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Biomedical subjects

Donald A Redelmeier

Publications and source records attributed to Donald A Redelmeier.

At least 19 recordsLinked to original sources
PubMed2006

Angiotensin-converting enzyme inhibitors and aortic rupture: a population-based case-control study.

BACKGROUND: Angiotensin-converting enzyme (ACE) inhibitors prevent the expansion and rupture of aortic aneurysms in animals. We investigated the association between ACE inhibitors and rupture in patients with abdominal aortic aneurysms. METHODS: We did a population-based case-control study of linked administrative databases in Ontario, Canada. The sample included consecutive patients older than 65 (n=15,326) admitted to hospital with a primary diagnosis of ruptured or intact abdominal aortic aneurysm between April 1, 1992, and April 1, 2002. FINDINGS: Patients who received ACE inhibitors before admission were significantly less likely to present with ruptured aneurysm (odds ratio [OR] 0.82, 95% CI 0.74-0.90) than those who did not receive ACE inhibitors. Adjustment for demographic characteristics, risk factors for rupture, comorbidities, contraindications to ACE inhibitors, measures of health-care use, and aneurysm screening yielded similar results (0.83, 0.73-0.95). Consistent findings were noted in subgroups at high risk of rupture, including patients older than 75 years and those with a history of hypertension. Conversely, such protective associations were not observed for beta blockers (1.02, 0.89-1.17), calcium channel blockers (1.01, 0.89-1.14), alpha blockers (1.15, 0.86-1.54), angiotensin receptor blockers (1.24, 0.71-2.18), or thiazide diuretics (0.91, 0.78-1.07). INTERPRETATION: ACE inhibitors are associated with a reduced risk of ruptured abdominal aortic aneurysm, unlike other antihypertensive agents. Randomised trials of ACE inhibitors for prevention of aortic rupture might be warranted.

Aged↗
PubMed2006

Administrative data accurately identified intensive care unit admissions in Ontario.

BACKGROUND AND OBJECTIVES: To evaluate the accuracy of Ontario administrative health data for identifying intensive care unit (ICU) patients. MATERIALS AND METHODS: Records from the Critical Care Research Network patient registry (CCR-Net) were linked to the Ontario Health Insurance Program (OHIP) database and the Canadian Institute for Health Information (CIHI) database. The CCR-Net was considered the criterion standard for assessing the accuracy of different OHIP or CIHI codes for identifying ICU admission. RESULTS: The highest positive predictive value (PPV) for ICU admission (91%) was obtained using a CIHI special care unit (SCU) code, but its sensitivity was poor (26%). A strategy based on a combination of CIHI SCU codes yielded a lower PPV (84%) but a higher sensitivity (92%). A strategy based purely on OHIP claims yielded further reductions in PPV (73%), gains in specificity (99%), and moderate sensitivity (56%). The highest sensitivity (100%) was obtained using a combination of CIHI and OHIP codes in exchange for poor PPV (32%). CONCLUSIONS: Administrative databases can be used to identify ICU patients, but no single strategy simultaneously provided high sensitivity, specificity, and PPV. Researchers should consider the study purpose when selecting a strategy for health services research on ICU patients.

Databases as Topic↗
PubMed2006

Statins and sepsis in patients with cardiovascular disease: a population-based cohort analysis.

BACKGROUND: Atherosclerosis and sepsis share several pathophysiological similarities, including immune dysregulation, increased thrombogenesis, and systemic inflammation. The relation between statins and risk of sepsis in patients with atherosclerosis is unknown. METHODS: We did a population-based cohort analysis through linked administrative databases in Ontario, Canada, with accrual from 1997 to 2002. We identified 141,487 patients older than 65 years who had been hospitalised for an acute coronary syndrome, ischaemic stroke, or revascularisation, who survived for at least 3 months after discharge. 46,662 (33%) were prescribed a statin within 90 days of discharge, 94,825 (67%) were not. Propensity-based matching, which accounted for each individual's likelihood of receiving a statin, yielded a cohort of 69,168 patients, of whom half (34,584) received a statin and half (34,584) did not. FINDINGS: Incidence of sepsis was lower in patients receiving statins than in controls (71.2 vs 88.0 events per 10,000 person-years; hazard ratio [HR] 0.81; 95% CI 0.72-0.91). Adjustment for demographic characteristics, sepsis risk factors, comorbidities, and health-care use gave similar results (HR 0.81; 95% CI 0.72-0.90). The protective association between statins and sepsis persisted in high-risk subgroups, including patients with diabetes mellitus, chronic renal failure, or a history of infections. Significant reductions in severe sepsis (HR 0.83; 95% CI 0.70-0.97) and fatal sepsis (0.75; 0.61-0.93) were also observed. No benefit was noted with non-statin lipid-lowering agents (0.95; 0.75-1.22). IMPLICATIONS: Use of statins in patients with atherosclerosis is associated with a reduced risk of subsequent sepsis. Randomised trials of statins for prevention of sepsis are warranted.

Aged↗
PubMed2006

Clinical teaching and clinical outcomes: teaching capability and its association with patient outcomes.

BACKGROUND: There is little research on the impact of medical education on patient outcome. We studied whether teaching capability is associated with altered short-term patient outcomes. METHODS: We performed a multicentre retrospective cross-sectional study involving 40 clinician teachers who had attended on the general internal medicine services in hospitals affiliated with the University of Toronto along with the clinical outcomes of consecutive patients treated for community-acquired pneumonia, congestive heart failure, chronic obstructive pulmonary disease and gastrointestinal bleeding (n = 4377) between 1999 and 2001. Doctors were characterised by teaching effectiveness scores (n = 677) as high-rated or low-rated according to house staff ratings. RESULTS: There was no correlation between the teaching effectiveness scores and the mean length of stay for those patients treated for community-acquired pneumonia (high-rated = 10.3 versus low-rated = 8.1 days, P = 0.058), congestive heart failure (high-rated = 10.1 versus low-rated = 9.9 days, P = 0.978), chronic obstructive pulmonary disease (high-rated = 9.4 versus low-rated = 9.9 days, P = 0.419) and gastrointestinal bleeding (high-rated = 6.3 versus low-rated = 6.8 days, P = 0.741). In addition, we observed no significant correlation between teaching effectiveness scores and 7-day, 28-day and 1-year readmission rates for all pre-specified diagnoses. CONCLUSION: There is no large correlation between teaching effectiveness scores and short-term patient outcomes, suggesting that doctor teaching capabilities, as perceived by house staff, does not generally impact clinical care.

Community-Acquired Infections↗
PubMed2006

The risk of suicide with selective serotonin reuptake inhibitors in the elderly.

OBJECTIVE: The authors explored the relationship between the initiation of therapy with selective serotonin reuptake inhibitor (SSRI) antidepressants and completed suicide in older patients. METHOD: The authors linked population-based coroner's records with patient-level prescription data, physician billing claims, and hospitalization data for more than 1.2 million Ontario residents 66 years of age and older from 1992 to 2000. For each suicide case, four closely matched comparison subjects were selected using propensity score methods. The authors determined the odds ratio for suicide with SSRIs versus other antidepressant treatment, calculated at discrete monthly intervals from the start of treatment. RESULTS: Of 1,329 suicide cases, 1,138 (86%) were each fully matched to four comparison subjects using propensity scores. During the first month of therapy, SSRI antidepressants were associated with a nearly fivefold higher risk of completed suicide than other antidepressants (adjusted odds ratio: 4.8, 95% confidence interval=1.9-12.2). The risk was independent of a recent diagnosis of depression or the receipt of psychiatric care, and suicides of a violent nature were distinctly more common during SSRI therapy. Numerous sensitivity analyses revealed consistent results. No disproportionate suicide risk was seen during the second and subsequent months of treatment with SSRI antidepressants, and the absolute risk of suicide with all antidepressants was low. CONCLUSIONS: Initiation of SSRI therapy is associated with an increased risk of suicide during the first month of therapy compared with other antidepressants. The absolute risk is low, suggesting that an idiosyncratic response to these agents may provoke suicide in a vulnerable subgroup of patients.

Age Factors↗
PubMed2005

Cardiovascular health after maternal placental syndromes (CHAMPS): population-based retrospective cohort study.

BACKGROUND: Maternal placental syndromes, including the hypertensive disorders of pregnancy and abruption or infarction of the placenta, probably originate from diseased placental vessels. The syndromes arise most often in women who have metabolic risk factors for cardiovascular disease, including obesity, pre-pregnancy hypertension, diabetes mellitus, and dyslipidaemia. Our aim was to assess the risk of premature vascular disease in women who had had a pregnancy affected by maternal placental syndromes. METHODS: We did a population-based retrospective cohort study in Ontario, Canada, of 1.03 million women who were free from cardiovascular disease before their first documented delivery. We defined the following as maternal placental syndromes: pre-eclampsia, gestational hypertension, placental abruption, and placental infarction. Our primary endpoint was a composite of cardiovascular disease, defined as hospital admission or revascularisation for coronary artery, cerebrovascular, or peripheral artery disease at least 90 days after the delivery discharge date. FINDINGS: The mean (SD) age of participants was 28.2 (5.5) years at the index delivery, and 75 380 (7%) women were diagnosed with a maternal placental syndrome. The incidence of cardiovascular disease was 500 per million person-years in women who had had a maternal placental syndrome compared with 200 per million in women who had not (adjusted hazard ratio [HR] 2.0, 95 CI 1.7-2.2). This risk was higher in the combined presence of a maternal placental syndrome and poor fetal growth (3.1, 2.2-4.5) or a maternal placental syndrome and intrauterine fetal death (4.4, 2.4-7.9), relative to neither. INTERPRETATION: The risk of premature cardiovascular disease is higher after a maternal placental syndrome, especially in the presence of fetal compromise. Affected women should have their blood pressure and weight assessed about 6 months postpartum, and a healthy lifestyle should be emphasised.

Adolescent↗
PubMed2005

Prognostic implications of warfarin cessation after major trauma: a population-based cohort analysis.

BACKGROUND: Warfarin therapy is often withheld from elderly patients who fall or otherwise experience injury because of concerns regarding the long-term risk of hemorrhage in these individuals. We studied whether stopping warfarin after trauma is associated with a higher risk of subsequent adverse cardiovascular events. METHODS AND RESULTS: We conducted a retrospective, population-based, cohort study using linked administrative databases in the province of Ontario, Canada for the years 1992 to 2001. A total of 8450 elderly patients (age >65 years) who survived an incident of major trauma and were receiving warfarin before injury were followed up for a mean of 3.3 years. During the 6-month interval after trauma, 1827 (22%) patients discontinued warfarin, whereas 6623 (78%) patients continued warfarin. Warfarin cessation was not associated with an increased risk of subsequent stroke (hazard ratio [HR] 0.99, 95% CI 0.82 to 1.21) or myocardial infarction (HR 0.94, 95% CI 0.74 to 1.20) but was associated with a lower risk of major hemorrhage (HR 0.69, 95% CI 0.54 to 0.88) and a higher risk of venous thromboembolism (HR 1.59, 95% CI 1.07 to 2.36). Adjustment for baseline demographics, stroke risk factors, other comorbidities, and characteristics of the trauma did not materially change these findings. On-treatment analyses yielded similar results. CONCLUSIONS: Cessation of warfarin in elderly patients after major trauma was not associated with an increased risk of arterial thrombotic events but was associated with a significantly increased risk of venous thromboembolism.

Aged↗
PubMed2005

Improving patient care. The cognitive psychology of missed diagnoses.

Cognitive psychology is the science that examines how people reason, formulate judgments, and make decisions. This case involves a patient given a diagnosis of pharyngitis, whose ultimate diagnosis of osteomyelitis was missed through a series of cognitive shortcuts. These errors include the availability heuristic (in which people judge likelihood by how easily examples spring to mind), the anchoring heuristic (in which people stick with initial impressions), framing effects (in which people make different decisions depending on how information is presented), blind obedience (in which people stop thinking when confronted with authority), and premature closure (in which several alternatives are not pursued). Rather than trying to completely eliminate cognitive shortcuts (which often serve clinicians well), becoming aware of common errors might lead to sustained improvement in patient care.

Aged↗
PubMed2005

Metabolic syndrome and the risk of placental dysfunction.

BACKGROUND: Placental dysfunction (PD), which may manifest partly as the hypertensive disorders of pregnancy and abruption or infarction of the placenta, occurs more commonly in women with obesity, chronic hypertension, diabetes mellitus, and dyslipidemia-each a major feature of the metabolic syndrome. However, the relationship between the metabolic syndrome and the future risk of PD or fetal demise is unknown. METHODS: We completed a retrospective cohort study of 1.03 million women who had a first documented delivery in the province of Ontario between 1990 and 2002. Using linked administrative databases, we categorized women as having zero, one, two, or three to four features of the metabolic syndrome up to 24 months before their index delivery hospitalization. Women were considered to have placental dysfunction if they had a diagnosis of preeclampsia, gestational hypertension, placental abruption, or placental infarction during their first hospitalization for delivery in the period of study. RESULTS: At the time of delivery, 75 380 women (7.3%) were diagnosed as having PD. There was a progressive increase in the risk of PD in women with one (adjusted odds ratio [OR] 3.1; 95% confidence interval [CI] 3.0-3.1), two (OR 5.5; 95% CI 5.2-5.8), or three to four (OR 7.7; 95% CI 6.7-8.9) features of the metabolic syndrome, compared with none. A similar gradient effect was seen for the combined outcome of PD with poor fetal growth, or of PD with concomitant fetal death. CONCLUSIONS: Women who exhibit features of the metabolic syndrome before pregnancy have a higher graded risk of PD and fetal demise. Studies are needed to determine whether modifying a woman's metabolic profile before pregnancy, through modest caloric restriction and increased physical activity, can lower her future risk of PD.

Abruptio Placentae↗
PubMed2005

Major trauma in pregnant women during the summer.

BACKGROUND: Pregnant women represent a major challenge in trauma care because of the risks to both mother and child and because of the difficulties in following standard protocols. METHODS: We analyzed data for all pregnant women admitted to the hospital in Canada over 7 years to test whether major trauma still clustered in the summer despite their aversion toward alcohol, recklessness, and extreme sports. RESULTS: A total of 2,618 pregnant women sustained major trauma. The prevalence of pregnancy was marginally lower in summer than in winter (decrease, 3%; 95% confidence interval, 2-4%), whereas the incidence of major trauma in pregnant women was significantly higher in summer than in winter (increase, 12%; 95% confidence interval, 3-21%; p = 0.005). No evidence of offsetting decreases in severity appeared in analyses of length of stay, number of surgical procedures, or mortality. CONCLUSION: We suggest that normal lifestyle choices contribute to an increased risk of major trauma during pregnancy and merit greater awareness throughout the year.

Adult↗
PubMed2004

Rates of hyperkalemia after publication of the Randomized Aldactone Evaluation Study.

BACKGROUND: The Randomized Aldactone Evaluation Study (RALES) demonstrated that spironolactone significantly improves outcomes in patients with severe heart failure. Use of angiotensin-converting-enzyme (ACE) inhibitors is also indicated in these patients. However, life-threatening hyperkalemia can occur when these drugs are used together. METHODS: We conducted a population-based time-series analysis to examine trends in the rate of spironolactone prescriptions and the rate of hospitalization for hyperkalemia in ambulatory patients before and after the publication of RALES. We linked prescription-claims data and hospital-admission records for more than 1.3 million adults 66 years of age or older in Ontario, Canada, for the period from 1994 through 2001. RESULTS: Among patients treated with ACE inhibitors who had recently been hospitalized for heart failure, the spironolactone-prescription rate was 34 per 1000 patients in 1994, and it increased immediately after the publication of RALES, to 149 per 1000 patients by late 2001 (P<0.001). The rate of hospitalization for hyperkalemia rose from 2.4 per 1000 patients in 1994 to 11.0 per 1000 patients in 2001 (P<0.001), and the associated mortality rose from 0.3 per 1000 to 2.0 per 1000 patients (P<0.001). As compared with expected numbers of events, there were 560 (95 percent confidence interval, 285 to 754) additional hyperkalemia-related hospitalizations and 73 (95 percent confidence interval, 27 to 120) additional hospital deaths during 2001 among older patients with heart failure who were treated with ACE inhibitors in Ontario. Publication of RALES was not associated with significant decreases in the rates of readmission for heart failure or death from all causes. CONCLUSIONS: The publication of RALES was associated with abrupt increases in the rate of prescriptions for spironolactone and in hyperkalemia-associated morbidity and mortality. Closer laboratory monitoring and more judicious use of spironolactone may reduce the occurrence of this complication.

Adrenergic beta-Antagonists↗