Early Response in Cellulitis: A Prospective Study of Dynamics and Predictors

Area of Science:

• Infectious Diseases
• Clinical Microbiology
• Pharmacology

Background:

• Skin and soft tissue infections, including cellulitis, are frequent reasons for medical consultations.
• Broad-spectrum antibiotic use and healthcare costs associated with these infections have risen.
• Early assessment of treatment response is crucial in clinical trials and practice, yet data on response dynamics and nonresponse causes are limited.

Purpose of the Study:

• To investigate the dynamics of early treatment response in hospitalized cellulitis patients.
• To identify predictors of early nonresponse to antibiotic therapy.
• To determine the impact of early nonresponse on resource utilization and patient outcomes.

Main Methods:

• Prospective enrollment of 216 patients hospitalized with cellulitis.
• Analysis of clinical and biochemical response data over the first 3 days of treatment.
• Multivariable logistic lasso regression to identify predictors of nonresponse.

Main Results:

• Most patients showed clinical or biochemical response by day 1; concordance peaked at days 2-3.
• Predictors of nonresponse at day 3 included female sex, cardiovascular disease, higher BMI, shorter symptom duration, and non-erysipelas cellulitis.
• Nonresponse at day 3 predicted longer treatment duration (>14 days) but not overall clinical failure. Early treatment escalation was common in nonresponders, but initial therapy was rarely inappropriate.

Conclusions:

• Nonpharmacological factors significantly influence early treatment response dynamics in cellulitis.
• Delayed response is infrequently due to incorrect initial antibiotic choice but often leads to premature treatment escalation.
• The findings suggest that broadening antibiotic therapy may be initiated too early in many cases of cellulitis.