Respiratory Function Analysis in Patients with Chronic Pain: An Umbrella Review and Meta-Analysis of Pooled Findings

BACKGROUND

The main aim of this umbrella review was to assess the respiratory function in patients with chronic pain (CP), including patients with chronic neck pain (CNP), chronic low back pain (CLBP), and fibromyalgia syndrome (FMS).

METHODS

We searched in PubMed, PEDro, EMBASE, CINAHL, and Google Scholar (4 February 2023). The outcome measures were respiratory muscle strength (MIP/MEP) and pulmonary function (VC, MVV, FVC, FEV₁, FEV₁/FVC ratio, FEV_25-75, and PEF). This review was previously registered in the international prospective register of systematic reviews, PROSPERO (CRD42023396722). The methodological quality was analyzed using AMSTAR and ROBIS scales, and the strength of the evidence was established according to the guidelines advisory committee grading criteria. To compare the outcomes reported by the studies, we calculated the standardized mean differences and the corresponding 95% confidence interval for the continuous variables.

RESULTS

Four systematic reviews with and without meta-analysis were included, from which a total of 15 primary studies were extracted. Five meta-analyses were carried out, using analyses by subgroup according to the type of CP. The meta-analyzing variables were MIP, MEP, MVV, FEV₁, and FVC.

CONCLUSIONS

Overall, patients with CP have decreased respiratory muscle strength with a moderate quality of evidence. Regarding the pulmonary function, patients with CNP showed a diminished VC, PEF, MVV, FEV₁, and FVC, while FEV_25-75 and the FEV₁/FVC ratio were conserved with a limited to moderate quality of evidence. Finally, patients with FMS and CLBP only showed a decrease in MVV with a limited quality of evidence.

Respiratory disturbances in fibromyalgia: A systematic review and meta-analysis of case control studies

Background: Fibromyalgia is a debilitating syndrome characterized by diffuse and chronic musculoskeletal pain.Objective: To perform a systematic review and meta-analysis of case-control studies to explore the respiratory disturbances among persons with fibromyalgia.Study appraisal and synthesis method: This review was performed in accordance with PRISMA guidelines (PROSPERO; identification number CRD: 42,020,196,835). We systematically searched seven electronic databases for articles published before December 2020.Eligibility criteria: Case-control studies comparing adults with fibromyalgia syndrome and healthy individuals with regard to the respiratory disturbances.Results: A total of six studies were included in the quantitative analysis. Pooled analysis showed that persons with fibromyalgia reported reduced chest expansion (MD -0.72, 95% CI, -1.70 to 0.27, I² = 95%, p = 0.016), maximum expiratory pressure (MD -10.67, 95% CI, -18.62 to -2.72, I² = 77%, p = 0.009), maximum inspiratory pressure (MD 11.04, 95% CI, -14.45 to -7.62, I² = 0%, p < 0.001) and maximal voluntary ventilation (MD 11.79, 95% CI, -16.80 to -7.78, I² = 0%, p < 0.001).Conclusion: Persons with fibromyalgia experience respiratory disturbances, such as reduced chest expansion, maximum expiratory pressure, maximum inspiratory pressure, and maximal voluntary ventilation.