Researchers establish handgrip strength thresholds for predicting mortality risk

Researchers have developed guidelines for testing handgrip strength that may help physicians gain insight into their patients’ mortality risk.

Muscle strength, which is often measured by handgrip strength, can be a “powerful predictor of mortality,” Sergei Scherbov, PhD, director of demographic analysis at the Wittgenstein Centre in Austria and deputy program director of the World Population Program at the International Institute for Applied Systems Analysis, and colleagues wrote in BMJ Open. Low handgrip strength has previously been linked to lung and heart issues, according to a press release related to the study.

Testing a patient’s handgrip strength has the potential to be an inexpensive screening tool for primary care physicians, but a lack of cut-off points that are both empirically meaningful and can be applied to the general population have made that difficult.

“In general, handgrip strength depends on gender, age, and the height of a person. Our task was to find the threshold related to handgrip strength that would signal a practitioner to do further examinations if a patient’s handgrip strength is below this threshold,” Scherbov said in the release. “It is similar to measuring blood pressure. When the level of blood pressure is outside of a particular range, the doctor can either decide to prescribe a particular medicine or to send the patient to a specialist for further examination.”

For the study, Scherbov and colleagues used a Smedley spring-type hand dynamometer to assess the handgrip strength of 8,156 U.S. adults aged 50 to 80 years.

The researchers established standardized handgrip strength thresholds based on age and gender. For men, the reference thresholds ranged from 45.9 kg to 49.4 kg among those aged 60 years and 41.2 kg to 44.8 kg for those aged 70 years. For women, the reference thresholds ranged from 28.4 kg to 30.7 kg among those aged 60 years and 25.4 kg to 27.7 kg among those aged 70 years.

Using these thresholds, Scherbov and colleagues said they found a connection between handgrip strength and remaining life expectancy (RLE). When they compared men in a reference group with men of the same age and height but slightly weaker handgrip strength, “the latter were shown to be 67% more likely to die earlier” (HR =1.67; 95% CI 1.23-2.26), Scherbov and colleagues wrote.

The correlation was further demonstrated when the researchers assessed the difference between the participants in groups with different levels of weak handgrip strength vs. the reference group. Among 60-year-old men in the group with a handgrip strength just below the standard, the estimated RLE was 18.4 years, which is three less than the standard, according to the researchers. In another group with even weaker handgrip strength, the RLE was 5.2 years less than standard. Meanwhile, the group differences in women were “somewhat smaller but still substantial,” the researchers wrote. Those aged 60 years who were in one of the weakest groups had an estimated RLE of 20.5, which was 3.3 years lower than the standard.

The results, the researchers wrote, “suggest that survival starts decreasing just below the group-specific average” handgrip strength, but there were no benefits for people with stronger handgrip strength.

The researchers additionally noted that “survival appears to decrease at much higher levels of muscle strength than is assumed in previous literature,” which suggests that physicians should be concerned even when their patient’s handgrip strength dips “slightly below that of the reference group.”

“The contributions may have wide applicability, given that the cut-off points provided in this paper, along with a visual illustration of them, can be routinely implemented in medical practice and that their link to RLE can be communicated to patients much more easily than previously reported,” the researchers wrote. “These thresholds can thus be used as a screening tool to identify patients who would benefit from further assessments, healthcare interventions or lifestyle changes.”

However, there are nuances that physicians must consider. The researchers wrote that handgrip strength “varies substantially with gender, age and body height,” which “confirms the importance of considering these heterogeneities when defining reference groups and risk thresholds.”

“Handgrip strength is a cheap and easy to perform test, but it may help with early diagnosis of health problems and other underlying health conditions,” Nadia Steiber, PhD, a professor of social stratification and quantitative methods at the University of Vienna, said in the release. “Monitoring the handgrip strength of the elderly (and in fact middle-aged people) may provide great benefits for the public health of aging populations. Our findings make it clear that handgrip strength is a very precise and sensitive measure of underlying health conditions. Therefore, we suggest it to be used as a screening tool in medical practice.”

References:

• Scherbov S, et al. BMJ Open. 2022;doi: 10.1136/bmjopen-2021-058489.
• Weak handgrip strength may signal serious health issues. https://www.eurekalert.org/news-releases/959790. Published July 25, 2022. Accessed Aug. 5, 2022.