Perceived control affects complication rates in patients with acute coronary syndrome

Patients admitted to hospital with obstructed heart arteries were three times more likely to experience complications when they were in hospital if they felt they were not in control of their condition, according to research published in the October issue of the Journal of Advanced Nursing.

However, persistent anxiety on its own appeared to have little effect on whether patients experienced complications or not.

Researchers looked at 171 patients admitted to hospitals in the USA, Australia and New Zealand with acute coronary syndrome (ACS), following them for two years. They concluded that giving patients greater perceived control of their heart illness could reduce complications after ACS.

"Coronary heart disease is the leading single cause of death in Australia and the USA, accounting for almost one in five deaths and leading to 50,000 hospital admissions a year in Australia and 1.76 million a year in the USA" says lead author Sharon McKinley, Professor of Critical Care Nursing at the University of Technology, Sydney, Australia.

Almost two-thirds of the patients studied were men (64 per cent), with an average age of 69 years.

The research team spoke to all the participants at three, 12 and 24 months and gave them a free telephone number to call if they attended hospital for suspected ACS symptoms.

Experienced cardiovascular nurses trained in data abstraction for the purposes of the study then examined the patients' records for a range of clinical characteristics and complications.

The anxiety and perceived control measures were obtained in face-to-face interviews when patients were enrolled in the study and by mailed questionnaires with follow-up telephone interviews at three and 12 months.

Key findings included:

• Fifteen per cent of the patients experienced complications when they were in hospital following admission for ACS, mainly due to an abnormal heart beat or reduced blood supply to the heart.
• Half of the patients studied were anxious at baseline and 56 per cent at three months. Over a third of patients (37 per cent) displayed anxiety at both points and were categorised as persistently anxious.
• 58 per cent of patients had low perceived control and these patients tended to be younger, have a higher body mass index and a higher pulse rate on admission.
• 73 per cent of the patients with persistent anxiety had low perceived control and the remaining 27 per cent had high perceived control.
• Patients with low perceived control over their heart conditions were 3.4 times as likely to experience in-hospital complications as patients with high levels of control.

"The findings that low perceived control, but not persistent anxiety, were predictive of in-hospital complications after ACS has two key implications for nursing practice and policy" says Professor McKinley.

"Firstly, it may be possible for nurses to increase cardiac patients' perception of control over their illness and secondly, increasing perceived control may reduce the risk of complications after ACS."