Utilization and outcomes of HbA1c testing: a population-based study.
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Adult↗
Biomedical subjects
Carl van Walraven
Publications and source records attributed to Carl van Walraven.
Effect of study setting on anticoagulation control: a systematic review and metaregression.
BACKGROUND: For patients receiving therapy with oral anticoagulants (OACs), the proportion of time spent in the therapeutic range (ie, anticoagulation control) is strongly associated with bleeding and thromboembolic risk. The effect of study-level factors, especially study setting, on anticoagulation control is unknown. OBJECTIVES: Describe anticoagulation control achieved in the published literature. We also used metaregressive techniques to determine which study-level factors significantly influenced anticoagulation control. STUDIES: All published randomized or cohort studies that measured international normalized ratios (INRs) serially in anticoagulated patients and reported the proportion of time between INRs ranging from 1.8 to 2.0 and 3.0 to 3.5. RESULTS: We identified 67 studies with 123 patient groups having 50,208 patients followed for a total of 57,154.7 patient-years. A total of 68.3% of groups were from anticoagulation clinics, 7.3% were from clinical trials, and 24.4% were from community practices. Overall, patients were therapeutic 63.6% of time (95% confidence interval [CI], 61.6 to 65.6). In the metaregression model, study setting had the greatest effect on anticoagulation control with studies in community practices having significantly lower control than either anticoagulation clinics or clinical trials (-12.2%; 95% CI, -19.5 to -4.8; p < 0.0001). Self-management was associated with a significant improvement of time spent in the therapeutic range (+7.0%; 95% CI, 0.7 to 13.3; p = 0.03). CONCLUSIONS: Patients who have received anticoagulation therapy spend a significant proportion of their time with an INR out of the therapeutic range. Patients from community practices showed significantly worse anticoagulation control than those from anticoagulation clinics or clinical trials. This should be considered when interpreting the results of, and generalizing from, studies involving OACs.
Anticoagulants↗
Improving patient safety: moving beyond the "hype" of medical errors.
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Canada↗
Identifying individuals with a reduced GFR using ambulatory laboratory database surveillance.
The use of outpatient laboratory databases to identify people with a low GFR may be part of an effective strategy to increase their use of treatments to prevent kidney failure. All renal function data from 17 independent outpatient laboratories in Eastern Ontario were combined to determine the proportion of adults with at least one serum creatinine measurement during a 1-yr period. The detection rates of low GFR were measured using different algorithms, and what proportion of identified low GFR was transient was considered. Canadian census data were used to calculate rates and proportions. Renal function testing was common. Of the 1,090,000 adult residents, 32% of the entire population and 63% of seniors had at least one serum creatinine measured during the study year. Sixteen percent of the population (49% of those with tests performed) had at least one GFR <80 ml/min per 1.73 m2, 5% (16%) had at least one GFR <60 ml/min per 1.73 m2, and 0.6% (1.7%) had at least one GFR <30 ml/min per 1.73 m2. Low GFR were usually not transient: 68% of individuals with subsequent testing at least 30 d later had a similar or worse GFR. Ambulatory laboratory database case finding, particularly in older patients, seems to be a promising method for easily identifying large segments of the population with persistent reductions in GFR. Whether such identification leads to improved health outcomes warrants further study.
Algorithms↗
Impact of specialist follow-up in outpatients with congestive heart failure.
BACKGROUND: There is uncertainty about whether physician specialty influences the outcomes of outpatients with congestive heart failure after adjustment for differences in case mix. Our objective was to determine the impact of physician specialty on outcomes in outpatients with new-onset congestive heart failure. METHODS: The study was a population-based retrospective cohort study involving patients with new-onset congestive heart failure discharged from 128 acute care hospitals in Alberta between Apr. 1, 1998, and July 1, 2000. Outcomes were resource utilization (clinic visits, emergency department visits and hospital admissions) and survival at 30 days and 1 year. RESULTS: A total of 3136 patients were discharged from hospital with a new diagnosis of congestive heart failure (median age 76 years, 50% men). Of these, 1062 (34%) received no follow-up visits for cardiovascular care, 738 (24%) were seen by a family physician (FP) alone, 29 (1%) by a specialist (cardiologist or general internist) alone and 1307 (42%) by both a specialist and an FP. Compared with patients who received no follow-up cardiovascular care, patients who received regular cardiovascular follow-up visits with a physician had fewer visits to the emergency department (38% v. 80%), fewer were admitted to hospital (13% v. 94%), and the adjusted 1-year mortality was lower (22% v. 37%) (all p < 0.001). Compared with patients who received combined specialist and FP care, patients cared for exclusively by FPs had fewer outpatient visits (median 9 v. 17 in the first year), fewer of these patients presented to the emergency department (24% v. 45% in the first year), and fewer were readmitted for cardiovascular care (7% v. 16%) (all p < 0.001). However, the adjusted mortality at 1 year was lower among patients treated with combined care (17% v. 28%, p < 0.001) despite a higher burden of comorbidities. In a multivariate model adjusting for comorbidities (with no cardiovascular follow-up visits as the reference category), the mortality was lower among patients followed on an outpatient basis by an FP alone (odds ratio [OR] 0.66, 95% confidence interval [CI] 0.53-0.82) or by an FP and a specialist (OR 0.34, 95% CI 0.28-0.42). In a proportional hazards model with time-dependent covariates (with adjustment for frequency of follow-up visits), the risk of all-cause mortality was reduced significantly (hazard ratio 0.98, 95% CI 0.97- 0.99) with each specialist visit compared with FP care alone. INTERPRETATION: Patients with congestive heart failure followed by both specialists and FPs had significantly better survival than those followed by FPs alone (or those who received no specific cardiovascular follow-up care). Methods to improve timely and appropriate access to specialists and to improve collaborative care structures are needed.
Aged↗
Effect of a nurse team coordinator on outcomes for hospitalized medicine patients.
PURPOSE: Several randomized trials have found that discharge planning improves outcomes for hospitalized patients. We do not know if adding a clinical nurse specialist (CNS) to physician teams in hospitals that already have discharge planning services makes a difference. METHODS: In 2 teaching hospitals, patients were randomly assigned to regular hospital care or care with a clinical nurse specialist. The clinical nurse specialist facilitated hospital care by retrieving preadmission information, arranging in-hospital consultations and investigations, organizing postdischarge follow-up visits, and checking up on patients postdischarge with a telephone call. In-hospital outcomes included mortality and length of stay. Postdischarge outcomes included time to readmission or death, patient satisfaction, and the risk of adverse event. Adverse events were poor outcomes due to medical care rather than the natural history of disease. RESULTS: A total of 620 sequential patients were randomized (CNS n = 307, control n = 313), of which 361 were followed after discharge from hospital (CNS n = 175, control n = 186). The groups were similar for the probability of in-hospital death (CNS 9.3% vs control 9.7%) or being discharged to the community (58.0% vs 60.0%). The groups did not differ for postdischarge outcomes including readmission or death (21.6% vs 15.6%; P = 0.16) or risk of adverse event (23.6% vs 22.8%). Mean [SD] patient ratings of overall quality of care on a scale of 10 was higher in the clinical nurse specialist group (8.2 [2.2] vs 7.6 [2.4]; P = 0.052). CONCLUSION: The addition of a clinical nurse specialist to a medical team improved patient satisfaction but did not impact hospital efficiency or patient safety.
Aged↗
Diabetic patients with prior specialist care have better glycaemic control than those with prior primary care.
OBJECTIVE: To compare glycaemic control, as reflected in the A1c level, of diabetic patients with primary care vs. with specialist care. METHODS: The study used administrative data from eastern Ontario, Canada, and a database containing the results of all A1c tests from this region between 1 September 1999 and 1 September 2000. To avoid referral bias, diabetic patients with an index specialist visit were selected and separated into those with exclusively primary care previously (n = 974) and those with prior specialist care (n = 3533). We compared A1c levels measured within 30 days of the index visit and hence attributable to the prior care. To control for confounding between the groups, both multiple linear regression and propensity score-based matching were used. RESULTS: After controlling for confounders, patients with prior specialist care had significantly lower A1c levels (P < 0.0001). Other predictors of lower A1c included older age, shorter diabetes duration, rural residence and higher neighbourhood income. In propensity score-matched cohorts, the A1c level was 8.3 +/- 2.0% with prior primary care vs. 7.9 +/- 1.6% with prior specialist care (P < 0.0001). CONCLUSIONS: Specialist care prior to the index visit was associated with a lower A1c level than prior primary care. This difference would result in reductions in diabetes complications for patients with ongoing specialist care.
Aged↗
Clinical inertia in response to inadequate glycemic control: do specialists differ from primary care physicians?
OBJECTIVE: Diabetic patients with inadequate glycemic control ought to have their management intensified. Failure to do so can be termed "clinical inertia." Because data suggest that specialist care results in better control than primary care, we evaluated whether specialists demonstrated less clinical inertia than primary care physicians. RESEARCH DESIGN AND METHODS: Using administrative data, we studied all non-insulin-requiring diabetic patients in eastern Ontario aged 65 or older who had A1c results >8% between September 1999 and August 2000. Drug intensification was measured by comparing glucose-lowering drug regimens in 4-month blocks before and after the elevated A1c test and was defined as 1) the addition of a new oral drug, 2) a dose increase of an existing oral drug, or 3) the initiation of insulin. Propensity score-based matching was used to control for confounding between groups. RESULTS: There were 591 patients with specialist care and 1,911 with exclusively primary care. In the matched cohorts, 45.1% of patients with specialist care versus 37.4% with primary care had drug intensification (P = 0.009). Most of this difference was attributed to specialists' more frequent initiation of insulin in response to elevated A1c. CONCLUSIONS: Fewer than one-half of patients with high A1c levels had intensification of their medications, regardless of specialty of their physician. Specialists were more aggressive with insulin initiation than primary care physicians, which may contribute to the lower A1c levels seen with specialist care. Interventions assisting patients and physicians to recognize and overcome clinical inertia should improve diabetes care in the population.
Aged↗
Validation of a discharge summary term search method to detect adverse events.
OBJECTIVE: Adverse events are poor health outcomes caused by medical care. Measuring them is necessary for quality improvements, but current detection methods are inadequate. We performed this study to validate a previously derived method of adverse event detection using term searching in physician-dictated discharge summaries. DESIGN: This was a retrospective, chart review study of a random sample of 245 adult medicine and surgery patients admitted to a multicampus academic medical center in 2002. MEASUREMENTS: The authors used a commercially available search engine to scan discharge summaries for the presence of 104 terms that potentially indicate an adverse event. Summaries with any of these terms were reviewed by a physician to determine the term's context. Screen-positive summaries had a term that was contextually indicative of an adverse event. We used a two-stage chart review as the gold standard to determine the true presence or absence of an adverse event. RESULTS: The average patient age was 62 years (standard deviation 18.6) and 55% were admitted to a medical service. By gold standard criteria, 48 of 245 patients had an adverse event. Term searching classified 27 cases with an adverse event, with 11 true positives; 218 cases were classified as not having an adverse event, with 181 true negatives. The sensitivity, specificity, and positive and negative predictive values were 0.23 (95% confidence interval [CI]=0.11-0.35), 0.92 (95% CI=0.88-0.96), 0.41 (95% CI=0.25-0.59), and 0.83 (95% CI=95% 0.77-0.97), respectively. CONCLUSION: Although the sensitivity of the method is low, its high specificity means that the method could be used to replace expensive manual chart reviews by nurses.
Academic Medical Centers↗
Selecting patients with atrial fibrillation for anticoagulation: stroke risk stratification in patients taking aspirin.
BACKGROUND: The rate of stroke in atrial fibrillation (AF) depends on the presence of comorbid conditions and the use of antithrombotic therapy. Although adjusted-dose warfarin is superior to aspirin for reducing stroke in AF, the absolute risk reduction of warfarin depends on the stroke rate with aspirin. This prospective cohort study tested the predictive accuracy of 5 stroke risk stratification schemes. METHODS AND RESULTS: The study pooled individual data from 2580 participants with nonvalvular AF who were prescribed aspirin in a multicenter trial (Atrial Fibrillation, Aspirin, Anticoagulation I study [AFASAK-1], AFASAK-2, European Atrial Fibrillation Trial, Primary Prevention of Arterial Thromboembolism in patients with nonrheumatic Atrial Fibrillation in primary care study, and Stroke Prevention and Atrial Fibrillation [SPAF]-III high risk or SPAF-III low risk). There were 207 ischemic strokes during 4887 patient-years of aspirin therapy. All schemes predicted stroke better than chance, but the number of patients categorized as low and high risk varied substantially. AF patients with prior cerebral ischemia were classified as high risk by all 5 schemes and had 10.8 strokes per 100 patient-years. The CHADS(2) scheme (an acronym for Congestive heart failure, Hypertension, Age >75, Diabetes mellitus, and prior Stroke or transient ischemic attack) successfully identified primary prevention patients who were at high risk of stroke (5.3 strokes per 100 patient-years). In contrast, patients identified as high risk by other schemes had 3.0 to 4.2 strokes per 100 patient-years. Low-risk patients identified by all schemes had 0.5 to 1.4 strokes per 100 patient-years of therapy. CONCLUSIONS: Patients with AF who have high and low rates of stroke when given aspirin can be reliably identified, allowing selection of antithrombotic prophylaxis to be individualized.
Aged↗
Ottawa Hospital Patient Safety Study: incidence and timing of adverse events in patients admitted to a Canadian teaching hospital.
BACKGROUND: Adverse events are poor patient outcomes that are due to medical care. Studies of hospital patients have demonstrated that adverse events are common, but few data describe the timing of them in relation to hospital admission. We evaluated characteristics of adverse events affecting patients admitted to a Canadian teaching hospital, paying particular attention to timing. METHODS: We randomly selected 502 adults admitted to the Ottawa Hospital for acute care of nonpsychiatric illnesses over a 1-year period. Charts were reviewed in 2 stages. If an adverse event was judged to have occurred, a physician determined whether it occurred before or during the index hospitalization. The reviewer also rated the preventability, severity and type of each adverse event. RESULTS: Of the 64 patients with an adverse event (incidence 12.7%, 95% confidence interval [CI] 10.1%-16.0%), 24 had a preventable event (4.8%, 95% CI 3.2%-7.0%), and 3 (0.6%, 95% CI 0.2%-1.7%) died because of an adverse event. Most adverse events were due to drug treatment, operative complications or nosocomial infections. Of the 64 patients, 39 (61%, 95% CI 49%-72%) experienced the adverse event before the index hospitalization. INTERPRETATION: Adverse events were common in this study. However, only one-third were deemed avoidable, and most occurred before the hospitalization. Interventions to improve safety must address ambulatory care as well as hospital-based care.
Adult↗
Adverse events among medical patients after discharge from hospital.
BACKGROUND: Adverse events (AEs) are adverse outcomes caused by medical care. Several studies have indicated that a substantial number of patients experience AEs before or during hospitalization. However, few data describe AEs after hospital discharge. We determined the incidence, severity, preventability and ameliorability of AEs in patients discharged from the general internal medicine service of a Canadian hospital. METHODS: At a multisite Canadian teaching hospital, we prospectively studied patients who were consecutively discharged home or to a seniors' residence from the general internal medicine service during a 14-week interval in 2002. We used telephone interview and chart review to identify outcomes after discharge. Two physicians independently reviewed each outcome to determine if the patient experienced an AE. The severity, preventability and ameliorability of all AEs were classified. RESULTS: During the study period, outcomes were determined for 328 of the 361 eligible patients, who averaged 71 years of age (interquartile range 54-81 years). After discharge, 76 of the 328 patients experienced at least 1 AE (overall incidence 23%, 95% confidence interval [CI] 19%-28%). The AE severity ranged from symptoms only (68% of the AEs) or symptoms associated with a nonpermanent disability (25%) to permanent disability (3%) or death (3%). The most common AEs were adverse drug events (72%), therapeutic errors (16%) and nosocomial infections (11%). Of the 76 patients, 38 had an AE that was either preventable or ameliorable (overall incidence 12%, 95% CI 9%-16%). INTERPRETATION: Approximately one-quarter of patients in our study had an AE after hospital discharge, and half of the AEs were preventable or ameliorable.
Adverse Drug Reaction Reporting Systems↗
Time-dependent bias was common in survival analyses published in leading clinical journals.
OBJECTIVE: In survival analysis, "baseline immeasurable" time-dependent factors cannot be recorded at baseline, and change value after patient observation starts. Time-dependent bias can occur if such variables are not analyzed appropriately. This study sought to determine the prevalence of such time-dependent bias in highly-cited medical journals. STUDY DESIGN AND SETTING: We searched Medline databases to identify all observational studies that used a survival analysis in American Journal of Medicine, Annals of Internal Medicine, Archives of Internal Medicine, British Medical Journal, Chest, Circulation, Journal of the American Medical Association, Lancet, and New England Journal of Medicine between 1998 and 2002. Studies with "baseline immeasurable" time-dependent factors were susceptible to time-dependent bias if a time-dependent covariate analysis was not used. RESULTS: Of 682 eligible studies, 127 (18.6%, 95% CI 15.8-21.8%) contained a "baseline immeasurable" time-dependent factor and 52 (7.6% [5.8-9.9%] of all survival analyses/40.9% [32.3-50.0%] of studies with a time-dependent factor) were susceptible to time-dependent bias. In 35 studies (5.1% [3.7-7.1%]/27.6% [20.5-35.9%]), the bias affected a variable highlighted in the study abstract and correction of the bias could have qualitatively changed the study's conclusion in over half of studies. CONCLUSION: In medical journals, time-dependent bias is concerningly common and frequently affects key factors and the study's conclusion.
Bias↗
Continuity of care and patient outcomes after hospital discharge.
BACKGROUND: Patients are often treated in hospital by physicians other than their regular community doctor. After they are discharged, their care is often returned to their regular community doctor and patients may not see the hospital physician. Transfer of information between physicians can be poor. We determined whether early postdischarge outcomes changed when patients were seen after discharge by physicians who treated them in the hospital. METHODS: This cohort study used population-based administrative databases to follow 938833 adults from Ontario, Canada, after they were discharged alive from a nonelective medical or surgical hospitalization between April 1, 1995, and March 1, 2000. We determined when patients were seen after discharge by physicians who treated them in the hospital, physicians who treated them 3 months prior to admission (community physicians), and specialists. The outcome of interest was 30-day death or nonelective readmission to hospital. RESULTS: Of patients studied, 7.7% died or were readmitted. The adjusted relative risk of death or readmission decreased by 5% (95% confidence interval [CI], 4% to 5%) and 3% (95% CI, 2% to 3%) with each additional visit to a hospital physician rather than a community physician or specialist, respectively. The effect of hospital physician visits was cumulative, with the adjusted risk of 30-day death or nonelective readmission reduced to 7.3%, 7.0%, and 6.7% if patients had 1, 2, or 3 visits, respectively, with a hospital rather than a community physician. The effect was consistent across important subgroups. CONCLUSIONS: Patient outcomes could be improved if their early postdischarge visits were with physicians who treated them in hospital rather than with other physicians. Follow-up visits with a hospital physician, rather than another physician, could be a modifiable factor to improve patient outcomes following discharge from hospital.
Aged↗
Prevalence of information gaps in the emergency department and the effect on patient outcomes.
BACKGROUND: Information gaps occur when previously collected information is unavailable to a physician who is currently treating a patient. In this study we measured the prevalence of physician-reported information gaps for patients presenting to an emergency department at a teaching hospital. METHODS: For 1002 visits to the emergency department made by 983 patients, we recorded all information gaps identified by the emergency physician immediately after the patient was assessed. When an information gap was present, the physician was asked to identify the required information, why it was required and how important it was to the patient's care. We reviewed the patient charts to measure severity of illness and to determine whether the patient was referred to the emergency department by a community physician. Multiple linear regression analysis was used to determine whether information gaps were associated with length of stay in the emergency department. RESULTS: At least 1 information gap was identified in 323 (32.2%) of the 1002 visits (95% confidence interval 29.4%-35.2%). Information gaps were associated with severity of illness, being significantly more common in patients who had serious chronic illnesses, those who arrived by ambulance, those who had visited the emergency department or had been in hospital recently, patients in monitored areas in the emergency department and older patients. Information gaps most commonly comprised medical history (58%) and laboratory test results (23.3%) and were felt to be essential to patient care in 47.8% of the cases. The presence of information gaps was not associated with admission to hospital. After adjusting for important confounders, including patient sex, previous hospital admissions, diagnosis and severity of illness, we found that stays in the emergency department were 1.2 hours longer on average for patients with an information gap than for those without one. INTERPRETATION: Information gaps were present in almost one-third of the visits to our emergency department. They were more common in sicker patients and were independently associated with a prolonged stay in the emergency department.
Confidence Intervals↗
A clinical prediction rule to identify patients with atrial fibrillation and a low risk for stroke while taking aspirin.
BACKGROUND: We sought to derive and internally validate a simple and easily applied clinical prediction rule to identify patients with nonvalvular atrial fibrillation (AF) whose stroke risk while taking aspirin is, irrespective of age, low enough that oral anticoagulation therapy is unnecessary. METHODS: We included 2501 patients with AF treated with aspirin during participation in 6 clinical trials. Patients were randomly divided into derivation and validation sets. Recursive partitioning was used to identify patients in the derivation set whose risk for stroke (ischemic or hemorrhagic) or transient ischemic attack was comparable to that observed in an age- and sex-matched cohort from the Framingham Heart Study. The derived prediction rules were tested on the validation set. RESULTS: Overall, 166 patients (6.6%) had an event during 4688.6 person-years (PYs) of observation for an incident rate of 3.5 events per 100 PYs. Patients in the derivation set classified as low risk (no previous stroke or transient ischemic attack, no treated hypertension or systolic blood pressure equal to or exceeding 140 mm Hg, no symptomatic coronary artery disease, and no diabetes) experienced 1.0 events per 100 PYs, compared with an age- and sex-matched rate of 1.2 events per 100 PYs. In the validation set, low-risk patients experienced 1.1 events per 100 PYs (expected rate of 1.2 events per 100 PYs). Low-risk patients made up 24% of the cohort and 16% of patients older than 75 years. Low-risk patients who were randomized to therapeutic oral anticoagulation therapy experienced 1.5 events per 100 PYs. CONCLUSION: Irrespective of age, patients with AF and none of these 4 clinical features and who take aspirin have stroke rates comparable to those of age-matched community cohorts and would not benefit substantially from anticoagulation.
Aspirin↗
Risk of subsequent thromboembolism for patients with pre-eclampsia.
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Adolescent↗
Oral anticoagulants vs. aspirin for stroke prevention in patients with non-valvular atrial fibrillation: the verdict is in.
There is an increased risk of stroke and other cardiovascular events in patients with atrial fibrillation (AF). Three meta-analyses of randomized clinical trials (RCTs) comparing oral anticoagulants (OAC) with aspirin (ASA) arrived at different conclusions regarding the relative efficacy of these agents to prevent ischemic stroke in AF patients. This article summarizes a recently published individual patient meta-analysis of all published RCTs comparing OAC and ASA in AF. In total, 4052 patients randomized to OAC or ASA were similar regarding important prognostic factors. Patients receiving OAC had a significantly lower risk of any stroke (hazard ratio [HR] 0.54 [95% CI 0.43-0.71]), ischemic stroke (HR 0.48 [0.37-0.63]), or cardiovascular events (HR 0.71 [0.59-0.85]). Patients receiving OAC were more likely to experience major bleeding (HR 1.71 [1.21-2.41]). The benefit of OAC was most prominent in patients at a high risk of stroke and other cardiovascular events, such as patients with hypertension, diabetes, or previous cerebrovascular events. Overall, OAC improves outcomes for cardiovascular events in AF patients but modestly increases the absolute risk of major bleeding. Since high-risk AF patients appear to benefit most from OAC, determining stroke risk in AF patients is very important.
Administration, Oral↗