Usefulness of inspiratory capacity measurement in COPD patients in the primary care setting

OBJECTIVE: To determine if inspiratory capacity (IC) assessment could be useful for chronic obstructive pulmonary disease (COPD) patient management in the primary care setting. METHODS: A descriptive cross-sectional study was conducted in 93 patients diagnosed with COPD according to Spanish Thoracic Society (SEPAR) criteria. Patients were recruited in eight primary care centers in Andalusia, Spain. Anthropometric, sociodemographic, resting lung function (forced expiratory volume in one second [FEV(1)], forced vital capacity, synchronized vital capacity, IC), and quality of life data based on the Spanish version of Saint George’s Respiratory Questionnaire (SGRQ) were obtained. RESULTS: Lung function results expressed as percentages of the predicted values were as follows: FEV(1), 49.04 (standard deviation [SD]: 16.23); IC, 61.73 (SD: 15.42). The SGRQ mean total score was 47.5 (SD 17.98). The Spearman’s Rho correlation between FEV(1) and SGRQ was r = −0.36 (95% confidence interval [CI]: −0.529 to −0.166), between IC and SGRQ was r = −0.329 (95% CI −0.502 to −0.131), and between FEV(1) and IC was r = −0.561. CONCLUSIONS: Measurement of IC at rest could be used as a complementary functional exploration to forced spirometry in the monitorization of patients with COPD in the primary care setting. We found a poor correlation between IC and quality of life at the same level as in FEV(1).