20 A comparative analysis of patients with acute skin and soft tissue infections: Hospitalization versus outpatient management
Authors: Sendra Elena , Gómez-Zorrilla Silvia , Membrilla-Fernández Estela , Gonzalez-Castillo Ana Maria , Castañeda Silvia , Montesinos Inmaculada López , Morera-Grau Alex , Jaume-Bottcher Sofia , Siverio-Parés Ana , Horcajada Juan Pablo 
Published: February 2025

Abstract

Background
Acute skin and soft tissue infections (ASSTIs) represent a common reason for attending emergency department (ED) and for hospitalization. We investigate characteristics of a cohort of ASSTIs-patients comparing patients managed with hospitalization versus outpatients.

Methods
Retrospective cohort study with all consecutive adults who consulted to an ED due to ASSTIs. Setting: Hospital del Mar (Barcelona, Spain). Period: January 2018–December 2020. Sample size (320) was calculated to detect a 10% difference in 30-day readmission (α-error 0.05, power 0.80, loss 0.05). Logistic regression models were conducted to assess the impact of inpatient/outpatient management on clinical outcomes. Primary endpoint: 30-days clinical failure (a composite endpoint with recurrence, unplanned readmission and/or ED attendance).

Results
320 patients were included. Table shows main characteristics comparing hospitalized patients versus outpatients. 82/320 patients had microbiological diagnosis being Staphylococcus aureus the most frequent pathogen isolated, followed by Streptococcus pyogenes, Streptococcus sp. and Pseudomonas aeruginosa. The most common empiric antimicrobial treatment in hospitalized patients were amoxicillin/clavulanic (75, 46.9%), ciprofloxacin plus clindamycin (23, 14.4%), and piperacillin/tazobactam (21, 13.1%). In outpatients: amoxicillin/clavulanic (116, 73.9%) and ciprofloxacin plus clindamycin (28, 17.8%). 26/160 (16.5%) of hospitalized patients required surgical management. The median of hospital stay was 9 days (IQR 5–15) and the most frequent complications were: phlebitis (9/160, 5.6%), delirium (8/160, 5%) and nosocomial infections (7/160, 4.3%). In logistic regression models adjusted by sex, age, Charlson and SAPS II index, no differences in clinical outcomes were observed between inpatients and outpatients. In outpatients, 30-days clinical failure was independently associated with male sex, severity of the illness (SAPS II) and homelessness.

Conclusions
In our study no significant differences in clinical outcomes was observed between inpatients and outpatients with ASSTIs. In ABSSTI-outpatients, 30-days clinical failure was associated with male sex, severity of the illness at admission and homelessness. These preliminary results open to further investigation to establish standard criteria for hospital admission in ABSSTIs. TableVariableAdmitted (n = 160)Non-admitted (n = 160)P-valueAge (years), m (IQR)62 (46–76)55 (40.25–71)0.035Male sex95 (59.4%)105 (65.6%)0.248Charlson comorbidity index, m (IQR)3 (1–5)2 (0–4)0.110Homeless26 (16.3%)13 (8.1%)0.026Previous aSSTIs episodes53 (33.1%)22 (13.8%)&lt;0.001Recurrent aSSTIs44 (27.5%)13 (8.1%)&lt;0.001Lymphedema/venous insufficiency17 (10.6%)2 (1.3%))&lt;0.001Fungal infection16 (10%)3 (1.9%)0.002Cellulitis124 (77.5%)130 (81.3%)0.407Abscess18 (11.3%)16 (10%)0.717Abscess + cellulitis14 (8.8%)6 (3.8%)0.065Surgical wound infection0 (0%)5 (3.1%)0.061Traumatic wound infection0 (0%)1 (0.6%)1.000Necrotizing fasciitis2 (1.3%)0 (0%)0.498SAPS II, m (IQR)26 (19–31.75)19 (19–28)&lt;0.001Bacteremia12 (7.5%)2 (1.3%)0.006Surgical source control26 (16.5%)1 (0.6%)&lt;0.001Clinical stability (Day 3)124/150 (82.6%)119/150 (79.3%)0.51330-days clinical failure Recurrence19 (11.9%)12 (7.5%)0.186 30-days unplanned readmission27 (16.9%)26 (16.3%)0.880 Related with infection14 (53.8%)20 (76.9%)0.080 30-days ED attendance46 (28.7%)54 (33.8%)0.335 Related with infection28 (59.6%)41 (78.8%)0.037 30-days mortality3 (1.9%)0 (0%)0.248