Clinical characteristics of older Japanese patients with acute appendicitis: A post hoc analysis

Background Acute appendicitis (AA) in older patients can look different from AA in younger patients. Although it is crucial that primary care physicians can recognize AA in patients of any age, few Japanese studies have examined the characteristics of older AA patients. To address this, we evaluated the clinical characteristics of older Japanese patients with AA. Methods We performed a post hoc analysis of the data from a previous Japanese single-center study. We analyzed the clinical information of both younger (age: 16-64 years) and older patients (age: >= 65 years). Results A cohort of 236 patients consisting of 219 (92.8%) younger patients and 17 (7.2%) older patients was evaluated. The median ages of the younger and older patients were 34 (interquartile range [IR], 24-45) and 78 years (IR, 74-81), respectively. The prevalence of complicated appendicitis (CA) (older: 41.2% vs. younger: 14.2%), comorbidities (70.6% vs. 13.2%), and thrombocytopenia (17.7% vs. 4.1%), along with serum C-reactive protein (CRP) level (6.7 mg/dl vs. 1.0 mg/dl), was significantly higher in older patients. Significantly fewer older patients had epigastric pain (17.7% vs. 53.0%). Logistic regression evaluating the characteristics of older AA patients showed that CRP >5 mg/dl had a high odds ratio (OR) (5.01; 95% CI, 1.73-14.54), while epigastric pain had a low OR (0.24; 95% CI, 0.06-0.90). Conclusion Our study reveals a higher prevalence of CA and comorbidities in older patients, and suggests that a lack of epigastric pain, thrombocytopenia, and higher serum CRP level are characteristics of older AA patients.