A recent study published in the journal Rheumatology has investigated the use of the Steritas Glucocorticoid Toxicity Index (GTI) for monitoring steroid-toxicity in clinical practice for individual rheumatology patients.^[1] The single-center prospective study evaluated glucocorticoid toxicity in patients seen at a rheumatology outpatient clinic between January 2021 and June 2022.

The study recruited adult patients (>18 years) with inflammatory arthritis (1A), connective tissue disease (CTD) and vasculitis. Patients were evaluated in two groups; those with newly prescribed glucocorticoid treatment (glucocorticoid-naïve) and patients already on steroids (glucocorticoid-experienced). Patients in the latter group were restricted to a maximum of 2 years prior treatment to ensure accuracy of reporting their historic glucocorticoid exposure. Patients with a history of lymphoma or cancer were excluded.  

A total of 156 patients were recruited after exclusions; 76 (48.7%) were glucocorticoid-naïve, 57.7% were women and the mean age was 49.1 +/-17 years (+/-s.d.). All patients were followed up with for 6 months, with GTI scores determined at baseline (t0), 3 months (t3) and 6 months (t6). The GTI Aggregate Improvement Score (AIS)* and Cumulative Worsening Score (CWS)** were assessed throughout the study, with higher GTI scores indicating higher levels of steroid- toxicity. The minimal clinically important difference (MCID) for the GTI is 10 points.

The overall findings were:

• For all patients, higher glucocorticoid exposure was associated with higher GTI scores (both AIS and CWS) (P<0.001) and higher toxicity
  • This remained true after adjusting for demographic (e.g., age and gender) and clinical variables (e.g., BMI)
  • In the glucocorticoid-naïve group, higher GTI scores were also associated with vasculitis (versus 1A), systolic blood pressure, HbA1c (AIS only), presence of diabetes at baseline (CWS only) and follow-up time at the third month (CWS only) (P<0.005)
• Both groups experienced increased steroid-toxicity over time as demonstrated by higher GTI-CWS scores at 6 months compared to 3 months
• Glucocorticoid-naïve patients exhibited higher rates of steroid-related side effects than glucocorticoid-experienced counterparts
  • Incidence of glucocorticoid-related toxicity was 2.17 per patient compared to 0.47 per patient for the glucocorticoid-experienced group
  • 68.4% had at least one steroid-related toxicity at 3 months compared to 20% for glucocorticoid-experienced patients
  • 6.3% had an improvement in their AIS score after 6 months compared to 30% for the glucocorticoid-experienced cohort 

The overall cohort exhibited a wide range of GTI scores (both AIS and GTI), which the authors attributed to the diverse diseases and treatment strategies. The authors were able to use the GTI scores to differentiate between those toxicities that were associated with the current dose of steroids (e.g., myopathy) and those that correlated with cumulative dose, such as osteoporosis and infection.

What difference does the study make?

This is the first study that prospectively uses the GTI in a practice setting to assess glucocorticoid-related toxicity in rheumatology patients. One of the key findings of this relatively short study was that the GTI is sensitive enough to determine prominent patient-specific differences in steroid-toxicities. The authors also noted that the electronic version of the GTI could be integrated into clinical practice, where it could be used to detect, monitor and manage glucocorticoid related side effects for individual patients.

John H. Stone, MD MPH, Professor of Medicine at Harvard Medical School, and the Edward A. Fox Chair in Medicine at Massachusetts General Hospital, commented on the study:

"It is very instructive to see how these clinicians were able to apply the GTI in clinical practice across a broad range of rheumatic diseases, from inflammatory arthritis to lupus to systemic vasculitis. Their results have strong internal consistency and underscore the ability of clinicians to use the GTI in practice."  

References

1. Bahap-Kara M, Sariyildiz E, Zengin HY, Karadag O and Bayraktar-Ekincioglu A.  Prospective assessment of glucocorticoid toxicity in rheumatology practice: a focus on the glucocorticoid toxicity index.  Rheumatology, 00:1-9 (2024) https://doi.org/10.1093/rheumatology/keae288

Notes

*The Aggregate Improvement Score (AIS) can be positive or negative as it detects improvement and worsening of toxicities over time.
**The Cumulative Worsening Score (CWS) measures the accumulated and worsening of steroid-toxicities over time and is always positive.

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