Measuring Lupus Disease Activity Over Time

Some say that the only thing constant is change. This can feel especially true for Lupus Warriors. Despite the value of tracking disease activity, measuring lupus disease activity remains a challenge.

Accurate, reliable measurements of disease activity are a crucial element of healthcare and research. Identifying changes in lupus disease activity can help people with lupus and their clinicians:

• Identify baseline levels of lupus involvement
• Evaluate effectiveness of treatments
• Develop optimal treatment roadmaps
• Discuss care decisions and participate in Shared Decision Making
• Track lupus over time

Researchers have worked to develop scales or laboratory tests for lupus but there are two main challenges:

1. The complicated, multi-system nature of lupus and the presence of flares
2. There is no “gold standard” and many scales are based on physician visual rating scales
   • Many scales are based on physician visual analog scales which include some level of bias due to variance in physician experience and opinion

Measuring lupus

Lupus can impact systems throughout the body, from the gastrointestinal tract to the skin. Many symptoms may not be easily seen or felt, such as kidney damage. And, the symptoms that are apparent may be hard to measure, like fatigue and pain.

Measures of lupus try to account for the elements that are indicative of future disease progression and give an accurate picture of the current lupus status. They are what is used as endpoints for clinical trials. The Outcome Measures Rheumatology group and the US Food and Drug Administration (FDA) recommend a rating scale that assesses 4 elements:

1. Disease activity
2. Cumulative organ damage
3. Health-related quality of life (QOL)
4. Adverse events

Lupus disease activity – measurement strategies

There are two main types of lupus activity measures: global score systems and individual organ/system involvement scales. As you would expect from the name, global score systems attempt to provide an overall assessment of lupus functioning. Examples of these scales are the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) and the Systemic Lupus Activity Measure (SLAM). In contrast, the British Isles Lupus Assessment Group Index (BILAG) provides breakdowns of the individual systems.

This is not an exhaustive list of measurement tools. For a full list and breakdown of the benefits and challenges with each (and clinical studies that used the different methods), check out this review.

The SLEDAI, SLAM, and BILAG measures correlate with one another. Additionally, they have been updated overtime to reflect more nuance or relevant factors.

Despite the work on these metrics, they are still used as research-grade or clinical measures only. The primary strategies for a Lupus Warrior to measure disease activity at home is to track symptoms using an app or journal.

Pros and cons of different lupus disease activity measures

Selecting the best measurement tool is often not an easy task. The different tools have strengths and weaknesses, varying price points, and administrative hurdles. For the scales listed below, a physician is required to perform and assessment. Below is an overview of the three measures listed here.

For an insight into the benefits and challenges of other tools, this chart published in the journal Arthritis Responsive Therapies provides a great overview.

SLEDAI

Systemic Lupus Erythematosus Disease Activity Index

Strengths:

• Most commonly used for clinical and research purposes
• Includes global disease activity and severity
• Includes laboratory tests (objective measures)

Weaknesses:

• Does not include severity in an organ system
• SLEDAI without SELENA element does not include improvement or decline

Time to complete: ~10 minutes

Cost: $

SLAM

Systemic Lupus Activity Measure

Strengths:

• Includes global disease activity and severity
• Includes laboratory tests (objective measures)

Weaknesses:

• Does not include severity in an organ system
• Subjective scoring by patients can decrease consistency

Time to complete: ~15 minutes

Cost: $

BILAG

British Isles Lupus Assessment Group Index

Strengths:

• Includes global disease activity and severity
• Measures and rates individual organs/systems

Weaknesses:

• Formal training is required for administration to get optimal results

Time to complete: ~50 minutes

Cost: $$$

What’s next

New measures of lupus disease activity are in development. New laboratory tests, including blood biomarker tests, may provide objective measures that do not require physician assessments. This would make it possible to compare disease activity across clinician visits, helping open the door for virtual clinical trials.