The value of health care vouchers for the elderly should be doubled to encourage more to seek treatment at private clinics, the Hong Kong Academy of Medicine says. The call came after an academy survey found that 90 per cent of elderly chronic patients still relied on public medical services and nearly 77 per cent spent less than HK$200 a month on medical expenses. By doubling the value vouchers to HK$100, the elderly would be encouraged to switch to private doctors as they would only need to pay HK$50 to HK$100 on top, said Professor John Leong Chi-yan, who led the survey. 'The government should not fully subsidise each consultation, as this may lead to abuse of the services.' The survey, which polled 1,000 people aged 65 or above, showed that 62.3 per cent suffered from chronic illnesses, such as hypertension and diabetes. Some 67 per cent of the chronic patients paid their own medical fees and 34 per cent found them a heavy financial burden. The government offers all people aged 70 or above five HK$50 vouchers a year redeemable at private clinics. But the response has been lukewarm, with about one-third of those eligible using the vouchers. The scheme, expiring next year, will be reviewed in coming months. Since most elderly people still preferred to be treated in public hospitals, the academy also proposed that retired private doctors could work part time at government clinics for a nominal fee, to ease the manpower shortage in the public sector. The survey, which also polled 112 doctors aged 60 or above, showed that 61 per cent were willing to take up such roles. Elderly patients make up about 25 per cent of all private doctors' clients, the survey showed. They enjoyed an average 40 per cent discount per consultation. The ageing population is posing an ever greater challenge to Hong Kong's health care system. By 2021, it is estimated that more than 17.2 per cent of Hongkongers, or 1.4 million people, will be 65 or above.