This observational study demonstrates some similarities and differences between the United Kingdom and Swedish patterns in the number of diagnosed cases of appendicitis, and its complications. In both countries the COVID-19 outbreak started in January 2020 and in the present study we can detect a much lower number of performed acute CT of abdomen in April 2020 than the corresponding month in 2019. In Sweden, there was an increase in the number and proportion of patients diagnosed with complicated CT-verified appendicitis (perforation/abscess) in May and June 2020 compared to April 2020.
In the United Kingdom, the results were not homogenous during the observation period. The decrease in number of abdominopelvic CTs persisted until July. Initially, both the number of cases with appendicitis and complications decreased and this trend continued for several months. The proportion of cases with complications were also initially lower in 2020, however the number and proportion of patients with abscesses were dramatically increased in July 2020.
Our study illustrates some findings not previously shown. One is that figures and patterns from different countries might be different. This could well be due to public measures and is beyond the scope of this article. Another important point is the temporal course of complications. Especially looking at the data from the United Kingdom one might get different results if different time intervals are chosen for the observation.
Several studies have published results showing an increased proportion of complicated cases in the COVID-era [1-3, 7-9]. However, some studies have found only reductions of uncomplicated cases [4, 10-15] or no change [16]. Several of these latter studies are registration studies having the advantage of having more data from more centres. They are prone to problems with registration studies however. It is conceivable that investigator/physician initiated studies such as our own might be triggered by observed clinical trends. Our study has some points of strength not seen in prior studies. It is the largest study on actual cases and not registries. It is also the only study encompassing two countries and many hospitals. Additionally, our study is probably the only study where the date of examinations was blinded, thus less likely to bias.
The results of our study are based on CT exams. CT is more accurate than any presurgical examination or test for diagnosis of appendicitis and detection of its complications. Although CT results are probably not as perfect as surgical exploration, surgical explorations are not always offered to all patients especially during COVID [17]. One caveat is that CT, similar to surgery, is not performed on every patient. In order to decrease this confounding factor, we chose to compare the same hospitals and countries during 2019 and 2020. We had access to other countries that were not the same in 2019 and 2020 and decided not include them. We cannot rule out that a higher percentage of patients suspected of appendicitis underwent CT during 2020 [18]. The use of teleradiology CT activity has been shown to correlate with COVID-19 epidemiology [19]. CT however provides another advantage not seen with surgery, i.e. the dates can be blinded and thus avoid some bias.
There are multiple reports of delay in diagnosis and treatment of patients with chronic diseases, including cancer [20, 21]. The increased mortality and morbidity from delay in diagnosis and treatment may only emerge at a later stage [22-24]. Ostensibly, emergency health care should be more dependant on the individual patient’s health and choice rather than on the pandemic. Evidence points out similar trends elsewhere. For instance; fewer acute coronary presentations but a higher proportion of severe cases [25].
Full and severe lockdown measures have not been associated with lower COVID-19 mortality [26]. One of the interesting aspects concerning Sweden was its rather different approach to lockdowns. The Swedish approach was somewhat different from many other countries. It relied more on the informed consent of its citizens rather than use of coercion and mandates. It, therefore, implemented milder forms of lockdowns, in the hope that the population would show more compliance with healthcare measures in the long term. The United Kingdom adopted a similar approach initially but soon changed course. As with other observational studies, it is difficult, if not impossible, to evaluate causal relationships [27]. Although lockdowns should not in theory lead to fewer people being able to seek emergency health care; i.e. system delay (although some data as well anecdotal evidence suggest otherwise [15]), it may have lead to increased anxiety and fear among patients [28] which in turn might have impacted patients seeking medical attention in time (patient delay).
Our study also demonstrates a different trend in appendicitis and its complications between the United Kingdom and Sweden. It is conceivable that in both countries patients with appendicitis sought medical attention later in 2020 than in 2019. However, the degree of delay was more pronounced in the United Kingdom. It could be that in Sweden delays were in the order of hours and days, and thus the rise of complication rate was evident early. In the United Kingdom, we suspect that patients were imaged much later, perhaps weeks later. This led to a significant drop in the number of diagnosed cases first, but as time progressed the complicated cases started coming in. Whatever the reason for such different patterns, it should be a reminder of the importance of timing of an observation.
Interestingly the pattern in April 2020 is similar to 2019 in the United Kingdom. This might have been due to United Kingdom being hit by COVID-19 later than Sweden leading to initially very few diagnosed, largely uncomplicated cases.
Our observational study has some drawbacks. One is that our studied period does not encompass the whole 24 hours. It is however unlikely that this plays any noticeable role. While our study is limited to on-call hours, these hours have been the same for studied hospitals and both 2019 and 2020. Another issue is reliance on CT. As detailed above, we believe that due to the increased use of CT in the COVID-era, the figures for 2020, especially for uncomplicated cases, might be exaggerated compared to 2019. It remains to be seen that if these features will remain in place even after the disappearance or more likely endemisation of COVID-19.