Grip Strength as a Screening Index for Severe Degenerative Cervical Myelopathy in Primary Care: Development of Cutoff Values Using Receiver Operating Curve Analysis

Hiroshi Kobayashi, Koji Otani, Takuya Nikaido, Kazuyuki Watanabe, Kinshi Kato, Junichi Handa, Shoji Yabuki, Shin-Ichi Konno Department of Orthopaedic Surgery, Fukushima Medical University School of Medicine, Fukushima, JapanCorrespondence: Hiroshi Kobayashi 1-Hikarigaoka, Fukushima, 960-1295, JapanTel +8124-547-1276Fax +81 24-548-5505Email hiroshik@fmu.ac.jpPurpose: Early diagnosis of degenerative cervical spondylosis (DCM) is desirable because late treatment can lead to irreversible sequelae. No screening method has yet been established. Grip strength is commonly used in primary care settings to evaluate disease activity and diagnose sarcopenia. This single-center, cross-sectional study aimed to determine the diagnostic accuracy of grip strength for cervical myelopathy (DCM) and cutoff values for primary care DCM screening using area under the curve (AUC) and sensitivity values.Patients and Methods: The DCM group comprised 249 consecutive participants (165 males, 84 females; mean age, 65.1 years) with DCM who had undergone surgery at the affiliated hospital. The control group comprised 735 (280 males, 455 females; mean age, 65.8 years) participants undertaking a local government health checkup. Stratifying by age and sex, receiver operating characteristic (ROC) analyses were constructed for each group using minimum grip strength values for both hands. Based on ROC analysis, cut-off values were established so that the screening sensitivity would be 90% for either sex or age group, respectively.Results: According to age group and sex (males/females [M/F]), AUC values for a diagnosis of DCM in M/F were as follows: 40– 59 years, 0.92/0.87; 60– 69 years, 0.94/0.89; 70– 79 years, 0.89/0.91; and 80– 89 years, 0.97/0.97. Calculated M/F cutoff values were 41/24.5, 27/16, 27/15, and 20/10 kg, which were similar to cutoff scores for sarcopenia in M/F patients aged 60– 69 and 70– 79 years. M/F sensitivities in each age groups were 0.94/0.91, 0.92/0.90, 0.95/0.96, and 0.92/0.93. M/F specificities were 0.62/0.59, 0.84/0.83, 0.61/0.71, and 0.83/0.88.Conclusion: Grip strength had moderate-to-high diagnostic accuracy for DCM between participants in the control and DCM groups. We developed easily applicable cutoff values for primary care DCM screening with ≥ 90% sensitivity. In patients with sarcopenia, DCM should be differentially diagnosed in primary care.Keywords: degenerative cervical myelopathy, cervical spondylotic myelopathy, ossification of posterior longitudinal ligament, cervical disc herniation, primary care, early detection, sarcopenia