Many consider smoking to be a personal choice for which individuals should be held accountable. We assessed whether there is any evidence of bias against smokers in cardiac care decision-making by determining whether smokers were as likely as non-smokers to undergo revascularization procedures after cardiac catheterization.
Prospective cohort study. Subjects and setting. All patients undergoing cardiac catheterization in Alberta, Canada.
Patients were categorized as current smokers, former smokers, or never smokers, and then compared for their risk-adjusted likelihood of undergoing revascularization procedures (percutaneous coronary intervention or coronary artery bypass grafting) after cardiac catheterization.
Among 20406 patients undergoing catheterization, 25.4% were current smokers at the time of catheterization, 36.6% were former smokers, and 38.0% had never smoked. When compared with never smokers (reference group), the hazard ratio for undergoing any revascularization procedure after catheterization was 0.98 (95% CI 0.93-1.03) for current smokers and 0.98 (0.94-1.03) for former smokers. The hazard ratio for undergoing coronary artery bypass grafting was 1.09 (1.00-1.19) for current smokers and 1.00 (0.93-1.08) for former smokers. For percutaneous coronary intervention, the hazard ratios were 0.93 (0.87-0.99) for current smokers and 1.00 (0.94-1.06) for former smokers.
Despite potential for discrimination on the basis of smoking status, current and former smokers undergoing cardiac catheterization in Alberta, Canada were as likely to undergo revascularization procedures as catheterization patients who had never smoked.
Previous studies have indicated that sex differences may exist in the pharmacological management of acute myocardial infarction (AMI), with female patients being treated less aggressively.
To determine if previously reported sex differences in AMI medication use were also evident among all AMI patients treated at hospitals in an urban Canadian city.
All patients who had a primary discharge diagnosis of AMI from all three adult care hospitals in Calgary, Alberta, in the 1998/1999 fiscal year were identified from hospital administrative records (n=914). A standardized, detailed chart review was conducted. Information collected from the medical charts included sociodemographic and clinical characteristics, comorbid conditions, and cardiovascular medication use during hospitalization and at discharge.
Similar proportions of female and male patients were treated with thrombolytics, beta-blockers, angiotensin-converting enzyme inhibitors, nitrate, heparin, diuretics and digoxin. Among patients aged 75 years and over, a smaller proportion of female patients received acetylsalicylic acid in hospital than did male patients (87% versus 95%; P=0.026). Multivariable logistic regression analysis revealed that, after correction for age, use of other anticoagulants/antiplatelets and death within 24 h of admission, sex was no longer an independent predictor for receipt of acetylsalicylic acid in hospital. Medications prescribed at discharge were similar between male and female patients.
The results from this Canadian chart review study, derived from detailed clinical data, indicate that the pattern of pharmacological treatment of female and male AMI patients during hospitalization and at discharge was very similar. No sex differences were evident in the treatment of AMI among patients treated in an urban Canadian centre.
Ethnic disparities in access to health care and health outcomes are well documented. It is unclear whether similar differences exist between Aboriginal and non-Aboriginal people with chronic kidney disease in Canada. We determined whether access to care differed between status Aboriginal people (Aboriginal people registered under the federal Indian Act) and non-Aboriginal people with chronic kidney disease.
We identified 106 511 non-Aboriginal and 1182 Aboriginal patients with chronic kidney disease (estimated glomerular filtration rate less than 60 mL/min/1.73 m(2)). We compared outcomes, including hospital admissions, that may have been preventable with appropriate outpatient care (ambulatory-care-sensitive conditions) as well as use of specialist services, including visits to nephrologists and general internists.
Aboriginal people were almost twice as likely as non-Aboriginal people to be admitted to hospital for an ambulatory-care-sensitive condition (rate ratio 1.77, 95% confidence interval [CI] 1.46-2.13). Aboriginal people with severe chronic kidney disease (estimated glomerular filtration rate
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Accurate prediction of survival for patients with end-stage renal disease (ESRD) and multiple comorbid conditions is difficult. In nondialysis patients, the Charlson Comorbidity Index has been used to adjust for comorbidity. The purpose of this study is to assess the validity of the Charlson index in incident dialysis patients and modify the index for use specifically in this patient population.
Subjects included all incident hemodialysis and peritoneal dialysis patients starting dialysis therapy between July 1, 1999, and November 30, 2000. These 237 patients formed a cohort from which new integer weights for Charlson comorbidities were derived using Cox proportional hazards modeling. Performance of the original Charlson index and the new ESRD comorbidity index were compared using Kaplan-Meier survival curves, change in likelihood ratio, and the c statistic.
After multivariate analysis and conversion of hazard ratios to index weights, only 6 of the original 18 Charlson variables were assigned the same weight and 6 variables were assigned a weight higher than in the original Charlson index. Using Kaplan-Meier survival curves, we found that both the original Charlson index and the new ESRD comorbidity index were associated with and able to describe a wide range of survival. However, the new study-specific index had better validated performance, indicated by a greater change in the likelihood ratio test and higher c statistic.
This study indicates that the original Charlson index is a valid tool to assess comorbidity and predict survival in patients with ESRD. However, our modified ESRD comorbidity index had slightly better performance characteristics in this population.
We have previously described a method for dealing with missing data in a prospective cardiac registry initiative. The method involves merging registry data to corresponding ICD-9-CM administrative data to fill in missing data 'holes'. Here, we describe the process of translating our data merging solution to ICD-10, and then validating its performance.
A multi-step translation process was undertaken to produce an ICD-10 algorithm, and merging was then implemented to produce complete datasets for 1995-2001 based on the ICD-9-CM coding algorithm, and for 2002-2005 based on the ICD-10 algorithm. We used cardiac registry data for patients undergoing cardiac catheterization in fiscal years 1995-2005. The corresponding administrative data records were coded in ICD-9-CM for 1995-2001 and in ICD-10 for 2002-2005. The resulting datasets were then evaluated for their ability to predict death at one year.
The prevalence of the individual clinical risk factors increased gradually across years. There was, however, no evidence of either an abrupt drop or rise in prevalence of any of the risk factors. The performance of the new data merging model was comparable to that of our previously reported methodology: c-statistic = 0.788 (95% CI 0.775, 0.802) for the ICD-10 model versus c-statistic = 0.784 (95% CI 0.780, 0.790) for the ICD-9-CM model. The two models also exhibited similar goodness-of-fit.
The ICD-10 implementation of our data merging method performs as well as the previously-validated ICD-9-CM method. Such methodological research is an essential prerequisite for research with administrative data now that most health systems are transitioning to ICD-10.
Intravenous immune globulin (IVIG) is an expensive and sometimes scarce blood product that carries some risk. It may often be used inappropriately. We evaluated the appropriateness of IVIG use before and after the introduction of an utilization control program to reduce inappropriate use.
We used the RAND/UCLA Appropriateness Method to measure the appropriateness of IVIG use in the province of British Columbia (BC) in 2001 and 2003, before and after the introduction of a utilization control program designed to reduce inappropriate use. For comparison, we measured the appropriateness of use during the same periods in the province of Alberta, which had no control program.
Of 2256 instances of IVIG use, 54.1% were deemed to be appropriate, 17.4% were of uncertain benefit, and 28.5% were deemed inappropriate. The frequency of inappropriate use in BC after the introduction of the utilization control program did not differ significantly from the frequency before the program or the frequency in Alberta.
Almost half of IVIG use in BC and Alberta was judged to be inappropriate or of uncertain benefit, and the frequency of inappropriate use did not decrease after implementation of a utilization control program in BC. More effective utilization controls are necessary to prevent wasted resources and unnecessary risk to patients.
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Canadian administrative hospital discharge data contain a diagnosis-type indicator for each coded diagnosis that allows researchers to distinguish complications from pre-existing diagnoses. Given that the validity of diagnosis-type indicators is unknown, we conducted a detailed chart review to evaluate the accuracy of diagnosis-type indicators for flagging complications.
We obtained administrative hospital discharge data for 1,200 randomly selected adult inpatient separations in Calgary, Alberta, occurring between April 1, 1996 and March 31, 1997. Each discharge record contains up to 16 diagnoses and 16 corresponding diagnosis-type indicators (value of "2"=complication). The corresponding medical charts were reviewed for evidence of diagnoses and complications. A complication was defined as a new diagnosis arising after the start of hospitalization. We determined the extent to which the diagnosis-type indicator in the administrative data agreed with the chart reviewer's assessment (criterion standard) of whether a diagnosis was a complication or not.
The agreement for complications between the two databases varied greatly across 12 conditions studied (kappa range: 0-0.72) and was often low (kappa
The goal of this study was to assess the validity of the International Classification of Disease, 10th Version (ICD-10) administrative hospital discharge data and to determine whether there were improvements in the validity of coding for clinical conditions compared with ICD-9 Clinical Modification (ICD-9-CM) data.
We reviewed 4,008 randomly selected charts for patients admitted from January 1 to June 30, 2003 at four teaching hospitals in Alberta, Canada to determine the presence or absence of 32 clinical conditions and to assess the agreement between ICD-10 data and chart data. We then re-coded the same charts using ICD-9-CM and determined the agreement between the ICD-9-CM data and chart data for recording those same conditions. The accuracy of ICD-10 data relative to chart data was compared with the accuracy of ICD-9-CM data relative to chart data.
Sensitivity values ranged from 9.3 to 83.1 percent for ICD-9-CM and from 12.7 to 80.8 percent for ICD-10 data. Positive predictive values ranged from 23.1 to 100 percent for ICD-9-CM and from 32.0 to 100 percent for ICD-10 data. Specificity and negative predictive values were consistently high for both ICD-9-CM and ICD-10 databases. Of the 32 conditions assessed, ICD-10 data had significantly higher sensitivity for one condition and lower sensitivity for seven conditions relative to ICD-9-CM data. The two databases had similar sensitivity values for the remaining 24 conditions.
The validity of ICD-9-CM and ICD-10 administrative data in recording clinical conditions was generally similar though validity differed between coding versions for some conditions. The implementation of ICD-10 coding has not significantly improved the quality of administrative data relative to ICD-9-CM. Future assessments like this one are needed because the validity of ICD-10 data may get better as coders gain experience with the new coding system.
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Physicians may use several validated risk indices to estimate perioperative cardiac risk, but there is little evidence for interventions to reduce this risk. We were interested in evaluating how general internists assess, define, communicate, and attempt to modify perioperative cardiac risk.
Cross-sectional survey of all 312 general internists in the Canadian Society of Internal Medicine with Canadian mailing addresses; 117 (38%) responded.
Respondents' mean age was 46 years, 79% were male, and on average they did 17 preoperative consults per month. Of the 104 respondents who routinely performed preoperative assessments, 96% (100/104) informed patients of their perioperative cardiac risk, but 77% did so only subjectively (i.e., stating risk as low, moderate, or high). Respondents provided 8, 27, and 12 different definitions for low, moderate, and high risk, respectively, with marked variability in the range of definitions they provided: from 2% to >50% for "high risk." The 67% of respondents who reported using a perioperative cardiac risk index used a variety of indices and exhibited just as much variability in their risk estimates and definitions as those who didn't use risk indices. While virtually all advised perioperative beta blockade in patients with known coronary artery disease, they varied substantially in the recommended agent or dose; further, these internists were evenly split on whether antiplatelet agents should be held or continued perioperatively.
These physicians differed widely in their assessment of perioperative cardiac risk and their definitions of low, moderate, or high risk. This raises concerns about whether patients (and surgeons) are provided with adequate information to make fully informed decisions about the potential risks of elective surgical operations.
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Low income is associated with adverse cardiovascular outcomes. Diabetes is more prevalent among low income groups, and low income patients with diabetes have been shown to have a greater burden of cardiovascular risk factors and worse cardiovascular outcomes. The objective of this study was to determine whether income status was associated with burden of coronary atherosclerosis in patients with diabetes.
All patients with diabetes presenting for cardiac catheterization between January 1, 2000, and December 31, 2002, in Calgary, Canada, were identified through the use of the Alberta Provincial Project for Assessing Outcomes in Coronary Heart Disease (APPROACH) database. This clinical database was merged with Canadian 2001 Census data on median household income per dissemination area using patient postal code data, and income quintiles were derived. Clinical profiles, severity of coronary atherosclerosis, and myocardial jeopardy were compared across income quintiles. Mean scores for severity and jeopardy were compared across income quintiles using analysis of variance. Multivariate linear regression was used to control for baseline differences across income groups. A total of 4596 patients were eligible for inclusion in this study. Clinical profiles differed significantly across income quintiles, with the highest income quintile being younger (P