Determinants of anthropometric measurement use amongst dieticians

Abstract

Background: Nutritional assessment, including the measurement and interpretation of anthropometric data, is a pivotal part of the dietitian’s role. However, the extent to which dietitians use anthropometry in their day-to-day activities is poorly documented. Anecdotal evidence suggests that this is below ideal levels. Attitudes and perceived barriers towards the use of anthropometry may further differ by work setting and patient group (e.g. between acute and community-based dietitians). In order to evaluate factors influencing the use of anthropometry amongst dietitians, sensitive, validated tools are needed. Visual analogue scales (VAS) are easily used and interpreted, but have not been validated for assessing confidence levels, in particular when taking body measurements. Aims: This study investigated the use of, and barriers/attitudes towards taking anthropometric measurements amongst dietitians using a cross-sectional survey. For this, a new type of confidence scale (VAS-based) was validated against two other commonly used scales (the Likert and the general-labelled magnitude scale, gLMS). Design and procedure: A pre-piloted questionnaire including confidence scales and attitudinal scales was sent to all NHS dietitians in the North West of England between March-April 2010. The pilot sample (n=32) rated their perceived confidence at taking various anthropometric measures using VAS, Likert and gLMS scales on 2 separate occasions, with scale order randomised. Results: ANOVA and Bland-Altman plot tests indicated VAS to be as sensitive and as reproducible as Likert; VAS also had greater level of agreement with Likert than gLMS, therefore VAS were chosen for the final questionnaire. Of the 397 questionnaires posted, 213 (54%) were returned. Highest confidence ratings were for BMI, height and weight, and lowest for BodPod and head circumference measurements. Average confidence scores across all measurements were lower for community dietitians compared with acute dietitians (mean + SEM scores for community: 54.21 + 14.78 mm; vs. acute: 60.27 + 12.11 mm; p<0.05). The majority of anthropometric measures were reported to be taken on an infrequent basis (‘Never’/’Less than monthly’). Height, weight and BMI were the most commonly used. Significantly more acute than community dietitians used ‘estimated’ (50% vs. 11.3%) and ‘recalled’ weight (50% vs. 11.4%) on a daily basis. The most common barriers against taking measurements were ‘Not appropriate for patient’, ‘Lack of equipment’ and ‘Time/work load constraints’. Significantly more acute responders reported ‘Time’ (81.4%, α=0.003) and ‘Confidence’ (75.5%, α=0.05) to be barriers to anthropometry use. Beyond half of the sample (61%) would attend future training, primarily to increase confidence and competency. Conclusions: Regardless of the importance/reported benefits of anthropometry, it is performed to a very limited degree by dietitians in the North West and is often limited to estimates, BMI, heights and weights. There are numerous barriers to anthropometry use for acute and community dietitians, namely time, equipment and confidence. It may therefore be unrealistic to expect many anthropometric measures to be taken and training should be adapted to reflect the reality of practice. This study also supports the use of VAS scales when assessing dietitians’ confidence at taking anthropometric measurements as a sensitive and reliable tool compared to the more widely used, however less sensitive, Likert scales.