Aims: Patients with chronic kidney disease are at high risk of cardiovascular morbidity and mortality. Increased left ventricular mass (LVM) has been shown to be an adverse prognostic factor. LVM may be indexed for body size by different methods related to height, weight, or body surface area (BSA). Our Null hypothesis was that different methods of indexation would not influence categorization as to whether LVM was within normal limits or increased.
Methods and results: Prospective study in children with renal disease. M-mode echocardiography assessed by single investigator blinded to medical therapy. Three different partition values and two different published z-scores were used: Method 1: indexation of LVM to the allometric height in metres raised to the power of 2.7 (m(2.7)), value of 38.6 g/m(2.7) denotes 95th percentile. Method 2: indexation of LVM by body weight, ratio of LVM in gm/kg of >3.0 indicating LVH. Method 3: indexation by BSA, 88.9 g/m(2) represents 95th percentile. Z-score based methods from recent studies with z-score >1.65 denoting LVH, Method 4: z-score indexed either for BSA or Method 5, z-score indexed for height(2.7). One hundred and twenty-three echocardiograms were performed in 80 patients with a mean +/- SD age of 13.1 +/- 3.1 years, height 147.2 +/- 15.3 cm, weight 46.4 +/- 15.8 kg, and body mass index 20.8 +/- 4.1 kg/m(2). Method 1, LVH was observed in 68 (55.3%) studies. Method 2, 32 (26%) studies had LVM/kg >3.0. Method 3, 51 studies (41.5%) demonstrated LVH. Method 4, 22 (17.9%) studies demonstrated LVH and Method 5, 25 studies (20%) demonstrated LVH (chi(2) test, P < 0.001).
Conclusion: Different methods of indexation have a profound influence on the categorization of children with respect to LVH. This will have a major impact on the number of patients who are treated as per current guidelines especially in high-risk groups.