Grip strength as a predictor of disease severity in hospitalized COVID-19 patients

BACKGROUND: Grip strength is one of the main components for the physical functioning in sarcopenia and physical frailty. OBJECTIVES: To explore the role of grip strength measurement at admission for predicting disease severity in COVID-19. METHODS: Demographic data, smoking status, comorbidities, COVID-19 related symptoms, grip strength, laboratory and computed tomography (CT) findings at admission were all noted. Using a Smedley hand dynamometer, the maximum grip strength value (kg) after three measurements on the dominant side was recorded. Low grip strength was defined as two standard deviations below the gender-specific peak mean value of the healthy young adults (<32 kg for males, <19 kg for females). Patients were categorized into three groups according to clinical and CT findings. Severe illness group had pneumonia with a respiratory rate >30/min, oxygen saturation ≤90%, or extensive lung involvement in CT. Moderate illness group had pneumonia with CT score ≤11. Mild illness group had normal CT findings. RESULTS: The study population included 312 patients (140 F, 172 M). The distribution of mild, moderate and severe disease groups were 36.9%, 51.0% and 12.2%, respectively. Cough, fever, dyspnea, hypertension, obesity, cardiovascular disease (CVD) and chronic obstructive pulmonary disease (COPD) were most frequent, and C-reactive protein (CRP), ferritin, D-dimer, and neutrophil levels were highest in the severe group (all p<.05). Absolute grip strength values were lowest and the frequency of having low grip strength were highest in the severe group (both p<.01). Since we found that the significant differences were stemming from the severe group, we combined the mild and moderate group as non-severe, and compared severe vs. non-severe groups with binary logistic regression analyses. When age, gender, body mass index, smoking status, presence of comorbidities and low grip strength, and abnormal laboratory findings were taken into analyses; age (odds ratio [OR]: 1.054 [95% confidence interval (CI): 1.020-1.089]), obesity (OR: 2.822 [95% CI: 1.143-6.966]), COPD (OR: 5.699 [95 %CI: 1.231-26.383]), CRP level (OR: 1.023 [95% CI: 1.010-1.036]) and low grip strength (OR: 3.047 [95% CI: 1.146-8.103]) were observed to be independent predictors for severe COVID-19 disease (all p<.05). CONCLUSIONS: In addition to the well-known independent risk factors (i.e. age, obesity, COPD, and CRP level), low grip strength independently increased (about three times) the severity of COVID-19.