G. Michael Allan

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

How confidence intervals become confusion intervals.

BackgroundControversies are common in medicine. Some arise when the conclusions of research publications directly contradict each other, creating uncertainty for frontline clinicians.DiscussionIn this paper, we review how researchers can look at very similar data yet have completely different conclusions based purely on an over-reliance of statistical significance and an unclear understanding of confidence intervals. The dogmatic adherence to statistical significant thresholds can lead authors to write dichotomized absolute conclusions while ignoring the broader interpretations of very consistent findings. We describe three examples of controversy around the potential benefit of a medication, a comparison between new medications, and a medication with a potential harm. The examples include the highest levels of evidence, both meta-analyses and randomized controlled trials. We will show how in each case the confidence intervals and point estimates were very similar. The only identifiable differences to account for the contrasting conclusions arise from the serendipitous finding of confidence intervals that either marginally cross or just fail to cross the line of statistical significance.SummaryThese opposing conclusions are false disagreements that create unnecessary clinical uncertainty. We provide helpful recommendations in approaching conflicting conclusions when they are associated with remarkably similar results.

Do scores on three commonly used measures of critical thinking correlate with academic success of health professions trainees? A systematic review and meta-analysis.

Purpose To determine whether the three commonly used measures of critical thinking correlate with academic success of medical professionals in training. Method The search for English-language articles (from 1980 to 2011) used Medline, Embase, Scopus, Cochrane Library on Ovid, Proquest Dissertations, Health and Psychosocial Instruments, PsychINFO, and references of included articles. Studies comparing critical thinking with academic success among medical professionals were included. Two authors performed study selection independently, with disagreement resolved by consensus. Two authors independently abstracted data on study characteristics, quality, and outcomes, with disagreement resolved by a third author. Critical thinking tests studied were the California Critical Thinking Skills Test (CCTST), California Critical Thinking Disposition Inventory (CCTDI), and Watson-Glaser Critical Thinking Appraisal. Correlation coefficients were pooled in meta-analysis. Results The search identified 557 studies: 52 met inclusion for systematic review, 41 of which were meta-analyzed. Critical thinking was positively correlated with academic success, r = 0.31 (95% confidence intervals [CI] 0.26, 0.35), with a moderate statistical heterogeneity (I2 = 67%). In subgroup analysis, only student type had statistical significance for correlation, although bias was likely due to low numbers for some student types. In direct comparison, using studies that employed two critical thinking tests, the CCTDI (r = 0.23, 95% CI 0.15, 0.30) was significantly inferior (P < .001) to the CCTST (r = 0.39, 95% CI 0.33, 0.45). Conclusions Critical thinking was moderately correlated with academic success of medical professionals in training. The CCTDI was inferior to the CCTST in correlating with academic success.

Interfacility Transport of Patients With Decompression Illness: Literature Review andConsensus Statement

Objective. Decompression illness (DCI) is a potentially lethal complication of diving andmay occur far from hyperbaric facilities. The need for prompt transport to a hyperbaric facility often involves air medical transport, but this may exacerbate DCI. The authors reviewed available literature to establish evidence-based transport strategies utilizing safe altitudes for patients, with DCI. Methods. MEDLINE, EMBASE, andmaterials from organizations with expertise in diving medicine were searched for the following terms: decompression sickness, caisson disease, hyperbaric oxygenation, depth intoxication, or diving. Two reviewers independently selected relevant citations involving patients with DCI andair medical transport for review andconsensus statement development by an expert working group. Results. A total of 341 citations were identified, and53 unique citations were reviewed. Nine relevant citations were selected for consensus statement development. There were no clinical trials or prospective cohort studies. Only two retrospective case series, including nine patients, specifically examined the effect of altitude on patients with DCI during transport. No symptom recurrence occurred when the cabin altitude remained within 500 feet of ground level. Seven citations were either letters or statements of expert opinion, recommending a maximum cabin altitude of 500–1000 feet (152–305 meters). Conclusions. The working group identified the paucity of clinical studies andevidence-based recommendations for air medical transport of patients with DCI. Transport selection should be based on minimizing total transport time and, when transporting by air, ensuring that a cabin altitude of the transporting vehicle does not exceed 500 feet (152 meters) above the departure point. Key words: decompression sickness; atmospheric pressure; depth intoxication; air ambulance; emergency medical services.

Measuring hsCRP—An Important Part of a Comprehensive Risk Profile or a Clinically Redundant Practice?

James McCormack and Michael Allan discuss issues and questions surrounding hsCRP measurements in patients.

Furthering the prostate cancer screening debate (prostate cancer specific mortality and associated risks)

Screening for prostate cancer remains a contentious issue. As with other cancer screening programs, a key feature of the debate is verification of cancer-specific mortality reductions. Unfortunately the present evidence, two systematic reviews and six randomized controlled trials, have reported conflicting results. Furthermore, half of the studies are poor quality and the evidence is clouded by key weaknesses, including poor adherence to screening in the intervention arm or high rates of screening in the control arm. In high quality studies of prostate cancer screening (particularly prostate-specific antigen), in which actual compliance was anticipated in the study design, there is good evidence that prostate cancer mortality is reduced. The numbers needed to screen are at least as good as those of mammography for breast cancer and fecal occult blood testing for colorectal cancer. However, the risks associated with prostate cancer screening are considerable and must be weighed against the advantage of reduced cancer-specific mortality. Adverse events include 70% rate of false positives, important risks associated with prostate biopsy, and the serious consequences of prostate cancer treatment. The best evidence demonstrates prostate cancer screening will reduce prostate cancer mortality. It is time for the debate to move beyond this issue, and begin a well-informed discussion on the remaining complex issues associated with prostate cancer screening and appropriate management.

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.

Health of Chinese illegal immigrants who arrived by boat on the West Coast of Canada in 1999.

This was a retrospective review and descriptive analysis of the findings from the medical screening examinations conducted on the illegal migrants from Fujian Province of China (n = 589) who arrived on four boats on the West Coast of Canada between June 14 and September 9, 1999. The Canadian Navy conducted a screening medical exam of the illegal migrants, with Health Canada and Citizenship and Immigration Canada providing suggestions on the format of the exam. The illegal Chinese migrants were predominantly young, male adults. The most prevalent medical conditions detected were dermatological (55.2%), dental problems (25%), trauma (9.2%), urogenital (7.6%), and head/neck (6.6%). Recently induced trauma was more prevalent among females (20.5%) than males (6.5%). One case of community-acquired pneumonia was identified and later diagnosed as active pulmonary tuberculosis. Physicians dealing with illegal migrants should look for unusual physical findings and have a higher clinical suspicion regarding infectious diseases (tuberculosis, scabies) and abuse. Future encounters with illegal migrants should include standardized immigration screening exams, with adequate history taking and follow-up.

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.