95% confidence interval (CI) 1.8–2.7]) and 1-year mortality (OR 3.0 [95% CI 2.5–3.7]), but not 7-day mortality. Pneumonia was associated with poor functional outcome. Higher access to organized inpatient care resulted in a reduction of 30-day mortality (OR 0.50 [95% CI 0.41–0.61]). Older age, male sex, stroke severity, dysphagia, chronic obstructive pulmonary disease, coronary artery disease, nonlacunar ischemic stroke, and preadmission dependency were independent predictors of pneumonia. Conclusions: Development of pneumonia after stroke was associated with mortality at 30 days and 1 year, longer length of stay, and dependency at discharge. Patients who received more inpatient stroke services had reduced mortality after pneumonia.

Hospital cost of complications associated with coronary artery bypass graft surgery

We identified 6,791 coronary artery bypass grafting (CABG) cases using the Massachusetts hospital discharge data to quantify the contribution of complications to the cost of a hospitalization for CABG. After adjusting for in-hospital mortality and baseline clinical severity as other contributors to cost, the additional costs associated with complications were substantial.

Prevalence of Individuals Experiencing the Effects of Stroke in Canada: Trends and Projections

Background and Purpose— Previous estimates of the number and prevalence of individuals experiencing the effects of stroke in Canada are out of date and exclude critical population groups. It is essential to have complete data that report on stroke disability for monitoring and planning purposes. The objective was to provide an updated estimate of the number of individuals experiencing the effects of stroke in Canada (and its regions), trending since 2000 and forecasted prevalence to 2038. Methods— The prevalence, trends, and projected number of individuals experiencing the effects of stroke were estimated using region-specific survey data and adjusted to account for children aged <12 years and individuals living in homes for the aged. Results— In 2013, we estimate that there were 405 000 individuals experiencing the effects of stroke in Canada, yielding a prevalence of 1.15%. This value is expected to increase to between 654 000 and 726 000 by 2038. Trends in stroke data between 2000 and 2012 suggest a nonsignificant decrease in stroke prevalence, but a substantial and rising increase in the number of individuals experiencing the effects of stroke. Stroke prevalence varied considerably between regions. Conclusions— Previous estimates of stroke prevalence have underestimated the true number of individuals experiencing the effects of stroke in Canada. Furthermore, the projected increases that will result from population growth and demographic changes highlight the importance of maintaining up-to-date estimates.

Identifying pre- and postoperative predictors of cost and length of stay for coronary artery bypass surgery

Prior studies of resource use for coronary artery bypass graft (CABG) surgery have either focused on a limited number of hospitals or have used charges instead of costs. We used a large statewide database (n = 6791) to study predictors of cost and length of stay (LOS) for CABG surgery. We used linear regression to sequentially model (a) specific procedures performed, (b) preoperative patient characteristics, and (c) postoperative events to determine the relative impact of these 3 factors on resource use. We then used the resulting models to calculate adjusted mean hospital costs and LOS. These 3 factors were all significantly associated with resource use. Postoperative events were the greatest determinant of costs, while preoperative characteristics were the greatest determinant of LOS. Despite risk adjustment for these factors, resource use differed significantly across 12 hospitals (mean cost range,

Effect of a provincial system of stroke care delivery on stroke care and outcomes

22,200 to

Variation in Hospital Rates of Intraaortic Balloon Pump Use in Coronary Artery Bypass Operations

41,900; mean LOS range, 11 to 18 days), suggesting that some institutions may need to reduce their resource use.

Who gets repeat screening mammography: the role of the physician.

Background: Systems of stroke care delivery have been promoted as a means of improving the quality of stroke care, but little is known about their effectiveness. We assessed the effect of the Ontario Stroke System, a province-wide strategy of regionalized stroke care delivery, on stroke care and outcomes in Ontario, Canada. Methods: We used population-based provincial administrative databases to identify all emergency department visits and hospital admissions for acute stroke and transient ischemic attack from Jan. 1, 2001, to Dec. 31, 2010. Using piecewise regression analyses, we assessed the effect of the full implementation of the Ontario Stroke System in 2005 on the proportion of patients who received care at stroke centres, and on rates of discharge to long-term care facilities and 30-day mortality after stroke. Results: We included 243 287 visits by patients with acute stroke or transient ischemic attack. The full implementation of the Ontario Stroke System in 2005 was associated with an increase in rates of care at stroke centres (before implementation: 40.0%; after implementation: 46.5%), decreased rates of discharge to long-term care facilities (before implementation: 16.9%; after implementation: 14.8%) and decreased 30-day mortality for hemorrhagic (before implementation: 38.3%; after implementation: 34.4%) and ischemic stroke (before implementation: 16.3%; after implementation: 15.7%). The system’s implementation was also associated with marked increases in the proportion of patients who received neuroimaging, thrombolytic therapy, care in a stroke unit and antithrombotic therapy. Interpretation: The implementation of an organized system of stroke care delivery was associated with improved processes of care and outcomes after stroke.

Gender Differences in Stroke Care and Outcomes in Ontario

BACKGROUND Little is known about regional patterns of intraaortic balloon pump (IABP) use in coronary artery bypass graft (CABG) operations. Our objectives were (1) to identify clinical variables associated with IABP use, and (2) to examine risk-adjusted rates of IABP use for 12 Massachusetts hospitals performing CABG operations. METHODS We used hospital discharge data to identify 6944 CABG surgical cases. Logistic regression was used to identify clinical variables associated with IABP use, and the resulting multivariate model was then used to risk adjust hospital rates of IABP use. RESULTS The IABP was used in 13.4% of the CABG surgical cases. The clinical variables independently associated with IABP use were cardiogenic shock, same admission angioplasty, prior CABG operation, cardiac arrest, congestive heart failure, recent myocardial infarction, and urgent admission status. Risk-adjusted rates of IABP use varied widely across hospitals from 7.8% to 20.8% (p < 0.0001). CONCLUSIONS Hospital rates of IABP use vary considerably in Massachusetts. This practice variation may be related to the persistent uncertainty regarding the precise clinical indications for the IABP in this patient population.