Timely Access to Essential Surgery, Surgical Workforce, and Surgical Volume: Global Surgery Indicators in Mexico

Our analysis of the 2020 national census data shows that while the majority of the Mexican population has timely access to essential surgery services, policy changes are needed to facilitate more equitable access to these services across the entire population.


INTRODUCTION
N early 5 billion people worldwide lack access to safe and affordable surgical and anesthetic care, with those in low-and middle-income countries most impacted. In 2015, the Lancet Commission on Global Surgery (LCOGS) published a report describing the current state of global surgical care and providing recommendations for improving access and equity, with the goal of working toward universal health coverage. It also defined 6 national indicators to assess surgical care access, quality, and economic impacts on health systems (Table 1), accompanied by recommended goals for these indicators by 2030. [1][2][3][4][5] Several studies have focused their analysis on the need for and quality of surgical care, focusing on surgical volume; surgical, anesthesiology, and obstetric workforce; and perioperative morbidity/mortality. Nevertheless, the concept of access to surgical care remains poorly defined. [6][7][8][9][10] Geographical information systems are valuable tools to assess health care access within a geographic region. Recent studies have successfully applied these tools to address the disparities in health care access throughout Africa. 11,12 According to a study by Holmer et al. on global surgery indicators, only 19 countries have evaluated LCOGS Indicator 1, with only 2 of them from Latin America. 13 Hanna et al. recently published a comprehensive situational analysis of the Colombian surgical system using the 6 core indicators. 14 Indicators 1, 2, and 3 have never been defined for Mexico. Determining the geographical access to surgery, surgical workforce, and surgical volume at a national level will allow policymakers to develop programs that address disparities in surgical health care.
According to the 2020 World Bank Country Classification, Mexico has an upper-middleincome economy. 15 For a Mexican patient, public health care access, including surgical procedures, depends on the type of system with which the patient is affiliated. This means that not all health facilities or hospitals in Mexico are available for a particular individual. The Mexican public health care system is highly fragmented, and affiliation depends on employment status and employment sector (private or public) (Box). Approximately 23% of the Mexican population has private health care insurance. 16 Our study aimed to assess what percentage of the Mexican population had access to essential surgical care (defined by the Bellwether procedures: urgent laparotomy, cesarean delivery, and open fracture treatment) within 2 hours (LCOGS Indicator 1). The secondary objective was to estimate the surgical workforce density (number of surgeons, anesthesiologists, and obstetricians per 100,000 people) (LCOGS Indicator 2), as well as the surgical volume per 100,000 people (LCOGS Indicator 3). These 3 indicators were estimated for the year 2020.

Geographic and Population Data
We obtained Mexican population distribution data from the Secretariat of Welfare and the 2015 National Census of the National Institute of Statistics and Geography. 17 Mexico comprises 32 states divided into municipalities that are further divided into localities (which are territorial and administrative divisions, each with a unique population nucleus and identity). 18 Medical health insurance information, which determines the hospital networks/facilities that are available to individuals, was extracted from the 2020 National Census. 19

Health Facilities
We accessed updated information regarding national public health facilities and their catchment area/population from the Secretariat of Health website. 20 Our analysis included active public health facilities that were affiliated with any public health insurance system and had surgical capabilities. This included facilities that were not traditional hospitals but harbored surgical capacity.

Travel Time Calculations
For the purpose of travel time calculations, an algorithm was developed in RStudio version 1.3.959 for MacOS using the R programming language. This algorithm used the TrueWay Matrix Application Programming Interface (Rapid API) that provides travel duration (in seconds) and distance (in meters) for a set of origins and destinations. Origins and destinations were established based on geographic coordinates of each locality and the closest applicable health care facility, given their known health care subsystem and insurance network. Appropriate, timely access to surgical care (LCOGS Indicator 1) was considered available if the minimum travel time for that population to an appropriate health facility with specific insurance coverage was less than 7,200 seconds (2 hours). The proportion of the population with timely access to surgical health care was calculated for the country, state, and municipality.
In scenarios where no health facilities were available in a specific municipality, travel times were calculated to the nearest facility in a municipality of the same state.

Surgical Workforce Density Calculation
LCOGS Indicator 2 was calculated using the total number of surgical, orthopedic, anesthesiology, and obstetric physicians per 100,000 population of each of the 32 states. 21

Surgical Procedure Rate Calculation
We estimated LCOGS Indicator 3 using the total number of surgical procedures performed in public health facilities and the total population of each of the 32 states. Data were once again accessed from the public Secretariat of Health records. Although data from the public health system were available, the COVID-19 pandemic significantly reduced the number of surgical procedures performed in 2020, making this indicator unreliable and not properly representative of the public health system's capacity to maintain surgical volume.

Map Data Construction
We constructed geographic data maps using QGIS Bucuresti version 3.12.3. Vectorial layers for Mexico's geography, including political and territorial geographic distribution by states, municipalities, and localities, were downloaded from the Comisión Nacional para el Conocimiento y Uso de la Biodiversidad (CONABIO) website and used for map layer elaboration. 22

Ethical Approval
We obtained approval from the National Institute of Medical Sciences and Nutrition Salvador Zubirán Institutional Review Board (CIBH 3644).

RESULTS
In 2020, there were 1,594 health facilities with Bellwether procedure capabilities distributed throughout the country. These were located in 719 (29

Surgical Volume
Surgical volume for 2020 was 916,120 procedures, suggesting LCOGS Indicator 3 was approximately 726.9 procedures per 100,000 inhabitants.

DISCUSSION
Based on our initial calculation, 96.1% of the Mexican population had timely access to a health facility with the capacity for surgical care based on geographic location alone. Although these data appear to reflect a strong indicator, the Mexican health system's accessibility is fragmented by    proportion reported in their study is consistent with our estimation for this state (77.7%). In addition, these authors' geographical distribution of the population with access to surgical care within 2 hours was congruent with our findings. After comparing this indicator between Mexico and previously reported data from 3 other uppermiddle-income Latin American countries (Belize, St. Vincent and Grenadines, and Brazil), we noticed inferior timely access to surgical care in the Mexican population. This can partially be explained due to a larger Mexican populationmore than 120 million inhabitants, compared to 109,148 inhabitants in St. Vincent and Grenadines and 360,933 inhabitants in Belize-in addition to a more vast national territory. 24 Furthermore, Belize has only 1 public health care system, in contrast with Mexico's fragmented public health infrastructure comprising at least 6 different health care subsystems. 25 Brazil's estimation of LCOGS Indicator 1 (97.2%) as reported by Massenburg et al. highlights the potential impact of a unified national health system. 26 Municipalities with the lowest proportion of individuals with timely access to surgical care are distributed throughout Mexico, with a tendency to form clusters (Figure 3, red highlight).
Although the primary aim of this study was to estimate the LCOGS Indicator 1 in Mexico, identification of these clusters is one of the most important findings, as these regions are susceptible to health care access improvement through the development of new public health policies.
Regarding the surgical specialist workforce, data showed an estimation for LCOGS Indicator 2 of 8.6 obstetricians per 100,000 inhabitants, 10.4 surgical specialists per 100,000 inhabitants, and 10.3 anesthesiologists per 100,000 inhabitants. Workforce increase has been proportional to the Mexican population growth during the last 5 years; therefore, no improvement has occurred in this area. According to our estimate for 2020, Mexico lacks health specialists, as the goal for this indicator is 20 specialists of each type (surgeon, obstetrician, and anesthesiologist) per 100,000 inhabitants.
It is difficult to make conclusions regarding the surgical volume for the year 2020, as the number of surgical procedures performed was significantly impacted by the COVID-19 pandemic. Countrywide health facilities were required to reallocate their human, financial, and medical equipment resources, detracting from other medical engagements. As reported before the   Table 2. 27 Our estimation for this indicator was 726.9 procedures per 100,000 inhabitants, which is a significantly inferior surgical volume when compared to the years prior. In 2019, Esqueda-Nuñez, et al. described the volume of surgical procedures in Mexico for the year 2015 stratified by states. 28 According to their findings, 3 states (Jalisco, Baja California Sur, and Nuevo León) had more than 5,000 surgical procedures per 100,000 inhabitants. According to Holmer et al., estimated surgical volumes for Mexico approach the calculated median (interquartile range [IQR]) surgical volume in the Americas and upper-middle-income countries, estimated around 3,005 (IQR: 1,744-4,800) and 3,375 (IQR: 2,034-12,352), respectively. 16 When compared with countries of Latin America, the Mexican surgical volume is below the averages for Brazil, Colombia, Cuba, Nicaragua, and Peru. Unfortunately, contrasting our results with previously published data is not appropriate given the impacts of the COVID-19 pandemic.
As suggested by Davies et al., access cannot be defined as just a matter of geographical proximity. In their review of the LCOGS goals, they address the importance of collecting detailed population data 1x1 km (including age and sex), facility location and surgical capability, and the type of facility (public vs. private facilities; primary, secondary, or tertiary centers). 29 We share this proposed definition of access to surgery, as many factors influence access in a fragmented health care system such as that found in Mexico.
Unifying the public health system proposes an interesting solution to accomplish surgical care delivery for the entire Mexican population, given that it would increase the true access rate to 96.1%. Changing the functional mechanisms and policies of an entire resource-limited public health system would require considerable time for planning, implementation, and improvement. Meanwhile, temporal solutions may be employed, such as a national policy that allows patients to access any health facility if any urgent surgical, obstetric, or orthopedic treatment is needed.
We are aware that some modifications in the Mexican public health system have been implemented to improve its infrastructure, increasing health care accessibility. An example of this is the IMSS-Bienestar program, running for more than 40 years and designed to provide health care in rural or marginal urban regions (including surgical care) distributed in the entire country. Other programs have addressed different global surgery indicators, such as the training of rural surgeons and rural anesthesiologists, as well as the creation of new medical schools and residency programs, which have a direct impact on workforce indicators. 30 Nevertheless, timely access to surgical care is currently an infrastructure problem; therefore, national programs directed to increase the health system infrastructure network are needed. The national surgical plan framework recommendations proposed by the LCOGS include exploring policies to equip first-level health facilities to provide surgical care and enhancing referral systems. 5 Timely access to surgical care depends on many factors other than the presence of a nearby health facility. Lack of suitable transport, patient finances, lower literacy, lack of hospital bed space, and patient overload have been reported. [31][32][33] This implies that increasing the health system and national road infrastructure are not the only solutions to achieve 100% surgical care coverage. Government investments in health human resources, medical equipment, public education, and social development programs are required on an ongoing basis. A future study addressing the interactions and impact of these factors on the access to high-quality surgical care in Mexico through neural network modeling is underway.

Limitations
Limitations of this study were mitigated but not entirely avoidable. First, data on low-volume population localities were summarized and not reported individually in the 2020 National Mexican Census. Second, our travel time calculations may underestimate the actual time required for travel and may overestimate access to surgical care facilities as optimistic parameters were used to search for these (toll usage and transportation by car). In addition, calculations for the year 2020 were performed in 2022, which may have led to a marginal change in travel time because of infrastructure developments that occurred in the interim. Moreover, information regarding 1% of the travel time calculations for a specific origin-destination binomial was not available and was not included in our assessment.
Timely access to surgical care depends on many factors other than proximity to a health facility.
Timely Access to Essential Surgery and Surgical Volume in Mexico www.ghspjournal.org Global Health: Science and Practice 2023 | Volume 11 | Number 1