Surgical epidemiology: a call for action

Background Surgical approaches are receiving increasing attention as a way to solve many global public health problems. The publication of the Disease Control Priorities monograph initiated discussions of the cost-effectiveness of surgical interventions in developing countries, (1) and many more recent publications have built upon its concepts. (2) Surgery can play a vital role in helping countries meet their Millennium Development Goals 4, 5 and 6. (3) To build a stronger case for surgery as part of the armamentarium of cost-effective interventions in developing countries, epidemiologists need to work alongside their surgical colleagues to develop the nascent field of surgical epidemiology. What is surgical epidemiology? Unfortunately, there is not yet an agreed definition for this field. This may reflect the emerging nature of the field, or the lack of clarity and consensus about its goals and objectives. A useful starting point is the definition of epidemiology as "the study of the distribution and determinants of health related states or events in specified populations and the application of this study to control of health problems" (4) An analysis of this definition in terms of its applicability to surgery suggests that clarity is needed in three components: (i) the distribution and determinants of health-related states or events, (ii) the populations involved, and (iii) its application to efforts to treat health problems. We focus on developing countries because we feel that discussions about the role and cost-effectiveness of surgery in the therapeutic armamentarium are most active in this setting. In addition, definitional issues and challenges are greater in developing countries, where we wish to encourage the debate on surgical epidemiology. Definitions What are the "health-related states or events" that we wish to study? Are they "states" such as obstructed labour? Or are they "events" such as a surgical intervention? From a surgical perspective an event often occurs after a state, so one could argue that we need to study both. In addition, events can also include sequelae and complications of surgery, such as nosocomial infections. (5) It is evident that a "state" refers to a surgical condition. But what exactly is a surgical condition? The Disease Control Priorities monograph defined this as "any condition that requires suture, incision, excision, manipulation, or other invasive procedure that usually, but not always, requires local, regional, or general anaesthesia". (1) This definition avoids the challenge of defining who is performing the sutures, incisions, etc. and may thus include surgical procedures done by nurses, paramedical staff and general practitioners in addition to surgeons. Another definition of surgical condition is "any condition for which the most potentially effective treatment is an intervention that requires suture, incision, excision, manipulation, or other invasive procedure that usually, but not always, requires anaesthesia" (6) This definition raises more questions than answers. What exactly does "potentially effective" mean? Does this criterion vary depending on clinical or geographic contexts? Yet another definition from a recent publication is that a surgical condition is "a disease state requiring the expertise of a surgically trained provider". (7) Here, we are left wondering about the precise nature of the expertise and surgical training required. In addition, we need to consider conditions for which only a minority of patients need surgery. For example, only one out of six persons with a severe head injury needs a neurosurgical operation. However, the ability to rapidly diagnose patients who need surgery along with the availability of a qualified provider and facilities to safely perform the procedure are critical to lowering overall mortality from severe head injuries. Similar considerations apply to the availability of Caesarean delivery to treat obstetrical complications. …