Respiratory muscle strength is related to handgrip performance in community-dwelling persons aged 80+ from the BUTTERFLY study

INTRODUCTION: This study aimed to evaluate the association of respiratory muscle strength with sarcopenia and its indicators in the oldest old.

METHODS: Maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP) and sarcopenia related factors (handgrip strength and appendicular lean mass) were evaluated in a cohort of n=286 (45.5% female) non-frail, community-dwelling persons aged 83.6±3.0 years (age range 80-97 years).

RESULTS: The sample presented a sarcopenia prevalence of 32.2%. Sarcopenic subjects showed comparable MIP and MEP as non-sarcopenic ones (female: MIP 43.9±18.9 versus 50.3±19.5, p=0.053; MEP 63.0±23.0 versus 69.2±19.1, p=0.067; male: MIP, 65.1±24.4 versus 64.4±23.9, p=0.433; MEP 87.7±33.3 versus 93.8±30.9, p=0.124). Statistically significant but very low associations were found between grip strength and MIP (r=0,193 for male, p<0.05 and r=0.257 for female participants, p<0.01) and MEP (r=0.200 for male, p<0.01 and r=0.191 for female participants, p<0.05). Lean mass was significantly correlated to MIP and MEP in female (r=0.253, p<0.01 and r=0.343, p<0.01 respectively), whereas this association was not found in male participants. Grip strength was the only statistically significant predictor of MEP (r-square=0.212, p<0.001), while MIP was independently predicted by age, male sex and grip strength (r-square=0.177, p<0.001).

CONCLUSIONS: Peripheral muscle strength is a statistically significant, albeit weak predictor for respiratory muscle strength in well-functioning, community-dwelling persons aged 80+. When confronted to a low grip strength, one should be aware of concomitant respiratory muscle weakness, as this is a known risk factor for atelectasis and pneumonia. Given the relatively low association with handgrip strength, respiratory muscle strength testing might be indicated.