African Americans experience a greater burden of pain and itch after major thermal burn injury than European Americans 1,2Mauck MC, 1,2Liu AY, 1,2Villard MA, 1,2Bortsov AV, 1,2Wesp B, 1,2Gellatly M, 1,2Doshi N, 1,2Bien M, 1,2Jia E, 1,2Jallah, D3Jones SW, 3Hwang J, 3Williams F, 8Shupp J, 5Karlnoski R, 5Smith D, Cairns B, Ji RR7, 1,2,4McLean SA. From the 1TRYUMPH Research Program, 2Department of Anesthesiology, 3Department of Surgery, and 4Department of Emergency Medicine, University of North Carolina, Chapel Hill, NC; 5Florida Gulf-to-Bay Anesthesiology, Tampa, FL; 6Department of Plastic Surgery, University of South Florida, Tampa, FL; 7Department of Anesthesiology, Duke University, Durham, NC; 8MedStar Health Research Institute, Washington, DC a INTRODUCTION Burn injuries affect 11 million people annually worldwide. Hospitalized burn patients commonly receive a tissue autograft to treat their burn injury, in which skin is removed from a healthy “donor” site and transferred to a burn injury site (the “graft” site). Chronic pain and chronic itch at the graft site are major causes of patient suffering and disability in this population. African Americans experience worse pain outcomes than European Americans in other settings (e.g., cancer, musculoskeletal injury), and the incidence of major thermal burn injury in African Americans vs. European Americans is increased . To our knowledge, ethnic differences in graft site pain and itch outcomes after major thermal burn injury have not previously been assessed. In this study, we compared graft site pain and itch outcomes over time in European and African Americans experiencing major thermal burn injury. METHODS This prospective, multicenter, longitudinal cohort study enrolled adult European Americans and African Americans who presented to the hospital within 72 hours of major thermal burn injury. Only individuals with total body surface area (TBSA) burned ≤30% also receiving tissue autograft were enrolled. Pain and itch severity (numeric rating scale (NRS) 0-10) were prospectively assessed during the year after MThBI via structured in-person and telephone interviews (daily during hospitalization, weekly post-discharge through study day 21, and then monthly through 12 months). Demographics, burn characteristics, and hospital length of stay were obtained by abstraction of the medical record. Moderate to severe pain and itch was defined as NRS≥4. The impact of pain and itch severity on function was explored by determination of the SF-12 physical component score and mental component score over the month prior to burn. Table 1: Participant Characteristics   All European American African American Male Sex (%) 72 (75) 38 (76) 34 (74) Mean Age (SD) 38.0 (13) 39.6 (14) 36.2 (12) Income (%) $0-19,999 13 (17) 5 (11) 8 (24) $20,000-$39,999 24 (31) 14 (31) 10 (30) $40,000-$59,999 17 (22) 10 (22) 7 (21) $60,000 or higher 16 (36) 8 (16) Education (%) 8-11 years 10 (11) 5 (10) 12 years 30 (32) 13 (26) 17 (38) Post-high school education 55 (58) 32 (64) 23 (51) % TBSA burn (SD) 5 (3) 5 (4) 4 (3) Type of burn injury (%) Contact 5 (5) 3 (6) 2 (4) Flame 43 (48) 28 (60) 15 (33) Scald 42 (46) 14 (30) 28 (62) Length of stay, days (SD) 9.8 (3) 10 (3) 10 (4) TBSA: total body surface area, SD: standard deviation, ED: emergency department RESULTS Study participant characteristics are shown in Table 1. Longitudinal pain and itch outcomes are shown in Figure 1a and 1b respectively. In linear mixed models adjusting for age, sex, income, and education, African Americans experienced greater pain severity 6 weeks to 12 months after burn injury compared to European Americans (β =0.8, t(72)=2.33, p=0.022) as well as increased itch symptoms ((β=1.7, t(72)=4.64, p<0.0001). Peritraumtic mental health characteristics are shown by ethnicity in Table 2. There was a significant difference in overall mental health between European Americans and African Americans. There was no difference in our sample in physical function, pre-burn depression or anxiety, and no difference in pain catastrophizing, or initial PTSD severity between European Americans and African Americans. CONCLUSIONS African Americans experience increased pain and itch symptoms after major thermal burn injury compared to European Americans. Future studies evaluating differences in pain and itch outcomes between African Americans and European Americans experiencing major thermal burn injury may both improve outcomes in African Americans and lead to new pathogenic insights that benefit all burn injury survivors. REFERENCES LaBorde P. Burn epidemiology: the patient, the nation, the statistics, and the data resources. Crit Care Nurs Clin North Am 2004;16(1):13-25. Hastie BA, Riley JL, Fillingim RB. Ethnic differences and responses to pain in healthy young adults. Pain Med 2005;6(1):61-71. Rahim-Williams FB, Riley JL, 3rd, Herrera D, Campbell CM, Hastie BA, Fillingim RB. Ethnic identity predicts experimental pain sensitivity in African Americans and Hispanics. Pain 2007;129(1-2):177-184. Research reported here was funded by the University of North Carolina Department of Anesthesiology and the Jaycee Burn Center. b Figure 2: Graft site pain and itch outcomes in European American and African Americans. Figure 1a shows the percentage of participants with moderate to severe graft site pain (NRS (numeric rating scale ≥ 4) in European Americans (open circles) and African Americans (closed circles) after of Major thermal burn injury (MThBI). Figure 1b shows the percentage of participants with moderate to severe graft site itch (NRS ≥ 4) in European Americans (open circles, dashed line) and African Americans (closed circles, solid line) after MThBI. Error bars represent the 95% confidence intervals calculated for proportions. a b c http://who.int/buruli/photos/Mesher2_Zilliox_large.jpg Table 2: Mental health characteristics by ethnicity surrounding burn injury European American African American P-value 1 month prior to burn injury   SF-12 Physical Component Score (SD) 53 (10) 54 (6) 0.46 SF-12 Mental Component Score (SD) 50 (12) 55 (7) 0.01 1 week prior to burn injury Depression, DASS (SD) 4 (9) 2 (5) 0.23 Anxiety, DASS (SD) 3 (7) 3 (5) 0.92 Since burn injury assessed at enrollment Pain Catastrophizing (SD) 21 (13) 22 (14) 0.97 PTSD Severity Score, PSSI (SD) 11 (10) 14 (13) 0.22 SD: standard deviation, DASS: depression anxiety stress scale, PSSI: PTSD Symptom Scale – Interview Figure 1: Skin graft procedure for coverage of burn injury site. Figure 2a shows the burn injury site after debridement. Figure 2b shows the process in which harvested from a donor site is meshed with a microtome to provide more extensive coverage of the burn injury site. Figure 2c shows an example burn injury site covered with meshed tissue autograft. Our sample in the study included only individuals whose burn injury was severe enough to require a tissue autograft.