A new evidence-based classification system for chronic sickle cell disease (SCD) pain was recently published in the Journal of Pain.1 The classification system was developed for the ACTTION-APS (Analgesic, Anesthetic, and Addiction Clinical Trial Translations Innovations Opportunities and Networks and American Pain Society) Pain Taxonomy (AAPT) initiative.
Recurrent acute pain in SCD poses a significant healthcare burden and is associated with increased morbidity and mortality.1-3 Recent data show that pain-related healthcare utilization increases with age in patients with SCD, and that the majority of adults with SCD experience non-acute pain on more than 50% of days.4,5 Chronic pain in SCD may also be associated with depression, anxiety, and functional disability.
Although chronic pain is prevalent in the SCD population, no established criteria exist for diagnosing chronic SCD pain. As a result, studies evaluating the epidemiology and management interventions in chronic SCD pain are lacking.
Tonya Palermo, PhD, from Seattle Children’s Research Institute, and colleagues in an AAPT working group developed a diagnostic classification system for chronic SCD pain based on an exhaustive literature review.1
The classification system utilizes a pain taxonomy framework that incorporates the 5 following dimensions: “(1) core diagnostic criteria; (2) common features; (3) common medical and psychiatric comorbidities; (4) neurobiological, psychological, and functional consequences; and (5) putative neurobiological and psychosocial mechanisms, risk factors, and protective factors.”
The core diagnostic criteria for chronic SCD pain developed by the working group included 3 modifiers to account for differing clinical features.
The working group found numerous evidence gaps with regard to research in chronic SCD pain, such as those relating to risk factors, protective factors, and psychosocial and functional outcomes. Although one diagnostic criterion requires having ongoing pain for at least 15 days per month, robust evidence to support this cutoff is lacking.
“Further studies are needed to verify the frequency characteristics and common features of chronic sickle cell pain,” Dr Palermo said.
“In addition, research is needed on contributory disease complications as a source of chronic pain and the prognosis associated with these pain subtypes. Longitudinal studies are particularly needed to understand risk factors for chronic SCD pain, especially in children,” she added.
Summary and Clinical Applicability
Chronic SCD pain is prevalent among the population of individuals with SCD, but the lack of classification criteria has hampered research into the diagnosis and management of this condition. The AAPT working group devised a set of diagnostic criteria for chronic SCD pain based on the available evidence.
“The system we developed expands the classification of sickle cell pain to include chronic pain, which previously was not well described,” Dr Palermo told Clinical Pain Advisor. “The system uses a pain frequency-based approach similar to that for chronic headaches. It also highlights the need to consider a biopsychosocial approach to understanding chronic pain in SCD.”
Limitations and Disclosures
The AAPT classification system for chronic SCD pain is appropriate for assessing chronic pain symptoms in patients with SCD, not acute vaso-occlusive pain.
While the classification criteria are derived from an exhaustive literature review, further studies are needed to validate these criteria.
- Dampier C, Palermo TM, Darbari DS, Hassell K, Smith W, Zempsky W. AAPT diagnostic criteria for chronic sickle cell disease pain [published online January 5, 2017]. J Pain. doi: 10.1016/j.jpain.2016.12.016
- Kauf TL, Coates TD, Huazhi L, Mody-Patel N, Hartzema AG. The cost of health care for children and adults with sickle cell disease. Am J Hematol. 2009;84(6):323-327. doi: 10.1002/ajh.21408
- Houston-Yu P, Rana SR, Beyer B, Castro O. Frequent and prolonged hospitalizations: a risk factor for early mortality in sickle cell disease patients. Am J Hematol. 2003;72(3):201-203.
- Smith WR, Scherer M. Sickle-cell pain: advances in epidemiology and etiology. Hematology Am Soc Hematol Educ Program. 2010;2010:409-415. doi: 10.1182/asheducation-2010.1.409
- Smith WR, Penberthy LT, Bovbjerg VE, et al. Daily assessment of pain in adults with sickle cell disease. Ann Intern Med. 2008;148(2):94-101.