Implementation of an intervention to reduce population-based screening for vitamin D deficiency: a cross-sectional study.

BACKGROUND: We describe the implementation of an intervention in Alberta in support of the Choosing Wisely Canada recommendation against population screening for vitamin D deficiency (as determined by serum total 25-hydroxyvitamin D testing). We hypothesized that the introduction of a specialized requisition for vitamin D testing would reduce the annual number of vitamin D tests performed. METHODS: We performed a cross-sectional observational study that included all vitamin D tests ordered in Alberta between Apr. 1, 2015, and Mar. 31, 2016. There were no exclusion criteria. A special requisition for ordering vitamin D tests in Alberta was introduced on Apr. 1, 2015. Using an interrupted time series model, we compared predicted versus observed vitamin D test volumes for the 12-month period following the introduction of the new requisition. The sole outcome measure was the monthly change in volume of vitamin D testing. In addition, we calculated any cost savings as a result of reduced testing. RESULTS: Over the first 12 months of the intervention, there was a reduction in the number of tests ordered from a predicted 342 477 tests to 29 525 tests (91.4% reduction). This decrease represented a direct spending decrease of Can$938 856-$1 564 760 per year in Alberta. INTERPRETATION: A provincially led implementation of a Choosing Wisely Canada recommendation resulted in a large and sustained reduction in serum total 25-hydroxyvitamin D testing in Alberta. This study shows that provincially led interventions based on Choosing Wisely Canada recommendations can result in substantial reductions in laboratory tests.

Statin Prescriptions for High-Risk Patients Are Increased by Laboratory-Initiated Framingham Risk Scores: A Quality-Improvement Initiative.

Low rates of cardiovascular preventive therapy with statin medications is a significant public health problem in Canada. There is a pressing need for public health interventions to increase the use of statin medications, especially among high-risk patients. In this article, we present the results of a quality assurance pilot program to provide laboratory-reported Framingham Risk Score (FRS) to physicians. This work was performed in a mixed urban and rural setting in southern Alberta. We provided FRSs and, for high-risk patients, statin treatment recommendations in conjunction with laboratory lipid panel requests. Adhesive labels were supplied to primary care physicians, and space was provided for information necessary for the calculation of the FRS by a laboratory information system. In total, 16 physicians from 4 different clinics participated in the pilot program. Data were collected from October 25, 2014-November 5, 2015, during which time 1266 patients had FRSs from the laboratory. Three hundred twenty-four individuals were identified as high risk for coronary heart disease (≥ 20% 10-year risk) and received a recommendation for treatment with a statin medication in the laboratory result report. These individuals had a 26% relative and a 6.4% absolute increase in statin prescriptions compared with before the pilot program. The laboratory-based provision of FRSs with statin treatment recommendations for high-risk individuals has the potential to significantly increase the use of statin drugs.

Comparison of 13 Commercially Available Cardiac Troponin Assays in a Multicenter North American Study.

BACKGROUND: We examined the concordance of 13 commercial cardiac troponin (cTn) assays [point-of-care, high-sensitivity (hs), and conventional] using samples distributed across a continuum of results. METHODS: cTnI (11 assays) and cTnT (2 assays) were measured in 191 samples from 128 volunteers. cTn assays included Abbott (iSTAT, STAT, and hs), Alere (Cardio 3), Beckman (AccuTnI+3), Pathfast (cTnI-II), Ortho (Vitros), Siemens (LOCI, cTnI-Ultra, Xpand, Stratus CS), and Roche [4th Generation (Gen), hs]. Manufacturer-derived 99th percentile cutoffs were used to classify results as positive or negative. Alternative 99th percentile cutoffs were tested for some assays. Correlation was assessed using Passing-Bablok linear regression, bias was examined using Bland-Altman difference plots, and concordance/discordance of each method comparison was determined using the McNemar method. RESULTS: Regression slopes ranged from 0.63 to 1.87, y-intercepts from 0.00 to 0.03 ng/mL, and r values from 0.93 to 0.99. The cTnT methods had a slope of 0.93, y-intercept of 0.02 ng/mL, and r value of 0.99. For the cTnI assays, positive, negative, and overall concordance was 76.2%-100%, 66.0%-100%, and 82.9%-98.4%, respectively. Overall concordance between the 4th Gen cTnT and hsTnT assays was 88.9%. A total of 30 of the 78 method comparisons showed significant differences in classification of samples (P <0.001); the iSTAT showed 10, hsTnT showed 9, AccuTnI+3 showed 5, Xpand showed 5, and Stratus CS showed 1. Using alternative 99th percentile cutoffs to those listed by manufacturers lowered the method discordance by 6-fold, from 30 to 5 (all involved iSTAT). CONCLUSIONS: These data provide insight into characteristics of cTn methods and will assist the healthcare community in setting expectations for relationships among commercial cTn assays.

Post-Policy Implementation Review of Rapid Fetal Fibronectin (fFN) Testing for Preterm Labour in Alberta.

OBJECTIVES: In 2006, the Alberta Ministry of Health issued a policy to implement fetal fibronectin (fFN) testing as a publicly funded service for pregnant women. The goals were to reduce maternity health care utilization and unnecessary treatment, which would result in cost-savings for the health system by more accurately diagnosing false preterm labour. We conducted a post-policy implementation review to determine whether the policy implementation achieved its goals. METHODS: We assessed the impacts of fFN testing on clinical decision-making for ambulance transfer, hospital admission, and length of hospital stay by comparing these variables between the tested and untested patients. This post-implementation analysis was conducted separately for inpatients and outpatients and for true and false preterm labour, using multilevel regressions with episodes or visits being nested within patients. We then assessed the impact of fFN testing on costs to the health system by using decision-tree models populated with actual data and results from the regressions. RESULTS: The additional information, provided by fFN testing, influenced clinical decision-making. However, physicians placed a greater significance on positive test results than on negative results, which resulted in an inadvertent increase in health care utilization. After including the costs of fFN testing, the total cost to the system increased by $4.2 million (in 2014 Canadian dollars) between 2008 and 2013, with contributions of $700 000 for false labour and $3.5 million for true preterm labour. CONCLUSION: The policy to adopt fFN testing in Alberta did not achieve the intended aims of reducing unnecessary health care utilization to achieve cost-savings for the health system. There was an inherent tendency to err on the side of caution, and physicians were influenced more by positive test results.

Factors Associated With Natriuretic Peptide Testing in Patients Presenting to Emergency Departments With Suspected Heart Failure.

BACKGROUND: Testing for natriuretic peptides (NPs) such as brain natriuretic peptide (BNP) or N-terminal prohormone brain natriuretic peptide (NT-proBNP) in the emergency department (ED) assists in the evaluation of patients with acute heart failure (HF). The aim of this study was to investigate factors related to the use of NP testing in the ED in a large population-based sample in Canada. METHODS: This was a retrospective cohort study using linked administrative data from Alberta in 2012. Patients were included if they had testing for an NP in the ED; a comparator group with HF but without NP testing was also included. RESULTS: Of the 16,223 patients in the cohort, 5793 were patients with HF (n = 3148 tested and n = 2645 not tested for NPs) and 10,430 were patients without HF but who were tested for NPs. Patients without HF who were tested for NPs had respiratory disease (34%), non-HF cardiovascular diseases (13%), and other conditions (52%). Patients with HF who were tested had a higher rate of hospital admission from the ED (78.4% vs 62.2%; P < 0.001) and lower 7-day and 90-day repeated ED visit rates compared with those who were not tested. Among patients with HF, male sex, being an urban resident, being seen by an emergency medicine or cardiology specialist, and being seen in hospitals with medium ED visit volumes were associated with increased likelihood of testing for NPs. CONCLUSIONS: Several factors, including the type of provider and ED clinical volume, influenced the use of NP testing in routine ED practice. Standardization of an NP testing strategy in clinical practice would be useful for health care systems.

Canadian family physician knowledge and attitudes toward laboratory utilization management.

OBJECTIVES: Mitigation of unnecessary and redundant laboratory testing is an important quality assurance priority for laboratories and represents an opportunity for cost savings in the health care system. Family physicians represent the largest utilizers of laboratory testing by a large margin. Engagement of family physicians is therefore key to any laboratory utilization management initiatives. Despite this, family physicians have been largely excluded from the planning and implementation of such initiatives. Our purposes were to (1) assess the importance of lab management issues to family physicians, and (2) attempt to define the types of initiatives most acceptable to family physicians. DESIGN AND METHODS: We invited all Alberta family practice residents and practicing physicians to participate in a self-administered online electronic survey. Survey questions addressed the perceived importance of lab misutilization, prevalence of various types of misutilization, acceptability of specific approaches to quality control, and responsibility of various parties to address this issue. RESULTS: Of 162 respondents, 95% considered lab misutilization to be either important or very important. Many physicians placed the responsibility for addressing lab misutilization issues on multiple parties, including patients, but most commonly the ordering physician (97%). Acceptability for common strategies for quality improvement in lab misutilization showed a wide range (35%-98%). CONCLUSIONS: These responses could serve as a framework for laboratories to begin discussions on this important topic with primary care groups.

The effect of paraproteins and rheumatoid factor on four commercial immunoassays for vancomycin: implications for laboratorians and other health care professionals.

BACKGROUND: Paraproteins, immunoglobulins (Igs), which are elevated in various autoimmune disorders, are known to interfere with various laboratory immunoassays, including vancomycin (VANC). Rheumatoid factor (RF), a known immunoassay interferant, may cause falsely elevated results. OBJECTIVES: The aims of this study were to (1) evaluate the effect of 3 paraproteins (IgA, IgG, and IgM) on 4 commercial VANC immunoassays [fluorescence polarization immunoassay; enzyme multiplied immunoassay; 2 particle-enhanced turbidimetric inhibition immunoassays]; (2) determine the concentration at which the effect is obtained, and (3) examine the influence of RF on the VANC methods. METHOD: Serum and plasma pools from patients prescribed VANC and a spiked VANC pool (20 mg/L) were each mixed 1:1 with individual patient specimens containing IgA (6-63 g/L), IgG (6-54 g/L), IgM (3-30 g/L) (n = 4 for each Ig), and a patient RF pool (196 IU/L). The mixtures (n = 39) were split and distributed for VANC analysis. RESULTS: IgA and IgG in serum and plasma did not affect any of the VANC immunoassays. RF added to plasma specimens did not interfere, but in serum, elevated VAN results were observed. IgM did not affect the fluorescence polarization immunoassay and enzyme multiplied immunoassay methods but did attenuate VANC concentrations by both particle-enhanced turbidimetric inhibition immunoassays (Siemens, Beckman Coulter), with a more pronounced effect on the latter, producing concentrations >20% lower than expected in the patient serum and spiked plasma pools. The effect was progressively negative at effective IgM concentrations of 10 and 15 mg/L. CONCLUSIONS: This phenomenon is a major analytical and clinical issue that must be communicated to health care professionals caring for patients receiving VANC, so optimal therapy is achieved.

Variation in the frequency of hemoglobin A1c (HbA1c) testing: population studies used to assess compliance with clinical practice guidelines and use of HbA1c to screen for diabetes.

BACKGROUND: The volume of hemoglobin A1c (HbA1c) testing has increased dramatically over the past decade and few studies have attempted to determine how the test is used. The goals of this study were to evaluate the frequency of HbA1c testing in regional populations to assess the extent of screening for diabetes and to determine if the HbA1c testing intervals of known diabetic patients were consistent with clinical practice guidelines. METHODS: Two years of HbA1c results were extracted from laboratory information systems in four regions of the province of Alberta that represent urban, mixed urban-rural, and rural populations. HbA1c testing frequencies and the proportions of nondiabetic patients undergoing HbA1c tests were derived. RESULTS: Approximately 60% of HbA1c tests in each region were done on patients who had only a single test during the 2-year interval. Testing of nondiabetic patients accounted for 24% of HbA1c tests and varied by region. While the cumulative frequency distributions of HbA1c test intervals resembled each other, detailed analyses of the frequency distributions depicted broad multimodal peaks and regional variations that suggest a great deal of heterogeneity among practices. The most common HbA1c testing interval was 3 months +/- 3 weeks in each region and is consistent with the 3-month test interval target in a clinical practice guideline. CONCLUSIONS: HbA1c testing is being performed on a substantial proportion of nondiabetic patients. On average, patients with diabetes in Alberta receive 1.5 HbA1c tests per year. However, we observed regional differences in the frequency of testing and variation in compliance with clinical practice guidelines.

Use of serial patient hemoglobin A1c differences to determine long-term imprecision of immunoassay and high-performance liquid chromatography analyzers.

BACKGROUND: The quality of the HbA1c assay is inversely proportional to the variation of the assay. Most published measures of HbA1c variation are limited by the data collection period, the statistical treatment of outliers, and even the noncommutability of the products used to generate the variation measurements. We have used an alternate approach to derive HbA1c variation, using serial patient data. METHODS: HbA1c measurements of outpatient blood sample pairs drawn within 30 days of each other were made on three different immunoassay systems: the Roche INTEGRA 700, the Roche INTEGRA 400, and the Dade Dimension RxL; and two high-performance liquid chromatography assays: the Tosoh G7 and the Tosoh 2.2+. The standard deviation of duplicates was calculated for the following time intervals: 1 to 3 days, 4 to 6 days, 7 to 9 days,.., 28 to 30 days. These intra-individual variations were then plotted; extrapolation to time zero yields the long term total random error which consists of both analytic and pre-analytic error. Data collection periods were usually 2 years. RESULTS: At the mean HbA1cs of 7.08%, 7.14%, 7.20%, 6.96%, and 7.51% for populations tested on the Roche INTEGRA 700, Roche INTEGRA 400, Dade Dimension RxL, Tosoh 2.2+, and Tosoh G7, respectively, the total analytic imprecisions (coefficient of variation) were 2.56%, 2.29%, 2.25%, 1.66%, and 1.14%, respectively. CONCLUSION: Assessment of the HbA1c long term total imprecisions shows that while the three immunoassay systems are acceptable, the Tosoh HbA1c analyzers demonstrate superior analytic performance.