Comparison of the Diagnostic Accuracy and Cost-Effectiveness of Various Screening Tools on Projected Intermediate-to-High Cardiovascular Risk
Date Issued
2011
Date
2011
Author(s)
Hung, Chung-Lieh
Abstract
Abstract
Background Owing to the high costs spent annually in cardiovascular diseases, there is an urgent need in identifying subjects at an early stage based on view point of preventive medicine. The development of a cost-effective screening tool with adequate diagnostic accuracy is thus crucial. Goals To investigate the diagnostic accuracy and cost-effectiveness of various cardiovascular screening tools in the estimation of intermediate-to-high risk Framingham risk score (FRS) subjects in asymptomatic population. Materials and Methods We consecutively studied 1200 asymptomatic subjects who underwent health evaluation from 2005-2009. FRS was calculated in all participants based on age, gender, blood pressure, body surface electrocardiography, medical histories, life styles and lipid profiles. We also assessed metabolic scores by additional anthropometric information. Data regarding high-sensitivity C reactive protein (Hs-CRP) serum level and carotid artery Doppler in assessing intima-media-thickness (IMT) and plaque existence were also obtained and correlated with FRS. Diagnostic accuracy and cost-effectiveness analysis were then conducted among these different tools aiming at a more efficient screen of intermediate-to-high Framingham risk population. Results Of all, totally 1101 participants (mean age: 50.6 ± 10.4, 38.6% women) were finally entered in our study. Higher Framingham risk score was associated with higher metabolic risk scores, higher prevalence of metabolic syndrome, elevated level of Hs-CRP, higher IMT thickness and higher prevalence of carotid artery plaque existence (all p<0.001 by linear regression or chi square test). In general, male had higher FRS than female gender, as well as higher metabolic risks scores, larger IMT (all p<0.001) though similar prevalence of carotid artery plaques (p=0.134). There was no gender-related difference in Hs-CRP level (p=0.15). By using metabolic score equal or larger than 1 as a cut-off, there seemed to be a very high sensitivity (94.43%, 95% CI: 92.05 - 96.27) in identifying a subject with intermediate-to-high Framingham risk score while the best specificity (98.27, 95% CI: 97.24 - 98.99) was achieved by utilizing carotid IMT equal or larger than 1mm as a cut-off. In addition, a metabolic score cut-off of 2, Hs-CRP of 0.101mg/dL and IMT of 0.65mm seemed to have the highest sum of both sensitivity and specificity. Compared to carotid artery study and metabolic score calculation, Hs-CRP with a cut-off value 0.1 seemed to have lowest cost (1519.3 NTD) in identifying an intermediate-to-high Framingham risk subject with highest screening cost occurred (62222.2 NTD) per positive case by simply using carotid echo-defined abnormal IMT (>=1mm). Conclusion Though diagnostic accuracy may differ to some degree by using different cut-off values in various studies, a low metabolic score has the best sensitivity with abnormal IMT had highest specificity in screening a subject at risk for future cardiovascular diseases. In addition, setting a low Hs-CRP serum level seemed to have the best cost-effectiveness in asymptomatic population.
Background Owing to the high costs spent annually in cardiovascular diseases, there is an urgent need in identifying subjects at an early stage based on view point of preventive medicine. The development of a cost-effective screening tool with adequate diagnostic accuracy is thus crucial. Goals To investigate the diagnostic accuracy and cost-effectiveness of various cardiovascular screening tools in the estimation of intermediate-to-high risk Framingham risk score (FRS) subjects in asymptomatic population. Materials and Methods We consecutively studied 1200 asymptomatic subjects who underwent health evaluation from 2005-2009. FRS was calculated in all participants based on age, gender, blood pressure, body surface electrocardiography, medical histories, life styles and lipid profiles. We also assessed metabolic scores by additional anthropometric information. Data regarding high-sensitivity C reactive protein (Hs-CRP) serum level and carotid artery Doppler in assessing intima-media-thickness (IMT) and plaque existence were also obtained and correlated with FRS. Diagnostic accuracy and cost-effectiveness analysis were then conducted among these different tools aiming at a more efficient screen of intermediate-to-high Framingham risk population. Results Of all, totally 1101 participants (mean age: 50.6 ± 10.4, 38.6% women) were finally entered in our study. Higher Framingham risk score was associated with higher metabolic risk scores, higher prevalence of metabolic syndrome, elevated level of Hs-CRP, higher IMT thickness and higher prevalence of carotid artery plaque existence (all p<0.001 by linear regression or chi square test). In general, male had higher FRS than female gender, as well as higher metabolic risks scores, larger IMT (all p<0.001) though similar prevalence of carotid artery plaques (p=0.134). There was no gender-related difference in Hs-CRP level (p=0.15). By using metabolic score equal or larger than 1 as a cut-off, there seemed to be a very high sensitivity (94.43%, 95% CI: 92.05 - 96.27) in identifying a subject with intermediate-to-high Framingham risk score while the best specificity (98.27, 95% CI: 97.24 - 98.99) was achieved by utilizing carotid IMT equal or larger than 1mm as a cut-off. In addition, a metabolic score cut-off of 2, Hs-CRP of 0.101mg/dL and IMT of 0.65mm seemed to have the highest sum of both sensitivity and specificity. Compared to carotid artery study and metabolic score calculation, Hs-CRP with a cut-off value 0.1 seemed to have lowest cost (1519.3 NTD) in identifying an intermediate-to-high Framingham risk subject with highest screening cost occurred (62222.2 NTD) per positive case by simply using carotid echo-defined abnormal IMT (>=1mm). Conclusion Though diagnostic accuracy may differ to some degree by using different cut-off values in various studies, a low metabolic score has the best sensitivity with abnormal IMT had highest specificity in screening a subject at risk for future cardiovascular diseases. In addition, setting a low Hs-CRP serum level seemed to have the best cost-effectiveness in asymptomatic population.
Subjects
Cardiovascular disease
Framingham risk score
metabolic risk score
biomarker
Carotid artery study
diagnostic accuracy
cost-effectiveness
SDGs
Type
thesis
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