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Am Fam Physician. 2021;104(1):41-48

Related letter: Should Muscle Relaxants Be Used as Adjuvants in Patients With Acute Low Back Pain?

Published online June 9, 2021.

This clinical content conforms to AAFP criteria for CME.

Author disclosure: Dr. Grad has no relevant financial affiliations. Dr. Ebell is cofounder and editor-in-chief of Essential Evidence Plus; see Editor's Note.

This article summarizes the top 20 research studies of 2020 identified as POEMs (patient-oriented evidence that matters), including the two most highly rated guidelines of the year on gout and chronic obstructive pulmonary disease (COPD). Regarding COVID-19, handwashing and social distancing through stay-at-home orders or quarantine measures are effective at slowing the spread of illness. Use of proper face masks (not gaiters or bandanas) is also effective at preventing transmission. This is important because the virus can infect others during the presymptomatic phase. Aspirin can no longer be recommended for the primary prevention of cardiovascular disease. Human papillomavirus vaccination is strongly associated with reduced risk of invasive cervical cancer, especially in women who were vaccinated before 17 years of age. When a woman who is postmenopausal has a screening bone mineral density test, rechecking the test after three years does not help to identify those who will have a fragility fracture. A higher daily step count is associated with lower all-cause mortality. After one year of follow-up, physical therapy is preferred to glucocorticoid injections for osteoarthritis of the knee; acetaminophen is ineffective for acute low back pain or pain due to knee or hip osteoarthritis; and adding a muscle relaxant to ibuprofen does not improve functional outcomes or pain in people reporting moderate to severe back pain one week after starting treatment. Although short-term antibiotics and steroids are effective in treating acute exacerbations of COPD, not much else is. Successful communication with patients seeking an antibiotic for a flulike illness can be achieved with combinations of messaging, including information on antibiotic resistance and the self-limiting nature of the illness. A new prediction rule effectively identifies patients with a history of penicillin allergy who have a low likelihood of positive findings on allergy testing. Low-value screening tests in asymptomatic, low-risk patients often lead to further testing, diagnostic procedures, or referrals. A new tool helps determine the amount of change needed to signify a real difference between two laboratory values in the same person over time. Finally, a pillar of our specialty, continuity of care, is associated with decreased all-cause mortality.

Annually for 22 years, a team of clinicians has systematically reviewed English-language medical journals to identify original research most likely to change and improve primary care practice. The team includes experts in family medicine, pharmacology, hospital medicine, and women's health.1,2

The goal of this process is to identify POEMs (patient-oriented evidence that matters). A POEM must report at least one patient-oriented outcome, such as improvement in symptoms, morbidity, or mortality. It should also be free of important methodologic bias, making the results valid and trustworthy. Finally, if applied in practice, the results would change what some physicians do by prompting them to adopt a new practice or discontinue an old one that has been shown to be ineffective or harmful. Adopting POEMs in clinical practice should improve patient outcomes. Of more than 20,000 research studies published in 2020 in the journals reviewed by the POEMs team, 306 met criteria for validity, relevance, and practice change. These POEMs are emailed daily to subscribers of Essential Evidence Plus (Wiley-Blackwell, Inc.).

The Canadian Medical Association purchases a POEMs subscription for its members, many of whom receive the daily POEM. As these physicians read a POEM, they can rate it using a validated questionnaire. This process is called the Information Assessment Method ( POEM ratings address the domains of clinical relevance, cognitive impact, use of this information in practice, and expected health benefits if that POEM is applied to a specific patient.3,4 In 2020, each of the 306 daily POEMs was rated by an average of 1,230 physicians.

In this article, we present the 20 most clinically relevant POEMs as rated by Canadian Medical Association members in 2020. This is the 10th installment of our annual series ( As we write this article, the pandemic rolls on. However, beyond COVID-19, our patients continue to face the usual (and unusual) health problems of everyday life. Thus, we summarize the clinical question and bottom-line answer for research studies identified as a top 20 POEM, organized by topic and followed by a brief discussion. This set of 20 POEMs includes the two most relevant practice guidelines of the year. The full POEMs are available online at


The year 2020 saw the emergence of SARS-CoV-2, a novel coronavirus that causes the COVID-19 illness, and 54 POEMs addressed the epidemiology, diagnosis, treatment, and prognosis of patients with COVID-19. Not surprisingly, the four most highly rated POEMs of the year and five in the top 20 provided evidence regarding preventive measures (Table 1).510 These were published early in the pandemic and provided important evidence for family physicians to share with their patients.

Clinical questionBottom-line answer
1. Can advice to wash hands frequently reduce the transmission of respiratory tract infections?5 Handwashing reduces respiratory infections.
A brief online handwashing intervention reduced respiratory tract infections during the four months after it was completed (number needed to treat = 12).
2. Do quarantine measures reduce the spread of infection during a pandemic?6 Quarantine measures reduce the spread of infection.
A systematic review of 10 modeling studies of COVID-19, four observational studies, and 15 modeling studies of previous coronavirus pandemics showed that quarantine measures, particularly in conjunction with other public health measures, are consistently effective for reducing the spread of an epidemic.
3. Do stay-at-home orders reduce the spread of COVID-19?7,8 Stay-at-home orders reduce the spread of COVID-19.
Retrospective data suggest that the implementation of stay-at-home policies in U.S. counties slowed the spread of COVID-19.
4. How effective are the different types of face masks for preventing the spread of COVID-19?9 Polypropylene or surgical masks work well, and N95 masks work best.
Based on laser testing, gaiters and bandanas are useless, cotton or knitted masks are not very good, and polypropylene or surgical masks are much better. N95 masks transmit less than 0.1% of respiratory droplets of COVID-19.
5. How common is the presymptomatic transmission of the virus that causes COVID-19?10 Nearly half of COVID-19 transmissions occur during the presymptomatic phase.
This analysis of the temporal pattern of viral shedding found that 44% of secondary cases were infected when the index case was presymptomatic.

The most highly rated POEM was originally published in 2015 and reissued in 2020 after the content was updated for COVID-19. The study was a large pragmatic trial in the United Kingdom that randomized participants to a brief online hand-washing intervention or usual care. Those who completed the intervention had fewer respiratory tract infections over the next four months (51% vs. 59%; P < .001; number needed to treat = 12).5

The next COVID-19 POEM was a Cochrane review.6 The authors reviewed the results of modeling studies of COVID-19 and previous coronavirus pandemics, as well as four observational studies. They concluded that quarantine measures are effective in slowing the spread of infection, especially when implemented early and in conjunction with other public health measures.

The third POEM summarized the results of two ecologic studies. The first compared COVID-19 incidence rates in eight Iowa counties that did not have stay-at-home orders with seven neighboring Illinois counties that had such orders in place.7 The second compared a Georgia county that implemented stay-at-home orders approximately two weeks before the rest of Georgia with seven surrounding counties.8 In both studies, earlier implementation of stay-at-home orders was associated with a lower incidence of COVID-19.

Another POEM summarized the results of one of the earliest studies to evaluate the effectiveness of different kinds of masks for preventing the spread of respiratory droplets.9 Using laser technology, 14 types of masks were evaluated. Gaiters and bandanas were essentially useless, polypropylene and surgical masks were much better, and N95 masks were best.

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