Avedis Donabedian was an Armenian, and his nationality was in many ways as important to him as were Cochrane’s roots in Scotland. In 2003, Oxford University Press published a book whose copyright rested with the American University of Armenia entitled An Introduction to Quality Assurance in HealthCare. In his preface, Donabedian states that: ‘It was with great reluctance that I undertook to write this book’, but from ‘the happy state’ of his retirement, he felt he was recalled by ‘the urgent need, insistently and repeatedly brought to my attention, for a brief, coherent account of quality assurance in health care for use by students of the subject in my native Armenia’.
Donabedian wrote the book during the end stages of what his editor describes as ‘combat with an avaricious cancer that weakened his musculature but left his mind untouched’, and the book was published in the year 2000, three years after his death at the age of 81. The book is outstanding, only 200 pages long, but pulling together a lifetime’s work of clear thinking. Donabedian’s previous classic was his three volume Explorations in Quality Assessment and Monitoring, published in 1980, and it was in this work that he described not only structure, process, and outcome but also his ‘unifying model of benefit, risk and cost’. The power of this model is that it described for the first time the fact that as resources are increased in healthcare, benefit increases, but the increase in benefit then flattens off, illustrating what some people have called the law of diminishing returns.
In contrast, the amount of harm done increases in direct proportion to the investment of resources. For each unit of increase in resource, there is a unit increase in the volume of care, and a unit increase in the amount of harm. In fact there may be a progressive increase in the amount of harm if, with each unit of increase in the availability of care, patients who are less fit and more at risk of harm are covered by the service.
As a consequence, there may come a point where the investment of additional resources will lead to a reduction in the net benefit, calculated by subtracting the harm from the benefit. This is sometimes called the “health gain”. Donabedian’s prose is crystal clear:
In his last book, Donabedian describes optimality explicitly as:
The balancing of improvements in health against the cost of such improvements. The definition implies there is a “best” or “optimum relationship” between costs and benefits of health care, a point below which more benefits could be obtained at costs that are low relative to benefits and above which additional benefits are obtained at costs too large relative to corresponding benefits.
Clinicians and patient groups often desire maximally effective healthcare, but for those who pay for healthcare, in a time in which need and demand are greater than the resources that are available, optimality is a more appropriate objective. When optimality is achieved, value is at a maximum.