Female (OR 4.438), fever (OR 2.395), leg weakness (OR 2.750), WBC (OR 1.110), CRP (OR 1.075), identification of causative bacteria (OR 3.200), bacteremia (OR 4.865), additional surgical treatment (OR 5.353), recurrence (OR 9.209), extent of lesion (OR 1.665), epidural abscess (OR 4.400), and psoas abscess (OR 2.229) in univariable analysis; and CRP (OR 1.071), bacteremia (OR 4.647), additional surgical treatment (OR 6.737), recurrence (OR 22.543), extent of lesion (OR 1.431) in multivariable analysis; were statistically significant factors for the above-average cost of hospitalization. The gene discussed is CRP; the disease is Psoas abscess.