Health services research spans multiple fields of scientific inquiry and informs healthcare policy making on various levels. Although both classic epidemiology and health services research are concerned with populations, health services research differs in its emphasis on the structure, process, and effects of health services as opposed to focusing on disease prevalence and prevention. Likewise, health services research differs from clinical epidemiology, which emphasizes the causation and natural history of disease. As a multidisciplinary field, however, health services research incorporates epidemiology, as well as economic and social science, into the analysis of healthcare delivery ( Figure 1 ).
Examining Structure, Process, and Effects
The structure of healthcare services relates to issues such as physician workforce considerations. For example, while evaluating patterns of care, trends in work effort, and models of population growth, Lee and associates concluded that ophthalmology will experience substantial challenges in manpower in the next 10 to 20 years. Projections for the ophthalmology workforce demonstrate how health services research can inform us about the future in addition to evaluating the healthcare delivery of the present.
The study of structure also pertains to medical education. Surgical fields such as ophthalmology may benefit from technological advances in simulation of medical procedures. Simulation-based surgical training is one avenue by which residency programs can form part of healthcare learning organizations, a concept that has gained traction in the business and policy community. Health services research allows educators to evaluate the success of such programs.
Health services research also evaluates the process by which healthcare is provided. Process issues include access to care and use of services and how such variables may differ for specific populations. For example, in reviewing rates of medical and surgical treatment for glaucoma from 1992 to 2002 among Medicare beneficiaries, Stein and associates found that Latino and Asian beneficiaries with glaucoma were less likely to receive treatment than were whites.
In the context of Health services research, effects includes the outcomes of health care. Outcomes assessment can take many forms. Traditionally, outcomes of interest in the medical literature were mortality or physiologic measures as defined by diagnostic tests. In ophthalmology, traditional outcomes include legal blindness and loss of acuity or visual field as well as physiologic measures such as intraocular pressure or retinal thickness. More recently, investigators have included patient-centered outcomes such as performance measures (reading speed, mobility) and quality-of-life indicators. In fact, ophthalmology was one of the first fields to develop instruments to quantify disease-specific quality of life. The VF-14, an index of visual functioning for use in patients with cataracts, was found to predict self-reported satisfaction with vision better than visual acuity or a general health status score. More recently, the National Eye Institute developed the Visual Function Questionnaire, which has been used to evaluate the impact on visual function by a multitude of ophthalmic conditions. Quality-of-life outcomes now are included commonly as secondary end points in major clinical trials such as the Collaborative Initial Glaucoma Treatment Study.
The cost of care from the perspective of the patient, provider, or society also is an outcome in health services research. Large clinical trials often include cost analysis. For example, the Ocular Hypertension Treatment Study investigators analyzed the cost effectiveness of treating versus observing patients with ocular hypertension. Cost analysis revealed that the treatment of patients with intraocular pressure of 24 mm Hg or more and 2% or more annual risk of the development of glaucoma is likely to be cost effective. Cost analysis can also be used to compare the costs of various treatments. Cantor and associates developed a Markov model to compare the 5-year costs of treating glaucoma with medications, laser trabeculoplasty, or filtering surgery and found that laser trabeculoplasty resulted in the least cost.
Recently, studies of comparative effectiveness have generated much discussion in the health services research community. Comparative effectiveness simply means comparing how effective different treatment strategies are at improving health outcomes. In February, an article in the New England Journal of Medicine stated that “the American Recovery and Reinvestment Act of 2009 authorizes the expenditure of $1.1 billion to conduct research comparing ‘clinical outcomes, effectiveness, and appropriateness of items, services, and procedures that are used to prevent, diagnose, or treat diseases, disorders, and other health conditions.’” Supporters of comparative effectiveness research argue that we can contain healthcare costs by limiting less-effective treatment options.
Methods in Health Services Research
Because health services research draws on different fields of scientific inquiry, research methods are diverse. Health services research can be basic (eg, the development of a vision-related quality-of-life instrument) or applied (eg, the use of the quality-of-life instrument to compare the outcomes of 2 treatment strategies). Study designs used in health services research can include secondary data analysis, survey research, or qualitative research including focus groups and interviews. Advanced statistical techniques such as propensity scores and case-mix adjustments often are needed to address large numbers of variables in real-world data. Health service research investigators also are involved in the development of interventions for patients, providers, and the healthcare system. The evaluation of these interventions and, if successful, their broad-scale implementation also are fields of study in health services research.