Cardial-MASS-Study: Influencing Factors on Reliability of Selfreported Weight and Height

Height and weight are important informations in clinical life. Medication is dosed by them and weight, especially overweight, is a risk factor for cardiovascular diseases. Mostly you have to rely on the self-reported informations, because there is plenty of work and little time to weigh and measure every patient. But can the investigators really trust this informations? Former studies have shown, that most of self-reported heights and weights differ from the measured ones. This fact might lead to a wrong dosage of medicine or underestimated risk factors. So the Cardial-MASS-Study tries to detect influencing factors on the reliability of self-reported informations especially among patients, treated at the cardiological department at Saarland University.

Weight and height of patients is often recorded in clinical practice, as well as in clinical research. They give important informations for medication dosages, e.g., anticoagulants or anesthesias. Furthermore, the body mass index (BMI), calculated by weight and height, is an easy instrument to estimate a patient's risk for cardiovascular diseases based on obesity.

In clinical practice, informations about height and weight do often rely on self-reported values instead of measured ones. This can be due to limited timely, but also instrumental resources, when scales or measuring tapes are not available. Unfortunately, these self-reported informations are often inaccurate. Age, education, weight, and sex seam to influence and distort them in different ways.

Former studies have shown, that a lot of patients overestimate their height \[1-8\] and underestimate their weight \[1-6\]. This might lead to a wrong classification in normal weight and overweight using BMI. Among elderly (\>60 years) informations relying on measured values and on self-reported values seem to be even more divergent \[10\].

People with overweight are tending to underestimate their weight stronger than people with normal weight. The higher the weight, the more the self-reported information deviates from the actual weight \[11,12\]. Men's informations are more exact than women's, like Niedhammer et al. has shown in a study with 7350 participants \[9\]. Men with a BMI lower than 25 even overestimated their weight. Compared to younger ones, elderly men underestimated their weight more often, and elderly women's self-reported weight was more accurate \[1,9\].

Next to age and gender, socioeconomic variables do influence self-reported measures. The higher the education or working position the more accurate the information about height. Noteworthy, women in high working positions overestimate their height, when compared to women in lower positions, who even underestimate their height \[2,5,6,8,9\].

Furthermore, external conditions of data acquisition may impact validity of self-reported information, too. Stewart supposed that informations given in an interview are more exact than those given in a questionnaire \[11\].

Most of the studies mentioned above are not exclusively related to patients with cardiovascular diseases. Studies referring to this patient population suggest, that men with cardiovascular diseases underestimate their weight less than others \[13\]. Nevertheless, Niedhammer et al. could not confirm this finding \[9\]. HEnce, the aim of this study is to identify factors that influence the validity of self-reported height and weight in patients with cardiovascular disease.

Eligibility Criteria:
Inclusion Criteria:

* Patients at Innere Medizin III (Cardiology), Universitätsklinikum des Saarlandes (UKS)
* cardiovascular disease (Coronar-Vessel-Disease, Arrhythmia, Heart-attack, Hypertonus, stable heart failure)
* Patients at a family doctor

Exclusion Criteria:

* younger than 18 years
* Dementia
* cardial decompensation
* severe anemia (Hemoglobin\<9 mg/dl)
* cardial shock
* acute kidney failure
* factors, that prevent patients from answering the questionnaire
* factors, that prevent patients from being measured and weighted