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What’s New in the Patient Safety World

January 2021

The Frailty Meter



Our August 17, 2010 Patient Safety Tip of the Week “Preoperative Consultation – Time to Change” suggested the 3 most important things to screen for during a preoperative evaluation are frailty, delirium risk, and obstructive sleep apnea. Frailty clearly has been linked to post-operative adverse events and poorer patient outcomes following surgery (see our multiple columns listed below).


We are always looking for simple tests for frailty that can be applied in brief sessions in a surgeon’s office or other preoperative assessment setting. In our May 16, 2017 Patient Safety Tip of the Week “Are Surgeons Finally Ready to Screen for Frailty?” we noted a study that looked at individual components of the Fried frailty phenotype measures (gait speed, hand-grip strength as measured by a dynamometer, and self-reported exhaustion, low physical activity, and unintended weight loss) in a primary care setting (Lee 2017). The researchers found that individual criteria all showed sensitivity and specificity of more than 80%, with the exception of weight loss. The positive predictive value of the single-item criteria in predicting the Fried frailty phenotype ranged from 12.5% to 52.5%. When gait speed and hand-grip strength were combined as a dual measure, the positive predictive value increased to 87.5%. They conclude that, while use of gait speed or grip strength alone was found to be sensitive and specific as a proxy for the Fried frailty phenotype, use of both measures together was found to be accurate, precise, specific, and more sensitive than other possible combinations and that assessing both measures is feasible within the primary care setting.


Almost all the scales we use for detecting frailty include measures of gait (such as the Timed Up-and-Go test or measures of gait speed). But what about those patients in whom it is not possible to assess gait?


Najafi and colleagues (Najafi 2020) came up with an innovative solution to screen for frailty in those patients where gait could not be assessed. Many of their patients had chronic limb-threatening ischemia (CLTI) and were often unable to perform gait-based assessments because of the presence of plantar wounds. So, they designed and assessed a device they call the Frailty Meter (“FM”). The FM consists of a wrist-worn sensor and a wirelessly connected tablet. It records the angular velocity during a 20-second repetitive elbow flexion-extension task and quantifies weakness, slowness, rigidity, and exhaustion during that exercise. It then displays a Frailty Index (“FI”). Participants were tested on their dominant arm, according to a standardized protocol.


The frailty measurement was performed within 1 week before limb revascularization in 152 patients. They then assessed the incidence of major adverse events (MAE’s) for up to 1 month after surgery. 78.2% of the patients were unable to perform the gait test, while all could perform the FM test. Overall, 34.9%, 38.1%, and 27.0% were classified as robust, pre-frail, or frail, respectively, by their FI scores.


Within 30 days after surgery, 15.7% of patients developed MAE’s, either major adverse cardiovascular events (MACE 5.2%) or major adverse limb events (MALE 10.5%). The FI was approximately 30% higher in the group that developed MAE’s than those who were MAE free.


There was a significantly lower mean FI score in the non-MAE group compared with MACE and MALE groups, but there was no significant difference of FI between MACE and MALE groups.


While this study only included patients with lower extremity vascular disease, we can see how use of the “frailty meter” could also be valuable in assessing patients whose gait cannot be assessed due to neurological or orthopedic conditions.



Some of our prior columns on preoperative assessment and frailty:






Lee L, Patel T, Costa A, Bryce E, Hillier LM, Slonim K, et al. Screening for frailty in primary care. Accuracy of gait speed and hand-grip strength. Can Fam Physician 2017; 63: e51-57



Najafi B, Veranyan N, Zulbaran-Rojas A, et al. Association Between Wearable Device–Based Measures of Physical Frailty and Major Adverse Events Following Lower Extremity Revascularization. JAMA Netw Open 2020; 3(11): e2020161

(Najafi 2020)





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