NLR, PLR, and GLUT-1: Predictors of Insulin Resistance in Rheumatoid Arthritis

A cross-sectional study published in Cureus has explored the use of specific haematological markers and a glucose transporter protein as predictors for insulin resistance in patients with rheumatoid arthritis (RA).

The research focused on the Neutrophil-to-Lymphocyte Ratio (NLR), the Platelet-to-Lymphocyte Ratio (PLR), and Glucose Transporter 1 (GLUT-1) to determine their effectiveness in identifying insulin resistance within this patient population.

The Link Between Rheumatoid Arthritis and Insulin Resistance

Insulin resistance occurs when cells in the muscles, fat, and liver do not respond properly to insulin, which prevents the body from easily absorbing glucose from the blood.

In patients with rheumatoid arthritis, this metabolic dysfunction is often linked to systemic inflammation. According to research available via PubMed Central, systemic inflammation and insulin resistance are linked, although the specific determinants of insulin resistance in RA and its impact on the progression of subclinical atherosclerosis are not yet fully understood.

Identifying predictors for insulin resistance is considered important because of the systemic nature of RA and its potential to contribute to further cardiovascular or metabolic complications.

Understanding the Predictors: NLR, PLR, and GLUT-1

The predictors examined in the Cureus study are derived from routine medical tests or specific cellular proteins:

• Neutrophil-to-Lymphocyte Ratio (NLR) and Platelet-to-Lymphocyte Ratio (PLR): These are inflammatory indexes derived from routine haematological parameters.
• Glucose Transporter 1 (GLUT-1): This represents a protein that facilitates the transport of glucose across cell membranes.

NLR and PLR have been previously utilized in clinical settings to help differentiate between patients with and without rheumatoid arthritis.

The utility of these ratios extends to other complications associated with the disease. A study published in the International Journal of General Medicine on February 19, 2025, examined the value of NLR and PLR in diagnosing rheumatoid arthritis combined with interstitial lung disease (RA-ILD).

That research identified that the optimal critical values for the diagnosis of RA-ILD were 3.15 for NLR and 152.62 for PLR.

Broader Clinical Context of Inflammatory Ratios

The use of neutrophil, lymphocyte, and platelet ratios to monitor metabolic health is not exclusive to rheumatoid arthritis. Similar markers are studied in other metabolic disorders characterized by insulin resistance.

For example, a study published on March 25, 2024, in BMC Endocrine Disorders examined the correlation between insulin resistance and the rates of neutrophils-lymphocytes, monocytes-lymphocytes, and platelets-lymphocytes in patients with type 2 diabetes mellitus.

Because NLR and PLR are calculated from standard blood counts, they offer a potentially accessible and non-invasive method for clinicians to screen for inflammation-related metabolic risks.

Study Limitations and Future Directions

The Cureus study was designed as a cross-sectional study. So the research provides a snapshot of the association between NLR, PLR, GLUT-1, and insulin resistance at a single point in time.

Because of this design, the findings identify predictors and associations rather than establishing a direct causal relationship between these markers and the development of insulin resistance.

Further research may be required to determine how these predictors change over the course of RA treatment and whether they can be used to tailor metabolic interventions for patients at higher risk of insulin resistance.