Cardiovascular disease (CVD) had become a leading cause of death among people in developing countries including Thai military officers. No long term data on preventing CVD events in this group had been published before. Thus, our main study purposes were to identify the target individuals who carried the substantial risk of developing CVD event and prevent them in advance.
After approved by the ethics committee and medical organization of Chandrubeksa hospital in 2006, all in service officers (aged of 35-60 years) who undergone annual screening, were voluntarily enrolled. We excluded officers who were beyond this age range, not willing to participate or already had CVD. To predict the 10-yr risk of developing CVD events, we used the modified Coronary Risk Chart (mCRC) to classify asymptomatic Air Force officers into three groups; the low, intermediate and the high risk candidates, according to the predicted cardiovascular risk of < 9.9%, 10-19.9% and > 20% respectively. For all participants, life-style modifications was given, but medication and further screening with exercise stress test were provided only in the intermediate and high risk groups. All subjects were followed from 2006-2016 by an annual physical check-up. After ten years, the clinical outcomes (acute coronary syndrome, stroke, total death and composite events) were compared between the three groups.
Of total 410 asymptomatic cases, 85.4% were men and had a mean age of 50.9 ± 6.1 years. During 10-yr follow-up, we were able to track the health status of all participants. There was total of 52 events, with only 5 events (5.7%) occurring in the low risk group (including one ACS, one ischemic stroke and 3 non-CVD deaths). In contradiction, 47 clinical events (14.6%, p = 0.026 for comparison with the low risk group) were observed in the combined intermediate and high risk groups (including 7 non-fatal ACS, 10 ischemic strokes, 2 CVD and 28 non-CVD deaths). Both ACS and stroke occurred less frequently than predicted rate and no statistical different of actual events was noted in each assigned risk group. The incidence of ACS and stroke among the low, intermediate and high risk candidates were 1.1%, 1.1% and 3.8% and 1.1%, 4.2% and 1.5% respectively. The mean time from entering the registry to the occurrence of an ACS was 4.9 years and the mean age of ACS cases was 55.1 years. Stroke was observed 7.1 years on average after entering the registry. All of strokes were ischemic in origin and the mean age of stroke cases was 61.4 years. A total of 33 deaths (8%) occurred 3.4%, 7.9% and 11.3% among the low, intermediate and high risk individuals. Death occurred after on average 6.7 years at a mean age was 59.4 years. The CVD death was very low (6%), each of them were from STE-ACS and stroke. The non-cardiovascular death was 31 cases (94%). The common causes were cancer (n = 12), cirrhosis (n = 6), accident and drowning (n = 6). The death rate and composite outcome of ACS , stroke or death were signifcantly higher in the highest risk group when compared with those of the low risk candidates: relative risk of 3.6 (95%CI: 1-12.8), p = 0.04 and 3.3(95%CI:1.2-9.0), p = 0.016, respectively.
By using the mCRC (available at www.thaiafheart.com), prediction and reduction of CVD events in asymptomatic officers were feasible. The observed ACS and stroke rate were > 50% lower than the predicted one and no statistically significance was found among the three risk groups. Progression to ACS or stroke was observed also in non-high risk cases. We therefore recommend re-assessing CV risk every 3-year and re-emphasizing the importance of CV preventive measures. While the ACS and stroke rates were lower than expected, we observed the high rate of non-CVD death which was significantly increased in the high-risk group. This group of individuals should be targeted for further preventive measures related e.g. smoking and alcohol consumption.