BEIJING - Violence against medical staff in Chinese hospitals has been on the rise in recent years, according to a sample survey released by the Chinese Hospital Association (CHA) on Thursday.

The annual average number of assaults on doctors per hospital increased from 20.6 assaults in 2008 to 27.3 assaults in 2012, the survey showed.

The survey was conducted among staff and patients at 316 hospitals nationwide from December 2012 to July 2013.

Unsatisfactory treatment, poor communication between patients and doctors, distorted media reports and hefty expenses were blamed for most of the assaults, while social conflicts, loss of trust and unbalanced demand and supply of medical resources underlie the rise in violence, the survey pointed out.

Meanwhile, medication side effects, product quality, no-fault medical behavior and damage caused by patients' personal conditions contributed to 50 percent of health care-related disputes, the survey said.

In 2012, a man attacked employees at a local hospital in the city of Hefei in east China's Anhui Province, killing a head nurse and injuring four other people.

Nearly 40 percent of surveyed medical staff said they plan to give up the profession due to the increase in violence, the survey said.

A sound medical insurance and risk management system, strengthened crisis management and third-party medication could help to ease tensions between patients and medical staff, the survey suggested.