How much of the care patients receive is determined by their doctor’s decision to provide it as opposed to their need and preference for it? And how much money might be saved if investigations and treatments of limited or no value to patients were stopped? These questions were debated at two recent meetings on practice variation, in the Netherlands, and the Wennberg International Collaborative in London. Both agreed on a fundamental point; if patients aren’t asked what their preferences for care are and their views of its outcome are not solicited then these questions can’t be answered.

The balance between the benefits and harms of the 21st century’s expensive healthcare industry is unknown. What is clear is that all countries who are looking systematically at regional variation in the rates of interventions, use of resources, and patient outcomes, including the UK, are finding  differences which can’t be explained by  patients needs or preferences. The trouble is, it can be hard to identify what tranche is  “unwarranted,”  and use this knowledge to inform rational disinvestment.

But there are some data to inform policy, Sandra Garcio-Armesto, a health service researcher told the London meeting, and basing cuts to services on such data makes a lot more sense than the current approach, which is characterised by “sound and fury.” Where there is professional consensus that interventions are of low value,  and her examples were spinal fusion, revision arthroplasty of the knee, and adenoidectomy, rates of which vary markedly across Spain, the “right rate”  is  almost certainly the lowest. If all regions in Spain adopted the lowest rate for spinal fusion, the costs saved would be around €454 m per annum, she said.

Speakers at both meetings underlined the cost effectiveness as well as the ethical case for using decision aids in routine care. Several referred to recent data from the US provider, Group Health, where the formal introduction of informed shared decision making has resulted in a 26% and 38% drop in the number of  hip and knee replacements respectively, with cost savings of 12-21% over six months. (Health Affairs 2012;31:2094-2104)

This summer the US providers who make up the High Value Health Collaborative (who care for around 50 million patients) won an award of  $26m from the Center for Medicare and Medicaid  Innovation to support patient engagement in shared decision making in chronic care, as well as elective surgery.  It’s estimated this will result in cost savings of $64 m over three years.

The extent to which medical interventions are subject to fashion is worthy of more study. At the Dutch meeting, a call to “put your hand up if you had your tonsils taken out as a child” showed that most participants, unlike their own children, had.

But while medical fashions come and go, sadly, the mismatch between doctor and patient perspectives persists. At the end of the Dutch meeting, delegates, some with tears in their eyes, rose to applaud a commissioned drama which poignantly illustrated how health professionals fail to recognise what matters to patients and just how much distress and heartache this causes.

Tessa Richards is the analysis editor, BMJ