Natural History of Keloids: A Sociodemographic Analysis Using Structured and Unstructured Data

Abstract

Introduction: Keloids are lesions characterized by the growth of dense fibrous tissue extending beyond original wound boundaries. Research into the natural history of keloids and potential differences by sociodemographic factors in the USA is limited. This real-world, retrospective cohort study aimed to characterize a population of patients with keloids compared with matched dermatology and general cohorts.

Methods: Patients with ≥ 2 International Classification of Diseases codes for keloid ≥ 30 days apart and a confirmed keloid diagnosis from clinical notes enrolled in the OM1 Real-World Data Cloud between 1 January 2013 and 18 March 2022 were age- and sex-matched 1:1:1 to patients without keloids who visited dermatologists ("dermatology cohort") and those who did not ("general cohort"). Results are presented using descriptive statistics and analysis stratified by cohort, race, ethnicity, household income, and education.

Results: Overall, 24,453 patients with keloids were matched to 23,936 dermatology and 24,088 general patients. A numerically higher proportion of patients with keloids were Asian or Black. Among available data for patients with keloids, 67.7% had 1 keloid lesion, and 68.3% had keloids sized 0.5 to < 3 cm. Black patients tended to have larger keloids. Asian and Black patients more frequently had > 1 keloid than did white patients (30.6% vs. 32.5% vs. 20.5%). Among all patients with keloids who had available data, 56.4% had major keloid severity, with major severity more frequent in Black patients. Progression was not significantly associated with race, ethnicity, income, or education level; 29%, 25%, and 20% of the dermatology, keloid, and general cohorts were in the highest income bracket (≥ US$75,000). The proportion of patients with income below the federal poverty line (< US$22,000) and patterns of education level were similar across cohorts.

Conclusion: A large population of patients in the USA with keloids was identified and characterized using structured/unstructured sources. A numerically higher proportion of patients with keloids were non-white; Black patients had larger, more severe keloids at diagnosis.

Keywords: Demographic factors; Keloid lesions; Keloids; Matched cohort; Natural history; Scarring; Socioeconomic factors; US claims database.

Fig. 1

Cohort selection. ^aClinical notes in the RWDC are sourced from the DataDerm registry, the American Academy of Otolaryngology–Head and Neck Surgery RegENT registry, and other general and specialty EMR sources. ^bThe index date is the first date a keloid was mentioned in the note or date of first ICD code; the definition of newly diagnosed patients is equivalent to having ≥ 12 months of data. Thus, the starting population for all objectives is the same. EMR Electronic medical record, ENT, Ear, nose, and throat, ICD International Classification of Diseases, RWDC Real-World Data Cloud

Fig. 2

Keloid characteristics, stratified by race. a Number of keloids, b size of keloids, c keloid type, d keloid severity at diagnosis, e progression of keloids within 24 months post diagnosis. Note: Keloid severity (d) was categorized as major (defined as either physician assessment of moderate, severe, or major in the clinical notes or ≥ 1 of the following: size ≥ 0.5 cm, symptomatic, widespread, cosmetically sensitive location, or treatment with triamcinolone acetonide dosage ≥ 20 mg within 90 days of the index date), minor (defined as either physician assessment of mild or asymptomatic in the clinical notes or ≥ 1 of the following: size < 0.5 cm, no symptoms, noncosmetically sensitive area, or minimally raised/flat within 90 days of the index date), or unknown. Note: Keloid progression (e) was assessed within 24 months post diagnosis and categorized as improved (described as improving, softer, becoming smaller, responding positively to treatment, improvement in symptoms, vanishing, regressing, or regression), stable/no change (described as stable, not changing, same, or not improving), worsening (defined as not responding to treatment, becoming worse/worsening, larger, higher, wider, painful, tender, erosions, infection, or marked post-treatment hypopigmentation), or unknown

Fig. 3

Association between risk factors and worsening^a of keloids. ^aKeloid progression was assessed within 24 months post diagnosis and categorized as improved (described as improving, softer, becoming smaller, responding positively to treatment, improvement in symptoms, vanishing, regressing, or regression), stable/no change (described as stable, not changing, same, or not improving), worsening (defined as not responding to treatment, becoming worse/worsening, larger, higher, wider, painful, tender, erosions, infection, or marked post-treatment hypopigmentation), or unknown. ^bReference: white race (n = 1170). ^cReference: not Hispanic/Latino (n = 1712). ^dReference: ≥ US$75,000 (n = 614). ^eReference: only medications (n = 1027)