Surgical outcomes in the elderly

Abstract

BackgroundAustralian’s life expectancy and health expenditure have increased, mainly due to population ageing and the increasing complexity of healthcare. Evidence based economic planning should study the consequences of aging to inform health expenditure and budgets.Surgical literature on hospital costs in the elderly mostly focuses on individual surgical operations/specialties. Costs and outcomes are not compared between different surgical operations/specialties. Surgical demand in elderly patients, typically with multiple comorbidities, is well documented. What is not clear is how the process of ageing impacts surgical variation, postoperative outcomes and costs. Surgery in nonagenarian and centenarian patients is increasing but reporting on variation in surgical procedures is scant as the very old are often either excluded from studies or included as one broad age group.Patient characteristics, types of surgery and surgical outcomes influence cost of care. This thesis has five components aimed to determine how chronological age, patient comorbidity and surgical outcomes contribute to health costs in elderly surgical patients and to validate a surgical risk tool. It adds to the literature by reporting the relationship of age with the types of surgery, postoperative outcomes and costs. Methods and results:Component one describes the relationship of age with preoperative factors and postoperative markers of care in surgical patients who died in hospital. Increased age was associated with emergency admission, malignancy, comorbidity, patient transfer and delay in diagnosis, but not trauma. Deceased patients aged ≥80 years used fewer resources and were less likely to have been treated in ICU (intensive care unit) than younger patients who died. They also had fewer re-operations and postoperative complications recorded but were more likely to have died with an infection.Component two explores hospital acquired infections (HAI) in surgical patients who died in hospital. It compares the care and hospital costs in patients with and without HAI. Like component one, the oldest patients were more likely to die with an HAI. Deceased HAI patients compared to those who died without infection had significantly longer hospital stays more postoperative complications, unplanned ICU admissions, and unplanned reoperations.Component three, a systematic review, focuses on the cost-effectiveness of antibiotic prophylaxis in preventing HAIs, particularly surgical site infections. In the twelve included studies health economic information varied more than clinical information. Eleven studies found the antibiotic prophylaxis to be clinically effective, in ten studies it was also cost-effective, and in one study it was more effective, but also more expensive. Antibiotic prophylaxis administration policy may not change based on these findings, but researchers are advised to embed health economic studies into clinical trials from the design stage. This could help ensure future antibiotic prophylaxis is cost-effective.Component four describes the relationship of age with the types of surgery and the perioperative mortality rates (POMR - defined as in-hospital death following a surgical procedure). Queensland death registry data were linked with the Queensland Public Hospital Admitted Patient Data Collection to determine POMR, 30-day mortality, and death at home. Queensland’s POMR (0.41%) was comparable with Australia’s national POMR (0.36%). POMR and the 30-day mortality rate (0.34%) both increased with age. Resection of the small bowel with anastomosis and exploratory laparotomy had the highest POMR (17.7% and 16.5%). Hemiarthroplasty and internal fixation of trochanteric/sub-capital femur fractures had the highest 30-day mortality rates especially in patients aged 80-89 years (4.5% and 5.1%). As age increased so too did digestive and orthopaedic system procedures.Component five describes the agreement between the predicted risks of the American College of Surgeons surgical risk calculator (SRC) and surgical patient outcomes. This was tested on patients undergoing high-mortality digestive and orthopaedic procedures (resection of the small bowel with anastomosis, freeing of abdominal adhesions, hemiarthroplasty, and internal fixation of trochanteric/sub-capital femur fractures). Using Australian surgical patient data, the SRC failed to accurately predict most outcomes. It argues for the need to develop an Australian quality improvement tool.Conclusion:These findings suggest that centenarians use fewer resources than younger patients. Older patients are more likely to die with HAIs and targeting HAI prevention in all age groups may reduce costs. Preoperative antibiotic prophylaxis should reduce hospital acquired infections.There is a clear age-related increase in in-hospital and at 30-day mortality rates. Chronological age is related with increased resource use as is low-value surgery provided to patients not expected to survive longer than 30-days post discharge. Patients may decide against pursuing low-value surgery if surgeons were to use surgical risk calculators to inform patients (especially in elderly patients) of their possible surgical risks. However, Australian surgeons using the SRC to inform patients should be aware that the SRC’s predicted risks are less than accurate in the Australian setting. Instead of developing another surgical risk tool, researchers should develop a data analysis and quality improvement program that includes monitoring of complication rates. This could lead to better outcomes in all surgical patients.