Complications and mortality in older surgical patients in Australia and New Zealand

Complications and mortality in older surgical patients in Australia and New Zealand


REASON study: Research into Elderly Patient Anaesthesia and Surgery Outcome Numbers

This prospective, observational study of 4158 older patients undergoing non-cardiac surgery found that 20% of patients had a complication within five days of surgery and 5% died within 30 days. Those with a complication stayed a week longer in hospital, and 14% died within 30 days. This highlighted the urgent need for research into strategies to reduce surgical complications in our ageing population.

Principal investigator


Patients were enrolled between June and September 2004, and December 2007 and December 2008.

Participating countries

23 centres in Australia and New Zealand


We conducted a prospective study of non-cardiac surgical patients aged 70 years or more in 23 hospitals in Australia and New Zealand. We studied 4158 consecutive patients of whom 2845 (68%) had pre-existing comorbidities. By day 30, 216 (5%) patients had died, and 835 (20%) suffered complications; 390 (9.4%) patients were admitted to the Intensive Care Unit. Pre-operative factors associated with mortality included: increasing age (80-89 years: OR 2.1 (95% CI 1.6-2.8), p < 0.001; 90+ years: OR 4.0 (95% CI 2.6-6.2), p < 0.001); worsening ASA physical status (ASA 3: OR 3.1 (95% CI 1.8-5.5), p < 0.001; ASA 4: OR 12.4 (95% CI 6.9-22.2), p < 0.001); a pre-operative plasma albumin < 30 g.l⁻¹ (OR: 2.5 (95% CI 1.8-3.5), p < 0.001); and non-scheduled surgery (OR 1.8 (95% CI 1.3-2.5), p < 0.001). Complications associated with mortality included: acute renal impairment (OR 3.3 (95% CI 2.1-5.0), p < 0.001); unplanned Intensive Care Unit admission (OR 3.1 (95% CI 1.9-4.9), p < 0.001); and systemic inflammation (OR 2.5 (95% CI 1.7-3.7), p < 0.001). Patient factors often had a stronger association with mortality than the type of surgery. Strategies are needed to reduce complications and mortality in older surgical patients.


Australian and New Zealand College of Anaesthetists Foundation

Primary results publication

Story DA, Leslie K, Myles PS, Fink M, Poustie SJ, Forbes A, Yap S, Beavis V, Kerridge R; REASON Investigators, Australian and New Zealand College of Anaesthetists Trials Group. Complications and mortality in older surgical patients in Australia and New Zealand (the REASON study): a multicentre, prospective, observational study. Anaesthesia. 2010 Oct;65(10):1022-30. 

Pubmed link

The full abstract can be viewed on Pubmed

Participating hospitals

Australian Hospitals
Alfred Hospital
Austin Health
Cairns Hospital
Coffs Harbour Health Campus
Dubbo Base Hospital
Flinders Medical Centre
John Hunter Hospital
Lismore Base Hospital
North West Regional Hospital
Prince of Wales Hospital (NSW)
Princess Alexandra Hospital
Redcliffe Hospital
Royal Brisbane and Women's Hospital
Royal Darwin Hospital
Royal Hobart Hospital
Royal Melbourne Hospital
Royal Perth Hospital
St Vincents Hospital, Melbourne
Western Health Service
Westmead Hospital
Wollongong Hospital
New Zealand Hospitals
Auckland City Hospital
Counties Manukau Health (Middlemore Hospital)

Last updated 12:27 1.03.2023