The role of basic laboratory parameters in diagnosing acute appendicitis and determining disease severity in the elderly Abstract Background: Abdominal pain constitutes the most common complaint for geriatric patients who present to the emergency department, with nearly 20% suffering from acute appendicitis (AA). Although key for diagnosis, clinical symptoms tend to be weak and atypical in the elderly. Therefore, patients present late to health institutions. Hence, prognosis and complication rates are worse in the elderly. Here, we aimed to reveal the role of basic laboratory parameters in diagnosing AA and determining disease severity. Methods: 143 elderly patients who underwent appendectomy were retrospectively analyzed. The patients were divided into three groups based on AA severity as Group I: negative appendectomy (n=15); Group IIa: uncomplicated appendicitis (n=79); Group IIb: complicated appendicitis (n=49). Results: We found no difference between the groups for age, sex, or comorbid diseases (p>0.05). As the time of admission to the hospital increases, the severity of the disease increases. Group IIb had higher length of stay and complication rates (p<.0.05) Conclusions: Preoperative WBC, neutrophil, NLR, MPV, CRP, and direct and total bilirubin levels can be used as biomarkers to determine AA diagnosis in the elderly. NLR, PLR, RDW, CRP, and direct and total bilirubin levels can be used to determine the presence of complications in appendicitis. Key Words: Geriatric patients, acute appendicitis, morbidity, laboratory parameters WHAT’S KNOWN? (what is already known about this subject?) Acute appendicitis is the most common surgical disease worldwide. Although known as a young person disease, it has an increased incidence among geriatric patients with increased life expectancy. AA constitutes 20% of elderly patients presenting to the emergency room with abdominal pain. Due to the obscurity of key clinical symptoms and findings, difficult access to basic imaging methods like USG and CT, and the low diagnostic values of these methods in elderly patients, basic laboratory parameters are important for this patient group. WHAT’S NEW? (what does this study contribute to the literature?) WBC, neutrophil, NLR, MPV, CRP, and direct and total bilirubin levels can be used in the diagnosis of AA in elderly patients. NLR, PLR, RDW, CRP, and direct and total bilirubin levels can be used to determine the complications in appendicitis. 1 INTRODUCTİON One of the most common causes of acute abdomen, acute appendicitis (AA) is caused by inflammation of the appendix. It is the most common disease that requires emergency abdominal surgery. The disease has an incidence of about 7-10% throughout life [1,2]. While known as a young person disease, incidence of AA has been increasing in the elderly with increased life expectancy [3]. Abdominal pain constitutes the most common complaint for geriatric patients who present to the emergency department, with nearly 20% suffering from acute appendicitis. In geriatric patients, emergency appendectomy is the third most common reason for abdominal surgery [4,5]. AA diagnosis includes the use of anamnesis, physical examination, laboratory tests, and radiologic methods [6]. Classical appendicitis findings like right lower abdominal pain and tenderness, leukocytosis, and fever are seen in only 26% of elderly patients [2,7]. Thus, it is difficult to diagnose AA in the elderly population. Geriatric patients undergo a number of physiological changes in their bodies. For this patient group, clinical symptoms and signs are also weaker and atypical. Patients tend to present late to the emergency department, leading to delayed diagnosis and treatment. Elderly patients have a worse prognosis and higher complication rates compared to young patients [2,3,8]. Besides, since elderly patients are likely to have more comorbid diseases, morbidity and mortality rates are also increased. Hence, early diagnosis and appropriate surgical intervention are vital for elderly patients [8,9]. Due to the obscurity of symptoms and findings, not using advanced imaging methods in the first place for diagnosis, and the difficulty to access such devices particularly in rural regions, basic laboratory tests gain even more importance. These tests are simple, inexpensive, and easily accessible in almost all health institutions, providing information on biomarkers with an acceptable diagnostic value [10]. Although studies on this matter have increased recently, there is limited research on the diagnostic efficiency of laboratory parameters in geriatric acute appendicitis [1,9]. The aim here was to analyze patients operated for the diagnosis of AA in light of the literature and to reveal the predictive value of basic preoperative laboratory parameters in diagnosing AA and determining disease severity. 2 MATERIALS AND METHODS Approval was obtained from the Ethics Committee of Erzurum Regional Training and Research Hospital (No. 2020/13-146). 3,856 adult patients aged over 18 years were operated for the diagnosis of acute appendicitis between January 2015 and August 2020. Data belonging to 160 patients (4.15%) aged over 65 years were retrospectively analyzed. 17 patients whose blood parameters were affected by causes other than acute appendicitis were excluded (3 patients whose blood parameters could not be determined, 3 with malignant pathology, 5 with multiple comorbid diseases, and 6 with other surgical pathologies). 143 patients aged over 65 years were found to be eligible for the research. Patients’ sex, age, time from symptom onset to admission, comorbidities, preoperative blood results, preoperative images, type of anesthesia, type of surgery, length of hospital stay, complication status, and histopathological results for appendectomy materials were obtained from the hospital’s digital records. The patients were divided into three groups based on the results of their appendix histopathology. Patients in group I (normal appendix, lymphoid hyperplasia, obliterative appendix) were evaluated as normal. (Negative appendectomy) Patients in group IIa (phlegmonous appendicitis, catarrhal appendicitis, suppurative appendicitis) were evaluated as noncomplicated appendicitis. Patients in group IIb (gangrenous appendicitis, perforated appendicitis, plastron appendicitis) were evaluated as complicated appendicitis. 2.1 Statistical Analysis Descriptive data were expressed as mean and standard deviation for the numerical variables and as number and percentages for the categorical variables. The distribution of the data was examined with histogram graphics. After examining the homogenity of the data, analysis was performed with One Way Anova, Kruskal Wallis tests. Tukey and Tamhane tests were used for post hoc analysis. Chi- square test used for two categorical data analysis. Receiver operating characteristic (ROC) curves were created to measure the ability of laboratory values to distinguish of acute appendicitis and complicated appendicitis status. The area under curve (AUC) and cut-off value of each measurement were determined. Specificity, Sensitivity and positive likely-hood ratio (LR+) cut-off values were calculated and evaluated together. A p value of <0.05 was considered statistically significant. Statistical analysis was performed using SPSS version 23.0 software. 2.2 Receiver operating characteristic curve analysis (ROC) ROC curves were created to examine the differentiation of laboratory parameters for pathology positivity. AUC and cut-off values of some parameters were determined and their sensitivity, specificity, and LR+ cut-off points were calculated. ROC analyses was carried out both for patients diagnosed with acute appendicitis and those with normal appendix (Table 2, Figure. 1). Also, separate ROC analyses were performed for complicated and uncomplicated patients (Table 3, Figure 2). 3 RESULTS 143 patients aged over 65 years were examined over a period of six years. Of the patients, 60 (41.95%) were male and 83 (58.05%) were female, with a mean age of 69.69±6.34 years (range: 65-104 years). 69.9% of the patients had a comorbid disease. The sample was divided into three groups as Group I: negative appendectomy (n=15, 10.49%); Group IIa: uncomplicated appendicitis (n=79, 55.24%); Group IIb: complicated appendicitis (n=49, 34.27%) (Table 1). There was no significant difference between the groups in terms of age, sex, or comorbid disease (p>0.05). Time from the onset of abdominal pain to hospital admission was 1.67±1.04 days in group I, 1.59±0.65 days in group IIa, and 3.33±1.28 days in group IIb, with a significant difference between the groups (p<0.05) (Table 1). Regarding advanced imaging methods, 77.6% of the patients were examined by ultrasonography (USG) and 69.9% by abdominal computed tomography (CT). CT was found to have a sensitivity of 77.7% and a specificity of 70%, while USG was found to have a sensitivity of 74.2% and a specificity of 18.2% (Table 1). Table 1. Demographic and clinical features of the patients Table 1. Demographic and clinical features of the patients Table 1. Demographic and clinical features of the patients Table 1. Demographic and clinical features of the patients Table 1. Demographic and clinical features of the patients Table 1. Demographic and clinical features of the patients Appendix Type Appendix Type Appendix Type P value Normal Appendix (n=15) Uncomplicated AA (n=79) Complicated AA (n=49) Sex male 8 27 25 0,110 female
total 7
15 52
79 24
49 Age Age 70.53±6.17 69,15±6,47 70,31±6,22 0,278 Comorbid disease present 9 58 33 0,518 apsent 6 21 16 Pre-hospital delay/ day Pre-hospital delay/ day 1.67±1.04 1.59±0.65 3.33±1.28 <0,001* Length of stay/day Length of stay/day 3.13±2.56 3.34±2.01 6.59±5.93 0,007* Post.op complication present 3 24 24 0,042 apsent 12 55 25 Diagnostic tools
Ultrasonogrophy
Computed tomography Diagnostic tools
Ultrasonogrophy
Computed tomography n Sensitivity (%) 74.2 77.7 Specificity (%)
18.2
70 ——–