Cost of postoperative complications: How to avoid calculation errors

Table 1 Types of costs to consider in the economic evaluation of postoperative complications

Direct costs
1 Health-related
1.1 Postoperative resources used/consumed by the patient during hospitalization:
(1) Shared or overhead costs. Financing of administrative infrastructure and fixed installations. Resources used by different services: Administration, records, electricity, heating, laundry, etc.
(2) Central services: Documentation, computer services, …
(3) Installations and catering.
(4) Health and non-health staff: Nurses, doctors, ancillary staff from the surgery service ...
(5) Use of other surgical and medical services at the hospital.
(6) Diagnostic procedures: Laboratory, radiological and endoscopic examinations, pathology studies, …
(7) Pharmacy.
(8) Surgical, endoscopic and radiological procedures. Ideally, recording of consumables for each procedure.
(9) Dressing materials.
1.2 Future postoperative costs related to the surgery performed and the postoperative complications arising:
(1) Primary care and hospital visits.
(2) Rehabilitation.
(3) Diagnostic procedures: Analytical, radiological and endoscopic examinations, ...
(4) Pharmacy.
(5) Readmissions associated with the surgery, however remote the relation.
(6) Care centres (for example, rehabilitation, convalecence or other long-term care centres)
(7) Health transport: Ambulances.
(8) Prostheses, wheelchaires, …
2 Non-health-related
2.1 Monetary:
(1) Social services: Home care, notification systems, …
(2) Time taken to receive medical care.
(3) Transport costs incurred by patients and families.
(4) Care for patient’s dependents.
(5) Adaptation of the home, vehicles, …
2.2 Non-monetary (opportunity cost):
(1) Time taken by the patient, families and friends in care of the illness.
Indirect costs
1.1 Productivity lost by patients (those in employment):
(1) Temporary or definitive incapacity for work.
(2) Readaptation in the workplace.
(3) Death.
1.2 Productivity lost by family members (those in employment):
(1) Paid time off work.
(2) Non-paid time off work.
1.3 Associated with the legal issues that may occur.

Table 2 Recommendations for the economic evaluations of costs associated with postoperative complications of surgical procedures

No.	Data to be described in the economic study
1	Type of study
2	Center: Particular characteristics
3	Period of inclusion of cases
4	Population and subgroups analyzed; clarify why they were chosen
5	Surgical interventions considered
6	Methods for managing the heterogeneity of the population and the surgical techniques used; clarify the possible influence of this heterogeneity on the results
7	If possible, describe the characteristics of the severity or complexity of patients (ASA, Charlson, Frailty ...)
8	Patients excluded and why
9	Patients and procedures lost for analysis. Economic data lost. Clarify whether these can compromise the validity of the results
10	Definition of complication
11	How complications are classified (better, Clavien-Dindo classification and comprehensive complication index)
12	Sources used to obtain data on the complications (specific forms, medical and nursing evolution comments)
13	Perspective from which the economic evaluation is carried out: the patient, the specific institution (e.g., the hospital), the target group for specific services e.g., rehabilitation), the Public Health Service, the Public Sector in general or from all perspectives (social perspective)
14	Health-related costs (direct and indirect), non-health-related costs (table 1). Sources used to obtain data. Specify the costs obtained en bloc (for example, general costs) those obtained in microcosts (radiology, pharmacy, ...) In the estimation of operating room costs, specify whether the cost of the consumable material used in each patient is individualized
15	Describe the postoperative follow-up time in which complications and costs will be evaluated for each perspective and procedure. From the hospital perspective, consider 90 d minimum
16	Methods for converting costs into a common monetary base and the exchange rate. If it includes more than one calendar year, specify corrections made for inflation
17	Biases and limitations of the study, and measures used to reduce them
18	Conflict of interests of researchers. Linking researchers to the surgical service and hospital
19	Source of study financing