Is the 6-minute pegboard and ring test valid to evaluate upper limb function in hospitalized patients with acute exacerbation of COPD?

Background: The 6-minute pegboard and ring test (6-PBRT) is a useful test for assessing the functional capacity of upper limbs in patients with stable COPD. Although 6-PBRT has been validated in stable patients, the possibility of a high floor effect could compromise the validity of the test in the hospital setting. The aim of this study was to verify the convergent validity of 6-PBRT in hospitalized patients with acute exacerbation of COPD (AECOPD).

Methods: A cross-sectional study was conducted in a tertiary hospital. Patients who were hospitalized due to AECOPD and healthy elderly participants, voluntarily recruited from the community, were considered for inclusion. All participants underwent a 6-PBRT. Isokinetic evaluation to measure the strength and endurance of elbow flexors and extensors, handgrip strength (HGS), spirometry testing, the modified Pulmonary Functional Status Dyspnea Questionnaire (PFSDQ-M), the COPD assessment test (CAT), and symptoms of dyspnea and fatigue were all measured as comparisons for convergent validity. Good convergent validity was considered if >75% of these hypotheses could be confirmed (correlation coefficient>0.50).

Results: A total of 17 patients with AECOPD (70.9±5.1 years and forced expiratory volume in 1 second [FEV] of 41.8%±17.9% of predicted) and 11 healthy elderly subjects were included. The HGS showed a significant strong correlation with 6-PBRT performance (=0.70; =0.002). The performance in 6-PBRT presented a significant moderate correlation with elbow flexor torque peak (=0.52; =0.03) and elbow extensor torque peak (=0.61; =0.01). The total muscular work of the 15 isokinetic contractions of the elbow flexor and extensor muscles showed a significant moderate correlation with the performance in 6-PBRT (=0.59; =0.01 and =0.57; =0.02, respectively). Concerning the endurance of elbow flexors and extensors, there was a significant moderate correlation with 6-PBRT performance (=-0.50; =0.04 and =-0.51; =0.03, respectively). In relation to the upper-extremity physical activities of daily living (ADLs) assessed by means of PFSDQ-M, there was a significant moderate correlation of 6-PBRT with three domains: influence of dyspnea on ADLs (=-0.66; <0.001), influence of fatigue on ADLs (=-0.60; =0.01), and change in ADLs in relation to the period before the disease onset (=-0.51; =0.03). The CAT was also correlated with 6-PBRT (=-0.51; =0.03). Finally, the performance in 6-PBRT showed a significant moderate correlation with the increase in dyspnea (=-0.63; =0.01) and a strong correlation with the increase in fatigue of upper limbs (=-0.76; <0.001) in patients with AECOPD. Convergent validity was considered adequate, since 81% from 16 predefined hypotheses were confirmed. There was no correlation between 6-PBRT and patients' height. The performance in 6-PBRT was worse in patients with AECOPD compared to healthy elderly individuals (248.7±63.0 vs 361.6±49.9 number of moved rings; <0.001).

Conclusion: The 6-PBRT is valid for the evaluation of functional capacity of upper limbs in hospitalized patients with AECOPD.