Using the Quetelet body mass index as a mortality indicator for patients starting renal replacement therapy

The purpose of this study was to compare clinical profiles and mortality risk of patients starting renal replacement therapy (RRT) across three Quetelet body mass index (BMI) classifications: lean, normal, and obese.

All patients applying for dialysis services using Health Care Financing Administration (HCFA) from 2728-U4 were sampled during the period of April 1, 1995 through June 30, 1995 in two end-stage renal disease (ESRD) Networks. These two ESRD networks encompassed 7 states and provided 846 patients for this analysis.

A descriptive survival study was used with a follow-up period of 18 months.

The Quetelet BMI was calculated based on dividing the predialysis (i.e. before the first dialysis) weight in kilograms by the height in meters squared (kg/m2). Lean, normal, and obese groups were established by quartiles for each gender. A normal BMI consisted of all patients in which the observed BMI was greater than the 25th percentile or less than the 75th percentile.

The lean risk group had more health problems than either the normal or obese group, most notably, a higher prevalence of chronic obstructive pulmonary disease (n = 35, 16.99%) [p = 0.007] and peripheral vascular disease (n = 51, 24.76%) [p = 0.005].

Death risk was higher in the lean group compared to the normal group after adjusting for age, sex, diabetes, coronary artery disease (CAD), and albumin ratio levels. Based on the simplicity of this technique, recommendations for using the Quetelet BMI as a part of routine patient screening is advocated. Obtaining height and weight are necessary assessment parameters for patients starting dialysis therapy. Using the Quetelet BMI will help nurses to identify those patients who are at nutritional risk.