Exploring Factors Linked to Home-Reported Acute Pain Events and Pain Crises in Sickle Cell Disease (SCD) through Flare Tracking in the Ascend Study

Introduction: Pain is a prominent symptom in sickle cell disease (SCD) and often broadly categorized as persistent chronic pain or more intense acute pain episodes compared to regular chronic pain experiences. Many research studies focus solely on pain events requiring healthcare utilization, neglecting those experienced at home, which may cloud the understanding of an individual's daily experience in managing their symptoms. Capturing home-reported evidence is crucial for comprehending SCD's impact on patients and potential effects of medical interventions.

Objective: The objective of the Ascend Study was to collect individuals' experiences with pain events in SCD, employing a flexible, home-reported outcomes data collection methodology in Folia Health's mobile and web-based platform.

Methods: The Advarra IRB-approved study recruited individuals with any genotype of SCD in the U.S., aged 13 and above, and caregivers of children aged 4 to 12. E-consent and data collection occurred through the Folia platform, where participants selected and tracked relevant symptoms (including, but not limited, to pain-specific symptoms) and treatments, along with health-related quality of life, over the course of 3 months per participant. Baseline severity scores were collected on a 1 to 10 Likert scale for symptoms that were pre-selected by participants at the start of the study. Participants also directly reported potential acute pain events and pain crises experienced in monthly surveys. Detailed flare tracking was set up for four symptom types (chronic pain, acute pain, pain crises, pain and discomfort), enabling structured follow-up questions on select pain flare events. Flare tracking was activated if participants reported a 2-point increase in severity compared to self-identified baselines or opted to track a pain symptom outside of their pre-selected routine. Overall pain burden was collected by participants who routinely tracked all of these various pain experiences, comprising the Ascend Study's home-reported pain hierarchy (Figure A).

Results: 89% (n=59) of tracking participants reported experiencing a potential pain crisis for at least 1 month through monthly surveys. Analysis using the flare threshold applied to all pain symptoms tracked (sensitivity 77.5%; specificity 44.9%) identified 2,660 potential pain flare events. Among participants, 86% (n=57) experienced at least one flare event based on the flare threshold. On average, each participant had 24.9 flare days. Flare events identified by the threshold included 9 pain types tracked on a 1-10 Likert scale and 26 pain types tracked as binary "yes/no."

A total of 812 potential pain flare events reported by 46 participants prompted flare tracking follow-up questions (Table 1). Increases in chronic pain were more common than new types. 74% of these participants (n=34) opted to provide additional information through flare tracking in 282 pain flare events. Real-time flare tracking was reported in 85% of flare tracking events. From follow-up responses, most common classifications of pain were stabbing(188, 30.3%), pulsing or throbbing(144, 23.2%), and dull or aching(143, 23.0%). The back (155, 15.7%) and leg (268, 27.2%) were the most prevalent pain locations, with weather (177) and seasonal change (92) identified as potential triggers. Top flare descriptors included 'can't do normal activities' (84, 24.4%) and 'not getting better with home pain meds’ (78, 22.7%).

Conclusion: The Ascend Study provides detailed insights into SCD acute pain experiences, showing a high percentage of real-time flare tracking. Chronic pain flares were frequently reported, back and leg pain being the most prevalent locations, and seasonal changes identified as potential triggers. While the flare threshold analysis identified many potential pain flare events, the method's sensitivity might lead to lower specificity for pain flare events and the inclusion of potentially non-flare events. Findings provide valuable insights into the acute pain experiences of individuals with SCD, emphasizing the significance of capturing home-reported evidence to improve patient care and SCD therapies.