Is preoperative anaemia associated with poor postoperative outcomes in non-cardiac surgery patients?

Background: Preoperative anaemia (PA), defined by the World Health Organisation (WHO) as a haemoglobin (Hb) measurement of <12.0 g/dL in women and <13.0 g/dL in men, is associated with poor postoperative outcomes (PPO) in overseas noncardiac surgery settings. This relationship has not been investigated in a South African (SA) setting. Addressing this gap in the knowledge would have implications related to perioperative risk stratification/perioperative blood management strategies in SA. Our study sought to answer the question: "Is PA associated with PPO in SA noncardiac surgery patients?" Patients and Methods: We conducted a case-control analysis of data from the "South African Surgical Outcomes Study" to ad-dress our research question. Cases were defined as patients who suffered a PPO (either postoperative inpatient mortality or postoperative unplanned critical care admission), while controls were defined as patients who did not suffer a PPO. The sample size used in this case-control analysis was 624 patients, with a case-control ratio of 1:3. Preoperative anaemia was determined from preoperative Hb measurements using WHO definitions. Other patient/clinical characteristics were included in the data analysis in order to control for potential confounders. Data were analyzed using crude (chi-squared or Fisher's Exact tests) and adjusted (unconditional logistic regression) statistical analysis. Results: After controlling for potential confounders, PA was associated with an almost two-fold higher risk of PPO in SA noncar-diac surgery patients (Odds Ratio: 1.93, 95% Confidence Interval: 1.20-3.11, p=0.007). Conclusion: Preoperative anaemia is an important risk factor for PPO in SA noncardiac surgery patients.