Christina Korownyk

Agreement among Cardiovascular Disease Risk Calculators

Background— Use of cardiovascular disease risk calculators is often recommended by guidelines, but research on consistency in risk assessment among calculators is limited. Method and Results— A search of PubMed and Google was performed. Five clinicians selected 25 calculators by independent review. Hypothetical patients were created with the use of 7 risk factors (age, sex, smoking, blood pressure, high-density lipoprotein, total cholesterol, and diabetes mellitus) dichotomized to high and low, generating 27 patients (128 total). These patients were assessed by each calculator by 2 clinicians. Risk estimates (and assigned risk categories) were compared among calculators. Selected calculators were from 8 countries, used 5- or 10-year predictions, and estimated either cardiovascular disease or coronary heart disease. With the use of 3 risk categories (low, medium, and high), the 25 calculators categorized each patient into a mean of 2.2 different categories, and 41% of unique patients were assigned across all 3 risk categories. Risk category agreement between pairs of calculators was 67%. This did not improve when analysis was limited to just the 10-year cardiovascular disease calculators. In nondiabetics, the highest calculated risk estimate from a calculator averaged 4.9 times higher (range, 1.9–13.3) than the lowest calculated risk estimate for the same patient. This did not change meaningfully for diabetics or when the analysis was limited to 10-year cardiovascular disease calculators. Conclusions— The decision as to which calculator to use for risk estimation has an important impact on both risk categorization and absolute risk estimates. This has broad implications for guidelines recommending therapies based on specific calculators.

Televised medical talk shows—what they recommend and the evidence to support their recommendations: a prospective observational study

Objective To determine the quality of health recommendations and claims made on popular medical talk shows. Design Prospective observational study. Setting Mainstream television media. Sources Internationally syndicated medical television talk shows that air daily (The Dr Oz Show and The Doctors). Interventions Investigators randomly selected 40 episodes of each of The Dr Oz Show and The Doctors from early 2013 and identified and evaluated all recommendations made on each program. A group of experienced evidence reviewers independently searched for, and evaluated as a team, evidence to support 80 randomly selected recommendations from each show. Main outcomes measures Percentage of recommendations that are supported by evidence as determined by a team of experienced evidence reviewers. Secondary outcomes included topics discussed, the number of recommendations made on the shows, and the types and details of recommendations that were made. Results We could find at least a case study or better evidence to support 54% (95% confidence interval 47% to 62%) of the 160 recommendations (80 from each show). For recommendations in The Dr Oz Show, evidence supported 46%, contradicted 15%, and was not found for 39%. For recommendations in The Doctors, evidence supported 63%, contradicted 14%, and was not found for 24%. Believable or somewhat believable evidence supported 33% of the recommendations on The Dr Oz Show and 53% on The Doctors. On average, The Dr Oz Show had 12 recommendations per episode and The Doctors 11. The most common recommendation category on The Dr Oz Show was dietary advice (39%) and on The Doctors was to consult a healthcare provider (18%). A specific benefit was described for 43% and 41% of the recommendations made on the shows respectively. The magnitude of benefit was described for 17% of the recommendations on The Dr Oz Show and 11% on The Doctors. Disclosure of potential conflicts of interest accompanied 0.4% of recommendations. Conclusions Recommendations made on medical talk shows often lack adequate information on specific benefits or the magnitude of the effects of these benefits. Approximately half of the recommendations have either no evidence or are contradicted by the best available evidence. Potential conflicts of interest are rarely addressed. The public should be skeptical about recommendations made on medical talk shows. Additional details of methods used and changes made to study protocol

An aspirin a day? Aspirin use across a spectrum of risk: cardiovascular disease, cancers and bleeds

Aspirin or acetylsalicylic acid (ASA) is commonly used in the general population for primary prevention of cardiovascular disease (CVD). Strong evidence supports the use of ASA in secondary prevention of CVD; however, for primary prevention, potential benefits are offset by potential harms (primarily major bleeds), with no benefit in overall mortality. Anti-platelet agents, including ASA, are one of the most commonly implicated medications for hospital admissions related to adverse medication events. Studies of primary prevention in patients with risk factors for CVD also fail to show a benefit with ASA. Finally, evidence supporting ASA use for cancer prevention is limited. Health care providers should be aware of the benefits and risks associated with ASA use in primary and secondary prevention and discuss these with their patients in the context of individual patient values and preferences.

Seasonality of Ankle Swelling: Population Symptom Reporting Using Google Trends

In our experience, complaints of ankle swelling are more common in summer, typically from patients with no obvious cardiovascular disease. Surprisingly, this observation has never been reported. To objectively establish this phenomenon, we sought evidence of seasonality in the public’s Internet searches for ankle swelling. Our data, obtained from Google Trends, consisted of all related Google searches in the United States from January 4, 2004, to January 26, 2016. Consistent with our expectations and confirmed by similar data for Australia, Internet searches for information on ankle swelling are highly seasonal (highest in midsummer), with seasonality explaining 86% of search volume variability.

Effectiveness of antidepressants

Lots of useful data but many important questions remain

The impact of breast reduction surgery on breastfeeding: Systematic review of observational studies

Background Almost half a million breast reduction surgeries are performed internationally each year, yet it is unclear how this type of surgery impacts breastfeeding. This is particularly important given the benefits of breastfeeding. Objectives To determine if breast reduction surgery impacts breastfeeding success and whether different surgical techniques differentially impact breast feeding success. Methods Databases were searched up to September 5, 2017. Studies were included if they reported the number of women successful at breastfeeding or lactation after breast reduction surgery, and if they reported either the total number of women who had children following breast reduction surgery, or the total number of women who attempted to breastfeed following surgery. Results Of 1,212 studies, 51 studies met the inclusion criteria; they were located worldwide and had 31 distinct breast reduction techniques. The percentage of breastfeeding success among studies was highly variable. However, when analyzed by the preservation of the column of parenchyma from the nipple areola complex to the chest wall (subareolar parenchyma), a clear pattern emerged. The median breastfeeding success was 4% (interquartile range (IQR) 0–38%) for techniques with no preservation, compared to 75% (IQR 37–100%) for techniques with partial preservation and 100% (IQR 75–100%) for techniques with full preservation. Conclusions Techniques that preserve the column of subareolar parenchyma appear to have a greater likelihood of successful breastfeeding. The preservation of the column of subareolar parenchyma should be disclosed to women prior to surgery. Guidelines on the best breast reduction techniques to be used in women of child bearing years may be advantageous to ensure women have the greatest potential for successful breastfeeding after breast reduction surgery.

Are potentially clinically meaningful benefits misinterpreted in cardiovascular randomized trials? A systematic examination of statistical significance, clinical significance, and authors’ conclusions

BackgroundWhile journals and reporting guidelines recommend the presentation of confidence intervals, many authors adhere strictly to statistically significant testing. Our objective was to determine what proportions of not statistically significant (NSS) cardiovascular trials include potentially clinically meaningful effects in primary outcomes and if these are associated with authors’ conclusions.MethodsCardiovascular studies published in six high-impact journals between 1 January 2010 and 31 December 2014 were identified via PubMed. Two independent reviewers selected trials with major adverse cardiovascular events (stroke, myocardial infarction, or cardiovascular death) as primary outcomes and extracted data on trial characteristics, quality, and primary outcome. Potentially clinically meaningful effects were defined broadly as a relative risk point estimate ≤0.94 (based on the effects of ezetimibe) and/or a lower confidence interval ≤0.75 (based on the effects of statins).ResultsWe identified 127 randomized trial comparisons from 3200 articles. The primary outcomes were statistically significant (SS) favoring treatment in 21% (27/127), NSS in 72% (92/127), and SS favoring control in 6% (8/127). In 61% of NSS trials (56/92), the point estimate and/or lower confidence interval included potentially meaningful effects. Both point estimate and confidence interval included potentially meaningful effects in 67% of trials (12/18) in which authors’ concluded that treatment was superior, in 28% (16/58) with a neutral conclusion, and in 6% (1/16) in which authors’ concluded that control was superior. In a sensitivity analysis, 26% of NSS trials would include potential meaningful effects with relative risk thresholds of point estimate ≤0.85 and/or a lower confidence interval ≤0.65.ConclusionsPoint estimates and/or confidence intervals included potentially clinically meaningful effects in up to 61% of NSS cardiovascular trials. Authors’ conclusions often reflect potentially meaningful results of NSS cardiovascular trials. Given the frequency of potentially clinical meaningful effects in NSS trials, authors should be encouraged to continue to look beyond significance testing to a broader interpretation of trial results.

Effect of medication timing on anticoagulation stability in users of warfarin (the INRange RCT): Study protocol for a randomized controlled trial

BackgroundWarfarin is an oral anticoagulant medication that disrupts the liver’s production of clotting factors. While this medication is highly effective for the prevention of thromboembolic events, it also has a narrow therapeutic range and a vulnerability to interactions with other drugs and vitamin K-containing foods. Warfarin is commonly ingested at dinnertime, the same time of day that dietary vitamin K consumption (found largely in green leafy vegetables) is most variable. While the long half-life of warfarin might make this irrelevant, the ultra short half-life of vitamin K and the possibility of a hepatic first-pass effect for warfarin make it worth evaluating whether morning ingestion of warfarin, when vitamin K levels are consistently low, leads to greater stability of its anticoagulant effect. An examination of the timing of administration on the effectiveness of warfarin has never before been conducted.Methods/designThis is a 7-month Prospective Randomized Open Blinded End-point (PROBE) study in which established evening warfarin users (primary care managed Canadian outpatients in the provinces of British Columbia and Alberta) will be randomized to either switch to morning ingestion of warfarin (the intervention) or to continue with evening use (the control). The primary outcome is the percent change in the proportion of time spent outside the therapeutic range of the international normalized ratio (INR) blood test. Secondary outcomes include change in proportion of time spent within the therapeutic INR range (TTR), percentage of patients with TTR >75 %, percentage of patients with TTR <60 %, and major warfarin-related cardiovascular events (including all-cause mortality, hospitalization for stroke, hospitalization for GI bleeding, and deep venous thrombosis/pulmonary embolism). We will also compare whether day-to-day variability in the consumption of high vitamin K-containing foods at baseline affects the baseline TTR in this cohort of evening warfarin users.DiscussionThis study addresses whether the timing of warfarin ingestion influences the stability of its anticoagulant effect. Should morning ingestion prove superior, the safety and effectiveness of this medication, and hence the prevention of stroke, pulmonary embolus, and major hemorrhage, could potentially be improved with no added cost or inconvenience to the patient.Trial registrationClinicalTrials.gov: NCT02376803. Registered on 25 February 2015.

A descriptive analysis of a novel intervention to help residents become evidence users

Background and objectives: To evaluate the educational and clinical effectiveness of the ‘Brief Evidence-Based Assessment of Research’ (BEAR), a template to assist residents in searching, evaluating and integrating relevant medical literature into daily practice. Methods: We completed a descriptive analysis of BEARs submitted by first year residents between 2005 and 2007 at the University of Alberta Family Medicine Residency program. Results: 317 BEARs were analyzed. The most common type of question for which information was searched was therapy (59%). Residents searched Pubmed most often (38%) followed by Summary (i.e. Clinical Evidence) (22%) and Filtered sites (i.e. ACP Journal Club) (19%). Original research articles were the largest resource category used to answer questions (41%). Secondary peer-reviewed resources (filtered articles, summary sites, reviews/meta-analysis and guidelines) accounted for 48% of all resources used. 19% of residents reported a large change in practice with completion of the BEAR, 50% reported a small change, 12% stated they were reassured and 8% reported that the intervention was of no help to them. Conclusions: The BEAR facilitates the use of a variety of resources in answering clinical questions. 69% of users reported at least a small change in clinical practice, suggesting that the BEAR may be a useful tool in evidence-based resident education.

Response to Letters Regarding “Agreement Among Cardiovascular Disease Risk Calculators”

We thank Drs Payne and Webb and Drs Echouffo-Tcheugui and Kengne for their letters regarding our article “Agreement Among Cardiovascular Disease Risk Calculators.”1 Drs Payne and Webb raised concern we did not explore why differences exist in the risk calculator estimations or examine how risk estimation may influence patient/clinician behavior. Those are both important issues. As mentioned in our article, our objective was to assess the consistency of a broad sample of commonly used calculators over a sample of patients with a range of cardiovascular risk factors. We wanted to describe the disagreement among calculators (if it occurred). The next but separate question is why does it occur. We explored some subgroups that might help explain the differences and found focusing on Framingham 10-year Cardiovascular Disease risk calculators improved agreement (same database, same duration, and similar outcomes). Furthermore, we also discussed some of the potential causes of disagreement in the conclusion. We focused on describing agreement primarily and stated that more research is …