VALIDATION OF THE CAMRY DIGITAL HANDGRIP DYNAMOMETER: A CROSS SECTIONAL STUDY COMPARING THE CAMRY DYNAMOMETER TO THE JAMAR DYNAMOMETER

Lupton-Smith A1,2, Fourie K2, Mazinyo A2, Mokone M2, Nxaba S2, Morrow B31Stellenbosch University, Health and Rehabilitation Sciences, Cape Town, South Africa, 2University of Cape Town, Health and Rehabilitation Sciences, Cape Town, South Africa, 3University of Cape Town, Paediatrics, Cape Town, South AfricaBackground: Grip strength has been identified as an important indicator of health status and predictor of clinical outcomes in a variety of health conditions. The current gold standard device for measuring grip strength is the Jamar® Hydraulic Hand Dynamometer. The Jamar® is expensive and not readily available in resource constrained settings. Less expensive dynamometers (such as the Camry Digital Handgrip Dynamometer) are available but have not been validated.Purpose: This study aimed to validate the Camry Digital Handgrip Dynamometer (Model EH101, Zhongshan Camry Electronic Co. Ltd, China) device for testing grip strength in hospital populations by comparing it to the gold standard Jamar® Hydraulic Hand Dynamometer (Model J00105, Lafayette Instrument Company, United States of America).Methods: A cross-sectional observational study, with a randomised cross-over component, was conducted at Groote Schuur Hospital (Cape Town, South Africa). Consenting, consecutive adult patients from randomly selected wards were included if they could follow instructions and had no conditions that would impact on shoulder, elbow, wrist or finger function of their dominant arm that could impact on testing. Testing order was randomised. Single blinding of participants was achieved by ensuring that participants could not see the readings of their results. Patients were not told which device was the gold standard and which device was the cheaper of the two. Three measures of grip strength of the dominant hand were taken with each device and the best was used in analysis.Results: Fifty-one participants (median (IQR) age 42 (30 - 58) years; n = 27 (52.9%) female) were enrolled in the study at a median 5 (4 - 8) days post hospital admission. Majority of participants were right hand dominant (44, 86.3%). The mean best score using the Jamar® device and the Camry was 28.8 ± 10.2 kg and 27.0 ± 10.1kg respectively (t-value 0.9; p = 0.4). The mean difference between the Jamar® and Camry device measurements was 1.9 ± 3.6kg. There was a strong positive correlation between the best measurements using the Jamar® and the Camry (R = 0.94; r² = 0.88; p < 0.05). Excellent agreement was found between Jamar® and Camry measurements (ICC=0.97, 95%CI 0.94-0.99, p< 0.001). Order of assignment had no effect on the agreement between measures (Jamar® first 2.3 ± 3.2kg vs. Camry first 1.7 ± 3.8kg; p = 0.8), while hand dominance significantly affected the agreement (Right hand 1.3 ± 3.3kg vs Left hand 5.5 ± 3.3kg, p=0.002).Conclusion(s): The Camry Digital Handgrip Dynamometer is a valid tool for assessing grip strength in hospitalised patients. Future work should aim to further validate the Camry in healthy populations and in those are left-hand dominant.Implications: The Camry Digital Handgrip Dynamometer is a valid tool for measuring grip strength. This alternative could assist in improving the prescription and monitoring of clinical intervention outcomes, particularly in low resourced environments where gold standard dynamometers are not available.Keywords: Grip Strength, Dynamometry, HandgripFunding acknowledgements: NoneTopic: Outcome measurement; Cardiorespiratory; Critical careEthics approval required: YesInstitution: University of Cape TownEthics committee: Human Research Ethics CommitteeEthics number: 175/2018All authors, affiliations and abstracts have been published as submitted.