Introduction
Anthropometric measures such as height and weight are indispensable measures in clinical practice. Patient-reported values are frequently used, but may be susceptible to reporting biases. Invalid self-reported measures can lead to incorrect or harmful drug administration or invalid height- or weight-dependent echocardiographic parameters .
Methods
After informed consent was given, 730 cardiological and general practice outpatients provided information regarding their current height and weight, without knowing that these data would be assessed with calibrated measures thereafter. Self-reporting took place under different conditions, which were operationalized by modality (questionnaire or face-to-face interview), sex (female or male) and profession (nurse or physician) of the interviewer. Additionally, medical history and psychological status (Cognitive function, Anxiety/Depression and Quality of Life) were assessed. Self-reported anthropometric measures were compared with calibrated measures by paired t-tests and Pearson correlations between deviations and a set of predictor variables were tested. Stepwise regression analyses were carried out to determine the effect of predictors that showed significant correlation. Finally, the potential amount of incorrect dosing and echocardiographic parameters such as LAVI or LVMI based on invalid anthropometric measures were calculated.
Results
Mean height (SD) of the participants (36 % were female) was 170.92 (9.34) cm (female: 162.71 (6.75) cm; male: 175.60 (7.12) cm). Patients significantly overestimated their height with 1.82 (2.33) cm ([1.64 to 2.33]; range: -8.00 – 11.00 cm). Misreporting was best predicted by age with older patients providing more height overestimations. Mean weight was 84.25 (17.41) kg (female: 76.08 (18.00) kg; male: 88.93 (15.24) kg) and was significantly underestimated with 1.49 (3.05) kg ([1.27 to 1.72], range: -36.00 to 26.00 kg). Misreporting was best predicted by higher BMI, cognitive impairment, a longer time to last weighing, and self-report with questionnaires were associated with a higher underreporting of weight. Overweight females showed a trend for higher underestimations of weight than overweight males. Unlike females, males underreported their weight more pronounced when asked by questionnaire compared to face to face interview. Comparison of doses for low-molecular-weight heparin according to self-reported and calibrated weight revealed a potential underdosing in 17 % and a potential overdosing in 77 % of all patients. Echocardiographic measures did not differ between both groups.
Conclusions
Self-reports of height and weight are invalid, especially in older and overweight patients. Misreporting can lead to incorrect drug administration. Calibrated measurement of height and weight is part of good clinical practice, and if self-reporting is unavoidable personal interviews should be preferred above questionnaires.
