Feasibility and Tolerability of Quantitative Sensory Testing in Patients with Sickle Cell Disease at the End of a Vasoocclusive Episode

Title: Feasibility and Tolerability of Quantitative Sensory Testing in Patients with Sickle Cell Disease at the End of a Vasocclusive Episode

Background: Children with Sickle Cell Disease (SCD) have increased sensitivity to heat and cold pain (Brandow et al) during steady state. It is unknown if sensitivity to pain varies with a Vaso-Occlusive Episode (VOE).Characterization of pain sensitivity during acute VOE is essential to the understanding of the transition to chronic pain. While the administration of pain stimuli associated with QST during a VOE is obviously untenable, it is unknown if patients will tolerate QST procedures at the end of a VOE.

Aim: To determine feasibility and tolerability of QST procedures at the end of VOE.

Methods: Patients with SCD were offered quantitative sensory testing (QST) at steady state (at least 2 weeks following a VOE) and prior to or following discharge from the hospital for a VOE-related admission. Patients were contacted during hospitalization for VOE and timing of QST was determined by patient preference and taking into account readiness for discharge from the hospital. QST procedures included estimation of pressure, mechanical and thermal pain thresholds and tolerance (excluding cold tolerance) as well as windup values. At each time point, participants completed the PROMIS measures of pain intensity, pain interference, anxiety, depressive symptoms, sleep, fatigue and peer relationships. Participants also completed the Pain Catastrophizing Scale ((PCS)-Sullivan et al), Child Somatization Inventory (Walker et al), Pain Coping Inventory (Varni et al)* as well as Peds QL Generic and SCD specific measures of Quality of life*. After the QST procedures, participants completed the Gracely box scales (0-20 scale rating pain unpleasantness/intensity).

Results: Ten patients who had an episode of VOE during the study period underwent QST at a median of 3.8 days after admission. The median age of participants who underwent testing was 16.5 years (IQR 11-20). 6 of 10 patients were female. Sixteen patients in VOE were offered QST testing. Eight of 12 patients who had undergone QST testing at steady state and 2 of 4 patients who had not previously undergone QST testing consented to QST testing. Nine patients completed testing at both steady state and following a VOE. Thermal testing was well tolerated by all participants (n=1 not offered due to equipment unavailability). Mechanical pain testing/windup was partially omitted (n=1) by patient request. The median Gracely Box Scale (0-20) score following QST was 0.5 (IQR 0-4, range 0-6) for pain unpleasantness and was 0 (IQR 0-6, range 0-8) for pain intensity.

Conclusions: Quantitative Sensory Testing is well accepted, feasible and well tolerated in patients with SCD at the end of a Vasoocclusive Episode.

Acknowledgments: 1- ASH Clinical Research Training Institute 2- Sickle Cell Disease Association of America 3- *PedsQL™ contact information and permission to use: Mapi Research Trust, Lyon, France. E-mail: PROinformation@mapi-trust.org – Internet: www.Mapi-trust.org and http://www.pedsql.org/index.html