The Validity of Patient-led Self- screens for Identifying Malnutrition in Inflammatory Bowel Disease

Abstract

Background: Malnutrition is common in Inflammatory Bowel Disease (IBD) and is associated with significant morbidity and mortality. Identification of high-risk patients using a sensitive and reliable screen is the first step to dietitian referral for nutritional assessment and intervention. Aim: The primary goal of this study was to determine the validity of patient led self-screens and health-care practitioner (HCP) screens against a dietitian-led nutritional assessment to detect malnutrition in outpatients with IBD. Our secondary objectives were to: i) determine the inter-rater reliability of patient-led self-screens compared to HCP screening and ii) determine the prevalence of malnutrition assessed by a range of assessment tools - subjective global assessment (SGA), body mass index (BMI), mid-arm muscle circumference (MAMC) and handgrip strength (HGS). Methods: Patients were prospectively recruited from IBD outpatient clinics in Edmonton and Calgary. Patients completed 4 self-screening questionnaires: abridged Patient-generated Subjective Global Assessment (abPG-SGA), Malnutrition Universal Screening Tool (MUST), Canadian Nutrition Screening Tool (CNST) and Saskatchewan IBD-Nutrition risk (SaskIBD-NR) tool, followed by independent nutrition screening performed by a HCP. A dietitian blinded to the results of the screens carried out a gold standard nutritional assessment using the SGA (primary assessment modality), BMI, MAMC and HGS. We identified the proportion of patients in each category, sensitivity and specificity against SGA (dietitian-led malnutrition assessment) using contingency tables, and agreement between patient-led self-screen and HCP-led screening using kappa statistics (inter-rater reliability). Results: A total of 204 IBD outpatients (131 Crohn’s (CD) and 73 Ulcerative colitis (UC)), 50.5% female, were assessed. According to Harvey-Bradshaw Index and partial Mayo scores, 12.8% of CD and 11.3% of UC patients had moderate to severe disease activity. The most common symptoms affecting dietary intake were diarrhea (21%), poor appetite (20%), pain (18%), and fatigue (18%). Of the 4 screening tools, the abPG-SGA and SaskIBD-NR tool showed the best predictive values (sensitivity of 89% and 70%; specificity of 75% and 81%, respectively) compared to dietitian-led SGA assessment. All self-screens demonstrated a moderate inter-rater agreement with the HCP-led screening (p < 0.001). According to dietitian-administered nutritional assessment, the prevalence of malnutrition in our IBD outpatients was 3%, 18%, 22% and 31% according to BMI, SGA, MAMC and HGS, respectively. Conclusion: The abPG-SGA and SaskIBD-NR tools are promising nutrition screening tools in an IBD outpatient setting. They are valid and can be completed by patients in the waiting room during the clinical visit. With the high sensitivity and high negative predictive value for malnutrition detection, the majority of patients who screen at risk of malnutrition with these tools would be appropriately referred for further assessment. Future clinical practice should integrate these tools into routine IBD nutrition screening and assess the ability of the screening tools to predict clinical outcomes.