Handgrip Strength as a Reflection of General Muscle Strength in Chronic Obstructive Pulmonary Disease

Muscle dysfunction is one of the main features in individuals with chronic obstructive pulmonary disease (COPD). Handgrip strength (HS) has been used as a representation of general muscle strength in various populations, and a few studies found correlation between HS and other measures of upper and lower limbs' muscle strength in the general population, although this was not yet studied in depth in COPD. The aims of this study were to verify if HS is cross-sectionally well correlated with upper and lower limbs' muscle strength in individuals with COPD, and to identify a new cutoff for handgrip weakness in this population. HS was assessed by a dynamometer, whereas other muscle strength assessments comprised maximal voluntary contraction (MVC) of the quadriceps femoris and 1-repetition maximum (1RM) of biceps and triceps brachii, pectoralis major, latissimus dorsi and quadriceps femoris. Additional assessments included pulmonary function and volumes, body composition and exercise capacity. Fifty individuals with COPD were studied (65 +/- 7 years; FEV1 51 +/- 14%pred). HS showed moderate-to-strong correlations with all 1-RM assessments (0.62<r < 0.75) and especially with MVC of the quadriceps femoris (r = 0.83) (p < 0.05 for all). Correlations were stronger for male than female individuals, and the assessment performed on right, left or dominant hand did not present significant differences. A cutoff of 0.3892 for HS/weight yielded an AUC = 0.90 to identify weakness. In conclusion, HS is a good reflection of upper and lower limbs' muscle strength in individuals with COPD. Its usefulness as a surrogate for more complex assessments must be based on the settings and conditions.