Hooi Min Lim

Validation of the Framingham general cardiovascular risk score in a multiethnic Asian population: a retrospective cohort study

Objective This study aims to examine the validity of the Framingham general cardiovascular disease (CVD) risk chart in a primary care setting. Design This is a 10-year retrospective cohort study. Setting A primary care clinic in a teaching hospital in Malaysia. Participants 967 patients’ records were randomly selected from patients who were attending follow-up in the clinic. Main outcome measures Baseline demographic data, history of diabetes and smoking, blood pressure (BP), and serum lipids were captured from patient records in 1998. Each patients Framingham CVD score was computed from these parameters. All atherosclerotic CVD events occurring between 1998 and 2007 were counted. Results In 1998, mean age was 57 years with 33.8% men, 6.1% smokers, 43.3% diabetics and 59.7% hypertensive. Median BP was 140/80 mm Hg and total cholesterol 6.0 mmol/L (1.3). The predicted median Framingham general CVD risk score for the study population was 21.5% (IQR 1.2–30.0) while the actual CVD events that occurred in the 10 years was 13.1% (127/967). The median CVD points for men was 30.0, giving them a CVD risk of more than 30%; for women it is 18.5, a CVD risk of 21.5%. Our study found that the Framingham general CVD risk score to have moderate discrimination with an area under the receiver operating characteristic curve (AUC) of 0.63. It also discriminates well for Malay (AUC 0.65, p=0.01), Chinese (AUC 0.60, p=0.03), and Indians (AUC 0.65, p=0.001). There was good calibration with Hosmer-Lemeshow test χ2=3.25, p=0.78. Conclusions Taking into account that this cohort of patients were already on treatment, the Framingham General CVD Risk Prediction Score predicts fairly accurately for men and overestimates somewhat for women. In the absence of local risk prediction charts, the Framingham general CVD risk prediction chart is a reasonable alternative for use in a multiethnic group in a primary care setting.

Long‐Term Visit‐to‐Visit Blood Pressure Variability and Renal Function Decline in Patients With Hypertension Over 15 Years

Background Visit‐to‐visit variability of systolic blood pressure (SBP) has been shown to contribute to cardiovascular events and all‐cause mortality. However, little is known about its long‐term effect on renal function. We aim to examine the relationship between visit‐to‐visit blood pressure variability (BPV) and decline in renal function in patients with hypertension and to determine the level of systolic BPV that is associated with significant renal function decline. Methods and Results This is a 15‐year retrospective cohort study of 825 hypertensive patients. Blood pressure readings every 3 months were retrieved from the 15 years of clinic visits. We used SD and coefficient of variation as a measure of systolic BPV. Serum creatinine was captured and estimated glomerular filtration rate was calculated at baseline, 5, 10, and 15 years. The mean SD of SBP was 14.2±3.1 mm Hg and coefficient of variation of SBP was 10.2±2%. Mean for estimated glomerular filtration rate slope was −1.0±1.5 mL/min per 1.73 m2 per year. There was a significant relationship between BPV and slope of estimated glomerular filtration rate (SD: r=−0.16, P<0.001; coefficient of variation: r=−0.14, P<0.001, Pearsons correlation). BPV of SBP for each individual was significantly associated with slope of estimated glomerular filtration rate after adjustment for mean SBP and other confounders. The cutoff values estimated by the receiver operating characteristic curve for the onset of chronic kidney disease for SD of SBP was 13.5 mm Hg and coefficient of variation of SBP was 9.74%. Conclusions Long‐term visit‐to‐visit variability of SBP is an independent determinant of renal deterioration in patients with hypertension. Hence, every effort should be made to reduce BPV in order to slow down the decline of renal function.

Does use of pooled cohort risk score overestimate the use of statin?: a retrospective cohort study in a primary care setting

BackgroundInitiation of statin therapy as primary prevention particularly in those with mildly elevated cardiovascular disease risk factors is still being debated. The 2013 ACC/AHA blood cholesterol guideline recommends initiation of statin by estimating the 10-year atherosclerotic cardiovascular disease (ASCVD) risk using the new pooled cohort risk score. This paper examines the use of the pooled cohort risk score and compares it to actual use of statins in daily clinical practice in a primary care setting.MethodsWe examined the use of statins in a randomly selected sample of patients in a primary care clinic. The demographic data and cardiovascular risk parameters were captured from patient records in 1998. The pooled cohort risk score was calculated based on the parameters in 1998. The use of statins in 1998 and 2007, a 10-year interval, was recorded.ResultsA total of 847 patients were entered into the analysis. Mean age of the patients was 57.2 ± 8.4 years and 33.1% were male. The use of statins in 1998 was only 10.2% (n = 86) as compared to 67.5% (n = 572) in 2007. For patients with LDL 70-189 mg/dl and estimated 10-year ASCVD risk ≥7.5% (n = 190), 60% (n = 114) of patients were on statin therapy by 2007. There were 124 patients in whom statin therapy was not recommended according to ACC/AHA guideline but were actually receiving statin therapy.ConclusionsAn extra 40% of patients need to be treated with statin if the 2013 ACC/AHA blood cholesterol guideline is used. However the absolute number of patients who needed to be treated based on the ACC/AHA guideline is lower than the number of patients actually receiving it in a daily clinical practice. The pooled cohort risk score does not increase the absolute number of patients who are actually treated with statins. However these findings and the use of the pooled cohort risk score need to be validated further.

Use of Chronic Kidney Disease to Enhance Prediction of Cardiovascular Risk in Those at Medium Risk.

Based on global cardiovascular (CV) risk assessment for example using the Framingham risk score, it is recommended that those with high risk should be treated and those with low risk should not be treated. The recommendation for those of medium risk is less clear and uncertain. We aimed to determine whether factoring in chronic kidney disease (CKD) will improve CV risk prediction in those with medium risk. This is a 10-year retrospective cohort study of 905 subjects in a primary care clinic setting. Baseline CV risk profile and serum creatinine in 1998 were captured from patients record. Framingham general cardiovascular disease risk score (FRS) for each patient was computed. All cardiovascular disease (CVD) events from 1998–2007 were captured. Overall, patients with CKD had higher FRS risk score (25.9% vs 20%, p = 0.001) and more CVD events (22.3% vs 11.9%, p = 0.002) over a 10-year period compared to patients without CKD. In patients with medium CV risk, there was no significant difference in the FRS score among those with and without CKD (14.4% vs 14.6%, p = 0.84) However, in this same medium risk group, patients with CKD had more CV events compared to those without CKD (26.7% vs 6.6%, p = 0.005). This is in contrast to patients in the low and high risk group where there was no difference in CVD events whether these patients had or did not have CKD. There were more CV events in the Framingham medium risk group when they also had CKD compared those in the same risk group without CKD. Hence factoring in CKD for those with medium risk helps to further stratify and identify those who are actually at greater risk, when treatment may be more likely to be indicated.

Visit-to-visit SBP variability and cardiovascular disease in a multiethnic primary care setting: 10-year retrospective cohort study

Objectives: The current study aims to determine the relationship of long-term visit-to-visit variability of SBP to cardiovascular disease (CVD) in a multiethnic primary care setting. Method: This is a retrospective study of a cohort of 807 hypertensive patients over a period of 10 years. Three-monthly clinic blood pressure readings were used to derive blood pressure variability (BPV), and CVD events were captured from patient records. Results: Mean age at baseline was 57.2 ± 9.8 years with 63.3% being women. The BPV and mean SBP over 10 years were 14.7 ± 3.5 and 142 ± 8 mmHg, respectively. Prevalence of cardiovascular event was 13%. In multivariate logistic regression analysis, BPV was the predictor of CVD events, whereas the mean SBP was not independently associated with cardiovascular events in this population. Those with lower SBP and lower BPV had fewer cardiovascular events than those with the same low mean SBP but higher BPV (10.5 versus 12.8%). Similarly those with higher mean SBP but lower BPV also had fewer cardiovascular events than those with the same high mean and higher BPV (11.6 versus 16.7%). Other variables like being men, diabetes and Indian compared with Chinese are more likely to be associated with cardiovascular events. Conclusion: BPV is associated with an increase in CVD events even in those who have achieved lower mean SBP. Thus, we should prioritize not only control of SBP levels but also BPV to reduce CVD events further.

OS 04-05 LONG TERM VISIT-TO-VISIT VARIABILITY OF SYSTOLIC BLOOD PRESSURE AND CARDIOVASCULAR DISEASE EVENTS IN A PRIMARY CARE SETTING: A 10-YEAR RETROSPECTIVE COHORT STUDY

Objective : This study aims to determine the relationship of long term visit to visit variability (VVV) of SBP and cardiovascular disease (CVD) in a primary care setting. Design and method : This is a retrospective study of a cohort of 1416 patients over a period of 10 years (1998–2007). Demographic data, three monthly clinic BP readings and CVD events were captured from patient records. We derived the mean BP and VVV of SBPs for each subject and divided them into three groups defined as non hypertension, developed hypertension along the 10-year follow-up and persistent hypertension. We examined differences in cardiovascular events across these groups. Results : Mean age of the participants at baseline was 56.5 ± 10.1 years, 34.6% were males. Table 1 describes mean SBP, BPV and CVD events of the study population. Those with both low mean SBP and low BPV have the lowest CVD events, conversely those with both high mean SBP and high BPV have highest CVD events. In those patients with the same mean SBP, whether high or low, those with higher BPV have more events than those with lower BPV. However patients with low mean SBP but high BPV have more CVD events compared with those patients with high mean SBP but low BPV (p = 0.04) suggesting BPV is more important than mean SBP in causing CVD events. We used ROC of VVV SBP to identify the cut off point of 12.9 mmHg as the indicator for increase in CVD events. Conclusions: In our study, we found that patients with hypertension have higher BPV than normotensive subjects. Furthermore those with higher BPV also had more CVD events. As such, we should prioritize lowering not only mean systolic BP but lowering BPV as well. Long term VVV SBP should be another target in the management of patients with hypertension.

PS 08-50 BLOOD PRESSURE LEVELS AND DECLINE IN RENAL FUNCTION AMONG PATIENTS WITH TREATED HYPERTENSION: A 15-YEAR RETROSPECTIVE STUDY.

Objective: We aimed to determine the association between office systolic and diastolic blood pressure (SBP and DBP) levels and further decline in renal function among treated hypertensive patients over short and long term periods. Design and Method: This is a retrospective study of 904 treated hypertensive patients over a 15 year period in a primary care clinic. We calculated the rate of annual decline in renal function using estimated glomerular filtration rate (&Dgr;eGFR). We defined a rate of &Dgr;eGFR ≥ 0 ml/year as renal decline and rate of decline of &Dgr;eGFR <0 ml/year as no decline in renal function, at 5 years, 10 years, and 15years of follow-up. We classified mean BPs into mean SBP < 120, 120–139 and ≥ 140 mmHg and mean DBP to < 80, 81–89 and ≥ 90 mmHg. Ethics approval was obtained. Chi square was used to show the association. Results: At baseline, mean age of patients was 56.0±9.4 years and 2/3 was female. Mean SBP at 5, 10 and 15 years were 141 ± 11 mmHg, 139 ± 9 mmHg and 138 ± 8 mmHg. Mean DBP at 5, 10 and 15 years were 84 ± 5 mmHg, 83 ± 5 mmHg and 81 ± 4 mmHg respectively. Median annual decline of eGFR at 5, 10 and 15 years were -1.2, -0.6 and −0.9 ml/min per 1.73 m2 per year. There is a positive relationship between mean SBP and deterioration of renal function at 10 years (p = 0.001) and at 15 years (p = 0.007) follow-up. All DBP readings and mean SBP in 5 years did not influence the decline in renal function. Conclusions: Our study demonstrated that mean SBP in long term but not SBP in short term is an independent determinant for decline in renal function among treated hypertensive patients. This would suggest that any benefit of treating hypertension and slowing the rate of decline of renal function requires long term therapy.

OS 37-05 LONG-TERM VISIT-TO-VISIT VARIABILITY OF SYSTOLIC BLOOD PRESSURE AND DECLINE IN RENAL FUNCTION IN HYPERTENSIVE PATIENTS OVER 15 YEARS.

Objective: We aim to examine the relationship between visit-to-visit systolic blood pressure variability (BPV) and decline in renal function in patients with hypertension and determine the level of systolic BPV that contribute to significant renal function decline. Design and Method: This is a 15-year (1998–2012) retrospective cohort study of 825 hypertensive patients with normal renal function at baseline in a primary care clinic. Three monthly blood pressure readings per year were retrieved from the 15 years of clinic visits. We used standard deviation (SD) and coefficient of variation (CV) as measures of systolic BPV. Serum creatinine was captured and eGFR was calculated at baseline, 5-year, 10-year and 15-year. Rate of renal function decline was estimated by fitting a linear regression line through the eGFR measurements for each individual patient and expressed as eGFR slope. Results: A total of 825 hypertensive patients with 15-year of clinic follow up were entered into analysis. The mean SD of SBP was 14.2 ± 3.1mmHg and CV of SBP was 10.2 ± 2.0%. Mean for eGFR slope was −1.0 ± 1.5 ml/min/1.73m2/year. There was significant relationship between BPV and slope of eGFR (SD of SBP r = −0.16, p < 0.001; CV of SBP r = −0.14, p < 0.001, using Pearsons correlation). BPV of SBP for each individual was significantly associated with eGFR slope after adjustment for mean SBP and other confounders. Using receiver operating characteristics curve (ROC) and maximum Youden index, the cutoff values as indicator for the onset of CKD for SD of SBP was 13.5mmHg (sensitivity 69%, specificity 50%) and CV of SBP was 9.74% (sensitivity 68%, specificity 48%). Conclusions: Our study has demonstrated that long-term visit-to-visit variability of SBP is an independent determinant of renal deterioration in patients with hypertension. Hence, every effort should be made to reduce the BPV in order to slow down the decline of renal function in patients with hypertension.

OS 14-04 NUMBER OF BLOOD PRESSURE MEASUREMENTS NEEDED TO ESTIMATE LONG TERM VISIT-TO-VISIT SYSTOLIC BLOOD PRESSURE VARIABILITY FOR PREDICTING 10-YEAR CARDIOVASCULAR RISK.

Objective: To determine the minimum number and duration of blood pressure(BP) measurement needed to estimate long term visit-to-visit blood pressure variability (BPV) for predicting 10-year cardiovascular (CV) risk. Design and Method: This is a 10-year retrospective cohort study of 1403 patients from a primary care clinic. Three monthly BP readings per year were retrieved from 10 years of clinic visits. Standard deviation (SD) of systolic blood pressure (SBP) was used as a measure of BPV. SD was calculated for each cumulative year of readings. CV events defined as fatal and nonfatal coronary heart disease and fatal and nonfatal stroke. We used Pearsons correlation to examine the concordance between the SD of each additional year of follow-up and SD at the end of 10 years. Multiple logistic regression was used to estimate the CV risk and compare the odd ratio (OR) between 10-year SD and SD of each additional year of follow-up. Results: Mean SD increased with more SBP measurements for each increasing year. Pearsons correlation increased with the years of SBP measurements indicating increasing concordance with 10-year SD when more years of SBP readings was included from the baseline. With 10-year SD, the OR for CV risk was associated with an increase in SD (OR 1.121, 95% CI 1.057–1.188, p < 0.001) after adjusting for age, sex, race, smoking, diabetes mellitus, hypertension, HbA1c, total cholesterol and LDL cholesterol. Fewer years of SBP readings led to smaller ORs and, consequently, a weaker association between SD and 10-year CV risk. However, the ORs remained significant even with only 5-year of SBP measurements (adjusted OR 1.062 95% CI 1.009–1.117, p = 0.021). Conclusions: Repeated BP measurements over a period of 5 years is sufficient to determine the long term visit-to-visit systolic BPV to predict the 10-year CV risk. Number and duration of BP readings to derive BPV should be taken into consideration when predicting long-term CV risk.