Lifetime Risk of Surgery in England: A Nationwide Observational Cohort Study

Academic Background

Surgery represents a significant portion of the UK National Health Service (NHS) activity, with approximately 4.4 million people undergoing surgical procedures in England each year. Although an increasing number of surgeries are performed as day-case procedures, a substantial portion still requires overnight hospital stays, with a median length of stay of 1.7 days. Notably, one in six patients develops postoperative complications, which vary in severity and can lead to prolonged hospital stays and increased resource use. Additionally, postoperative complications occurring within 30 days of surgery double the one-year mortality rate. The surgical population is aging, with patients undergoing surgery being, on average, 14.5 years older than the general population. In 2015, 20% of the population aged 75 and older in England underwent surgery, and this number is increasing. Older age is associated with poorer postoperative outcomes, potentially resulting in greater healthcare resource utilization. The recent COVID-19 pandemic has also influenced how healthcare systems are organized, impacting surgical trends and volumes. However, it remains unknown how many times the average person will undergo surgery in their lifetime and the extent of their healthcare resource use.

Lifetime risk is a measure of the average person’s risk of experiencing a specific event over their lifetime. This concept is commonly used to calculate the risk of developing certain diseases, such as cancer or diabetes, but has not been previously used to quantify exposure to surgical procedures. Understanding the lifetime risk of surgery supports public health strategists in planning resource and workforce requirements across the healthcare system. The COVID-19 pandemic had a substantial impact on elective surgical services, with global estimates suggesting that 72.3% of all operations were canceled or postponed during the 12-week peak of the pandemic. In England and Wales, surgical volume decreased by 33.6%, representing the cancellation of over 1.5 million surgeries in 2020 alone. Therefore, studying the lifetime risk of surgery and its changes during the pandemic is of significant importance.

Source of the Paper

This paper was co-authored by Sarah-Louise Watson, Alexander J. Fowler, Priyanthi Dias, Bruce Biccard, Yize I. Wan, Rupert M. Pearse, and Tom E. F. Abbott, affiliated with Barts and The London School of Medicine and Dentistry at Queen Mary University of London, the Critical Care and Perioperative Medicine Research Group at the William Harvey Research Institute, and the Department of Anaesthesia and Perioperative Medicine at Groote Schuur Hospital, University of Cape Town. The paper was published online ahead of print on July 31, 2024, in the British Journal of Anaesthesia.

Study Design and Methods

Study Design

This study conducted a population-based cohort analysis using Hospital Episode Statistics (HES) data from England between January 1, 2016, and December 31, 2020. The study calculated age- and sex-specific incidence rates of surgery and combined these with routinely available population and mortality data from the Office for National Statistics (ONS). The lifetime risk of surgery was calculated using the life table method, and the impact of the COVID-19 pandemic on this risk was assessed.

Data Sources

The study used HES Admitted Patient Care (HES-APC) data to calculate the number of surgeries occurring in each age interval and the 30-day mortality rate of surgery during the defined period. The HES database encompasses data on all admitted patient care, outpatient attendances, and urgent and emergency care activities in England. The study also used ONS data for age- and sex-specific population size and all-cause mortality.

Participants

The study included all patients who underwent surgery in England between January 1, 2016, and December 31, 2020, totaling 23,427,531 surgical procedures, of which 11,937,062 were first surgeries. The denominator population was the annual general population of England, averaging 55.9 million.

Statistical Methods

The study used both the life table method and cumulative incidence to calculate the lifetime risk of surgery. The life table method considers both mortality and incidence rates, while cumulative incidence only considers incidence rates. The study calculated the lifetime risk of surgery for the pre-pandemic period (2016-2019) and compared it with the pandemic period (2020).

Key Findings

Lifetime Risk of Surgery

Using the life table method, the lifetime risk of first surgery was 60.2% (95% CI: 55.1%-65.4%) for women and 59.1% (95% CI: 54.2%-64.1%) for men. The lifetime risk of all surgery was 80% (95% CI: 78.6%-81.4%) for men and 79.5% (95% CI: 78.1%-80.9%) for women.

Women had a higher lifetime risk of all surgery between the ages of 25-29 and 65-69 compared to men, likely due to obstetric and gynecological surgeries. When obstetric surgeries were excluded, women’s lifetime risk was only slightly higher than men’s.

Impact of COVID-19

The COVID-19 pandemic significantly reduced the lifetime risk of first surgery, with women’s risk decreasing from 60.2% to 40.8% and men’s from 59.1% to 40.4%. The lifetime risk of all surgery also decreased, with women’s risk dropping from 79.5% to 72.2% and men’s from 80% to 75.4%.

Sensitivity Analysis

When obstetric surgeries were excluded, the lifetime risk of first surgery was 57.8% (95% CI: 52.6%-62.9%) for women and 58.7% (95% CI: 53.8%-63.6%) for men. The lifetime risk of all surgery was 78% (95% CI: 76.5%-79.4%) for women and 79.5% (95% CI: 78.1%-80.9%) for men.

Discussion

The primary finding of this study is that the lifetime risk of undergoing surgery in England is approximately 60%. The COVID-19 pandemic significantly reduced the lifetime risk of surgery, particularly for first surgeries. The lifetime risk of surgery is a useful public health statistic for understanding the burden of surgery and provides the public with an estimate of their risk of undergoing surgery in their lifetime.

Highlights of the Study

1. First Quantification of Lifetime Risk of Surgery: This study is the first to use the concept of lifetime risk to quantify exposure to surgical procedures, filling a gap in this field.
2. Impact of COVID-19: The study provides a detailed analysis of the impact of the COVID-19 pandemic on the lifetime risk of surgery, showing a significant reduction in risk.
3. Gender Differences: The study found that women have a higher lifetime risk of surgery in certain age groups, particularly between 25-29 and 65-69 years, likely due to obstetric and gynecological surgeries.

Conclusion

This study calculated that the lifetime risk of surgery in England is approximately 60% using the life table method. The COVID-19 pandemic significantly reduced the lifetime risk of surgery, particularly for first surgeries. The lifetime risk of surgery is a useful public health statistic for understanding the burden of surgery and provides the public with an estimate of their risk of undergoing surgery in their lifetime.