Prediction of Cardiovascular Disease Mortality in a Middle Eastern Country: Performance of the Globorisk and Score Functions in Four Population-Based Cohort Studies of Iran.

BACKGROUND: Considering the importance of cardiovascular disease (CVD) risk prediction for healthcare systems and the limited information available in the Middle East, we evaluated the SCORE and Globorisk models to predict CVD death in a country of this region. METHODS: We included 24 427 participants (11 187 men) aged 40-80 years from four population-based cohorts in Iran. Updating approaches were used to recalibrate the baseline survival and the overall effect of the predictors of the models. We assessed the models' discrimination using C-index and then compared the observed with the predicted risk of death using calibration plots. The sensitivity and specificity of the models were estimated at the risk thresholds of 3%, 5%, 7%, and 10%. An agreement between models was assessed using the intra-class correlation coefficient (ICC). We applied decision analysis to provide perception into the consequences of using the models in general practice; for this reason, the clinical usefulness of the models was assessed using the net benefit (NB) and decision curve analysis. The NB is a sensitivity penalized by a weighted false positive (FP) rate in population level. RESULTS: After 154 522 person-years of follow-up, 437 cardiovascular deaths (280 men) occurred. The 10-year observed risks were 4.2% (95% CI: 3.7%-4.8%) in men and 2.1% (1.8-2%.5%) in women. The c-index for SCORE function was 0.784 (0.756-0.812) in men and 0.780 (0.744-0.815) in women. Corresponding values for Globorisk were 0.793 (0.766- 0.820) and 0.793 (0.757-0.829). The deviation of the calibration slopes from one reflected a need for recalibration; after which, the predicted-to-observed ratio for both models was 1.02 in men and 0.95 in women. Models showed good agreement (ICC 0.93 in men, and 0.89 in women). Decision curve showed that using both models results in the same clinical usefulness at the risk threshold of 5%, in both men and women; however, at the risk threshold of 10%, Globorisk had better clinical usefulness in women (Difference: 8%, 95% CI: 4%-13%). CONCLUSION: Original Globorisk and SCORE models overestimate the CVD risk in Iranian populations resulting in a high number of people who need intervention. Recalibration could adopt these models to precisely predict CVD mortality. Globorisk showed better performance clinically, only among high-risk women.

An office-based cardiovascular prediction model developed and validated in cohort studies of a middle-income country.

OBJECTIVE: Prediction models for cardiovascular disease (CVD) mortality come from high-income countries, comprising laboratory measurements, not suitable for resource-limited countries. This study aims to develop and validate a non-laboratory model to predict CVD mortality in a middle-income setting. STUDY DESIGN AND SETTING: We used data of population aged 40-80 years from three cohort studies: Tehran Lipid and Glucose Study (n = 5160), Isfahan Cohort Study (n = 4350), and Golestan Cohort Study (n = 45,500). Using Cox proportional hazard models, we developed prediction models for men and women, separately. Cross-validation and bootstrapping procedures were applied. The models' discrimination and calibration were assessed by concordance statistic (C-index) and calibration plot, respectively. We calculated the models' sensitivity, specificity and net benefit fraction in a threshold probability of 5%. RESULTS: The 10-year CVD mortality risks were 5.1% (95%CI: 4.8-5.5) in men and 3.1% (95%CI: 2.9%-3.3%) in women. The optimism-corrected performance of the model was c = 0.774 in men and c = 0.798 in women. The models showed good calibration in both sexes, with a predicted-to-observed ratio of 1.07 in men and 1.09 in women. The sensitivity was 0.76 in men and 0.66 in women. The net benefit fraction was higher in men compared to women (0.46 vs. 0.35). CONCLUSION: A low-cost model can discriminate well between low- and high-risk individuals, and can be used for screening in low-middle income countries.

Effect of long-term exposure to ambient particulate matter on prevalence of type 2 diabetes and hypertension in Iranian adults: an ecologic study.

Air pollution is considered as an environmental risk to health worldwide. Current evidence is mostly from Western populations exposed to lower levels of pollutants. This study was to explore the association of type 2 diabetes (T2D) and hypertension prevalence with exposure to high levels of air pollution in Iranian adults. The air pollution data were obtained from the air quality monitoring stations of five large cities in Iran from 2006 to 2011. The air quality monitoring stations could only detect ambient particulate matter_10 (PM10) during the study period; therefore, the average PM10 concentration was considered for comparison. We grouped the cities as group 1 (Tehran, Shiraz) with PM10 concentration < 100 µg/m3, and group 2 (Kermanshah, Ahwaz, Esfahan) with PM10 concentration > 100 µg/m3. Data from the Surveillance of Risk Factors of Non-Communicable Disease (SuRFNCD) study were used to calculate the prevalence of T2D and hypertension. We assessed the association between air pollution and the prevalence of T2D using logistic regression models. Odds ratios (ORs) with 95% CI for each outcome were calculated after adjusting for age, sex, BMI, physical activity, and other covariates. The 5-year average of PM10 concentration was higher in group 2 (120.15 ± 6.81 µg/m3) compared to group 1 (83.95 ± 7.81 µg/m3). The prevalence of T2D in group 2 was 13.8%, while it was 10.7% in group 1 (p = 0.01), OR = 1.32 (95% CI 1.03-1.69). Similarly, hypertension was more prevalent in group 2 (15.7 vs. 11.9%, p = 0.005, OR = 1.55, 95% CI 1.20-1.99). PM10 is associated with higher prevalence of T2D and hypertension in Iranian adults.

Prevalence of Metabolic Syndrome and Its Components in the Iranian Adult Population: A Systematic Review and Meta-Analysis.

CONTEXT: Metabolic syndrome (MetS) increases the risk of most non-communicable diseases; gathering information about its prevalence can be very effective in formulating preventive strategies for metabolic diseases. There are many different studies about the prevalence of MetS in Iran, but the results and the study populations of these studies are very different; therefore, it is very important to have an overall estimation of its prevalence in Iran. OBJECTIVES: This study systematically reviewed the findings of all available studies on MetS in the adult Iranian population and estimated the overall prevalence of MetS in this population. DATA SOURCES: International databases (Scopus, ISI Web of Science, and PubMed) were searched for papers published from January, 2000 to December, 2013 using medical subject headings (MeSH), Emtree, and related keywords (metabolic syndrome, dysmetabolic syndrome, cardiovascular syndrome, and insulin resistance syndrome) combined with the words "prevalence" and "Iran." The Farsi equivalent of these terms and all probable combinations were used to search Persian national databases (IranMedex, Magiran, SID, and Irandoc). STUDY SELECTION: All population-based studies and national surveys that reported the prevalence of MetS in healthy Iranian adults were included. DATA EXTRACTION: After quality assessment, data were extracted according to a standard protocol. Because of between-study heterogeneity, data were analyzed by the random effect method. RESULTS: We recruited the data of 27 local studies and one national study. The overall estimation of MetS prevalence was 36.9% (95% CI: 32.7 - 41.2%) based on the Adult Treatment Panel III (ATP III) criteria, 34.6% (95% CI: 31.7 - 37.6%) according to the International Diabetes Federation (IDF), and 41.5% (95% CI: 29.8 - 53.2%) based on the Joint Interim Societies (JIS) criteria. The prevalence of MetS determined by JIS was significantly higher than those determined by ATP III and IDF. The prevalence of MetS was 15.4% lower in men than in women (27.7% versus 43.1%) based on the ATP III criteria, and it was 11.3% lower in men based on the IDF criteria; however according to the JIS criteria, it was 8.4% more prevalent in men. CONCLUSIONS: There is a high prevalence of MetS in the Iranian adult population, with large variations based on different measurement criteria. Therefore, prevention and control of MetS should be considered a priority.

Prevalence of dyslipidemia in iran: a systematic review and meta-analysis study.

More than 80% cardiovascular disease (CVD) is preventable despite the fact that it is currently the ultimate cause of disability in the world. Assessment of the nationwide prevalence of dyslipidemia as a major CVD risk factor is essential to efficiently conduct prevention programs. We extracted data according to the cut-off points of dyslipidemia used in each study. All published papers on this topic in Iranian and international journals with affiliation of "Iran" were reviewed using standard keywords up to September 2011. We included all available population-based studies and national surveys conducted in individuals aged ≥ 15 years. We excluded studies with < 300 individuals, non-population-based studies, or duplicated citations. We analyzed by random effect method due to between-study heterogeneity. The estimated prevalence and 95% confidence intervals in 29 eligible articles and one un-published data for hypercholesterolemia (≥200 mg/dl), hypertriglyceridemia (≥150 mg/dl), high levels of low density lipoprotein cholesterol ([LDL-C] [≥ 130 mg/dl]) and low levels of high density lipoprotein cholesterol ([HDL-C] <40 mg/dl in males, <50 mg/dl in females), in Iranian people were 41.6% (36.1-47.0), 46.0% (43.3-48.7), 35.5% (24.0-47.1) and 43.9% (33.4-54.4), respectively among both sexes and in both rural and urban areas. Hypercholesterolemia, high LDL-C and low HDL-C were more prevalent in women, whereas hypertriglyceridemia was more prevalent in men. All types of lipid component abnormalities were more prevalent in urban residents. Prevalence of dyslipidemia is considerable in Iran. It is necessary to enforce current measures of dyslipidemia control in the Iranian people to reduce CVD burden.