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Lancet promotes its death-grip study without key context and caveats

Weak grip strength is linked with shorter survival and a greater risk of having a heart attack or stroke, according to an international study involving almost 140000 adults from 17 culturally and economically diverse countries [1].

 

The study, published in The Lancet, also found that grip strength is a stronger predictor of death than systolic blood pressure, and the authors suggest that it could be used as a quick, low-cost screening tool by doctors or other healthcare professionals to identify high-risk patients among people who develop major illnesses such as heart failure and stroke.

 

Reduced muscular strength, which can be measured by grip strength, has been consistently linked with early death, disability, and illness. But until now, information on the prognostic value of grip strength was limited, and mainly obtained from select high-income countries.

 

The current study followed 139691 adults aged between 35 and 70 years living in 17 countries from The Prospective Urban-Rural Epidemiology (PURE) study for an average (median) of four years. Grip strength was assessed using a handgrip dynamometer.

 

The findings show that every 5kg decline in grip strength [2] was associated with a 16% increased risk of death from any cause; a 17% greater risk of cardiovascular death; a 17% higher risk of non-cardiovascular mortality; and more modest increases in the risk of having a heart attack (7%) or a stroke (9%).

 

These associations persisted even after taking into account differences in other factors that can affect mortality or heart disease such as age, education level, employment status, physical activity level, and tobacco and alcohol use.

A low grip strength was linked with higher death rates in people who develop cardiovascular (eg, heart attack or stroke) and non-cardiovascular diseases (eg, cancer), suggesting that muscle strength can predict the risk of death in people who develop a major illness.

 

According to lead author Dr Darryl Leong from the Population Health Research Institute, Hamilton Health Sciences and McMaster University, Hamilton, Canada, “Grip strength could be an easy and inexpensive test to assess an individual’s risk of death and cardiovascular disease. Further research is needed to establish whether efforts to improve muscle strength are likely to reduce an individual’s risk of death and cardiovascular disease.” [3]

 

Writing in a linked Comment, Professor Avan Aihie Sayer from the University of Southampton, Southampton, UK, and Professor Thomas Kirkwood from Newcastle University, Newcastle upon Tyne, UK discuss whether grip strength could be a new biomarker of ageing, writing that, “This is not a new idea, but findings from PURE add support. Loss of grip strength is unlikely to lie on a single final common pathway for the adverse effects of ageing, but it might be a particularly good marker of underlying ageing processes, perhaps because of the rarity of muscle-specific diseases contributing to change in muscle function.”

 

NOTES TO EDITORS:

[1] The countries involved were Canada, Sweden, United Arab Emirates, Argentina, Brazil, Chile, Malaysia, Poland, South Africa, Turkey, China, Colombia, Iran, Bangladesh, India, Pakistan, and Zimbabwe.

[2] Grip strength is measured as the force exerted when a subject squeezes an object as hard as possible with their hands.

[3] Quote direct from author and cannot be found in text of Article.

 

Article: For interviews with Article author Dr Darryl Leong, Population Health Research Institute, McMaster University, Hamilton, Canada, please contact Veronica McGuire, Media Relations, McMaster University  T) +1 905-525-9140, ext. 22169 E) vmcguir@mcmaster.ca

 

Comment: For interviews with Professor Avan Aihie Sayer, MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK please email her directly at aas@mrc.soton.ac.uk

 

For full Article and Comment see: http://press.thelancet.com/gripstrength.pdf

 

For Appendix see: http://press.thelancet.com/gripstrengthappx.pdf

NOTE: THE ABOVE LINK IS FOR JOURNALISTS ONLY; IF YOU WISH TO PROVIDE A LINK TO THIS PAPER FOR YOUR READERS, PLEASE USE THE FOLLOWING, WHICH WILL GO LIVE AT THE TIME THE EMBARGO LIFTS: http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)62000-6/abstract

Caroline Brogan

Media Relations Assistant

The Lancet journals

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Email: c.brogan@lancet.com

Rating

2 Star

Testing hand-grip strength could be a simple, low-cost way to predict heart attack and stroke risk

Our Review Summary

This release about the ability of grip strength testing to predict death and disease rates leaves readers without enough context and ultimately overstates the importance of the findings. While the tone of the release is measured and the quotes include some caution about interpreting the results, there’s no mention anywhere in the release about the limits of observational studies — which are discussed both in the study that’s the basis for the release and the accompanying editorial. And although overall death rates are unquestionably an important outcome, the release does not tell readers what it would mean for a person to be identified as having a 17 percent higher risk. What use is that information and how would it affect how that person is cared for?

 

Why This Matters

“Why This Matters” is something this news release should have educated us about. A clinical test result is useful only when it helps people make decisions. This release should have spent more time addressing how the study results might be applied. Would identifying a person as being at a 17 percent increased risk of death or a 7 percent increased risk of a heart attack change how doctors would monitor or treat him or her? Would someone be prescribed a statin based on a finding of decreased hand grip strength? Even though the study was intended only to assess how grip test results in a wider variety of countries compare to previous findings in high-income countries, the release could have at least briefly mentioned how such test results are commonly used in clinical settings.

What’s more, it’s clear that news coverage, feeding off this news release, is reporting on this without caveats about observational studies, and therefore, delivering an incomplete message to the public. And it all started with this news release, because the caveats appear in both the journal article and in an accompanying commentary. Here are a handful of examples:

Your Handshake Tells the Story of Your Health

Patients’ grip strengths reveal heart attack risk: study

Palm ‘holds secrets of future health’

Why a weak handshake is bad news for your heart

Criteria

Does the news release adequately discuss the costs of the intervention?

Not Satisfactory

The release says that grip strength is low-cost, but a dynamometer is not something used routinely in clinical practice. Why not provide a cost estimate for both the dynamometers, the cost of administering the test in the clinical setting, and the cost of potential widespread risk-stratifying use?  Would this still be low-cost? Maybe so, but some projections are possible IF you deal with real numbers, not just the researchers’ value judgment that it is “low-cost.”

Does the news release adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

The release does not tell readers how important a 7 to 17 percent increase in risk for the measured outcomes really is. There are no absolute figures included, only relative risks. What’s more, the release makes no mention of how this sort of risk stratification would be used. Would people identified as having a 10-20 percent higher risk of certain conditions be offered different tests or treatments than those with stronger grips? Without this sort of context, readers of this release don’t have any way of knowing what the benefits of grip testing might be.

It is also odd that the headline and lead paragraph of the release highlighted heart attack and stroke, when the risk stratifications for those events were smaller than those for other outcomes.

Does the news release adequately explain/quantify the harms of the intervention?

Not Satisfactory

As mentioned in the section on benefits, the release does not explain how the test results might be used. If the intent is to steer people identified as being at higher risk toward more testing or treatment, then the release should have mentioned the risk of doing more harm through overtreatment. 

Does the news release seem to grasp the quality of the evidence?

Not Satisfactory

The release would have been better if it had included a clear statement near the top highlighting that this observational study cannot say whether poor grip strength itself predisposes a person to health problems or is merely a result of factors that also lead to health problems. The journal article included that caveat: “The observational nature of this study does not allow us to make strong conclusions on the causal role of muscular strength in death or cardiovascular disease. Although we adjusted for many potential confounders, we cannot exclude the possibility that residual confounding underlies the associations between grip strength and these outcomes.” And an accompanying editorial also described “the limitations of observational epidemiology to address causal pathways.”  Yet the Lancet news release made no mention of these clearly-stated limitations. Journal news releases could do a great deal to help educate journalists and the public about the value of, and the limitations of, such research.

Does the news release commit disease-mongering?

Satisfactory

The outcomes highlighted in the release, including overall death rates and cardiovascular disease, are indeed important, as is evidence on ways of improving clinical practice. But we’re troubled by the introduction of the concept of hand grip strength being a “new biomarker of aging” — as if aging were some type of disease that we need better tools to diagnose and/or monitor. We’ll rule it Satisfactory with some reservations.

Does the news release identify funding sources & disclose conflicts of interest?

Not Satisfactory

This rating is for a sin of omission. It does not appear that any conflicts were hidden, but all news releases should routinely report a summary of funding sources and disclosures.

The journal article reports funding sources for the study and lead authors. There are no competing interests reported. The maker of the dynamometer used does not appear to have played any role in the study. But even in cases like this, where it does not appear that there any funding or other conflicts of interest, news releases should routinely include some reference to funding and disclosures by researchers.

Does the news release compare the new approach with existing alternatives?

Not Satisfactory

The release specifically notes that grip strength results are a stronger predictor of death than systolic blood pressure. But what about the most common ways that clinicians currently assess the health risks of patients, such as with Framingham data and the related NHLBI heart risk assessment tool — free and online?  Call us picky, but we can easily recall widespread news coverage of whether wrinkles in your earlobes can predict heart attack risk.  So we don’t think it’s unreasonable to expect some reference to an enduring, well-supported alternative to the risk predictor of the day.

Does the news release establish the availability of the treatment/test/product/procedure?

Satisfactory

The release implies that the type of dynamometer used to assess grip strength in this study is widely available, but a clearer statement about availability, especially in low-income countries, would have made the release better.

Does the news release establish the true novelty of the approach?

Satisfactory

The release notes that this association between grip strength and health risks has been documented previously in high-income countries, and that a key feature of this study is the inclusion of people from low- and middle-income countries.

Does the news release include unjustifiable, sensational language, including in the quotes of researchers?

Not Satisfactory

This is a close call. The tone of the release is generally measured. However, the release headline suggests that hand grip strength is “simple” and “low cost” — neither of which have been proven in widespread clinical practice. It takes training to use this device and interpret the results correctly. And it’s not clear how accurate this test is or if it’ll lead to unnecessary tests or treatments. In other words, the release conveys a certainty about this test that just doesn’t exist — something we think is unjustified.

Total Score: 3 of 10 Satisfactory

Comments (3)

Please note, comments are no longer published through this website. All previously made comments are still archived and available for viewing through select posts.

Gary Schwitzer

May 15, 2015 at 10:51 am

The day after we published this review of a news release by The Lancet, we again criticized two news releases sent to journalists on the same day by BMJ. Both were on observational studies in journals published by BMJ. One had caveats, one did not. The confusion caused by these inconsistent and adjacent messages may be seen in the news stories based on those releases. https://www.healthnewsreview.org/2015/05/continued-problems-with-bmj-news-releases/

Gary Schwitzer, Publisher, HealthNewsReview.org

Reply

Martin Sharman

May 18, 2015 at 9:43 am

The point of measuring grip strength is that it is a predictor of general muscle strength. General muscle strength is a predictor of mortality. If you have damage to your hands that weakens the strength of your grip it’s no longer a good predictor of general muscle strength, so the strength of grip in people with damaged hands is not a pointer to general muscle strength and hence not a predictor of mortality.

Reply

Gary Schwitzer

May 19, 2015 at 11:23 am

On his journal review blog for The BMJ, Dr. Richard Lehman wrote about the study upon which this news release was based: “Hang on, get a grip on yourselves, dear epidemiologists. By bunging a massive amount of data into your software you have come up with a plausible association between having weak hands and dying a bit sooner. Are you seriously expecting us to test the hypothesis that strengthening peoples’ hands will help them live longer?”

Reply