Integrating Pulmonology and Metabolism: Adipokines in COPD from a Systematic Review and Meta-analysis Perspective

Background: Chronic Obstructive Pulmonary Disease (COPD) is increasingly recognized not just as a pulmonary disorder but as a complex systemic syndrome involving chronic inflammation, metabolic dysregulation, and immune imbalance. This systematic review and meta-analysis aim to evaluate circulating adipokine profiles in COPD patients, exploring their diagnostic significance, correlation with disease severity, and potential as biomarkers or therapeutic targets. Methods: Following PRISMA 2020 guidelines, a comprehensive literature search was conducted across PubMed, Scopus, and Web of Science. A random-effects meta-analysis assessed standardized mean differences (SMDs) for key adipokines. Risk of bias was evaluated using the Newcastle-Ottawa Scale, and evidence certainty was assessed using the GRADE framework. Results: Twelve eligible studies comprising 2,100 COPD patients and 2,100 controls were included. Leptin (1.57 [-0.02 to 3.16] double armed; 19.59 [14.01-25.18] single armed), resistin (0.67 [-0.27 to 1.60]), and adiponectin (-0.18 [-2.13 to 1.77] double armed; 7.83 [6.95 to 8.71] single armed) levels showed statistically significant differences between COPD patients and controls (p < 0.001 for all), with high heterogeneity (>60%). Elevated leptin and resistin levels were associated with systemic inflammation and poorer clinical outcomes, whereas adiponectin was often reduced despite its anti-inflammatory properties. Sensitivity and subgroup analyses reinforced these findings. The certainty of evidence ranged from low to moderate. Discussion: Adipokines reflect systemic inflammation and metabolic imbalance in COPD, highlighting their potential role in phenotypic stratification and disease monitoring. While promising, translation to clinical practice requires further standardized, longitudinal, and mechanistic research.