Case Control Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Jun 6, 2020; 8(11): 2127-2136
Published online Jun 6, 2020. doi: 10.12998/wjcc.v8.i11.2127
Clinical prediction of complicated appendicitis: A case-control study utilizing logistic regression
Yosuke Sasaki, Fumiya Komatsu, Naoyasu Kashima, Takeshi Suzuki, Ikutaka Takemoto, Sho Kijima, Tadashi Maeda, Taito Miyazaki, Yoshiko Honda, Hiroaki Zai, Nagato Shimada, Kimihiko Funahashi, Yoshihisa Urita
Yosuke Sasaki, Fumiya Komatsu, Naoyasu Kashima, Takeshi Suzuki, Ikutaka Takemoto, Sho Kijima, Tadashi Maeda, Taito Miyazaki, Yoshiko Honda, Nagato Shimada, Yoshihisa Urita, Department of General Medicine and Emergency Care, Toho University School of Medicine, Ota-ku, Tokyo 143-8541, Japan
Kimihiko Funahashi, Department of General and Gastroenterological Surgery, Toho University Omori Medical Center, Otaku, Tokyo 143-8541, Japan
Author contributions: Sasaki Y designed the research, collected data, and wrote the manuscript; Komatsu F, Kashima N, and Suzuki T collected data with Sasaki Y; Takemoto I and Kijima S assisted in data collection; Maeda T and Miyazaki T advised on the discussion as experts of infectious diseases; Honda Y, Shimada N, and Funahashi K advised on the discussion as surgeons; and Urita Y supervised the research and advised on statistical analyses.
Institutional review board statement: The ethics committee of Toho University Medical Center Omori Hospital approved the study’s protocol (M19023).
Informed consent statement: The center’s ethics committee approved the waiver of individual informed consent subject to public announcement of the research because of the retrospective and noninvasive study design.
Conflict-of-interest statement: None.
STROBE statement: The authors have read the STROBE Statement checklist of items, and the manuscript was prepared and revised according to the STROBE Statement.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Yosuke Sasaki, MD, PhD, Assistant Professor, Department of General Medicine and Emergency Care, Toho University School of Medicine, Omori Hospital, 6-11-1 Omori-Nishi, Ota-Ku, Tokyo 143-8541, Japan. yousuke.sasaki@med.toho-u.ac.jp
Received: February 13, 2020
Peer-review started: February 13, 2020
First decision: April 1, 2020
Revised: April 8, 2020
Accepted: May 13, 2020
Article in press: May 13, 2020
Published online: June 6, 2020
Processing time: 115 Days and 17 Hours
ARTICLE HIGHLIGHTS
Research background

Because evidence on conservative treatment of acute appendicitis has increased, differentiation of patients with complicated appendicitis (CA) from those with simple appendicitis (SA) has become increasingly important. Previous studies have revealed that male gender, advanced age, comorbid conditions, prehospital delay, fever, and anorexia are risk factors of perforated appendicitis. Elevated serum C-reactive protein (CRP) level and hyponatremia have also been reported as predictive biomarkers of CA.

Research motivation

Confounding between various factors is problematic because most previous studies were univariate analyses. Thus, we performed a study using logistic regression analyses.

Research objectives

The objective of the study was to evaluate non-laboratory and laboratory predictive factors of CA using logistic regression analyses using logistic regression analyses.

Research methods

We performed a single-center, retrospective case-control study that evaluated 198 patients (83.9%) with SA and 38 patients (16.1%) with CA. Diagnoses were confirmed by computed tomography images for all cases. We compared age, sex, clinical symptoms, past medical history, vital signs, physical findings, and laboratory data. Based on the comparisons, we performed logistic regression for clinical differentiation between CA and SA using only non-laboratory factors and also including both non-laboratory and laboratory factors.

Research results

The 236 eligible patients consisted of 198 patients (83.9%) with SA and 38 patients (16.1%) with CA. The median ages were 34 years old in the SA group and 49 years old in the CA group. The median onset-to-visit interval was 1 d and 1 d in the SA and CA groups, respectively. Heart rate, body temperature, and serum CRP level in the CA group were significantly higher than in the SA group; glomerular filtration rate (GFR) and serum sodium were significantly lower in the CA group. Anorexia was significantly more prevalent in the CA group. The regression model including age, onset-to-visit interval, anorexia, tachycardia, and fever as non-laboratory predictive factors of CA (Model 1) showed that age ≥ 65 years old, longer onset-to-visit interval, and anorexia had significantly high odds ratios. The logistic regression for prediction of CA including age, onset-to-visit interval, anorexia, serum CRP level, hyponatremia, and glomerular filtration rate < 60 mL/min/1.73 m2 (Model 2) showed that only elevated CRP levels had significantly high odds ratios.

Research conclusions

Our logistic regression analysis on differentiating factors of CA from SA showed that high CRP level was a strong dose-dependent predictor of CA.