Cancellation on the Day of Surgery in an Ambulatory Setting - A Retrospective Analysis

Background: Cancellations on the day of surgery represent an important setback for patients and pose considerable drawbacks for healthcare management. Part of these cancellations are due to patients’ factors. Some studies have addressed this issue in inpatient care, but scarce information is found regarding ambulatory setting. This work intended to analyse the parameters that are important in patient cancellation on the day of surgery for ambulatory surgery, with a closer analysis on those that are patient dependent, specifying those that are signicant in order to anticipate which patients will be cancelled beforehand. Methods: This work analysed a total of 19781 patients enrolled for elective day-case surgery in 2018, from which 1253 (6.33%) made a cancellation on their day of surgery. Results: Patients residing closer to the hospital (< 10 Km) had statistically more cancellations than those residing > 10 km away (p<0.05). Also, patients with 65 years of age or more had a higher cancellation rate (p<0.05). Finally, patients without a prior pre operative medical appointment might have a higher likelihood of same day cancellation (5.8% vs 14.01%, p<0.05). T-test and Chi-square tests were used with a level of signicance of 0.05. Conclusions: We expect this work can contribute to anticipate the cancellation of a given patient, enabling quicker treatment with optimised resources.

(p<0.05). Finally, patients without a prior pre operative medical appointment might have a higher likelihood of same day cancellation (5.8% vs 14.01%, p<0.05). T-test and Chi-square tests were used with a level of signi cance of 0.05.
Conclusions: We expect this work can contribute to anticipate the cancellation of a given patient, enabling quicker treatment with optimised resources.

Background
Cancellations on the day of surgery cause a heavy burden for the patients and pose a signi cant setback to health systems.
Previous works have shown that cancellations on the day of surgery can be globally due to patient factors, medical factors and external factors [1][2]. Tan et al. showed that clinical parameters such as history of heart failure, advanced chronic disease or history of hip fracture were signi cant regarding cancellations on multivariate analysis. Also, others not clinically directed such as low economic status, history of ≥ 4 cancelled surgeries in the past 3 years or day period for elective surgery were also signi cant [3].
Ambulatory surgery has been developing in the last 20-30 years in western societies mostly, but also in developing countries [4][5]. The development of both anaesthetical and minimally invasive surgical protocols has allowed clinically more complex patients to be enrolled for outpatient care throughout a diverse range of surgical specialties [6][7][8].
Ambulatory surgery has been gaining an increasing role in terms of surgical relevance for the patients, since it typically does not involve hospital stays and poses a lighter burden in terms of loss of working days, allowing also important results in terms of casuistic.
Indeed, as noticed for inpatient care, the cancellations in ambulatory surgery also contribute negatively for patients and healthcare systems from a global perspective. One important feature on this matter is the cancellation due to patients' factors. The literature is however quite scarce concerning the parameters that condition patients missing a surgery appointment in the ambulatory setting. The cancellations on the day of surgery frequently limit the enrolment of a new patient waiting for surgery due to logistic and clinical constraints. In such a way, an available surgical period is lost, which might have been lled if one could anticipate with a reasonable amount of accuracy which patients might be more prone to miss surgery and beforehand notify a surrogate patient for this possibility.
The objective of this work is the analysis of the parameters that are important in patient cancellation on the day of surgery for ambulatory surgery, with a closer analysis on those that are patient dependent.

Data collection and analysis
The data was collected from digital medical records. The variables presented in Table 1 were analysed for all the patients. The Chi-square test was used with data reported as number (%) for the categorical variables presented with 95% con dence intervals. Signi cance was attributed at the 5% level. Data analysis was performed in SPSS Statistics vs 23.

Results
From a total of 19781 patients enrolled for elective day-case surgery in 2018, 1253 (6.33%) made a cancellation on their day of surgery. Figure 1 presents the yearly variation in terms of cancellations (in %). Figure 2 presents the absolute frequencies through medical speciality regarding same day cancellations.
Ophthalmology presented the highest value (66,2%; n=830), followed by Maxillofacial Surgery (7,82%; n=98), Vascular Surgery (6,22%; n=78), General Surgery (6,06%; n=76) and Dermatology (4,55%; n=57). When comparing the number of enrolled patients against the number of same day cancellations, Neuropathology exhibits the highest percentage (10,86%), followed by Dermatology (8,62%) and Ophthalmology (7,59%). Figure 3 details the motifs for cancellation on the day of surgery as registered on the patient digital clinical registry. Alteration in patient status (33,04%; n=414) missing surgery with a plausible reason (28,01%; n=351) and missing surgery without a plausible reason (20,67%; n=259) were the most prevalent reasons for same day cancellation. Figure 4 describes the proportions of same day cancellation in terms of distance to the hospital. A cut-off of 10 Km was de ned for creating the nominal variable and the group that included patients residing closer to the hospital was more prone to cancellation. The differences between the two groups were found to be statistically signi cant (p < 0.05). Figure 5 details the proportions of same day cancellation for the different age groups. A cut-off was de ned above 65 years for creating the nominal variable and the group that included patients with 65 years or more presented a higher cancellation rate. These differences were also found to be statistically signi cant (p < 0.05).
As for gender, the percentage of cancellation was quite balanced between both with 6.2% cancellation in males and 6.5% in females, as shown in Figure 6. No statistical signi cance was encountered for the differences.
Finally, regarding the existence of a pre operative medical appointment, a statistically signi cant difference was encountered when considering the variable "Alteration in patient status", as shown in Figure 7. Indeed, from the 414 patients with a same day cancellation only 24 had a pre operative medical appointment (5,80%). Comparatively, from the 16172 patients that were effectively enrolled and submitted to surgery, 2266 (14.01%) had a pre operative medical appointment.

Discussion
Cancellations on the same day of surgery constitute an important drawback in terms of medical care and management of healthcare resources.
Other authors have previously addressed this issue and have categorized these cancellations into 3 groups, namely: patient derived, medical derived, external factors.
This work dedicated closer attention to patient derived cancellations on the same day of surgery in our ambulatory hospital in a 1-year time in 2018.
A set of digitally available parameters were retrospectively analysed in order to gain insight on the possible reasons that may contribute to patient derived cancellation. Additionally, this work also has the goal to anticipate and modify changeable variables in order to decrease the rate of patient cancellation in the same day of surgery.
Based on the descriptive statistical analysis, 6.33% of cancellations occurred in the total amount of patients enrolled for surgery in our ambulatory centre. This is in accordance with data present in the literature and suggests that the ndings presented in this work may be valid when extrapolated to the general population [9].
No relevant yearly variation was found which suggest that no speci c efforts should be seasonally dedicated in order to tackle this issue, but, on the other hand, these should be present homogeneously throughout the year (Figure 1).
Ophthalmology showed the highest absolute value for same day cancellations, ranking 3rd when comparing the number of enrolled patients against the number of same day cancellations.
Neuropathology and Dermatology were 1st and 2nd respectively. This observation might reside in the fact that these medical specialties frequently have short surgical procedures (e.g. facoemulsi cation in Ophthalmology or nevus excision in Dermatology) while other specialities have more time-expanded surgeries. This enables the enrolment of more patients in one operating room period by Ophthalmology, being therefore not surprising that more patients may cancel their surgery on the same day. Vascular surgery was also located in the top 25% of cancellations (ranked 3rd with 6.22% same day cancellations) which follow previously published data [3].
Regarding the motifs for patient cancellation based on the digital records, the parameter "alteration in patient status" was the most prevalent. It is reasonable to assume that such an event would be noticed in the pre-op medical appointment. When analysing through the pre op medical appointment of patients that cancelled due to "alteration in patient status", a total of 5.8% of patients had a pre op medial appointment. Signi cantly more patients (p<0.05) which were enrolled and were subjected to surgery attended the pre operative medical appointment (14.01%). This suggests that, apart from what is already state of the art that refers that attendance at preoperative medical appointment is associated with a reduced likelihood of cancellation, patients without a prior pre operative medical appointment despite the motif, might have a higher likelihood of same day cancellation in ambulatory surgery [10][11][12].
The analysis of cancellations considering distance to the hospital revealed that patients residing closer to the hospital (< 10 Km) had statistically more cancellations than those residing > 10 km away (p<0.05).
This might be because patients residing closer to the hospital have quicker geographical access to the hospital facilities and rescheduling of medical appointments. This may predispose the patients to be less reluctant in cancelling/postponing a surgical procedure. Patients residing in areas that are more distant may be more hesitant to postpone the procedure.
Cancellations considering the age parameter showed patients with 65 years of age or more had a higher cancellation rate (p<0.05). Indeed, patients of older age groups commonly have more pathologies, increased limitations and constraints in individual locomotion. These factors may hinder the adequate completion of the process towards surgical treatment.
As for gender comparison, no statistically signi cant difference was found between both groups in relative proportion of cancellations.
This study has inherent limitations. It is limited to a single institution (one of the major central hospitals in Portugal providing tertiary care) in the year 2018.
Another limitation is the partial availability of parameters from patients to be obtained retrospectively. Although all the digitally available variables were gathered, these provide only partial information on the motifs for cancellation by the patients. Indeed, patients' motifs for cancellation are not entirely objective with this dataset. Nonetheless, this information is valuable as a preliminary assessment towards the optimization of the healthcare system with the possible creation of algorithms to anticipate the cancellation of a given patient and her/his replacement by a surrogate patient for surgery.
Future investigations could focus on the de nition of a typical pro le of a patient that cancels surgery on the same day based on its speci c variables. A predictive tool to identify with su cient accuracy those with a higher likelihood of cancellation on the same day could be put forth, enabling the enrolment of a substitute in case of effective cancellation. Such an approach might allow quicker treatment for patients with associated optimization of healthcare resources.

Conclusion
This work showed that patients located closer to the hospital facilities and of older age groups (>= 65 years) are more likely to cancel or be cancelled (p<0.05). Based on this preliminary evaluation, further studies can be planned in order to ascertain which variables, namely patient related, can be depicted in order to de ne a patient pro le with higher likelihood of cancellation on the same day of ambulatory surgery. This may allow for a surrogate patient that is already enrolled and waiting for surgery, to be pre booked in advance, thereby permitting quicker treatment without loss of operative time.

Declarations
Ethics approval and consent to participate: All protocols were carried out in accordance with relevant guidelines and regulations and were approved by the institutional Ethical Committee Consent for publication: Not applicable.
Availability of data and materials: The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.
Competing interests: The authors declare that they have no competing interests.
Funding: No funding was collected for this study.