Association Between Bottle-Opening Ability and Muscle Weakness in Patients With Coronary Artery Disease

Difficulties opening plastic bottles may be associated with muscle weakness. We investigated association between the ability to open plastic bottles and muscle weakness, and determined cut-off values for and sex-related differences in handgrip strength and pinch strength associated with opening plastic bottles in patients with coronary artery disease (CAD).

This cross-sectional study enrolled 224 consecutive patients with CAD who underwent in-hospital cardiac rehabilitation. Multiple linear regression analyses was used to determine the association between the ability to open plastic bottles and muscle weakness, with cut-off values for handgrip strength, lateral pinch strength, and 3-fingered pinch strength required to open plastic bottles determined by receiver operating characteristic curve analyses. Multiple linear regression showed that the ability to open plastic bottles was independently associated with handgrip, lateral pinch, and 3-fingered pinch strength after adjusting for confounders. Areas under the curves for all patients were 0.96 (95% confidence interval [CI] 0.93-0.99), 0.91 (95% CI 0.83-0.99), and 0.93 (95% CI 0.88-0.99) for handgrip, lateral pinch, and 3-fingered pinch strength, respectively, with corresponding cut-off values of 20.0, 7.1, and 6.1 kgf.

The ability to open plastic bottles was independently associated with handgrip strength and pinch strength in patients with CAD. Evaluating the ability to open plastic bottles may be a simple and practical tool for assessing muscle weakness in patients with CAD.