Approaches to statistical analysis of repeated echocardiographic measurements after myocardial infarction and its relation to heart failure: Application of a random-effects model.
BACKGROUND
Extensive left ventricular (LV) dilatation after myocardial infarction (MI) is associated with increased heart failure risk.


OBJECTIVE
To investigate whether the power to demonstrate the relation between LV dilatation and heart failure depends on the method applied to predict LV dilatation after MI.


METHODS
A random-effects model and ANOVA model for repeated measurements (MANOVA) were applied to predict LV volume index during 1 year for 298 post-MI patients. Spearman correlation coefficients (r) were calculated and Cox regression analysis was used to calculate risk ratio's (RR).


RESULTS
LV volume indices were more accurately predicted by a random-effects model than by a MANOVA model (systolic/diastolic respectively r = 0.93/0.91 vs. r = 0.67/0.64). Furthermore, patients with high LV volume index as predicted by the random-effects model, had significantly increased heart failure risk (systolic RR 2.04 (95% CI: 1.31 to 3.17; P = 0.001), diastolic RR 1.80 (95% CI: 1.16 to 2.78; P = 0.007). Using the same data, MANOVA failed to demonstrate this relation significantly (systolic RR 1.77 (95% CI: 0.79 to 3.98; P = 0.16), diastolic RR 1.49 (95% CI: 0.68 to 3.30; P = 0.31).


CONCLUSIONS
When analyzing repeated measurement data, random-effect models are more powerful in detecting clinical relations than are MANOVA models, especially in the presence of missing values.
de Kam
Pieter-Jan
PJ
Trial Co-ordination Center, University Hospital Groningen, Groningen, The Netherlands.
Voors
Adriaan A
AA
Brouwer
Jan
J
St John Sutton
Martin
M
van Gilst
Wiek H
WH
D004108:Dilatation, Pathologic; D018450:Disease Progression; D004311:Double-Blind Method; D004452:Echocardiography; D005260:Female; D006333:Heart Failure / Q000209:etiology*; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009203:Myocardial Infarction / Q000150:complications* / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D020257:Ventricular Remodeling