The Toronto HCM Genotype Score for Prediction of a Positive Genotype in Hypertrophic Cardiomyopathy.

Gruner C, Ivanov J, Care M, Williams L, Moravsky G, Yang H, Laczay B, Siminovitch K, Woo A, Rakowski H.

Source

1 Toronto General Hospital, University Health Network, Toronto, Ontario, Canada;

Abstract

BACKGROUND:

-Genotyping in hypertrophic cardiomyopathy (HCM) has gained increasing attention in the past decade. Its major role is for family screening, and only rarely influences decision-making processes in any individual patient. It is associated with substantial costs, and cost-effectiveness can only be achieved in the presence of high detection rates for disease-causing sarcomere protein gene mutations. Therefore, our aim was to develop a score based on clinical and echocardiographic variables that allows prediction of the probability of a positive genotype.

METHODS AND RESULTS:

-Clinical and echocardiographic variables were collected in 471 consecutive patients undergoing genetic testing at a tertiary referral center between July 2005 and November 2010. Logistic regression for a positive genotype was employed to construct integer risk weights for each independent predictor variable. These were summed for each patient to create the Toronto HCM genotype score. A positive genotype was found in 163/471 patients (35%). Independent predictors with associated risk weights in parentheses were as follows: age at diagnosis 20-29 (-1), 30-39 (-2), 40-49 (-3), 50-59 (-4), 60-69 (-5), 70-79 (-6), ≥80 (-7); female gender (4); arterial hypertension (-4); positive family history for HCM (6); morphology category (5); ratio of maximal wall thickness to posterior wall thickness <1 .46=".46" 0.80="0.80" 1.47-1.70="1.47-1.70" 1.71-1.92="1.71-1.92" 1.93-2.26="1.93-2.26" a="a" and="and" curve="curve" goodness-of-fit="goodness-of-fit" had="had" hosmer-lemeshow="hosmer-lemeshow" model="model" of="of" operator="operator" p="0.22.</p" receiver="receiver" the="the">