Myocardial infarction and the validation of physician billing and hospitalization data using electronic medical records.

OBJECTIVE: Population-based identification of patients with a myocardial infarction is limited to patients presenting to hospital with an acute event. We set out to determine if adding physician billing data to hospital discharge data would result in an accurate capture of patients who have had a myocardial infarction. METHODS: We performed a retrospective chart abstraction of 969 randomly selected adult patients using data abstracted from primary care physicians on an electronic medical record in Ontario, Canada, as the reference standard. RESULTS: An algorithm of 3 physician billings in a one-year period with at least one being by a specialist or within a hospital or emergency room plus one hospital discharge abstract performed with a sensitivity of 80.4% (95% CI: 69.5-91.3), specificity of 98.0% (95% CI: 97.1-98.9), positive predictive value of 69.5% (95% CI: 57.7-81.2), negative predictive value of 98.9% (95% CI: 98.2% to 99.6%) and kappa statistic of 0.73 (95% CI: 0.63-0.83). CONCLUSION: Using a combination of hospital discharge abstracts and physician billing data may be the best way of assessing trends of MI occurrence over time since it increases the capture of MI beyond those patients who have been hospitalized.

Defibrillation testing at the time of ICD insertion: an analysis from the Ontario ICD Registry.

BACKGROUND: increasingly, ICD implantation is performed without defibrillation testing (DT). OBJECTIVES: To determine the current frequency of DT, the risks associated with DT, and to understand how physicians select patients to have DT. METHODS: between January 2007 and July 2008, all patients in Ontario, Canada who received an ICD were enrolled in this prospective registry. RESULTS: a total of 2,173 patients were included; 58% had new ICD implants for primary prevention, 25% for secondary prevention, and 17% had pulse generator replacement. DT was carried out at the time of ICD implantation or predischarge in 65%, 67%, and 24% of primary, secondary, and replacement cases respectively (P = <0.0001). The multivariate predictors of a decision to conduct DT included: new ICD implant (OR = 13.9, P < 0.0001), dilated cardiomyopathy (OR = 1.8, P < 0.0001), amiodarone use (OR = 1.5, P = 0.004), and LVEF > 20% (OR = 1.3, P = 0.05). A history of atrial fibrillation (OR = 0.58, P = 0.0001) or oral anticoagulant use (OR = 0.75, P = 0.03) was associated with a lower likelihood of having DT. Age, gender, NYHA class, and history of stroke or TIA did not predict DT. Perioperative complications, including death, myocardial infarction, stroke, tamponade, pneumothorax, heart failure, infection, wound hematoma, and lead dislodgement, were similar among patients with (8.7%) and without (8.3%) DT (P = 0.7) CONCLUSIONS: DT is performed in two-thirds of new ICD implants but only one-quarter of ICD replacements. Physicians favored performance of DT in patients who are at lower risk of DT-related complications and in those receiving amiodarone. DT was not associated with an increased risk of perioperative complications.

Validity of the GRACE (Global Registry of Acute Coronary Events) acute coronary syndrome prediction model for six month post-discharge death in an independent data set.

OBJECTIVE: To determine the validity of the GRACE (Global Registry of Acute Coronary Events) prediction model for death six months after discharge in all forms of acute coronary syndrome in an independent dataset of a community based cohort of patients with acute myocardial infarction (AMI). DESIGN: Independent validation study based on clinical data collected retrospectively for a clinical trial in a community based population and record linkage to administrative databases. SETTING: Study conducted among patients from the EFFECT (enhanced feedback for effective cardiac treatment) study from Ontario, Canada. PATIENTS: Randomly selected men and women hospitalised for AMI between 1999 and 2001. MAIN OUTCOME MEASURE: Discriminatory capacity and calibration of the GRACE prediction model for death within six months of hospital discharge in the contemporaneous EFFECT AMI study population. RESULTS: Post-discharge crude mortality at six months for the EFFECT study patients with AMI was 7.0%. The discriminatory capacity of the GRACE model was good overall (C statistic 0.80) and for patients with ST segment elevation AMI (STEMI) (0.81) and non-STEMI (0.78). Observed and predicted deaths corresponded well in each stratum of risk at six months, although the risk was underestimated by up to 30% in the higher range of scores among patients with non-STEMI. CONCLUSIONS: In an independent validation the GRACE risk model had good discriminatory capacity for predicting post-discharge death at six months and was generally well calibrated, suggesting that it is suitable for clinical use in general populations.

The high risk of stroke immediately after transient ischemic attack: a population-based study.

BACKGROUND: The risk of stroke is elevated in the first 48 hours after TIA. Previous prognostic models suggest that diabetes mellitus, age, and clinical symptomatology predict stroke. The authors evaluated the magnitude of risk of stroke and predictors of stroke after TIA in an entire population over time. METHODS: Administrative data from four different databases were used to define TIA and stroke for the entire province of Alberta for the fiscal year (April 1999-March 2000). The age-adjusted incidence of TIA was estimated using direct standardization to the 1996 Canadian population. The risk of stroke after a diagnosis of TIA in an Alberta emergency room was defined using a Kaplan-Meier survival function. Cox proportional hazards modeling was used to develop adjusted risk estimates. Risk assessment began 24 hours after presentation and therefore the risk of stroke in the first few hours after TIA is not captured by our approach. RESULTS: TIA was reported among 2,285 patients for an emergency room diagnosed, age-adjusted incidence of 68.2 per 100,000 population (95% CI 65.3 to 70.9). The risk of stroke after TIA was 9.5% (95% CI 8.3 to 10.7) at 90 days and 14.5% (95% CI 12.8 to 16.2) at 1 year. The risk of combined stroke, myocardial infarction, or death was 21.8% (95% CI 20.0 to 23.6) at 1 year. Hypertension, diabetes mellitus, and older age predicted stroke at 1 year but not earlier. CONCLUSIONS: Although stroke is common after TIA, the early risk is not predicted by clinical and demographic factors. Validated models to identify which patients require urgent intervention are needed.

Utilisation of coronary angiography after acute myocardial infarction in Ontario over time: have referral patterns changed?

OBJECTIVE: To examine how physicians in Ontario, Canada, have altered their referral patterns for coronary angiography after acute myocardial infarction (AMI) over time. DESIGN: Retrospective analysis of multilinked administrative data. SETTING: Province of Ontario, Canada. PATIENTS: 146 365 Ontario AMI patients hospitalised between 1 April 1992 and 31 March 1999. MAIN OUTCOME MEASURES: Utilisation trends of coronary angiography among all patients, as well as within six subgroups: elderly (versus young), women (versus men), high (versus low) risk of 30 day mortality, high (versus low) socioeconomic status, cardiology (versus non-cardiology) attending physician specialty, and hospitals with (versus without) onsite revascularisation capacity. Cox proportional hazard models were adjusted for variations in patient, physician, and hospital characteristics over time. RESULTS: Angiography rates in Ontario increased from 23.2% in 1992 to 35.5% in 1999 (p < 0.0001). Increases in utilisation of coronary angiography were most pronounced among the elderly (12.4-24.3% v 39.3-54.4% for non-elderly patients, p < 0.0001), the affluent (24.6-38.7% v 22.0-32.3% for less affluent patients, p = 0.01), and those tended to by cardiologists (32.0-47.1% v 20.3-30.1% for non-cardiology attending specialties, p < 0.0001) after adjusting for changes in baseline patient, physician, and hospital characteristics over time. CONCLUSIONS: Despite universal health care availability, not all patients benefited equally from increases in service capacity for coronary angiography after AMI in Ontario. Wider implementation of data monitoring and explicit management systems may be required to ensure that appropriate utilisation of cardiac services is allocated to patients who are most in need.

Biology or bias: practice patterns and long-term outcomes for men and women with acute myocardial infarction.

OBJECTIVES: The goal of our study was to examine how age and gender affect the use of coronary angiography and the intensity of cardiac follow-up care within the first year after acute myocardial infarction (AMI). Another objective was to evaluate the association of age, gender and treatment intensity with five-year survival after AMI. BACKGROUND: Utilization rates of specialized cardiac services inversely correlate with age. Gender-specific practice patterns may also vary with age in a manner similar to known age-gender survival differences after AMI. METHODS: Using linked population-based administrative data, we examined the association of age and gender with treatment intensity and long-term survival among 25,697 patients hospitalized with AMI in Ontario between April 1, 1992, and December 31, 1993. A Cox proportional hazards model was used to adjust for socioeconomic status, illness severity, attending physician specialty and admitting hospital characteristics. RESULTS: After adjusting for baseline differences, the relative rates of angiography and follow-up specialist care for women relative to men, respectively, fell 17.5% (95% confidence interval [CI], 13.6 to 21.3, p < 0.001) and 10.2% (95% CI, 7.1 to 13.2, p < 0.001) for every 10-year increase in age. Conversely, long-term AMI survival rates in women relative to men improved with increasing age, such that the relative survival in women rose 14.2% (95% CI, 10.1 to 17.5, p < 0.001) for every 10-year age increase. CONCLUSIONS: Gender differences in the intensity of invasive testing and follow-up care are strongly age-specific. While care becomes progressively less aggressive among older women relative to men, survival advantages track in the opposite direction, with older women clearly favored. These findings suggest that biology is likely to remain the main determinant of long-term survival after AMI for women.

Nursing-related determinants of 30-day mortality for hospitalized patients.

The purpose of this study was to further our understanding of the effects of nursing-related hospital variables on 30-day mortality rates for hospitalized patients. A retrospective design was used to test the proposed 30-Day Mortality Model. The sample consisted of 75 acute-care hospitals in the province of Ontario, Canada. To develop hospital mortality rates, 46,941 patients discharged from these hospitals who had a most responsible diagnosis of acute myocardial infarction, stroke, pneumonia, or septicemia were included. To develop hospital-level nursing predictor variables, 3,998 responses to the Ontario Registered Nurse Survey of Hospital Characteristics were also included. The findings support a relationship between lower 30-day mortality and 3 predictors: a richer registered nurse skill mix, more years of experience on the clinical unit, and reported larger number of shifts missed. These findings can be used to predict the effects of hospital changes in nursing skill mix and years of RN experience on patient mortality.

Quality of congestive heart failure treatment at a Canadian teaching hospital.

BACKGROUND: Practice guidelines for the management of congestive heart failure (CHF) emphasize the need for assessment of left ventricular function and treatment with angiotensin-converting enzyme (ACE) inhibitors. However, previous studies have shown that many patients do not receive these tests or medications. The objective of this study was to evaluate the compliance of physicians at a large Canadian teaching hospital with published CHF management guidelines. METHODS: We conducted a retrospective review of the charts of 200 patients admitted to Sunnybrook & Women's College Health Sciences Centre, Toronto, in 1997 for whom CHF was the diagnosis most responsible for the hospital admission. Quality of care was measured with 3 indicators: the use of left ventricular function testing to determine systolic versus diastolic dysfunction; the prescription of ACE inhibitors to appropriate patients (those with systolic dysfunction, no contraindications to ACE inhibitor therapy and no angiotensin II receptor blocker use); and the prescription of target doses of ACE inhibitors. RESULTS: Of the 200 patients 177 (88.5%) received left ventricular function testing before or during their hospital stay; of the 177, 117 (66.1%) had systolic dysfunction. A total of 100 patients were considered to be ideal candidates for ACE inhibitor treatment. Of the 100, 89 (89.0%) received ACE inhibitors; however, only 23 (23.0%) were prescribed target doses. INTERPRETATION: Most patients who had CHF at this Canadian hospital received left ventricular function testing and ACE inhibitor therapy. Future educational efforts should focus on the importance of adequate dosing of ACE inhibitors.

Inhaled corticosteroids and the risk of mortality and readmission in elderly patients with chronic obstructive pulmonary disease.

There is considerable controversy concerning the utility of inhaled corticosteroids for the long-term treatment of patients with COPD. Recent studies have suggested that although inhaled corticosteroids do not alter the rate of decline in lung function, they may reduce airway hyperresponsiveness, decrease the frequency of exacerbations, and slow the rate of decline in the patients' health status. The relationship between inhaled corticosteroids and subsequent risk of hospitalization or mortality remains unknown. We therefore conducted a population-based cohort study using administrative databases in Ontario, Canada (n = 22,620) to determine the association between inhaled corticosteroid therapy and the combined risk of repeat hospitalization and all-cause mortality in elderly patients with COPD. Patients who received inhaled corticosteroid therapy postdischarge (within 90 d) had 24% fewer repeat hospitalizations for COPD (95% confidence interval [CI], 22 to 35%) and were 29% less likely to experience mortality (95% CI, 22 to 35%) during 1 yr of follow-up after adjustment for various confounding factors. This cohort study has suggested that inhaled corticosteroid therapy is associated with reduced COPD-related morbidity and mortality in elderly patients. Although not definitive, because of the observational nature of these findings, these data provide a compelling rationale for a large randomized trial to determine the effect of inhaled corticosteroids on COPD-related morbidity and mortality.

Problems for clinical judgement: 4. Surviving in the report card era.

Health care report cards involve comparisons of health care systems, hospitals or clinicians on performance measures. They are going to be an important feature of medical care in Canada in the new millennium as patients demand more information about their medical care. Although many clinicians are aware of this growing trend, they may not be prepared for all of its implications. In this article, we provide some historical background on health care report cards and describe a number of strategies to help clinicians survive and thrive in the report card era. We offer a number of tips ranging from knowing your outcomes first to proactively getting involved in developing report cards.

Investigating the determinants of decreasing postmyocardial infarction mortality: an analysis of in-hospital data from 1992 and 1997.

BACKGROUND: Although acute myocardial infarction (AMI) is the leading cause of mortality in the industrialized world, postmyocardial infarction mortality rates have been declining in recent decades. Two possible contributing factors toward this encouraging trend include changing patient characteristics and improved patient management. OBJECTIVES: To compare temporal changes in the characteristics and management of patients with AMI at a tertiary care hospital (Sunnybrook and Women's College Health Sciences Centre) in Toronto, Ontario. METHODS: Two hundred hospital charts of patients with AMI as the most responsible diagnosis were reviewed (100 from 1992 and 100 from 1997). One hundred thirty prespecified variables were extracted from each chart, with emphasis placed on baseline clinical characteristics, AMI management and survival. RESULTS: Between 1992 and 1997, AMI in-hospital mortality declined from 20% to 15%. Most baseline clinical characteristics (age, sex, comorbidity, cardiac history, and presenting symptoms and signs) were similar across the 1992 and 1997 patient populations. The only significant risk factor change involved an increase in the prevalence of hypercholesterolemia. In contrast, between 1992 and 1997 there was an increased in-hospital use of anticoagulants, antiplatelets, thrombolytics, beta-blockers, angiotensin-converting enzyme inhibitors and statins. Similarly, there was an increased use of coronary angioplasty and coronary bypass surgery. There was no significant change in the use of AMI therapies that are potentially harmful, including antiarrythmic agents and calcium channel blockers. CONCLUSIONS: AMI patient characteristics were similar between 1992 and 1997 but there were striking changes in AMI treatment patterns. The increased use of evidence-based pharmacotherapy may be the most significant contributing factor to declining postmyocardial infarction mortality.

Inhaled corticosteroid therapy reduces the risk of rehospitalization and all-cause mortality in elderly asthmatics.

Elderly patients with asthma have relatively high rates of hospitalization and mortality. Although inhaled corticosteroids have been shown to improve outcomes among younger patients with asthma, their usefulness in elderly patients has not been established. Therefore, a population-based study of patients 65 yrs of age or older, who have been hospitalized at least once with asthma in Ontario, Canada was conducted to determine the impact of inhaled corticosteroids on rehospitalization for asthma and all-cause mortality rates. Data from the Canadian Institute of Health Information was used to capture all patients 65 yrs of age and older who were hospitalized at least once, with the most responsible diagnosis of asthma in Ontario, Canada between fiscal year 1992 and 1996. This database was then linked with drug claims, physician billing and mortality databases. In total, 6,254 consecutive elderly patients with asthma were identified. Sixty percent of these patients were given at least one prescription for inhaled corticosteroids within 90 days postdischarge from their index hospitalization for asthma. Users of inhaled corticosteroids postdischarge were 29% (95% confidence interval (CI) 20%-38%) less likely to be readmitted to hospital for asthma and 39% (95% CI, 20%-53%) less likely to experience all-cause mortality compared to those who did not receive these drugs postdischarge over a one year follow-up period. These findings suggest that inhaled corticosteroids are beneficial in reducing the risk for rehospitalization and all-cause mortality in elderly patients with asthma who have recently been hospitalized for their disease.

Relationship between annual volume of patients treated by admitting physician and mortality after acute myocardial infarction.

CONTEXT: Acute myocardial infarction (AMI) is a common condition that is treated by physicians with varying levels of clinical experience, but whether the level of experience affects outcome remains uncertain. OBJECTIVE: To evaluate the relationship between the average annual volume of cases treated by admitting physicians and mortality after AMI. DESIGN, SETTING, AND PATIENTS: Retrospective cohort study using linked administrative databases containing patient admission information for 98 194 patients treated by 5374 physicians between April 1, 1992, and March 31, 1998, in Ontario, Canada. MAIN OUTCOME MEASURES: Mortality risk rates for 30 days and 1 year post-AMI, adjusted by physician volume and patient, physician, and hospital characteristics. RESULTS: The 30-day mortality rate was 13.5% and the 1-year mortality rate was 21.8%. A strong inverse relationship between the average annual volume of AMI cases treated by the admitting physician and mortality after an AMI was observed. The 30-day risk-adjusted mortality rate was 15.3% for physicians who treated 5 or fewer AMI cases per year (lowest quartile) compared with 11.8% for physicians who treated more than 24 AMI cases annually (highest quartile; P<.001). The 1-year risk-adjusted mortality rate was 24.2% for physicians who treated 5 or fewer AMI cases per year (lowest quartile) compared with 19.6% for physicians who treated more than 24 AMI cases annually (highest quartile; P<.001). CONCLUSION: Patients with AMI who are treated by high-volume admitting physicians are more likely to survive at 30 days and 1 year.

Problems for clinical judgement: 3. Thinking clearly in an emergency.

The resuscitation of a patient in extremis is frequently characterized by chaos and disorganization, and is one of the most stressful situations in medicine. We reviewed selected studies from the fields of anesthesia, emergency medicine and critical care that address the process of responding to a critically ill patient. Individual clinicians can improve their performance by increased exposure to emergencies during training and by the incorporation of teamwork, communication and crisis resource management principles into existing critical care courses. Team performance may be enhanced by assessing personality factors when selecting personnel for high-stress areas, explicit assignment of roles, ensuring a common "culture" in the team and routine debriefings. Over-reliance on technology and instinct at the expense of systematic responses should be avoided. Better training and teamwork may allow for clearer thinking in emergencies, so that knowledge can be translated into effective action and better patient outcomes.

Long-term MI outcomes at hospitals with or without on-site revascularization.

CONTEXT: Many studies have found that patients with acute myocardial infarction (AMI) who are admitted to hospitals with on-site revascularization facilities have higher rates of invasive cardiac procedures and better outcomes than patients in hospitals without such facilities. Whether such differences are due to invasive procedure rates alone or to other patient, physician, and hospital characteristics is unknown. OBJECTIVE: To determine whether invasive procedural rate variations alone account for outcome differences in patients with AMI admitted to hospitals with or without on-site revascularization facilities. DESIGN: Retrospective, observational cohort study using linked population-based administrative data from a universal health insurance system. SETTING: One hundred ninety acute care hospitals in Ontario, 9 of which offered invasive procedures. PATIENTS: A total of 25 697 patients hospitalized with AMI between April 1, 1992, and December 31, 1993, of whom 2832 (11%) were in invasive hospitals. MAIN OUTCOME MEASURES: Mortality, recurrent cardiac hospitalizations, and emergency department visits in the 5 years following the index admission, adjusted for patient age, sex, socioeconomic status, illness severity, and index revascularization procedures; attending physician specialty; and hospital volume, teaching status, and geographical proximity to invasive-procedure centers and compared by hospital type. RESULTS: Patients admitted to invasive-procedure hospitals were much more likely to undergo revascularization (11.4% vs 3.2% at other hospitals; P<.001). However, many other clinical and process-related factors differed between the 2 groups. Although mortality rates were similar between the 2 institution types, the nonfatal composite 5-year event rate (ie, recurrent cardiac hospitalization and emergency department visits) was lower for patients initially admitted to invasive-procedure hospitals (71.3% vs 80.4%; unadjusted odds ratio [OR], 0.65; 95% confidence interval [CI], 0.52-0.82; P<.001). This advantage persisted after adjustment for sociodemographic and clinical factors and procedure utilization (adjusted OR, 0.68; 95% CI, 0.53-0.89; P<.001). However, the nonfatal outcome advantages of invasive-procedure hospitals were explained by their teaching status (adjusted OR, 0.98; 95% CI, 0.73-1.30; P =.87). CONCLUSIONS: In this sample of patients admitted with AMI, the differing outcomes of apparently similar patients treated in 2 different practice settings were explained by multiple competing factors. Researchers conducting observational studies should be cautious about attributing patient outcome differences to any single factor.

Problems for clinical judgement: 1. Eliciting an insightful history of present illness.

This article presents the results of a review of studies of psychology that describe how ordinary human reasoning may lead patients to provide an unreliable history of present illness. Patients make errors because of mistakes in comprehension, recall, evaluation and expression. Comprehension of a question changes depending on ambiguities in the language used and conversational norms. Recall fails through the forgetting of relevant information and through automatic shortcuts to memory. Evaluation can be mistaken because of shifting social comparisons and faulty personal beliefs. Expression is influenced by moods and ignoble failures. We suggest that an awareness of how people report current symptoms and events is an important clinical skill that can be enhanced by knowledge of selected studies in psychology. These insights might help clinicians avoid mistakes when eliciting a patient's history of present illness.

Development and validation of the Ontario acute myocardial infarction mortality prediction rules.

OBJECTIVES: To develop and validate simple statistical models that can be used with hospital discharge administrative databases to predict 30-day and one-year mortality after an acute myocardial infarction (AMI). BACKGROUND: There is increasing interest in developing AMI "report cards" using population-based hospital discharge databases. However, there is a lack of simple statistical models that can be used to adjust for regional and interinstitutional differences in patient case-mix. METHODS: We used linked administrative databases on 52,616 patients having an AMI in Ontario, Canada, between 1994 and 1997 to develop logistic regression statistical models to predict 30-day and one-year mortality after an AMI. These models were subsequently validated in two external cohorts of AMI patients derived from administrative datasets from Manitoba, Canada, and California, U.S. RESULTS: The 11-variable Ontario AMI mortality prediction rules accurately predicted mortality with an area under the receiver operating characteristic (ROC) curve of 0.78 for 30-day mortality and 0.79 for one-year mortality in the Ontario dataset from which they were derived. In an independent validation dataset of 4,836 AMI patients from Manitoba, the ROC areas were 0.77 and 0.78, respectively. In a second validation dataset of 112,234 AMI patients from California, the ROC areas were 0.77 and 0.78 respectively. CONCLUSIONS: The Ontario AMI mortality prediction rules predict quite accurately 30-day and one-year mortality after an AMI in linked hospital discharge databases of AMI patients from Ontario, Manitoba and California. These models may also be useful to outcomes and quality measurement researchers in other jurisdictions.

A comparison of a Bayesian vs. a frequentist method for profiling hospital performance.

The objective of this study was to compare the classification of hospitals as outcomes outliers using a commonly implemented frequentist statistical approach vs. an implementation of Bayesian hierarchical statistical models, using 30-day hospital-level mortality rates for a cohort of acute myocardial infarction patients as a test case. For the frequentist approach, a logistic regression model was constructed to predict mortality. For each hospital, a risk-adj usted mortality rate was computed. Those hospitals whose 95% confidence interval, around the risk-adjusted mortality rate, excludes the mean mortality rate were classified as outliers. With the Bayesian hierarchical models, three factors could vary: the profile of the typical patient (low, medium or high risk), the extent to which the mortality rate for the typical patient departed from average, and the probability that the mortality rate was indeed different by the specified amount. The agreement between the two methods was compared for different patient profiles, threshold differences from the average and probabilities. Only marginal agreement was shown between the Bayesian and frequentist approaches. In only five of the 27 comparisons was the kappa statistic at least 0.40. The remaining 22 comparisons demonstrated only marginal agreement between the two methods. Within the Bayesian framework, hospital classification clearly depended on patient profile, threshold and probability of exceeding the threshold. These inconsistencies raise questions about the validity of current methods for classifying hospital performance, and suggest a need for urgent research into which methods are most meaningful to clinicians, managers and the general public.