The objectives are to characterise clinical pathways, outcomes and corresponding costs attributable to managing patients who develop an infected wound around the site of their surgical procedure, called a surgical site infection (SSI).
The study population will comprise patients who were 18 years of age or older at the time of their surgery and be classified as being high- or low risk depending on their body mass index, whether they smoked and their other illnesses.
Information will be extracted from patients’ records including baseline characteristics, other illnesses, healthcare resource use and clinical outcomes.
The analysis would estimate (1) percentage of patients who developed a SSI, classified by their risk and anatomical site of surgery, (2) percentage of infections that resolved, (3) percentage of patients whose surgical wound healed, classified by risk and whether they developed a SSI, (4) percentage of patients whose surgical wound broke down, classified by risk and whether they developed a SSI, (5) percentage of patients who died, classified by risk and whether they developed a SSI, (6) risk factors that may have affected onset of a SSI, (7) healthcare resources required to manage patients who developed a SSI and (8) NHS cost of patient management, classified by risk and anatomical site of surgery.
Appropriate statistical tests will be performed to detect whether there are any statistically significant differences between patients considered to be of high-risk and low-risk at the time of their surgery.
The objectives are to estimate the incidence, patterns of care, clinical outcomes and costs attributable to the UK’s NHS managing SSIs in clinical practice.
The study population will comprise patients who were ≥18 years of age at the time of surgery in accordance with the attached codes. Data sources would be the electronic records of patients randomly extracted from CPRD Gold and CPRD Aurum which are linked to HES Accident and Emergency, HES Admitted Patient Care and HES Outpatient care.
The analysis would estimate the incidence of SSIs and amelioration rate; surgical wound healing rate and time to healing; surgical wound dehiscence rate and time to wound dehiscence; mortality rate; healthcare resource use attributable to managing SSIs and associated wound management. Patients would be classified into high- or low risk according to their body mass index, smoking status and comorbidity profile and by anatomical site of surgery and followed-up for a period of up to 1 year, or wound healing if that occurred sooner.
Regression analyses would be undertaken to identify risk factors for SSI development and amelioration. Kaplan–Meier analyses would be undertaken to compare the surgical wound healing distribution of different subgroups and the amelioration of SSIs.
NHS reference costs would be assigned to healthcare resources to estimate the NHS cost of managing SSIs and associated wound management, stratified by risk and anatomical site of surgery.
SSI prevention is a high-priority goal for NHS organisations. From a health policy perspective, this new study would provide robust estimates of the incidence of SSI, stratified by risk and surgical category, enabling better identification of patients who are more likely to develop a SSI. It would also enable resources to be allocated cost-effectively so that clinical practice guidelines could be implemented which would potentially minimise the risk of patients developing a SSI.
Baseline characteristics and comorbidities of patients who develop a SSI; onset of a SSI; time to develop a SSI following surgery; location of onset of SSI (e.g. during the initial admission, in the community post-discharge, during hospital re-admission); consequences of a SSI in terms of amelioration or local complications (e.g. delayed and non-healing of the surgical wound, cellulitis, abscess formation, osteomyelitis) or systemic complications (e.g. bacteremia, sepsis); onset of wound healing; time to wound healing; wound dehiscence; mortality; onset of Covid-19 infection after a surgical procedure; healthcare resource use among patients who developed a SSI (e.g. length of hospital stay, re-admission, additional procedures required as a result of a SSI, post-discharge hospital outpatient visits, post-discharge community-based clinician visits, post-discharge primary care-based clinician visits, post-discharge attendance at Accident & Emergency units, dressings and use of related devices).
Julian Guest - Chief Investigator - Catalyst Health Economics Consultants
Julian Guest - Corresponding Applicant - Catalyst Health Economics Consultants
Graham Fuller - Collaborator - Catalyst Health Economics Consultants
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient