Relationship Between Metabolic Profile, Pain, and Functionality in Patients with Frozen Shoulder: A Cross-Sectional Study

Abstract

Background: Frozen shoulder (FS), or adhesive capsulitis, is a disabling condition characterized by pain and restricted shoulder mobility.

Aims: This study investigates the relationship between metabolic biomarkers-liver enzymes and thyroid function-and pain and shoulder functionality in patients with FS.

Methods: A total of 32 patients (22 women and 10 men) were included in this cross-sectional study. Participants underwent clinical evaluations and blood tests to assess metabolic biomarkers, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), and thyroid-stimulating hormone (TSH). Pain and functionality were measured using the Shoulder Pain and Disability Index (SPADI). Correlation and multiple regression analyses were performed to assess the associations between biomarkers, pain, and functionality.

Results: Significant negative correlations were found between AST (r = -0.528, p = 0.029), ALT (r = -0.533, p = 0.027), GGT (r = -0.602, p = 0.011), and TSH (r = -0.556, p = 0.017) with total pain scores. A significant negative correlation was also observed between TSH and SPADI scores (r = -0.511, p = 0.039). Multiple regression analysis showed that GGT (β = -0.335, p = 0.008) and TSH (β = -0.298, p = 0.014) were the strongest predictors of pain. These findings suggest that metabolic biomarkers, particularly liver enzymes and thyroid function, play a significant role in the pathophysiology of frozen shoulder. The results highlight the importance of assessing these biomarkers for better understanding and managing pain and functionality in patients with FS.

Conclusions: Further research is needed to explore the underlying mechanisms and potential therapeutic targets.

Keywords: biomarkers; frozen shoulder; functionality; metabolism; pain.

Figure 1

Flow diagram of participants. Abbreviations: BMI: body mass index; NRS: numerical rating scale; SPADI: Shoulder Pain and Disability Index.

Figure 2

This figure displays scatter plots for each liver enzyme (AST, ALT, and GGT) against total pain levels (NRS), with trendlines representing the negative correlations. Each plot includes the respective correlation coefficient (r) and p-value, illustrating the strength of each relationship.

Figure 3

This scatter plot demonstrates the relationship between TSH levels and total pain scores (NRS). The figure includes a regression line to show the negative trend and the correlation coefficient, with visual emphasis on the strength of the association between TSH and pain.

Figure 4

This scatter plot illustrates the relationship between TSH levels and SPADI scores, showing how lower thyroid hormone levels are linked to higher levels of functional impairment. The trend line and correlation coefficient provide a clear representation of the data.

Figure 5

This figure includes two bar charts, one for men and one for women, comparing the strength of the correlations (r values) between the key metabolic biomarkers (AST, ALT, GGT, and TSH) and both pain and functionality. These charts highlight any differences in the magnitude of the relationships across genders.

Figure 6

A forest plot is used to visualize the beta values (β) and 95% confidence intervals for each variable in the regression model (AST, ALT, GGT, and TSH). This figure highlights the relative contributions of each predictor to the model and shows the significance of each factor in determining pain levels.