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A self–administered questionnaire for detection of unrecognised coronary heart disease

A self–administered questionnaire for detection of unrecognised coronary heart disease James D. Cameron L a Trobe University, Melbourne, and Baker Medical Research Institute, Melbourne Garry L. Jennings, Sally Kay, Sudhir Wahi, Kristina E. Bennett, Christopher Reid and Anthony M. Dart Baker Medical Research Institute, Melbourne Abstract: On an individual and a population basis, an increased incidence of coronary heart disease is associated with classical cardiovascular risk factors, but many cases occur in people not identified as at high risk. Conversely, many people at high statistical risk do not develop coronary disease. We used a questionnaire to identify unrecognised coronary heart disease in people attending large-scale health survey centres. Participants were required to report the presence and characteristics of any chest pain. Those returning responses consistent with myocardial ischaemia were offered treadmill exercise ECG tests. Over 18 months, 4070 questionnaires were returned. Of 475 respondents offered testing, 229 (198 male, 131 female) accepted. Thirty-two subjects (15 male, 17 female: a detection rate of 13.9 per cent of those assessed as likely on questionnaire, or 0.8 per cent of all respondents) had results consistent with significant coronary heart disease. Follow-up was available in 30 cases. There was no difference in classical risk-factor distribution (including multivariate risk percentiles: 42.4 (male) and 46.7 (female)) between those newly diagnosed with coronary heart disease and their community counterparts. More women than men were identified as suffering from unrecognised coronary heart disease, with a preponderance of younger women. Cost per case identified was A$l220. Screening by self-administered questionnaire is a useful and relatively cost-effective means of identifjmg unrecognised coronary heart disease. (Aust N ZJPublic Health 1997; 21: 545-7) and treatment. Improved identification of this group is an important health issue, both for the instigation of strategies of individual patient management as well as, in broader terms, to decrease the community cost associated with unrecognised coronary heart disease. The purpose of this study was to assess the usefulness of a self-assessment questionnaire to identify people with unrecognised coronary heart disease. Methods The questionnaire (Figure 1 ) was based on the WHO Rose questionnaire,? and was made available to all subjects attending large community-based health and diet survey centres (Health 2000 program, Anti-Cancer Council of Victoria) or the risk reduction clinic of the Baker Medical Research Institute. The study protocol was approved by institutional ethics committees and all participants gave informed consent. All attenders at the centres were offered questionnaires for subsequent unassisted completion, but since participation in the study was not part of the standard procedure of the centres, return of a questionnaire was entirely voluntary. The questionnaire required respondents to indicate yes or no to having recognised coronary heart disease and, if responding in the negative, to indicate whether they had experienced chest pain, to indicate diagrammatically its position and to state whether it had been associated with exertion. Returned questionaries were assessed by one of the authors (JDC, SW), and coded as known coronary heart disease, or a response not suggestive of coronary heart disease (no further action), or a response consistent with coronary heart disease (for followup). Respondents coded as possibly having coronary heart disease were contacted by mail with an offer of a no-cost exercise electrocardiograph (ECG) test. Those accepting were medically screened for their ability to perform a treadmill exercise ECG, but were not excluded if, as a result of screening, they were thought unlikely to be suffering from coronary heart disease, that is, the criteria for testing remained based on the questionnaire response. No participants accepting the offer were unable to perform treadmill exercise and subjects underwent exercise ECG testing using a modified Bruce protocol according to our usual clinical routine. The test was terminated if it was assessed as positive (flat ST segment depression 20.15 mV), if the predicted ageand sex-matched maximal heart rate was reached, or VOL. N a population basis, an increased incidence of coronary heart disease is associated with higher levels of classical cardiovascular risk factors, considered to be clinical or biochemical markers of a statistically increased likelihood of having or developing the disease.' Much coronary heart disease morbidity and mortality occurs in people not classified as at excessively high risk. This is because, at least partly, of the high proportion of the population who fall into the mild-to-moderate-risk group and to the complex multifactorial interactions involved in the development of coronary heart disease. Population screening on the basis of classical risk factors is therefore likely to miss a significant number of people who warrant further investigation Correspondence to Dr J.D. Cameron. Alfred Baker Medical Unit, Baker Medical Research Institute, Commercial Road, Prahran, Vic 3181. Fax (03) 9471 0524. AUSTRALIAN AND NEW ZEALAND JOURNAL O PUBLIC HEALTH 1997 F NO. 5 Q U E S T I O N N A I R E Name Address Rstcode Phone 0 SexMO F O Table 1 : Results of exercise ECG tests, and other factors, for those subjects attending Melbourne community-based health screening centres, whose questionnaire responses indicated likely coronary heart disease Sex Variable Number of respondents Number offered testing Number accepting testing Number of positive test results % of positive test results [HI Date nee Please circle the Male Female correct answer and supply any information requested 1 Have you ever had a heart O n w k myccardlal infarct or coronary ihrombosis? Yes Yes No No 2 Has a doctor ever told you that you suffer from angina? H (he answer lo 0 1 or Q2 I1 'Yes' do not answer any more questlonr. 3 Have you ever had any pain or discomfort in your chest? Yes Yes For hose entering h e study" Number in age group: No 4 Do you get this paln or discomfort when you wolk uphill or hurry7 No No 5 Do you get it when you walk at an ordinary poce on the IeveP Yes 45-59 5+54 55-59 60-64 6 When you get any pain or discomfort In your chest whot do you dd) 3 7 Does it go away when you stand still? stop Slwdown Continue a the same pace t Yes 65-69 0 2 5 7 0 6.26k0.09 134.8k1.44 No Howsoon? 10 minutes or less More than I0 minutes 9 Where do you get this paln or discomfort? Mark the p/aCes wfth on X on the diagram Total cholesterol, mean* standard error (mmol/L) 5.58i0.05 Systolic blood pressure, mean* 139.0k1.42 standard error (mm Hg) Number smoking cigarettes in past 5 years 0 Clinical coronary heart disease 1 4 requiring treatment 7 Number having angiogram Number with significant disease confirmed on angiogram 7 Number having percutaneous transluminal coronary angioplasiy (PTCA) 1 Number having bypass surgery 3 Number having PTCA and bypass surgery 1 Note: Figure 1: Questionnaire for the detection of unrecognised coronary heart disease. (a) Excluding 2 subjects who chose to leave the study after the initial positive exercise ECG test if the subject was unable to continue owing to fatigue. A fasting lipid profile was obtained from all subjects and cardiovascular risk percentiles were calculated, as described by Reid et al. for the Australian population.g Results Over 18 months, approximately 5000 questionnaires were distributed, with 4070 returned. Of 475 respondents offered exercise ECG tests, 229 (98 male, 131 female) or 48.2 per cent accepted the offer and attended for testing. The characteristics and results o those who accepted testing are shown in Table 1. f From the 32 identified subjects with presumptive coronary heart disease, follow-up information was available on 30 (one male and one female choosing to exit the study). There was no difference in total serum cholesterol distribution or blood pressure between the 30 persons identified and their background p ~ p u l a t i o n . ~ Mean coronary risk percentile was 42 (standard error (SE) 6) for men in the group and 48 (SE 7) for women, and 4 of 14 men and 6 of 16 women identified with unrecognised coronary heart disease had risk percentiles higher than 50 per cent. 546 Discussion Although exercise electrocardiography of asymptomatic subjects is of low positive predictive value in detecting coronary heart disease,5,6 is known to be it a useful and relatively low-cost diagnostic procedure for those with a high pretest likelihood of disease.' Our study differs from indiscriminate testing of asymptomatic subjects in that those tested had, by completion of a questionnaire, reported at least one episode of chest pain suspicious of coronary ischaemia. This study was directed at identifylng clinically significant coronary heart disease, not necessarily angiographically apparent coronary artery atheromatous disease. Our results represent an identified incidence of coronary heart disease of 14 per cent, which can be compared to an expected incidence of 4 to 5 per cent from a comparable asymptomatic population,* and show that when a population is first screened, even by a relatively simple questionnaire, the pretest likelihood is increased to an extent that the return rate is significant in terms of identification of unrecognised coronary heart disease. Such an approach, therefore, has the potential to provide a 1997 vot. 2 1 NO. 5 AUSTRALIAN AND NEW ZEALAND JOURNAL O PUBLIC HEALTH F UNRECOGNISED CORONARY HEART DISEASE cost-effective way of screening for coronary heart disease in the community, and offers an opportunity of decreasing subsequent cardiac morbidity and mortality. The cost of producing and circulating (with prepaid reply) 5000 questionaries was A$8640. The 229 exercise ECG tests were performed at a nominal cost, based on the Australian Medicare benefits schedule fee, of $27 480. On the same basis, initial cardiological consultations for 32 subjects returning a positive result would have amounted to $3392, resulting in a total cost per identified case of approximately $1235. The association of lipid level and cardiovascular risk is continuous rather than dichotomous; however, the high cost of intervention has led to the arbitrary establishment of levels of risk that are considered appropriate for treatment. Nine of the 30 identified and followed cases had a total fasting serum cholesterol of higher than 6.5 mmol/L, the level often considered to warrant lipid-lowering medication.' The relatively low cost per case and significant yield identified in this study indicates that questionnaire responses may be a good method of selecting for further assessment individuals from the groups considered at low risk but from whom a significant amount of coronary heart disease morbidity arises. Two aspects of our results warrant consideration. First, not unexpectedly, was the lack of identification of patients with unrecognised coronary heart disease by consideration of classical risk factors. This can partly be attributed to the multifactorial influences discussed previously, but also to the likelihood of those with clearly elevated classical risk factors having already been selected for preventive intervention. Second, the age and sex comparison provides room for speculation. In each age decade after the fourth, more women than men with symptoms suggestive of coronary heart disease were identified by questionnaire; in the same group, fewer women than men reported that they had ever been told by a doctor that they suffered from angina or had suffered a myocardial infarction. Overall, more women than men were identified as suffering from unrecognised coronary heart disease, with a greater number of younger (under 60 years) women than men identified. Although involving only small numbers, one possible interpretation of this data supports speculation that women are both less likely to report their symptoms, and having done so, are less likely to be fully investigated. It remains to speculate why those identified as having coronary heart disease had not previously obtained medical attention. In virtually all instances, subjects had a medical attendant whom they would see on a regular basis for minor ailments. Either they had not thought it necessary to mention their chest pain or it had not been considered ischaemic, and the patients had not persisted with any concerns regarding the pain. This is surprising, given that respondents appeared to be a health conscious group, demonstrated by their nonsmoking status and attendance for health screening. It is possible that the anonymity of the questionnaire approach encourages frankness without the fear of being labelled fanciful or hypochondriacal. This study relied on treadmill exercise ECG results to confirm the presence of exertional myocardial ischaemia. In those identified subjects who proceeded to coronary angiography on clinical grounds all male subjects were found to have significant epicardial coronary artery disease; however, only three of six female subjects had significant large coronary artery disease. This is consistent with other reported findings, but it does not rule out other causes of exertional myocardial ischaemia. Other confounding factors in our study are the possibility of some true cases being missed owing to false-negative exercise test results or to inappropriate coding of questionnaires. Both of these factors would tend to cause underestimation of the potential for questionnaires in identification of coronary heart disease. Increased emphasis is being placed on secondary prevention of coronary heart disease, which by definition involves treatment of known myocardial ischaemia. We have shown that the use of questionnaires is a potentially useful strategy to maximise the reach and benefit of secondary preventive treatment. Our results suggest that use of a simple selfadministered questionnaire is an effective and cost-efficient method of identifylng persons at high risk of unrecognised coronary heart disease. It appears to be a useful means of looking beyond classical risk-factor levels for identifymg patients arbitrarily classified as at low risk but who warrant further cardiological assessment. Acknowledgments This study was funded in its entirety by a grant from the Victorian Health Promotion Foundation. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Australian and New Zealand Journal of Public Health Wiley

A self–administered questionnaire for detection of unrecognised coronary heart disease

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Publisher
Wiley
Copyright
Copyright © 1997 Wiley Subscription Services, Inc., A Wiley Company
ISSN
1326-0200
eISSN
1753-6405
DOI
10.1111/j.1467-842X.1997.tb01749.x
Publisher site
See Article on Publisher Site

Abstract

James D. Cameron L a Trobe University, Melbourne, and Baker Medical Research Institute, Melbourne Garry L. Jennings, Sally Kay, Sudhir Wahi, Kristina E. Bennett, Christopher Reid and Anthony M. Dart Baker Medical Research Institute, Melbourne Abstract: On an individual and a population basis, an increased incidence of coronary heart disease is associated with classical cardiovascular risk factors, but many cases occur in people not identified as at high risk. Conversely, many people at high statistical risk do not develop coronary disease. We used a questionnaire to identify unrecognised coronary heart disease in people attending large-scale health survey centres. Participants were required to report the presence and characteristics of any chest pain. Those returning responses consistent with myocardial ischaemia were offered treadmill exercise ECG tests. Over 18 months, 4070 questionnaires were returned. Of 475 respondents offered testing, 229 (198 male, 131 female) accepted. Thirty-two subjects (15 male, 17 female: a detection rate of 13.9 per cent of those assessed as likely on questionnaire, or 0.8 per cent of all respondents) had results consistent with significant coronary heart disease. Follow-up was available in 30 cases. There was no difference in classical risk-factor distribution (including multivariate risk percentiles: 42.4 (male) and 46.7 (female)) between those newly diagnosed with coronary heart disease and their community counterparts. More women than men were identified as suffering from unrecognised coronary heart disease, with a preponderance of younger women. Cost per case identified was A$l220. Screening by self-administered questionnaire is a useful and relatively cost-effective means of identifjmg unrecognised coronary heart disease. (Aust N ZJPublic Health 1997; 21: 545-7) and treatment. Improved identification of this group is an important health issue, both for the instigation of strategies of individual patient management as well as, in broader terms, to decrease the community cost associated with unrecognised coronary heart disease. The purpose of this study was to assess the usefulness of a self-assessment questionnaire to identify people with unrecognised coronary heart disease. Methods The questionnaire (Figure 1 ) was based on the WHO Rose questionnaire,? and was made available to all subjects attending large community-based health and diet survey centres (Health 2000 program, Anti-Cancer Council of Victoria) or the risk reduction clinic of the Baker Medical Research Institute. The study protocol was approved by institutional ethics committees and all participants gave informed consent. All attenders at the centres were offered questionnaires for subsequent unassisted completion, but since participation in the study was not part of the standard procedure of the centres, return of a questionnaire was entirely voluntary. The questionnaire required respondents to indicate yes or no to having recognised coronary heart disease and, if responding in the negative, to indicate whether they had experienced chest pain, to indicate diagrammatically its position and to state whether it had been associated with exertion. Returned questionaries were assessed by one of the authors (JDC, SW), and coded as known coronary heart disease, or a response not suggestive of coronary heart disease (no further action), or a response consistent with coronary heart disease (for followup). Respondents coded as possibly having coronary heart disease were contacted by mail with an offer of a no-cost exercise electrocardiograph (ECG) test. Those accepting were medically screened for their ability to perform a treadmill exercise ECG, but were not excluded if, as a result of screening, they were thought unlikely to be suffering from coronary heart disease, that is, the criteria for testing remained based on the questionnaire response. No participants accepting the offer were unable to perform treadmill exercise and subjects underwent exercise ECG testing using a modified Bruce protocol according to our usual clinical routine. The test was terminated if it was assessed as positive (flat ST segment depression 20.15 mV), if the predicted ageand sex-matched maximal heart rate was reached, or VOL. N a population basis, an increased incidence of coronary heart disease is associated with higher levels of classical cardiovascular risk factors, considered to be clinical or biochemical markers of a statistically increased likelihood of having or developing the disease.' Much coronary heart disease morbidity and mortality occurs in people not classified as at excessively high risk. This is because, at least partly, of the high proportion of the population who fall into the mild-to-moderate-risk group and to the complex multifactorial interactions involved in the development of coronary heart disease. Population screening on the basis of classical risk factors is therefore likely to miss a significant number of people who warrant further investigation Correspondence to Dr J.D. Cameron. Alfred Baker Medical Unit, Baker Medical Research Institute, Commercial Road, Prahran, Vic 3181. Fax (03) 9471 0524. AUSTRALIAN AND NEW ZEALAND JOURNAL O PUBLIC HEALTH 1997 F NO. 5 Q U E S T I O N N A I R E Name Address Rstcode Phone 0 SexMO F O Table 1 : Results of exercise ECG tests, and other factors, for those subjects attending Melbourne community-based health screening centres, whose questionnaire responses indicated likely coronary heart disease Sex Variable Number of respondents Number offered testing Number accepting testing Number of positive test results % of positive test results [HI Date nee Please circle the Male Female correct answer and supply any information requested 1 Have you ever had a heart O n w k myccardlal infarct or coronary ihrombosis? Yes Yes No No 2 Has a doctor ever told you that you suffer from angina? H (he answer lo 0 1 or Q2 I1 'Yes' do not answer any more questlonr. 3 Have you ever had any pain or discomfort in your chest? Yes Yes For hose entering h e study" Number in age group: No 4 Do you get this paln or discomfort when you wolk uphill or hurry7 No No 5 Do you get it when you walk at an ordinary poce on the IeveP Yes 45-59 5+54 55-59 60-64 6 When you get any pain or discomfort In your chest whot do you dd) 3 7 Does it go away when you stand still? stop Slwdown Continue a the same pace t Yes 65-69 0 2 5 7 0 6.26k0.09 134.8k1.44 No Howsoon? 10 minutes or less More than I0 minutes 9 Where do you get this paln or discomfort? Mark the p/aCes wfth on X on the diagram Total cholesterol, mean* standard error (mmol/L) 5.58i0.05 Systolic blood pressure, mean* 139.0k1.42 standard error (mm Hg) Number smoking cigarettes in past 5 years 0 Clinical coronary heart disease 1 4 requiring treatment 7 Number having angiogram Number with significant disease confirmed on angiogram 7 Number having percutaneous transluminal coronary angioplasiy (PTCA) 1 Number having bypass surgery 3 Number having PTCA and bypass surgery 1 Note: Figure 1: Questionnaire for the detection of unrecognised coronary heart disease. (a) Excluding 2 subjects who chose to leave the study after the initial positive exercise ECG test if the subject was unable to continue owing to fatigue. A fasting lipid profile was obtained from all subjects and cardiovascular risk percentiles were calculated, as described by Reid et al. for the Australian population.g Results Over 18 months, approximately 5000 questionnaires were distributed, with 4070 returned. Of 475 respondents offered exercise ECG tests, 229 (98 male, 131 female) or 48.2 per cent accepted the offer and attended for testing. The characteristics and results o those who accepted testing are shown in Table 1. f From the 32 identified subjects with presumptive coronary heart disease, follow-up information was available on 30 (one male and one female choosing to exit the study). There was no difference in total serum cholesterol distribution or blood pressure between the 30 persons identified and their background p ~ p u l a t i o n . ~ Mean coronary risk percentile was 42 (standard error (SE) 6) for men in the group and 48 (SE 7) for women, and 4 of 14 men and 6 of 16 women identified with unrecognised coronary heart disease had risk percentiles higher than 50 per cent. 546 Discussion Although exercise electrocardiography of asymptomatic subjects is of low positive predictive value in detecting coronary heart disease,5,6 is known to be it a useful and relatively low-cost diagnostic procedure for those with a high pretest likelihood of disease.' Our study differs from indiscriminate testing of asymptomatic subjects in that those tested had, by completion of a questionnaire, reported at least one episode of chest pain suspicious of coronary ischaemia. This study was directed at identifylng clinically significant coronary heart disease, not necessarily angiographically apparent coronary artery atheromatous disease. Our results represent an identified incidence of coronary heart disease of 14 per cent, which can be compared to an expected incidence of 4 to 5 per cent from a comparable asymptomatic population,* and show that when a population is first screened, even by a relatively simple questionnaire, the pretest likelihood is increased to an extent that the return rate is significant in terms of identification of unrecognised coronary heart disease. Such an approach, therefore, has the potential to provide a 1997 vot. 2 1 NO. 5 AUSTRALIAN AND NEW ZEALAND JOURNAL O PUBLIC HEALTH F UNRECOGNISED CORONARY HEART DISEASE cost-effective way of screening for coronary heart disease in the community, and offers an opportunity of decreasing subsequent cardiac morbidity and mortality. The cost of producing and circulating (with prepaid reply) 5000 questionaries was A$8640. The 229 exercise ECG tests were performed at a nominal cost, based on the Australian Medicare benefits schedule fee, of $27 480. On the same basis, initial cardiological consultations for 32 subjects returning a positive result would have amounted to $3392, resulting in a total cost per identified case of approximately $1235. The association of lipid level and cardiovascular risk is continuous rather than dichotomous; however, the high cost of intervention has led to the arbitrary establishment of levels of risk that are considered appropriate for treatment. Nine of the 30 identified and followed cases had a total fasting serum cholesterol of higher than 6.5 mmol/L, the level often considered to warrant lipid-lowering medication.' The relatively low cost per case and significant yield identified in this study indicates that questionnaire responses may be a good method of selecting for further assessment individuals from the groups considered at low risk but from whom a significant amount of coronary heart disease morbidity arises. Two aspects of our results warrant consideration. First, not unexpectedly, was the lack of identification of patients with unrecognised coronary heart disease by consideration of classical risk factors. This can partly be attributed to the multifactorial influences discussed previously, but also to the likelihood of those with clearly elevated classical risk factors having already been selected for preventive intervention. Second, the age and sex comparison provides room for speculation. In each age decade after the fourth, more women than men with symptoms suggestive of coronary heart disease were identified by questionnaire; in the same group, fewer women than men reported that they had ever been told by a doctor that they suffered from angina or had suffered a myocardial infarction. Overall, more women than men were identified as suffering from unrecognised coronary heart disease, with a greater number of younger (under 60 years) women than men identified. Although involving only small numbers, one possible interpretation of this data supports speculation that women are both less likely to report their symptoms, and having done so, are less likely to be fully investigated. It remains to speculate why those identified as having coronary heart disease had not previously obtained medical attention. In virtually all instances, subjects had a medical attendant whom they would see on a regular basis for minor ailments. Either they had not thought it necessary to mention their chest pain or it had not been considered ischaemic, and the patients had not persisted with any concerns regarding the pain. This is surprising, given that respondents appeared to be a health conscious group, demonstrated by their nonsmoking status and attendance for health screening. It is possible that the anonymity of the questionnaire approach encourages frankness without the fear of being labelled fanciful or hypochondriacal. This study relied on treadmill exercise ECG results to confirm the presence of exertional myocardial ischaemia. In those identified subjects who proceeded to coronary angiography on clinical grounds all male subjects were found to have significant epicardial coronary artery disease; however, only three of six female subjects had significant large coronary artery disease. This is consistent with other reported findings, but it does not rule out other causes of exertional myocardial ischaemia. Other confounding factors in our study are the possibility of some true cases being missed owing to false-negative exercise test results or to inappropriate coding of questionnaires. Both of these factors would tend to cause underestimation of the potential for questionnaires in identification of coronary heart disease. Increased emphasis is being placed on secondary prevention of coronary heart disease, which by definition involves treatment of known myocardial ischaemia. We have shown that the use of questionnaires is a potentially useful strategy to maximise the reach and benefit of secondary preventive treatment. Our results suggest that use of a simple selfadministered questionnaire is an effective and cost-efficient method of identifylng persons at high risk of unrecognised coronary heart disease. It appears to be a useful means of looking beyond classical risk-factor levels for identifymg patients arbitrarily classified as at low risk but who warrant further cardiological assessment. Acknowledgments This study was funded in its entirety by a grant from the Victorian Health Promotion Foundation.

Journal

Australian and New Zealand Journal of Public HealthWiley

Published: Aug 1, 1997

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