Respiratory dysfunction in patients with chronic neck pain: systematic review and meta-analysis

Purpose To determine the differences in respiratory muscle strength and pulmonary function between patients with chronic neck pain (CNP) and asymptomatic individuals. Methods Databases were MEDLINE, CINAHL, Scopus, Web of Science and EMBASE up to the end of September 2021. Studies with cross-sectional and longitudinal design were selected, with adult patients with CNP and asymptomatic individuals with reports respiratory function. Results 11 studies met the inclusion criteria and 10 were included in the meta-analysis showing a statistically significant reduction in inspiratory/expiratory muscle strength (MIP/MEP) in the patients with CNP compared with the asymptomatic individuals (mean difference (MD) for MIP, -11.67 [-14.57 to -8.77]; MD for MEP, -11.80 [-14.99 to -8.60]) and pulmonary function: vital capacity (standardized mean difference (SMD), -0.31 [-0.56 to -0.06]); maximum voluntary ventilation (SMD, -0.36 [-0.59 to -0.14]); forced vital capacity (SMD, -0.53 [-0.99 to -0.06]); peak expiratory flow (SMD, -0.58 [-1.03 to -0.12]); and forced expiratory volume in the first second (SMD, -0.28 [-0.51 to -0.05]). Conclusions Patients with CNP have reduced respiratory muscle strength and pulmonary function compared with asymptomatic individuals, and this difference could be clinically meaningful. However, more studies of high methodological quality and longitudinal studies are needed to strengthen the results of this meta-analysis.