Relationship between lung function and grip strength in older hospitalized patients: a pilot study

OBJECTIVE: Older people with reduced respiratory muscle strength may be misclassified as having COPD on the basis of spirometric results. We aimed to evaluate the relationship between lung function and grip strength in older hospitalized patients without known airways disease. METHODS: Patients in acute medical wards were recruited who were aged ≥70 years; no history, symptoms, or signs of respiratory disease; Mini Mental State Examination ≥24; willing and able to consent to participate; and able to perform hand grip and forced spirometry. Data including lung function (forced expiratory volume in 1 second [FEV(1)], forced vital capacity [FVC], FEV(1)/FVC, peak expiratory flow rate [PEFR], and slow vital capacity [SVC]), grip strength, age, weight, and height were recorded. Data were analyzed using descriptive statistics and linear regression unadjusted and adjusted (for age, height, and weight). RESULTS: A total of 50 patients (20 men) were recruited. Stronger grip strength in men was significantly associated with greater FEV(1), but this was attenuated by adjustment for age, height, and weight. Significant positive associations were found in women between grip strength and both PEFR and SVC, both of which remained robust to adjustment. CONCLUSION: The association between grip strength and PEFR and SVC may reflect stronger patients generating higher intrathoracic pressure at the start of spirometry and pushing harder against thoracic cage recoil at end-expiration. Conversely, patients with weaker grip strength had lower PEFR and SVC. These patients may be misclassified as having COPD on the basis of spirometric results.