A general factor model for the Beck Depression Inventory-II: validation in a sample of patients hospitalized with acute myocardial infarction.

OBJECTIVE: Many studies have linked symptoms of depression after an acute myocardial infarction (AMI) to negative health outcomes, including mortality. It has been suggested, however, that this link may be due to biased measurement of depressive symptoms in post-AMI patients related to confounding with somatic symptoms related to AMI. The objective of this study was to validate a factor model for the Beck Depression Inventory-II (BDI-II) that would allow for modeling of depressive symptoms after explicitly removing bias related to somatic symptom overlap. METHODS: A total of 477 hospitalized post-AMI patients from 10 cardiac care units were administered the BDI-II. Confirmatory factor analysis models for ordinal data were conducted with MPLUS to test the fit of a model with a single General Depression factor (all 21 BDI-II items) and uncorrelated Somatic (5 items) and Cognitive (8 items) factors (G-S-C model) compared to standard correlated two-factor models. RESULTS: The G-S-C model fit as well or better than previously published correlated two-factor models. Seventy-three percent of variance in BDI-II scores is accounted for by the General Depression factor, whereas 11% and 13% respectively are accounted for by uncorrelated Somatic and Cognitive factors. CONCLUSIONS: The G-S-C model is a novel approach to understanding the measurement structure of the BDI-II, presents advantageous statistical and interpretive properties compared to standard correlated factor models, and provides a viable mechanism to test links between symptoms of depression, as measured by the General Depression factor, and health outcomes among patients with AMI after explicitly removing variance from somatic symptoms unrelated to the General Depression factor.

Comparing invasive and noninvasive management strategies for acute myocardial infarction using administrative databases.

PURPOSE: The aim of this study was to compare outcomes after acute myocardial infarction between regions with low and high catheterization access. METHODS: Observational study using administrative databases of patients with acute myocardial infarction in provinces with low (Ontario) and high (Quebec and British Colombia) access to invasive cardiac procedures (ICP, n = 141718). Using instrumental variables to control for confounding, effectiveness of treatment was measured on 1-year mortality among marginal patients (patients for whom treatment is discretionary and highly dependent on access to ICP). RESULTS: The ICP approach was associated with overall decreased mortality (-11%, 95% CI -13% to -8%) with statistically significant reductions in low-access regions (-16%, 95% CI -21% to -10%). High-access regions (QC -8%, 95% CI -19% to 4%) (BC -2%, 95% CI -12% to 7%) exhibited smaller marginal benefits. CONCLUSION: The invasive approach benefits all marginal patients, with greater benefits in regions of lower access, indicating a threshold of availability above which further mortality benefits are negligible.

Impact of on-site cardiac catheterization on resource utilization and fatal and non-fatal outcomes after acute myocardial infarction.

BACKGROUND: Patterns of care for acute myocardial infarction (AMI) strongly depend on the availability of on-site cardiac catheterization facilities. Although the management found at hospitals without on-site catheterization does not lead to increased mortality, little it known about its impact on resource utilization and non-fatal outcomes. METHODS: We identified all patients (n = 35,289) admitted with a first AMI in the province of Quebec between January 1, 1996 and March 31, 1999 using population-based administrative databases. Medical resource utilization and non-fatal and fatal outcomes were compared among patients admitted to hospitals with and without on-site cardiac catheterization facilities. RESULTS: Cardiac catheterization and PCI were more frequently performed among patients admitted to hospitals with catheterization facilities. However, non-invasive procedures were not used more frequently at hospitals without catheterization facilities. To the contrary, echocardiography [odds ratio (OR), 2.04; 95% confidence interval (CI), 1.93-2.16] and multi-gated acquisition imaging (OR, 1.24; 95% CI, 1.17-1.32) were used more frequently at hospitals with catheterization, and exercise treadmill testing (OR, 1.02; 95% CI, 0.91-1.15) and Sestamibi/Thallium imaging (OR, 0.93; 95% CI, 0.88-0.98) were used similarly at hospitals with and without catheterization. Use of anti-ischemic medications and frequency of emergency room and physician visits, were similar at both types of institutions. Readmission rates for AMI-related cardiac complications and mortality were also similar [adjusted hazard ratio, recurrent AMI: 1.02, 95% CI, 0.89-1.16; congestive heart failure: 1.02; 95% CI, 0.90-1.15; unstable angina: 0.93; 95% CI, 0.85-1.02; mortality: 0.99; 95% CI, 0.93-1.05)]. CONCLUSION: Although on-site availability of cardiac catheterization facilities is associated with greater use of invasive cardiac procedures, non-availability of catheterization did not translate into a higher use of non-invasive tests or have an impact on the fatal and non-fatal outcomes available for study in our administrative database.

Administrative Data Feedback for Effective Cardiac Treatment: AFFECT, a cluster randomized trial.

CONTEXT: Hospital report cards are increasingly being implemented for quality improvement despite lack of strong evidence to support their use. OBJECTIVE: To determine whether hospital report cards constructed using linked hospital and prescription administrative databases are effective for improving quality of care for acute myocardial infarction (AMI). DESIGN: The Administrative Data Feedback for Effective Cardiac Treatment (AFFECT) study, a cluster randomized trial. SETTING AND PATIENTS: Patients with AMI who were admitted to 76 acute care hospitals in Quebec that treated at least 30 AMI patients per year between April 1, 1999, and March 31, 2003. INTERVENTION: Hospitals were randomly assigned to receive rapid (immediate; n = 38 hospitals and 2533 patients) or delayed (14 months; n = 38 hospitals and 3142 patients) confidential feedback on quality indicators constructed using administrative data. MAIN OUTCOME MEASURES: Quality indicators pertaining to processes of care and outcomes of patients admitted between 4 and 10 months after randomization. The primary indicator was the proportion of elderly survivors of AMI at each study hospital who filled a prescription for a beta-blocker within 30 days after discharge. RESULTS: At follow-up, adjusted prescription rates within 30 days after discharge were similar in the early vs late groups (for beta-blockers, odds ratio [OR], 1.06; 95% confidence interval [CI], 0.82-1.37; for angiotensin-converting enzyme inhibitors, OR, 1.17; 95% CI, 0.90-1.52; for lipid-lowering drugs, OR, 1.14; 95% CI, 0.86-1.50; and for aspirin, OR, 1.05; 95% CI, 0.84-1.33). In addition, adjusted mortality was similar in both groups, as were length of in-hospital stay, physician visits after discharge, waiting times for invasive cardiac procedures, and readmissions for cardiac complications. CONCLUSIONS: Feedback based on one-time, confidential report cards constructed using administrative data is not an effective strategy for quality improvement regarding care of patients with AMI. A need exists for further studies to rigorously evaluate the effectiveness of more intensive report card interventions.

Invasive versus noninvasive management of ST-elevation acute myocardial infarction: a review of clinical trials and observational studies.

BACKGROUND: Despite decades of research, it is still unclear whether patients with uncomplicated ST-segment elevation acute myocardial infarction (AMI) should be managed with an invasive or a noninvasive approach after successful thrombolysis. METHODS: We reviewed randomized trials in which patients were randomized to a strategy of routine cardiac catheterization after thrombolysis (invasive) or a strategy whereby patients received cardiac catheterization only if they demonstrated reversible ischemia by noninvasive testing (noninvasive). We also reviewed observational studies that compared outcomes for patients who were admitted to hospitals with and without availability of cardiac catheterization facilities or in different geographic regions. RESULTS: Evidence to date suggests that invasive approach does not result in mortality or reinfarction benefits for patients with uncomplicated ST-segment elevation AMI. However, all except one of the trials performed are dated in view of recent treatment advances, and long-term outcomes for the recent trial have not been published. Several observational studies suggest that the invasive approach may improve "softer" outcomes such as quality of life and functional status. CONCLUSION: In conclusion, there is currently no evidence to support widespread use of the invasive approach among patients with uncomplicated ST-segment elevation AMI. However, trials with long-term follow-up should be repeated in the current clinical context and should include both hard and softer outcome measures.

Secondary prevention after acute myocardial infarction in four Canadian provinces, 1997-2000.

BACKGROUND: Publication of population-based analyses of medication use after acute myocardial infarction (AMI) could encourage the use of effective secondary prevention medications. OBJECTIVE: To describe outpatient use of beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, statins, calcium channel blockers and nitrates in elderly survivors of AMI over the fiscal years from 1997/98 to 1999/2000 in Nova Scotia, Quebec, Ontario and British Columbia. METHODS: Linked administrative databases were used to identify all AMI patients 65 years of age or older admitted in Quebec (n=14,880), Ontario (n=28,647) and British Columbia (n=7549) over the study period, and to measure 90-day postdischarge utilization rates of cardiac medications for these patients. A population-based clinical registry was used to measure rates of prescription at discharge for elderly patients in Nova Scotia admitted to an acute care hospital from 1997 to 2000 (n=1997). RESULTS: Utilization rates for beta-blockers, ACE inhibitors and statins increased over time, while rates for calcium channel blockers and nitrates decreased only slightly. The largest increases were for statins (Nova Scotia: 26% to 42%, Quebec: 27% to 43%; Ontario: 28% to 40%; British Columbia: 30% to 42%) and for ACE inhibitors in Ontario (55% to 65%) and Nova Scotia (46% to 68%). Of the three drugs recommended for secondary prevention, overall utilization rates for beta-blockers were highest in Nova Scotia, lowest in British Columbia, and similar in Quebec and Ontario. Rates for ACE inhibitors were highest in Ontario and similar in Quebec, Nova Scotia and British Columbia. Rates for statins were slightly higher in Quebec and British Columbia than in Ontario and Nova Scotia. The proportion of patients without a prescription for any of the recommended drugs was highest in British Columbia (20%), lowest in Nova Scotia (8%), and similar in Quebec and Ontario (Ontario: 12%; Quebec: 13%). There was marked regional variation in utilization rates within the four provinces. CONCLUSIONS: Although utilization rates for recommended cardiac medications are increasing over time, there remains room for improvement. Overall utilization rates and temporal trends are generally similar in all four provinces, but there are wide regional variations within provinces.

Depression and prognosis following hospital admission because of acute myocardial infarction.

BACKGROUND: Whether there is an association between depression at the time of acute myocardial infarction and subsequent risk of cardiac complications and death remains controversial. Most studies of this risk factor have been limited to patients of single institutions, and this might account for the varying results. We prospectively evaluated patients admitted to 5 tertiary care and 5 community hospitals and followed them for 1 year to measure the prevalence and prognostic impact of depressive symptoms after acute myocardial infarction. METHODS: Patients were recruited for the study by trained nurse interviewers who had documented acute myocardial infarction within 2-3 days of admission. The nurses collected information from the medical records and asked study subjects to complete the Beck Depression Inventory questionnaire during their stay in hospital and using a mailed questionnaire 30 days, 6 months and 1 year later. We obtained information on vital status for patients lost to follow-up from a central death registry. RESULTS: Of the 587 study subjects, 550 (94%) completed the Beck Depression Inventory at baseline and 191 (35%) had a score of 10 or more, indicating at least mild depression. Rates of depression did not vary over the follow-up period and were similar among patients admitted to tertiary care or community hospitals. Depressed patients were more likely to undergo catheterization (57% v. 47%, 95% confidence interval [CI] around the difference 0.1%-19.6%) and were more likely to undergo percutaneous coronary intervention (32% v. 24%, 95% CI around the difference 0.1%-16.2%) within 30 days of first admission to hospital. Patients with depression on admission had higher rates of a composite of cardiac complications, including recurrent ischemia, infarction or congestive heart failure during their first stay in hospital or readmission for angina, recurrent acute myocardial infarction, congestive heart failure or arrhythmia (adjusted hazard ratio 1.4, 95% CI 1.05-1.86), compared with patients who were not depressed on admission. After 1 year, death rates were higher among patients who were depressed at admission (30 patients, 16%) compared with nondepressed patients (28 patients, 8%), although the difference was not statistically significant (hazard ratio 1.3, 95% CI 0.59-3.05). INTERPRETATION: Depressive symptoms are common after acute myocardial infarction and are associated with a slight increase in risk of in-hospital catheterization and angiography and readmission because of cardiac complications. Death was infrequent, with no statistically significant difference between the 2 groups.

Does aggressive care following acute myocardial infarction reduce mortality? Analysis with instrumental variables to compare effectiveness in Canadian and United States patient populations.

BACKGROUND: Previous U.S. studies suggest that the incremental ("marginal") use of the aggressive approach to care for acute myocardial infarction (AMI) in patients differing only in their distance to hospitals offering aggressive care may be associated with small mortality benefits. We hypothesized that the marginal benefits should be larger in Canada, as the country is operating on a lower margin because the approach to care is more conservative overall. METHODS: This retrospective study used administrative data of hospital admissions and health services for all patients admitted for a first AMI in Quebec in 1988 (n = 8,674). We used differential distances to hospitals offering aggressive care as instrumental variables when measuring mortality up to four years after AMI. RESULTS: Of the 4,422 subjects who were > or = 65 years old, 11 percent received cardiac catheterization within 90 days after admission. In a previous study that applied similar methodology to the 1987 U.S. Medicare population, 23 percent of subjects received catheterization within 90 days. As in the U.S. study, we found that subjects living closer to hospitals offering aggressive care were more likely to receive aggressive care than subjects living further away (26 percent versus 19 percent received cardiac catheterization within 90 days; 95 percent CI: 5 percent to 9 percent). Unlike the U.S. study, we found no differences in mortality across the "close" versus "far" differential distance groups (unadjusted differences at one year: 1 percent; 95 percent CI: -1 percent to 3 percent). This absence of association held in elderly (> or = 65 years) and younger age groups. Adjusted results also showed no differences between subjects receiving aggressive versus conservative care (at one year: 4 percent; 95 percent CI: -11 percent to 20 percent). CONCLUSIONS: Contrary to our hypothesis, but consistent with results from numerous randomized trials and observational studies, we cannot confirm that, on the margin, the aggressive approach to post-AMI care is associated with mortality benefits in Canada.