J Clla Epi&miol Vol. 46, No. 11, pp. 1249-1256, 1993 0895-4356/93 S6.00 + 0.00 Printed in Great Britain. All rights reserved Copyright 0 1993 Pergamon Press Ltd A SELF-ADMINISTERED QUALITY-OF-LIFE QUESTIONNAIRE AFTER ACUTE MYOCARDIAL INFARCTION L. L-Y LIM,* L. A. VALENTI, J. C. KNAPP, A. J. DOBSON, R. PLOTNIKOPP, N. HIGGINB~THAM and R. F. HELLER Centre for Clinical Epidemiology and Biostatistics, University of Newcastle, NSW 2300, Australia (Received in revised form 30 April 1993) Abatraet-A slightly modified version of the Quality-of-Life after Myocardial Infarction (QLMI) questionnaire developed by Oldridge and colleagues was applied in a self-ad- ministered mode to patients with suspected acute myocardial infarction (AMI) in a randomized controlled trial of secondary prevention. Acceptability of the questionnaire was good, with 93% of responders answering all items. Factor analysis suggested three quality-of-life (QL) dimensions which we called “emotional”, “physical” and “social” . These differed somewhat from the dimensions proposed by Oldridge and colleagues. However, a sensitivity analysis showed relative invariance of results to weighting schemes. Scores on our three dimensions were responsive to differences between the treatment groups, and demonstrated construct validity based on associations between the measured QL and variables expected to affect QL. We conclude that the QLMI questionnaire has good potential as an instrument for assessing QL in post-AM1 patients and that it can be successfully self-administered. Quality of life Factor analysis Self-administered questionnaire Acute myocardial infarction INTRODUCTION The concept of quality-of-life (QL) has received increasing attention as an outcome factor in clinical studies of coronary heart disease (CHD) [l]. A wide range of instruments, both generic and disease-specific, have been used in QL assessment of subjects with CHD [l]. Well- known generic instruments previously used on CHD subjects include the Nottingham Health Profile [2,3] and the Sickness Impact Profile [4,5]. Other researchers have opted for disease- specific instruments and have developed instru- ments ranging from one or several simple *All correspondence should be addressed to: Dr Lynette L-Y Lim, Centre for Clinical Epidemiology and Biostatistics, David Maddison Clinical sciences Building, Royal Newcastle Hospital, Newcastle NSW 2300, Australia. questions [6,7] to comprehensive questionnaires [S-10]. Most QL questionnaires comprise multiple items. Besides problems of interpretation, analysis of each item separately raises methodo- logical problems because of multiple compari- sons. Developers of questionnaires typically aggregate items into a small number of concep- tually meaningful QL dimensions [8,9]. Often QL dimensions are defined intuitively in a man- ner considered meaningful by the investigators [8, lo] or identified via a data analytic technique such as factor analysis [l]. During 1990 and 1991, we carried out a randomized controlled trial of secondary pre- vention on subjects with suspected acute myo- cardial infarction (AMI) [12]. To assess QL, we required a self-administered questionnaire and reviewed several instruments for this purpose. 1249 CE 464 I-c