Population-based incidence rate of inpatient and outpatient surgical procedures in a high-income country

Background: The WHO and the World Bank ask countries to report the national volume of surgery. This report describes these data for Sweden, a high-income country. Methods: In an 8-year population-based observational cohort study, all inpatient and outpatient care in the public and private sectors was detected in the Swedish National Patient Register and screened for the occurrence of surgery. The entire Swedish population was eligible for inclusion. All patients attending healthcare for any disease were included. Incidence rates of surgery and likelihood of surgery were calculated, with trends over time, and correlation with sex, age and disease category. Results: Almost one in three hospitalizations involved a surgical procedure (30.6 per cent). The incidence rate of surgery exceeded 17 480 operations per 100 000 person-years, and at least 58.5 per cent of all surgery was performed in an outpatient setting (range 58.5 to 71.6 per cent). Incidence rates of surgery increased every year by 5.2 (95 per cent c.i. 4.2 to 6.1) per cent (P<0.001), predominantly owing to more outpatient surgery. Women had a 9.8 (95 per cent c.i. 5.6 to 14.0) per cent higher adjusted incidence rate of surgery than men (P<0.001), mainly explained by more surgery during their fertile years. Incidence rates peaked in the elderly for both women and men, and varied between disease categories. Conclusion: Population requirements for surgery are greater than previously reported, and more than half of all surgery is performed in outpatient settings. Distributions of age, sex and disease influence estimates of population surgical demand, and should be accounted for in future global and national projections of surgical public health needs.