Monday, November 26, 2018

Out-of-hospital management of low-risk patients with acute pulmonary embolism

I've practiced family medicine long enough to remember when treatment of any patient with acute deep venous thrombosis (DVT) required hospitalization for several days administering intravenous unfractionated heparin and oral warfarin while waiting for the patient's international normalized ratio (INR) to reach a therapeutic level. Thanks to the development of low molecular-weight heparins and direct-acting oral anticoagulants (DOAC), outpatient treatment of uncomplicated DVT is now the norm. But patients with newly diagnosed pulmonary embolism (PE) are still typically hospitalized, since they often have hemodynamic instability or other potentially life-threatening conditions.

According to a 2017 article in American Family Physician, the American College of Chest Physicians suggests considering outpatient treatment of acute PE "if the risk of nonadherence is low and the patient is clinically stable; has no contraindications to anticoagulation, such as recent bleeding, severe renal or liver disease, or platelet count of less than 70; and feels capable of managing the disease at home." A recent Point-of-Care Guide reviewed clinical decision tools that predict mortality in patients with newly diagnosed PE. The simplified Pulmonary Embolism Severity Index (sPESI) stratifies patients into low and high risk categories. Low risk patients have a 30-day mortality rate of 1%, while high risk patients have a 9% mortality rate.

A prospective cohort study published in CHEST earlier this year enrolled 200 consecutive adults with newly diagnosed PE and a low risk of mortality using the related Pulmonary Embolism Severity Index (PESI). Participants were observed in the emergency department (ED) for 12 to 24 hours, then treated with anticoagulant medications in the outpatient setting (173 patients were treated with DOACs). After 90 days, no patients had died or suffered a recurrent venous thromboembolism (VTE). One patient had a major bleed after a traumatic thigh injury that required a blood transfusion and surgery.

A pragmatic controlled trial in Annals of Internal Medicine evaluated the effect of implementing an electronic clinical decision support system (CDSS) that included the PESI tool and an educational intervention on decision making for patients with acute PE in the 21 community EDs of Kaiser Permanente Northern California. 10 EDs received access to the CDSS and in-person education and feedback from an onsite emergency physician-researcher ("study champion"); the other 11 EDs served as control sites. The primary outcome was discharge to home from the ED or an ED-based outpatient observation unit. At the intervention sites, home discharge increased from 17.4% to 28%, while there were no changes in discharge practices at control sites. The intervention was not associated with increases in 30-day major adverse events (recurrent VTE, major hemorrhage, or all-cause mortality).

One day, one of my trainees will be able to write, "I've practiced family medicine long enough to remember when even low-risk patients with acute PE required hospitalization ..."


This post first appeared on the AFP Community Blog.

Tuesday, November 20, 2018

Delving deeper into the problem of overdiagnosis in medicine

Over the summer, two family physician colleagues and I published a commentary in Public Health Reviews on the implications of overscreening for carotid artery stenosis, prediabetes, and thyroid cancer. A theme connecting these three abnormalities (I won't call them "diseases," as evidence suggests that the most persons who receive these diagnoses through screening would be better off not knowing and being spared premature, costly, and/or invasive therapies) is that they are largely creations of modern medicine. A person can't feel a narrowing in a carotid artery, a slightly higher than normal blood sugar level, or a tiny thyroid nodule - instead, they learn about them after a doctor performs a test, either specifically to look for the abnormality or as an incidental finding. If the diagnosis leads to improved health outcomes, that's good news; if it only causes anxiety and unnecessary interventions, that's overdiagnosis.

2018 has seen the publication of several excellent reviews of the effects of overdiagnosis in primary care. In the Annals of Internal Medicine, Evidence-based Practice Center researchers affiliated with the U.S. Preventive Services Task Force (USPSTF) wrote about defining, estimating, and communicating overdiagnosis in cancer screening. They observed that several different study designs and approaches have been used to estimate the percentages of cancer cases that are overdiagnosed, all with limitations. (Sidebar: in a commentary in JAMA Internal Medicine, former USPSTF member Mark Ebell, MD, MS and I explored how these methods were used to produce varying estimates of overdiagnosis in randomized trials of lung cancer screening with low-dose CT scans.)

Members of the Canadian Task Force on Preventive Health Care (the evidence-based prevention panel after which the USPSTF was modeled) reviewed "causes and consequences" of overdiagnosis in primary care in a case-based discussion in Canadian Family Physician. Across the pond, the BMJ published a state-of-the-art review by two U.S. internists. Drs. Minal Kale and Deborah Korenstein pointed out that drivers of overdiagnosis include broadening disease definitions, advanced technology, public health screening programs, culture around medicine and health (e.g., "more screening is always better"), system factors (e.g., profit-driven testing, direct-to-consumer advertising, industry influence on guidelines and medical education), and limitations in evidence application. Finally, the World Organization of Family Doctors (WONCA) Europe released a position paper that defined overdiagnosis as "transforming people into patients unnecessarily" and urged family physicians, on behalf of their patients, to "demand balanced evidence informed and non emotional information material from providers and authorities in relation to cancer screening, health checks, etc."

Potential solutions to the problem of overdiagnosis should address each of the drivers, as outlined in a 2017 BMJ article by researchers at Bond University in Australia, which will co-host next year's international Preventing Overdiagnosis conference. One cancer-specific solution is to re-name low risk conditions currently labelled as cancer, such as small papillary thyroid cancers, ductal carcinoma in situ (DCIS), localized low-grade prostate cancer, melanoma in situ, and certain small lung and kidney cancers.

Tuesday, November 13, 2018

For mild hypertension in low-risk adults, harms of drug therapy outweigh benefits

Prior to publication of the controversial 2017 ACC/AHA clinical practice guideline, stage 1 or "mild" hypertension was defined as a systolic blood pressure of 140-159 mm Hg and/or diastolic blood pressure of 90-99 mm Hg. Although guidelines have recommended that persons with mild hypertension receive anti-hypertensive drug therapy if lifestyle modification does not lower blood pressure below 140/90, a Cochrane review found that such therapy did not reduce cardiovascular disease (CVD) events, stroke, or mortality compared to placebo. A 2015 meta-analysis that included high-risk persons (patients with diabetes and/or who had received prior antihypertensive treatment) suggested that drug therapy for mild hypertension may prevent CVD events, but others have argued that this analysis mixed apples with oranges and did not establish benefits for adults at low CVD risk.

A retrospective cohort study recently published in JAMA Internal Medicine sought to clarify the benefits and harms of drug therapy in low-risk adults with mild hypertension using data from 40,000 patients in an electronic health records database in the United Kingdom. The authors compared the outcomes of persons aged 18 to 74 with mild hypertension who were prescribed anti-hypertensive medications within 12 months of diagnosis to those in similar untreated persons. Persons with a history of CVD, left ventricular hypertrophy, atrial fibrillation, diabetes, chronic kidney disease, or a family history of premature heart disease were excluded from the study.

After a median follow-up duration of 5.8 years, there were no differences between the groups in all-cause mortality, stroke, myocardial infarction, acute coronary syndrome, or heart failure. However, the treated group had an increased risk of hypotension (number needed to harm = 41 at 10 years), syncope (NNH = 35), electrolyte abnormalities (NNH = 111), and acute kidney injury (NNH = 91).

Although ideally the findings from this observational study should be confirmed in a randomized, controlled trial, it is unlikely that a trial will ever be performed due to the large number of participants that would be needed in order to provide enough statistical power to detect a difference in mortality or rare CVD events in this population. In the meantime, the best available evidence suggests that the harms of drug therapy outweigh benefits for low-risk adults with a systolic blood pressure of 140-159 mm Hg and/or diastolic blood pressure of 90-99 mm Hg (recently redefined by the ACC/AHA as stage 2 hypertension). In these patients, family physicians and other primary care clinicians should emphasize nonpharmacologic management strategies such as a diet with a high intake of vegetables, fruits, and whole grains; moderating excessive sodium intake and alcohol consumption; and at least 150 minutes per week of moderate-intensity aerobic physical activity, as recommended in the latest Physical Activity Guidelines for Americans.


A slightly different version of this post first appeared on the AFP Community Blog.