Comparison of three methods for measuring height in rehabilitation inpatients and the impact on body mass index classification: An open prospective study

Aim: To compare standing height, estimated current height and demi-span estimated height and examine their impact on body mass index (BMI) classification. Methods: Cross-sectional data was collected on 104 patients admitted to an adult rehabilitation ward and seen by the dietitian. Patient's standing, estimated current height and demi-span estimated height were collected and grouped by age: 19-64 and ≥65 years. Results: The limits of agreement (95% confidence interval) for estimated current height compared with standing height were +9.9 cm and -7.9 cm, in contrast to +8.7 cm and -14.3 cm for demi-span estimated height. Demi-span underestimated height when compared with standing height in both age groups, 19-64 years: (mean ± SD) 3.0±6.5 cm (P=0.001, n=68) and≥65 year age group 4.0±6.0 cm (P<0.001, n=36), resulting in a significantly greater mean BMI (analysis of variance P<0.001, P=0.02). In the 19-64 and ≥65 year age groups, 3% (2/68) and 10% (4/36) of patients, respectively, had a different BMI classification using demi-span estimated height compared with standing height. Conclusions: Estimated current height is a simple and practical alternative if standing height is unable to be obtained when performing a nutrition assessment. Demi-span estimated height should be used with caution when calculating BMI to assess nutritional status, particularly in the elderly.