Life expectancy is increasing and consequently there is an increasing elderly population with multiple concomitant and more severe co-morbidities. (5, 6) With this increase of the lifespan, a growing incidence of acute appendicitis has been registered in the elderly (≥ 65 years old) population and also in the oldest old (> 80 years old). (9, 29) Moreover, emergency surgery in the elderly is challenging in terms of decision-making, managing co-morbidity and post-operative rehabilitation with high morbidity and mortality rate. (2, 3, 7) On the light of this, it is pivotal to define the possible clinical-pathological features and treatment of such disease in a well-known frailer portion of the population.
New pathophysiology acknowledgement and improved surgical and anaesthetic skills allowed the surgeon to achieve better results in treating these high-risk patients. (3), However, diagnosis and treatment of acute appendicitis in elderly patients still remain a challenge. (12–15).
We particularly focused on the age-related clinical differences and investigated the role of age as independent risk factor for the main clinical course and outcomes.
We have herein reported, to the best of our knowledge, the largest series of comparison of clinical features and outcomes between patients aged 80 years and older and elderly patients with an age comprised between 65 and 79 years presenting with AA, since no series with similar design were found in the current literature. The elderly account for approximately 10% of the population and between them about a quarter is represented by patient > 80 years old. Several studies evidenced significant differences in terms of AA clinical course between patients older and younger than 65 years with an increased morbidity and length of stay in the elderly. (12–15) Interestingly enough, in our study population, age ≥ 80 years was not an independent risk factor for both major and overall morbidities as well as for frailty which surprisingly is not statistically associated with postoperative complications. Focusing on the clinical presentation of AA, we found no difference in terms of pre-operative variables such us sex, BMI, BT, MPI and presence of comorbidities between the two groups. Regarding laboratories value, only few studies have investigated the predictive role of preoperative laboratory parameters. (30, 31). According to the literature, the age of the patient is one of the most important factor affecting the degree of elevation in inflammatory markers. Although there are many studies that have evaluated the benefits of using WBC, consensus has not yet been reached. (32, 33) Moreover, elderly patients have generally less remarkable inflammatory factors, due to decreased immune system response ability. (34, 35). At this regard, our study shows no difference in terms of WBC, PCR and glycaemia between the two groups and we evidenced also a similar rate of SIRS and q-SOFA. On the contrary, we reported a significant higher level of lactate and creatinine in the oldest old group. A possible explanation could be linked to the long-terms pre-existing comorbidities in the oldest old group that negatively influence the already reduced physiological functions of elderly patients, leading to an insufficient organ reserve to cope with an inflammatory insult such as AA.
Several studies have shown a higher rate of complicated AA in the elderly group. (24, 36, 37) This finding may be explained by the fact that elderly patients with perforated appendix would show poor exacerbation of pain as well as more generalized lower abdominal tenderness and guarding leading to a delay in presentation to the hospital. (38, 39) This is in line with other studies who report a reduction of pain in oldest old patients, probably linked to a greater capacity to endure or to report it. (40, 41)
However, our series did not show a significant increase rate of complicated AA in the oldest group, but nevertheless perforation or abscess at presentation are independent risk factors for overall morbidities.
Based on this premise, we can assume that it is absolutely necessary to consider all clinical and laboratory findings, as well as the radiological methods for diagnosing acute appendicitis, above all in the oldest old. According to the recent literature, the role of diagnostic imaging, such as POCUS and CECT is another major controversy. (14, 42) In our series, more than half of the patients underwent preoperative POCUS with no difference in terms of positive findings between the elderly and the oldest old group. However, an abdomen CECT scan was done in the 81% of the patients, reaching a rate of 92,7% in the oldest-old group. This finding is consistent with the number of ileocolic resection performed, since in the presence of a not clear diagnosis of appendicitis only at CECT (e.i. ileocecal abscess or pseudo inflammatory tumour) a major resection was carried out. The recently published Cochrane systematic review on CECT scan for diagnosis of AA in adults identified 64 studies including 71 separate study populations with a total of 10280 participants (4583 with and 5697 without AA). Summary sensitivity of CECT scan was 0.95, and summary specificity was 0.94. At the median prevalence of AA (0.43), the probability of having AA following a positive CECT result was 0.92, and the probability of having AA following a negative CECT result was 0.04. (43). According to the last World Society of Emergency Surgery guidelines (WSES), we agree that POCUS is the most appropriate first-line diagnostic tool, however as the elderly have often not typical laboratories values and symptoms unlikely to be acute appendicitis, cross-sectional imaging such us CECT scan is recommended before surgery. (14). Delay in presentation was found by many authors to be the reason behind the higher rate of perforation seen in the elderly population while in a meta-analysis of van Dijk a delaying appendectomy for up to 24 hours after admission does not appear to be a risk factor for complicated appendicitis, SSI or other morbidities. (44, 45)
Our research showed a slight lower time to surgery in the OOG. This can be interposed in light of the fact that when facing with oldest old, having them a smaller functional reserve, a more timely intervention is needed, and it also run with the greater rate of major resection carried out in this group. However, time to surgery was not a risk factor for overall and major complications. Regarding treatment strategies, even if over the last few years, several reports have been published describing non-operative-management (NOM) of AA, in our series all but seven patients underwent surgical procedure. (46–49) However 6 out of 7 of NOM patients were > 80 years old. Such findings, reflects the tendency of avoiding surgical procedures in patients generally defined as not fit for surgery.
Appendectomy was the overall most common surgical procedure, the rate of major surgery such as ileocecal resection was similar in both groups and it was an independent risk factor for major post-operative complication at both univariate and multivariate analysis. This could be linked with another evidence emerged from our study which shows how the presence of complicated appendicitis is an independent risk factor for overall and major complications both at univariate and multivariate analysis.
Regarding the surgical approach, several systematic reviews of randomized control trials comparing laparoscopic appendectomy (LA) versus open appendectomy (OA), conclude that LA leads to less postoperative pain, lower overall hospital stays, and significantly decreases postoperative complications, in particular SSI. (14, 51) From our experience, the laparoscopic approach was statistically more frequent in the elderly group. This could be linked to the fact that being the oldest old often less autonomous and often more bedridden, the advantages of laparoscopy are less important.
Of note, according to our analysis, there was no difference regarding the conversion rate in both groups and it was not a risk factor for post-operative morbidity. On the other side, an ASA ≥ 3 score was an independent factor for overall and major complications both at univariate and multivariate analysis, so we can assume that concomitant comorbidities might contribute the most to higher morbidity rate in aged patients.
Focusing on major complications, another important finding of our study is that there was an inverse relationship between increasing age and AA related major complications, highlighted how oldest patients in their frailty, achieve a more stable physiologic status compared to elderly patient with equal comorbidity rate. Moreover, comorbidities such us hypertension, diabetes, use of OAD and kidney dysfunction are independent risk factors for major comorbidity regardless patient age.
Although our study represents, to the best of our knowledge, the largest case series that specifically focuses on the AA clinical course in the over 80-year population, some limitations should be outlined. The observational multicenter cohort design, without a control population to compare is the most important. Another limitation concerns the epidemiological data, that are limited by the number responder centres
However, the prospective data collection and “a priori” definition of criteria to identify postoperative complications might mitigate these limitations. Moreover, a wide multicenter study allows more variables and reproducible results than a single center, while the large series of patients allowed excluding confounders by multiple logistic analyses.