Tussles between doctors and insurers are nothing new in Hong Kong. Insurers have long lambasted doctors for charging inflated fees and conspiring with patients to cheat them. Now, doctors are complaining that insurers are abusing their market power to dictate the way they treat patients. It is a standoff in which both sides claim to be acting in the best interests of patients, which should certainly be the priority. So far, the government has resisted calls to intervene. But the issue is one that officials can no longer dodge as they seek to promote private medical insurance as part of an overall strategy to reform the financing of health care. At the heart of the issue is whether and how the business relationships between patients, doctors, insurers and health maintenance organisations should be regulated. The traditional view is that the provision of medical services is a professional relationship between medical practitioners and their patients. Irrespective of whether a doctor is in private practice, a salaried employee or bound by a service contract with an insurer or an HMO, he should be held responsible for the treatment of his patients. However, this is a view that is increasingly being challenged. The consumption of medical services is now so heavily shaped by insurance arrangements that insurers and HMOs have come to wield considerable influence over the way medicine is practised by doctors who have signed service contracts with them. Last week, the Medical Council disclosed that some of these contracts imposed caps on the number of referrals to specialists and diagnostic tests that doctors could make. The council warned doctors that the constraints posed serious ethical problems and would not be a defence in disciplinary proceedings. In the latest development, the council is asking doctors to inform patients how fees are split between doctors and insurers. The move is aimed at showing patients why, even if they or their employers pay what they consider to be high fees, they do not necessarily get the best drugs or treatment available. The argument is that this is because insurers pass on just a small percentage of the payment to doctors. In medicine, as in any other line of business, the bargaining powers of market players are a function of their clout as demand and supply fluctuate. But where people's health is concerned, ethics are of prime importance. By international standards, the proportion of the population covered by medical insurance remains low, but it is growing. Currently, an estimated one million people are serviced by so-called panel doctor groups that have signed contracts with insurers and HMOs. That is why many doctors in solo practice are eager to join the groups in order to ensure a steady flow of patients. Doctors argue that HMOs should be regulated to ensure their professional care of patients is not compromised. But whether or not such regulations are put in place, doctors have a responsibility to ensure they behave ethically and in the best interests of patients. That said, it should be recognised that medical practitioners are coming under pressure from the market. A solution must be found. The government should carefully consider regulating HMOs. This could provide doctors and patients with greater protection. But it will not necessarily end the disputes. In the US, where HMOs flourish, they are subject to strict regulation to ensure doctors will not be at their mercy. Still, disputes between them abound. This conflict is one that officials responsible for reforming Hong Kong's health-care system cannot afford to ignore. So is the related issue of developing a mechanism to ensure the quality and integrity of medical insurance products. Whatever the arguments put forward by each side, the public interest in ensuring good quality health services must be paramount.