Size and distribution of the global volume of surgery in 2012.

Introduction Surgical care is essential for managing diverse health conditions --such as injuries, obstructed labour, malignancy, infections and cardiovascular disease--and an indispensable component of a functioning health system. (1-3) International organizations, including the World Health Organization (WHO) and the World Bank, have highlighted surgery as an important component for global health development. (3,4) However, surgical care requires coordination of skilled human resources, specialized supplies and infrastructure. As low- and middle-income countries expand their economies and basic public health improves, noncommunicable diseases and injuries comprise a growing proportion of the disease burden. (5) Investments in health-care systems have increased in the last decade, but the effect on surgical capacity is mostly unknown. (6,7) Based on modelling of available data, it was estimated that 234.2 million operations were performed worldwide in 2004. (8) The majority of these procedures took place in high-income countries (58.9%; 138.0 million), despite their relative lower share of the global population. Here, we estimated the global volume of surgery in 2012. We also estimated the proportion of surgery due to caesarean delivery, since studies done in low-income countries have found that emergency obstetric procedures--especially caesarean deliveries--represent a high proportion of the total surgical volume. (9,10) Methods Population and health databases For the years 2005 to 2012, we obtained population and health data for 194 WHO Member States. These data included total population, life expectancy at birth, percentage of total urban population, gross domestic product (GDP) per capita in United States dollars (US$) and total health expenditure per capita in US$. (6,11) For 11 Member States, where certain population or health data were not available from either WHO or the World Bank, we used data from other similar sources. (12,13) All US$ were adjusted for inflation to the year 2012, using the consumer price index for general inflation. (14) For Member States with reported surgical data, we also obtained population and health data from the year for which surgical volume was reported. We classified Member States based on their health spending. Member States spending US$ 0-100 per capita on health were classified as very-low-expenditure Member States (n = 50); US $101-400 as low-expenditure Member States (n = 54); US$ 401-1000 as middle-expenditure Member States (n = 46); and over US$ 1000 as high-expenditure Member States (n = 44). (8) Surgical data sources Operations were defined as procedures performed in operating theatres that require general or regional anaesthesia or profound sedation to control pain. We searched PubMed for the most recent annual surgical volume reported after 2004, using each Member State name along with the following keywords and phrases for all WHO Member States: "surgery", "procedures", "operations", "national surgical volume" and "national surgical rate". Depending on the Member State, we conducted our search in English, French and/or Spanish. To obtain email addresses for ministers or officials working for the ministry of health or individuals responsible for auditing surgical data at a national level, we searched the internet for the websites of ministries of health or national statistical offices. We contacted these persons to request the most recently reported total volume of operations based on the above definition. From the database of the Organisation for Economic Co-operation and Development (OECD) we obtained surgical volume for 26 countries; 14 of these countries had total surgical volume data as well as detailed data for a subset of procedures (termed a shortlist by OECD), while the other 12 countries only had data for the shortlist. (15) For the 14 countries, we used both data sets in combination with publicly available data on total health expenditure to define the relationship between the shortlist and the reported total surgical volume. …