The impact of metabolic health on fibromyalgia: insights from insulin resistance and related indexes.

Objectives: To assess the association between fibromyalgia (FM) and insulin resistance (IR) using multiple IR indices in FM patients and to investigate how these indices vary with the severity of FM.

Methods: This cross-sectional study included 70 female patients diagnosed with FM and 70 age-matched female healthy controls. The data collected included demographics, clinical characteristics, and laboratory parameters. FM severity was evaluated using the Fibromyalgia Impact Questionnaire-Revised (FIQR). The metabolic indices calculated were the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), Quantitative Insulin Sensitivity Check Index (QUICKI), triglyceride - glucose index (TyG), triglyceride to HDL cholesterol ratio (TG/HDL-C), and Metabolic Score for Insulin Resistance (METS-IR).

Results: FM patients exhibited significantly higher HOMA-IR values (p = 0.002), and lower QUICKI values (p = 0.000) than controls. METS-IR also showed significant differences between FM patients and controls (p = 0.026). HOMA-IR and METS-IR values increased with FM severity, whereas QUICKI values decreased (p < 0.05). Duration of FM showed a moderately positive correlation with HOMA-IR (r = 0.249, p = 0.027). For TG/HDL-C and METS-IR, the correlations were weaker, but still positive (r = 0.094, p = 0.378, and r = 0.184, p = 0.056, respectively).

Conclusion: This study observed a significant association between FM and IR, as evidenced by metabolic indices in FM patients compared to controls. IR levels tended to increase with FM severity and duration. These findings suggest that IR could play a role in FM pathogenesis. Non-invasive and practical methods, such as METS-IR, may provide advantages for metabolic screening in FM patients; however, further studies are needed to establish their clinical utility.