Supplementary Online Content Weng QY, Raff AB, Cohen JM, Gunasekera N, et al. Costs and consequences associated with misdiagnosed lower extremity cellulitis. JAMA Dermatol. doi:10.1001/jamadermatol.2016.3816 etable 1. Literature review etable 2. Formula to estimate the annual number of misdiagnosed lower extremity cellulitis resulting in unnecessary inpatient admission from the ED etable 3. Calculations etable 4. Pseudocellulitis diagnoses This supplementary material has been provided by the authors to give readers additional information about their work.
Supplemental etable 1: Literature review Numbe r Publicatio n Year 1 2015 2 2015 3 2015 4 2014 5 2014 6 2014 Title Trends in department management of skin abscesses Treatment of bacterial skin infections in ED observation units: factors influencing prescribing practice Variation in US Hospital Emergency Department Admission Rates by Clinical Condition Factors Associated with Decision to Hospitalize Emergency Department Patients with Skin and Soft Tissue Infection Clinical Management of Skin and Soft Tissue Infections in the U.S. Emergency Departments Skin and skin structure infections (SSSIs) in the department First Author Prusakowsk i Haran Venkatesh Talan Mistry # ED cellulitis cases/yea r Absces s Rate (%) 4,222,659 35.0 1,923,000 15.0 Lower extremit y rate (%) Admissio n rate (%) 13.9 67.0 39.4 15.2 Khachatrya n 2,323,096 17.0
7 2013 8 2012 9 2010 10 2010 11 2008 12 2008 (ED): Who gets admitted? All purulence Merritt is local: epidemiology and management of skin and soft tissue infections in three urban departments 41.9 Identifying Volz patients with cellulitis who are likely to require inpatient admission after a stay in an ED observation unit 31.3 23.1 Report: Krasagakis Analysis of epidemiology, clinical features and management of erysipelas 66.0 The role of Jeng beta-hemolytic streptococci in causing diffuse, nonculturable cellulitis: a prospective investigation 75.8 Predicting observation unit treatment failures in patients with skin and soft tissue infections Schrock 53.1 56.5 38.0 National Trends in Ambulatory Visits and Hersch 3,250,500
13 2005 14 2005 15 2005 Antibiotic Prescribing for Skin and Soft- Tissue Infections Erysipelas and Lazzarini cellulitis: clinical and microbiological spectrum in an Italian tertiary care hospital 66.0 Randomised Corwin controlled trial of intravenous antibiotic treatment for cellulitis at home compared with hospital 78.4 Increased US department visits for skin and soft tissue infections, and changes in antibiotic choices, during the emergence of communityassociated methicillinresistant Staphylococcu s aureus Pallin 2,590,380 Median 2,590,380 38.5 66.0 16.1
Supplemental etable 2: Formula to estimate the annual number of misdiagnosed lower extremity cellulitis resulting in unnecessary inpatient admission from the ED: aa (1 bb) cc dd xx yy zz a = median annual # of adults presenting to ED nationally with diagnosis of cellulitis b = median fraction of cellulitis cases involving abscess c = median fraction of cellulitis cases involving the lower extremities d = median fraction of ED patients admitted for inpatient management of cellulitis x = rate of cellulitis misdiagnosis y = fraction of included patients in which cellulitis was the primary reason for inpatient admission z = fraction of pseudocellulitis patients whose admission was not necessary (as determined by consensus across study dermatologists) Variable Value a 2,590,380 b range 12.9%* 67.0%; median 35% c median 66.0% d median 16.1% x 30.5%* y 65.8%* z 84.6%* *: current study
Median # adults presenting to the ED nationally Exclude patients with abscess (rate range 12.9 67%) Only include patients with lower extremity cellulitis (median rate 66.0%) Only include admitted patients (median rate 16.1%) Only include patients where cellulitis is the primary reason for admission (rate 65.8%) # patients misdiagnosed (rate 30.5%) # of patients with unnecessary admissions (rate 84.6%) Excess inpatient days (average length of stay 4.3) Cost of admissions ($12656.9 per 4.3 day admission) # of patients receiving unnecessary antibiotics (rate 92.3%) Supplemental etable 3: Calculations Low abscess rate (12.9%) High abscess rate (67.0%) 2,590,380 2,590,380 2,256,221 854,825 1,489,106 564,185 239,746 90,834 157,753 59,769 48,114 18,229 40,705 15,422 175,031 66,315 $515,199,114 $195,194,712 44,409 16,826
Supplemental etable 4: Pseudocellulitis diagnoses Pseudocellulitis diagnosis, n (%) 79 (100.0) Vascular 48 (60.8) Venous stasis dermatitis 15 (19.0) Venous stasis ulcers 6 (7.6) Congestive heart failure 5 (6.3) Non-specific edema 5 (6.3) Deep venous thrombosis 5 (6.3) Hematoma 3 (3.8) Peripheral vascular disease 3 (3.8) Calciphylaxis 3 (3.8) Limb ischemia 2 (2.5) Thrombophlebitis 1 (1.3) Inflammatory 15 (19.0) Gout or pseudogout 6 (7.6) Allergic contact dermatitis 3 (3.8) Vasculitis 2 (2.5) Drug reaction 2 (2.5) Spider bite 1 (1.3) Pyoderma gangrenosum 1 (1.3) Infectious 6 (7.6) Ecthyma gangrenosum 2 (2.5) Tinea pedis 1 (1.3) Septic bursitis 1 (1.3) Osteomyelitis 1 (1.3) Disseminated zoster 1 (1.3) Other 10 (12.7) Musculoskeletal injury 2 (2.5) Complex regional pain syndrome 1 (1.3) Metastatic malignancy 1 (1.3) Multiple sclerosis 1 (1.3) Inguinal hernia 1 (1.3) Wound 1 (1.3) Unknown 3 (3.8)