Methodology
Our analysis assumes a basic surgical package with various therapeutic interventions that could be provided at first-level hospitals. These conditions were selected based on recommendations and guidelines in the literature (Mock and others 2010; WHO 2003); consultation with experts in global surgery; practicality in quantifying health outcomes, for example, the existence of clear health outcomes corresponding to specific surgical procedures; and a corresponding cause in GBD 2010. We examined the following:
Four digestive diseases: Appendicitis, paralytic ileus
3 and intestinal obstruction, inguinal and femoral hernia, and gallbladder and bile duct disease
Four maternal-neonatal conditions: Maternal hemorrhage, obstructed labor, abortion, and neonatal encephalopathy
Injuries that could be treated with basic interventions: Resuscitation, surgical airway, peripheral venous access, suturing, laceration and wound management, chest tube or needle decompression, fracture reduction, escharotomy, fasciotomy, skin grafting, trauma-related amputation, and trauma-related laparotomy
To investigate which surgical procedures would be required to treat this group of surgical conditions, we searched Surgical Care for the District Hospital (WHO 2003) for procedures that corresponded to the GBD causes. Our review showed that almost 50 surgical procedures are required to treat these GBD causes, illustrating that a broad spectrum of procedures are required to treat even a limited list of surgical conditions (annex 2D).
Our burden estimates were based on data from the GBD 2010 (Murray, Vos, and others 2012). Parameters included population, standard life expectancy, cause-specific mortality, incidence, prevalence, and disability weights (Lozano and others 2012; Salomon and others 2012; Vos and others 2012). The parameters were specific by cause, age, gender, region, and year. The GBD 2010 groups countries into 21 epidemiological regions (17 of which contain LMICs) and seven superregions (six of which contain LMICs) (). Our analysis was conducted at the superregion level by aggregating regional-level parameters.
GBD 2010 Epidemiological Regions and Groupings into LMIC Superregions.
Our approach recognized that some conditions, such as maternal hemorrhage and neonatal encephalopathy, are not fully amenable to surgical care and required adjustments to limit the effect of surgery. Other GBD causes (such as drowning, poisoning, self-harm, venomous animal contact, and injuries not classified elsewhere) were assumed to be not amenable to surgery. When questions on the proportions of conditions that could be managed by surgical care arose, we referred to the literature and adjusted the avertable burden accordingly. Additional details on the adjustments to account for the burden not amenable to surgical care can be found in annex 2E.
The overall concept of the approach was to split the reported DALYs of surgical conditions in 2010 into surgically avertable burden and surgically nonavertable burden. The avertable burden was calculated as follows:
in which DALYCurrentdenotes the DALYs reported in GBD 2010, and DALYcf the estimated DALYs if the delivery of surgical care had existed in a counterfactual state in which the entire population had access to appropriate and safe surgical care appropriate for delivery at the first-level hospital. The counterfactual level equates to the outcome that is achievable across all segments of the health care system in HICs.
To determine the DALYcf quantity, we estimated YLLcf and YLDcf for the counterfactual state in separate steps. Such separation in estimating fatal and nonfatal burden is consistent with the approach used in generating the GBD 2010 estimates.
We first estimated the number of deaths for the counterfactual state in LMIC superregions with the following equation:
in which
is the age- and gender-specific number of deaths for the counterfactual state in each superregion,
the age- and gender-specific number of incident cases from GBD 2010 in each superregion, and CFRcfage, gender the age- and gender-specific case fatality rates for the counterfactual state.
CFRcfage, gender values would ideally be informed by complete data on coverage, access, quality, and effectiveness of surgical care in each region. Although such data exist for some LMICs and a subset of causes in our analysis, it is very sparse (Choo and others 2010; Galukande and others 2010; Kushner and others 2010).
We therefore assigned the lowest fatality rates among the 21 epidemiological regions for each age and gender to be representative of CFRcfage, gender. In addition to being consistent across conditions, we believe this value best reflects the situation of the counterfactual state in which diagnosis is reasonably prompt, treatment is available, and there is access to appropriate and safe surgical care. Not surprisingly, the majority of lowest CFRs were from one of the HICs: high-income Asia Pacific, Western Europe, Australasia, and high-income North America.
After calculating
, we multiplied this quantity by the age-specific standard life expectancy used in GBD 2010 to estimate the fatal burden for the counterfactual state (Lozano and others 2012; Murray, Ezzati, and others 2012) using the following formula:
The next step was to estimate the nonfatal burden (YLDcf) for the counterfactual state. Although scaling up surgical coverage would reduce fatal burden (YLL), the averted deaths would still contribute to the nonfatal burden for a shorter—or sometimes longer—duration, as estimated by YLDs. YLDs in GBD 2010 were calculated by multiplying the prevalent cases by disability weights that are unique to each health state. However, we did not know the direct impact of reduced CFRs on prevalence. For diseases that had a short duration, defined as less than one year, we calculated the YLDs for the counterfactual state as follows:
in which
is the nonfatal burden in the counterfactual state, Duration is the duration of disease calculated by dividing the prevalence by incidence, and DW the disability weight attached to each condition from the GBD 2010 study. For injury conditions with long-term sequelae that exceeded a year, we used a slightly different equation:
The final step was to calculate the avertable burden, which was accomplished by summing the YLDcf and YLLcf for each region and then subtracting the total from the total DALYs estimate from GBD 2010, and aggregating the results to the superregion level. Additional details on how burden calculations were performed can be found in the four manuscripts included in annex 2F.
Results were expressed as the number of deaths and burden (DALYs) that would be averted per year by scaling up care for a group of surgically treatable conditions in LMICs. This care would be appropriate for first-level hospitals and would include treatment for four digestive diseases, four maternal-fetal conditions, and injuries that could be treated with basic interventions. Our estimates are based on the assumption that surgical care could be scaled up to match the accessibility and quality of care provided in HICs—the counterfactual rate—either at first-level hospitals or at higher levels of care.
Because surgical care can never completely prevent or reverse disability, we have also included an estimate of the nonavertable burden. The nonavertable burden refers to the fraction of the burden that is currently not preventable or reversible with surgical care. Perhaps the best examples of nonavertable burden occur in injured patients for whom death and disability often occur even when the best possible surgical care is available. Two examples are an amputation for a severely mangled extremity and a fatality from a severe head injury before the patient arrives at the hospital. The outcomes are unavoidable and thus nonavertable with surgical care.
Some may question the value of including data on the nonavertable burden given that we have focused our efforts on trying to define the role of surgery in reducing death and disability. Nevertheless, we have included these data for two important reasons. First, nonavertable does not necessarily imply a problem that cannot be addressed: nonavertable burden can be reduced through nonsurgical means, for example, injury prevention, improved delivery of care, or innovation. Second, without a complete accounting of total burden—the avertable and nonavertable burden—it is impossible to appreciate the magnitude of the problem and the limitations of surgical care.
Impact on Population Health
Scaling up basic surgical care across all sectors of the health care system in LMICs could prevent 1.4 million deaths and 77.2 million DALYs per year. The details of these preventable deaths and avertable DALYs, by superregion, are shown in and . Overall, scaling up surgical care to treat four gastrointestinal diseases, four maternal-neonatal conditions, and injuries treated with simple interventions could prevent 3.2 and 3.5 percent of all deaths and DALYs, respectively, that occur each year in LMICs.
Estimated Number of Deaths per Year That Could Be Prevented If Basic Surgical Care Could Be Provided in LMICs.
Estimated Number of DALYs per Year That Could Be Averted If Basic Surgical Care Could Be Provided in LMICs.
The majority of the preventable deaths were due to injuries (77 percent), followed by maternal-neonatal conditions (14 percent) and digestive diseases (9 percent). Road injury (292,000 deaths per year) and falls (184,000 deaths per year) were the two most common causes of preventable death. In the maternal-neonatal category, neonatal encephalopathy was the leading cause of preventable death (166,000 deaths per year). The South Asia and Sub-Saharan Africa superregions have the largest number of preventable deaths per year, 485,000 and 327,000 deaths, respectively.
Injuries also accounted for the largest fraction of avertable DALYs (). Road injury is the leading cause of injury-related avertable DALYs in LMICs (16.1 million DALYs per year) followed by fire, heat, and hot substances (9.7 million DALYs per year) (). Of the total injury burden in LMICs, 21 percent is potentially avertable by providing basic trauma care at first-level hospitals and higher levels of care. Sub-Saharan Africa has the largest proportion of potentially avertable DALYs related to injuries (25 percent); South Asia the highest absolute number of avertable DALYs (17.4 million per year).
Distribution of Burden Avertable by Scaling Up Basic Surgical Care Deliverable at First-Level Hospitals in Low- and Middle-Income Countries. Percent
Of the burden associated with the maternal-neonatal conditions that we analyzed, 36 percent is potentially avertable by full coverage of quality obstetric surgery in LMICs (20.0 million DALYs). The South Asia superregion has the highest total number of avertable maternal-neonatal DALYs (10.4 million). Neonatal encephalopathy comprises the largest portion of avertable burden among the five conditions analyzed, followed by abortion (16.2 and 2.1 million DALYs, respectively).
Of the burden related to the four digestive diseases (4.8 million DALYs per year), 65 percent is potentially avertable with first-level surgical care in LMICs. Sub-Saharan Africa has the largest avertable burden in absolute DALYs (1.7 million per year) and in avertable proportion (83 percent). Paralytic ileus and intestinal obstruction accounted for the largest portion of avertable burden among the four digestive diseases (2.2 million DALYs per year; 64 percent avertable).
The majority of the burden associated with the four gastrointestinal diseases, four maternal-neonatal conditions, and injuries analyzed cannot be averted by surgical care (). The nonavertable burden from the group (238.5 million DALYs per year; 10.7 percent of the GBD in LMICs) was 2.5 times greater than the burden averted by the basic surgical package. The majority (84 percent) of the total nonavertable burden was due to injuries (200.4 million DALYs per year), followed by maternal-neonatal conditions (34.5 million DALYs per year). shows the nonavertable burden by LMIC superregion and its relationship to the avertable burden. South Asia had the largest number of nonavertable DALYs (75.6 million DALYs per year), while the Latin American and the Caribbean superregion had the highest fraction of the total regional GBD (17.9 percent). The latter reflects the devastating earthquake in Haiti in January 2010.
Nonavertable Burden (DALYs) Associated with a Group of Conditions That Can Be Treated with Basic Surgical Care in LMICs.
Burden Associated with a Group of Conditions That Can Be Treated with Basic Surgical Care in Low- and Middle-Income Countries.