Characterizing Longitudinal Outcomes Of Keloid And Hypertrophic Scars
Pooja S. Yesantharao, MS, Kevin Klifto, PharmD, Andres Makarem, BS, Waverley He, BS, Olga Duclos, PA, Carisa M. Cooney, MPH, Damon S. Cooney, MD, PhD.
Johns Hopkins Medicine, Baltimore, MD, USA.
PURPOSE: Keloid and hypertrophic burn scars are relatively common and can cause substantial morbidity, including both psychosocial issues as well as functional limitations due to contracture, pain, and pruritis. However, due to the complex pathophysiology and diversity of manifestations of these scars, no universally-effective management strategy currently exists. We performed the current study to better characterize the etiology, treatment, and longitudinal outcomes of patients with keloid and/or hypertrophic scars.
METHODS: This is a single-institution, retrospective cohort study of adults treated for keloid and/or hypertrophic scars between June 2017-June 2019. Demographic, treatment, and outcomes data were abstracted from medical records. Chi square and ANOVA analyses were used where appropriate. Bonferroni adjustments were used for post-hoc testing. Univariate followed by stepwise inclusion into multivariate logistic regression was used to study treatment failure. Kaplan-Meier and Cox proportional-hazards analyses were used to study time to first treatment failure.
RESULTS: Two-hundred thirty patients with 963 scars met inclusion criteria. Among these patients, 41.2% had keloids, 58.8% had hypertrophic scars, and 3% had both. The most common etiologies for keloids were surgery (31.4%), piercings (21.8%), and idiopathic (14.8%), while the most common etiologies for hypertrophic scars were burn injury (87.3%) and surgery (11.2%; p<0.0001). Keloids were more common in African Americans (75.0%) while hypertrophic scars were more common in Caucasians (53.7%; p<0.001). One third of patients (33.8%) had failed treatment prior to presentation at our institution; treatment failure varied by scar type (34.5% for keloids and 9.9% for hypertrophic scars, p<0.0001) and by etiology (p<0.0001). Keloids were significantly more likely to be primarily treated with excision than hypertrophic scars (83.9% versus 43.5%, p<0.0001), while hypertrophic scars were significantly more likely to be primarily treated with laser. Scar etiology also significantly impacted treatment choice: burn scars were significantly more likely to be treated with laser while trauma scars were significantly more likely to be treated with intralesional injection upon post hoc analyses (p<0.00001). Among surgically-managed patients, the mean number of intralesional injections prior to index surgery was 0.8 (SD: 1.6) and the mean number after index surgery was 9.4 (SD: 8.9). Among keloid patients, those treated with surgery and intralesional steroid injections or adjuvant laser therapy demonstrated significantly lower rates of treatment failure (p=0.01), while among hypertrophic scar patients, those treated with laser alone had significantly lower treatment failure rates (p=0.02). Also, hypertrophic burn scars treated with laser demonstrated a significantly greater decline in pruritis and pain scores after treatment than did other scar types/etiologies (mean change in pain/pruritis score over 1 year: -4.2 points on a scale of 10, p<0.01). Upon Cox proportional-hazards modeling adjusting for baseline demographics and scar etiology, keloid patients treated with excision/adjuvant intralesional steroid injections and hypertrophic scar patients treated with laser had significantly greater times to first treatment failure.
CONCLUSIONS: Though both originate from dysregulated wound healing, keloid and hypertrophic scars vary by etiology, management, and outcomes. By longitudinally-investigating outcomes by scar type, etiology, and treatment methodology, this study hopes to inform treatment algorithms for keloid and hypertrophic scars.
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