Donald J. Willison

Adherence to National Guidelines for Drug Treatment of Suspected Acute Myocardial Infarction: Evidence for Undertreatment in Women and the Elderly

BACKGROUND Evidence-based guidelines for the treatment of patients with acute myocardial infarction (AMI) have been published and disseminated by the American College of Cardiology and the American Heart Association. Few studies have examined the rates of adherence to these guidelines in eligible populations and the influence of age and gender on highly effective AMI treatments in community hospital settings. METHODS Medical records of 2409 individuals admitted to 37 Minnesota hospitals between October 1992 and July 1993 for AMI, suspected AMI, or rule-out AMI, and meeting electrocardiographic, laboratory, and clinical criteria suggestive of AMI were reviewed to determine the proportion of eligible patients who received thrombolytic, beta-blocker, aspirin, and lidocaine hydrochloride therapy. The effects of patient age, gender, and hospital teaching status on the use of these treatments were estimated using logistic regression models. RESULTS Eligibility for treatment ranged from 68% (n=1627) for aspirin therapy, 38% (n=906) for lidocaine therapy, and 30% (n=734) for thrombolytic therapy to 19% (n=447) for beta-blocker therapy. Seventy-two percent of patients eligible to receive a thrombolytic agent received this therapy; 53% received beta-blockers; 81% received aspirin; and 88% received lidocaine. Among patients ineligible for lidocaine therapy (n=1503), 20% received this agent. Use of study drugs was lower among eligible elderly patients, especially those older than 74 years (thrombolytic agent: odds ratio, 0.2; 95% confidence interval, 0.1 to 0.4; aspirin: odds ratio, 0.4, 95% confidence interval, 0.3 to 0.6; beta-blocker: odds ratio, 0.4; 95% confidence interval, 0.2 to 0.8). Female gender was associated with lower levels of aspirin use among eligible patients (odds ratio, 0.7; 95% confidence interval, 0.6 to 0.9); and there was a trend toward lower levels of beta-blocker and thrombolytic use among eligible women. CONCLUSIONS Use of lifesaving therapies for eligible patients with AMI is higher than previously reported, particularly for aspirin and thrombolytic use in nonelderly patients. Lidocaine is still used inappropriately in a substantial proportion of patients with AMI. Increased adherence to AMI treatment guidelines is required for elderly patients and women.

Association between the 2008-09 seasonal influenza vaccine and pandemic H1N1 illness during Spring-Summer 2009: four observational studies from Canada.

BACKGROUND In late spring 2009, concern was raised in Canada that prior vaccination with the 2008-09 trivalent inactivated influenza vaccine (TIV) was associated with increased risk of pandemic influenza A (H1N1) (pH1N1) illness. Several epidemiologic investigations were conducted through the summer to assess this putative association. METHODS AND FINDINGS STUDIES INCLUDED (1) test-negative case-control design based on Canadas sentinel vaccine effectiveness monitoring system in British Columbia, Alberta, Ontario, and Quebec; (2) conventional case-control design using population controls in Quebec; (3) test-negative case-control design in Ontario; and (4) prospective household transmission (cohort) study in Quebec. Logistic regression was used to estimate odds ratios for TIV effect on community- or hospital-based laboratory-confirmed seasonal or pH1N1 influenza cases compared to controls with restriction, stratification, and adjustment for covariates including combinations of age, sex, comorbidity, timeliness of medical visit, prior physician visits, and/or health care worker (HCW) status. For the prospective study risk ratios were computed. Based on the sentinel study of 672 cases and 857 controls, 2008-09 TIV was associated with statistically significant protection against seasonal influenza (odds ratio 0.44, 95% CI 0.33-0.59). In contrast, estimates from the sentinel and three other observational studies, involving a total of 1,226 laboratory-confirmed pH1N1 cases and 1,505 controls, indicated that prior receipt of 2008-09 TIV was associated with increased risk of medically attended pH1N1 illness during the spring-summer 2009, with estimated risk or odds ratios ranging from 1.4 to 2.5. Risk of pH1N1 hospitalization was not further increased among vaccinated people when comparing hospitalized to community cases. CONCLUSIONS Prior receipt of 2008-09 TIV was associated with increased risk of medically attended pH1N1 illness during the spring-summer 2009 in Canada. The occurrence of bias (selection, information) or confounding cannot be ruled out. Further experimental and epidemiological assessment is warranted. Possible biological mechanisms and immunoepidemiologic implications are considered.

Delayed Hospital Presentation in Patients Who Have Had Acute Myocardial Infarction

The time from the onset of symptoms of acute myocardial infarction to hospital presentation has long been observed to correlate with in-hospital and long-term mortality [1]. With the advent of the thrombolytic era, delayed hospital presentation has been recognized as both the largest contributor to postponed treatment of acute myocardial infarction and a critical determinant of the initial management strategy. The findings of the large clinical trials of thrombolysis in acute myocardial infarction have consistently shown a relation between early treatment and improvements in short-term survival [2]. In the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Arteries (GUSTO-1) trial [3], the 30-day mortality rates were 5.6% in patients who came to the hospital within 1 hour of symptom onset and 8.6% in patients who delayed presentation for more than 4 hours. The time between symptom onset and presentation is often the most important determinant of eligibility for thrombolytic therapy. Several population-based studies have confirmed a strong inverse association between the length of delay and the use of thrombolytic agents [4, 5]. For example, findings from the Worcester heart Attack Study [6] have indicated that patients arriving at the emergency department within 1 hour of the onset of acute symptoms are more than six times more likely to receive thrombolytic therapy than are patients presenting more than 6 hours after symptom onset. The identification of factors contributing to delayed hospital presentation in patients who have had acute myocardial infarction is essential to the development of appropriate patient-directed educational interventions to reduce delay. To examine this issue, we studied 2409 patients in whom acute myocardial infarction was suspected at the time of admission to 37 hospitals in Minnesota between October 1992 and July 1993. Methods Setting The Minnesota Clinical Comparison and Assessment Program is a quality improvement program of the Healthcare Education and Research Foundation that involves hospitals throughout Minnesota; the 45 participating hospitals account for 60% of all hospital admissions statewide. Of these hospitals, 37 participated in our study. Fifty-four percent of the study hospitals were located in urban areas. Fifty-one percent had fewer than 100 beds; 43% had 100 to 500 beds; and 5% had 500 or more beds. Two hospitals were academic medical centers, and the rest were community hospitals. Study Sample To define a sample of patients in whom acute myocardial infarction was suspected at the time of hospital presentation, all admissions to the study hospitals from October 1992 to July 1993 were retrospectively screened for the following admission diagnoses: acute myocardial infarction, rule-out acute myocardial infarction, and suspected acute myocardial infarction [7]. Information on clinical symptoms at the time of hospital presentation, as well as electrocardiographic results and serum enzyme levels during the first 24 hours of hospitalization, was obtained from medical records. Patients were included if they met two of the following clinical criteria: 1) typical symptoms of acute myocardial infarction [chest discomfort, arm or shoulder pain, diaphoresis, dyspnea, nausea or vomiting, and neck or jaw pain]; 2) explicit medical record documentation by a physician that electrocardiographic findings were considered compatible with acute myocardial infarction; and 3) elevated serum creatine kinase and MB isoenzyme levels that were above the upper limit of normal (as specified by the laboratory at each participating hospital). Of 4968 persons with the specified admission diagnoses, 2559 were excluded for the following reasons: failure to meet clinical criteria (44.4%); transfer from a nonstudy hospital (30.5%); inability to access the medical record (22.0%); history of myocardial infarction during the 2 weeks before the hospital admission of interest (2.7%); and death by the time of arrival at the hospital (0.4%). Length of Delay The amount of time that elapsed between the onset of symptoms suggestive of an acute coronary event and hospital presentation was categorized as follows: less than 2 hours, 2 to 6 hours, more than 6 hours to 12 hours, more than 12 hours to 24 hours, more than 24 hours to 72 hours, and more than 72 hours. Delay categories were defined a priori to be clinically relevant to making decisions about the management of acute myocardial infarction, particularly the use of thrombolytic therapy. Patients whose medical records indicated that they had developed symptoms within the day of admission but gave no additional information on timing were placed in a separate category. For analyses of the relation between various demographic and clinical factors and delay, we considered these patients to have presented to the hospital more than 12 hours to 24 hours after symptom onset; this time category was outside the window during which benefit could be achieved from thrombolytic therapy [2]. Patient Characteristics Demographic and socioeconomic variables of interest were age (<55, 55 to 64, 65 to 74, 75 to 84, or 85 years), sex, marital status (married, never married, widowed, or divorced), living arrangement (not alone, alone, or residing in a long-term care facility), location of residence based on ZIP code (urban or rural), employment status (employed, unemployed, or retired), and health insurance status (Medicare, health maintenance organization, or other commercial coverage; Medicaid; or no insurance). Each patient was also characterized according to the median income of the ZIP code of residence for 1993, obtained from U.S. census data. Use of emergency medical transport was determined from information in the medical record. Clinical characteristics noted at the time of admission included a history of hypercholesterolemia, hypertension, diabetes mellitus, angina, myocardial infarction, congestive heart failure, mechanical revascularization (percutaneous transluminal coronary angioplasty or coronary artery bypass graft surgery), family history of coronary artery disease, and previous use of sublingual nitroglycerin. Patients were characterized according to the presence or absence of chest discomfort as a symptom of acute myocardial infarction. We used the Index of Co-existent Disease to characterize the burden of comorbid disease among the study patients. Details on the development of this index and scoring guidelines have been described elsewhere [8, 9]. The index consists of two dimensions: 1) severity of coexisting medical conditions and 2) degree of physical impairment. These dimensions were determined on the basis of information contained in the medical record at the time of hospital admission. The assessments for both dimensions were condensed into a single composite index consisting of four levels that ranged from no coexisting disease or no significant physical impairment to severe coexisting disease or severe physical impairment (none, mild, moderate, severe). The day of symptom onset was characterized according to whether it was a weekday or occurred on a weekend. The time of day during which symptoms developed was categorized as follows: 6:00 a.m. to 11:59 a.m., noon to 5:59 p.m., 6:00 p.m. to 11:59 p.m., and midnight to 5:59 a.m. To determine the time-of-day category for a particular patient, the number of hours reflecting the midpoint of the delay category for that patient was subtracted from the time of hospital presentation. This measure was determined only for patients with delays of 24 hours or less because the relevance of this factor for patients with delays of more than 1 day was believed to be questionable. Data Collection and Integrity All information that was relevant to our study was abstracted from medical records. Trained nurse abstracters collected all data. Abstracters were required to show ongoing inter-rater agreement with a criterion review of 95% or higher. A random sample of 10% of each abstracters completed cases was retrospectively audited to ensure that this standard was met. Statistical Analysis Patients were classified according to whether the delay between onset of symptoms suggestive of acute myocardial infarction and hospital presentation was 6 hours or less or more than 6 hours. Factors potentially associated with a delay of more than 6 hours were first examined by using chi-square statistics. Logistic regression models were used to determine factors that were independently associated with delay of more than 6 hours. Regression models initially included terms for patient age, sex, marital status, living arrangement, location of residence, employment status, health insurance status, median income, presence of chest discomfort as a symptom, medical history (hypercholesterolemia, hypertension, diabetes mellitus, angina, myocardial infarction, congestive heart failure, mechanical revascularization, family history of coronary artery disease, and use of sublingual nitroglycerin), and Index of Co-existent Disease category. A term was also included in the model to indicate the day of the week on which symptoms developed. To examine the independent effect on delay of the time of day at which symptoms occurred, an analysis was done only for patients whose symptoms had lasted 24 hours or less. Final models were constructed by using the standard stepwise regression procedure available in SAS PROC LOGIST (SAS Institute, Cary, North Carolina) [10]; all dummy variables associated with a unique study characteristic were forced into the final model if any of the dummy variables was associated with a P value of 0.05 or less. Selected variables (age and sex) were forced into the models regardless of the significance level. Odds ratios and 95% CIs were calculated directly from the estimated regression coefficients and their SEs. Results Length of delay could be assigned for all but 5 of the 2409 patients (99.8%)

Written informed consent and selection bias in observational studies using medical records: systematic review

Objectives To determine whether informed consent introduces selection bias in prospective observational studies using data from medical records, and consent rates for such studies. Design Systematic review. Data sources Embase, Medline, and the Cochrane Library up to March 2008, reference lists from pertinent articles, and searches of electronic citations. Study selection Prospective observational studies reporting characteristics of participants and non-participants approached for informed consent to use their medical records. Studies were selected independently in duplicate; a third reviewer resolved disagreements. Data extraction Age, sex, race, education, income, or health status of participants and non-participants, the participation rate in each study, and susceptibility of these calculations to threats of selection and reporting bias. Results Of 1650 citations 17 unique studies met inclusion criteria and had analysable data. Across all outcomes there were differences between participants and non-participants; however, there was a lack of consistency in the direction and the magnitude of effect. Of 161 604 eligible patients, 66.9% consented to use of data from their medical records. Conclusions Significant differences between participants and non-participants may threaten the validity of results from observational studies that require consent for use of data from medical records. To ensure that legislation on privacy does not unduly bias observational studies using medical records, thoughtful decision making by research ethics boards on the need for mandatory consent is necessary.

Views on health information sharing and privacy from primary care practices using electronic medical records.

OBJECTIVE To determine how patients and physicians balance the perceived benefits and harms of sharing electronic health data for patient care and for secondary purposes. DESIGN Before-after survey of patients and providers in practices using electronic medical records (EMRs) enrolled in a clinical trial in Ontario, Canada. MEASUREMENTS Outcomes were measured using the Health Information Privacy Questionnaire (HIPQ) at baseline and end of study. Thirteen questions in 4 general domains investigated attitudes towards the privacy of EMRs, outsiders use of patients health information, the sharing of patients information within the health care system, and the overall perception of benefits versus harms of computerization in health care. RESULTS 511 patients (mean age 60.3 years, 49.6% female) and 46 physicians (mean age 47.2 years, 37.0% female) participated. Most (>90%) supported the computerized sharing of the patients health records among their health care professionals and to provide clinical advice. Fewer agreed that the patients de-identified information should be shared outside of the health care circle (<70%). Only a minority of either group supported the notion that computerized records can be keep more private than paper records (38-50%). Overall, a majority (58% patients, 70% physicians) believed that the benefits of computerization were greater than the risks of confidentiality loss. This was especially true for patients who were frequent computer users. DISCUSSION While these primary care physicians and their patients valued the clinical features of EMRs, a substantial minority have concerns about the secondary use of de-identified information.

Alternatives to Project-specific Consent for Access to Personal Information for Health Research: What Is the Opinion of the Canadian Public?

OBJECTIVES This study sought to determine public opinion on alternatives to project-specific consent for use of their personal information for health research. DESIGN The authors conducted a fixed-response random-digit dialed telephone survey of 1,230 adults across Canada. MEASUREMENTS We measured attitudes toward privacy and health research; trust in different institutions to keep information confidential; and consent choice for research use of ones own health information involving medical record review, automated abstraction of information from the electronic medical record, and linking education or income with health data. RESULTS Support was strong for both health research and privacy protection. Studying communicable diseases and quality of health care had greatest support (85% to 89%). Trust was highest for data institutes, university researchers, hospitals, and disease foundations (78% to 80%). Four percent of respondents thought information from their paper medical record should not be used at all for research, 32% thought permission should be obtained for each use, 29% supported broad consent, 24% supported notification and opt out, and 11% felt no need for notification or consent. Opinions were more polarized for automated abstraction of data from the electronic medical record. Respondents were more willing to link education with health data than income. CONCLUSIONS Most of the public supported alternatives to study-specific consent, but few supported use without any notification or consent. Consent choices for research use of ones health information should be documented in the medical record. The challenge remains how best to elicit those choices and ensure that they are up-to-date.

Access to medical records for research purposes: varying perceptions across research ethics boards

Introduction: Variation across research ethics boards (REBs) in conditions placed on access to medical records for research purposes raises concerns around negative impacts on research quality and on human subject protection, including privacy. Aim: To study variation in REB consent requirements for retrospective chart review and who may have access to the medical record for data abstraction. Methods: Thirty 90-min face-to-face interviews were conducted with REB chairs and administrators affiliated with faculties of medicine in Canadian universities, using structured questions around a case study with open-ended responses. Interviews were recorded, transcribed and coded manually. Results: Fourteen sites (47%) required individual patient consent for the study to proceed as proposed. Three (10%) indicated that their response would depend on how potentially identifying variables would be managed. Eleven sites (38%) did not require consent. Two (7%) suggested a notification and opt-out process. Most stated that consent would be required if identifiable information was being abstracted from the record. Among those not requiring consent, there was substantial variation in recognising that the abstracted information could potentially indirectly re-identify individuals. Concern over access to medical records by an outside individual was also associated with requirement for consent. Eighteen sites (60%) required full committee review. Sixteen (53%) allowed an external research assistant to abstract information from the health record. Conclusions: Large variation was found across sites in the requirement for consent for research involving access to medical records. REBs need training in best practices for protecting privacy and confidentiality in health research. A forum for REB chairs to confidentially share concerns and decisions about specific studies could also reduce variation in decisions.

Cost Effectiveness of Multi-Therapy Treatment Strategies in the Prevention of Vertebral Fractures in Postmenopausal Women with Osteoporosis

AbstractObjective: The aim of this study was to evaluate the cost effectiveness of multitherapy treatment strategies in the prevention of vertebral fractures in postmenopausal women with osteoporosis. Design: A retrospective, incremental cost-effectiveness analysis was conducted from a societal perspective. It compared 9 treatment strategies over 3 years and incorporated the willingness of patients to initiate and continue each therapy. Main outcome measures and results: Four nondominated strategies formed the efficient frontier in the following order: (i) calcium → no therapy; (ii) ovarian hormone therapy (OHT) → calcium → no therapy [166 Canadian dollars (

Association of physician and hospital volume with use of aspirin and reperfusion therapy in acute myocardial infarction.

Can)]; (iii) OHT → etidronate → calcium → no therapy (

What makes public health studies ethical? Dissolving the boundary between research and practice

Can2331); and (iv) OHT → alendronate → calcium → no therapy (