The Use of Biochemical Parameters as Nutritional Screening Tools in Surgical Patients

Abstract

Nutritional status influences surgical outcome and complication rates. The National Institute of Clinical Excellence (NICE) recommends screening patients on admission; yet traditional nutritional screening tools are underutilised. This retrospective case-control study investigates the association between biochemical factors and adverse outcomes in orthopaedic patients to ascertain whether they could provide more suitable alternatives to traditional screening tools. 66 patients with fractured neck of femur were investigated. Adverse outcomes including Length of Stay (LOS), and deaths were recorded. Total Lymphocyte Counts (TLC), Serum Albumin Levels and Haemoglobin levels, were recorded pre-operatively (pre-op) and post-operatively (post-op). Adverse outcomes in those with normal and abnormal biochemical values were compared using Chi Squared and T Testing. Linear associations were tested for using Pearson rank correlation. Automated Nutrition Scores Beta (ANSB) were calculated and their relationship to adverse outcomes investigated. Protein energy malnutrition was common on admission. However, only 2 patients were nutritionally screened during admission. Those patients with abnormal pre-op TLC had an increased LOS in hospital. Those with abnormal albumin and/or TLC had increased mortality rates. Abnormal albumin levels were associated with a significant 3 fold increase in mortality (p = 0.009) and post-operative TLC were found to be negatively correlated with LOS (r = –0.3, p = 0.038). ANSB were also found to correlate with increased adverse outcomes although this was not significant. This study demonstrates that nutritional status is poorly assessed on admission in orthopaedic patients and consequently that provision of nutritional supplements is suboptimal. This study also demonstrates a highly significant relationship between abnormal albumin and adverse outcomes and identifies a new correlation between post-operative TLC and LOS. This study confirms that individual biochemical parameters and biochemical scores can be used to identify orthopaedic patients at particular risk of adverse post-op outcomes. These biochemical screening methods may be a more efficient and reliable way of stratifying malnutrition associated risk on admission.