title: Comparative assessment of absolute cardiovascular disease risk characterization from non-laboratory-based risk assessment in South African populations.
abstract: BACKGROUND
  All rigorous primary cardiovascular disease (CVD) prevention guidelines recommend absolute CVD risk scores to identify high- and low-risk patients, but laboratory testing can be impractical in low- and middle-income countries. The purpose of this study was to compare the ranking performance of a simple, non-laboratory-based risk score to laboratory-based scores in various South African populations.
  
  
  METHODS
  We calculated and compared 10-year CVD (or coronary heart disease (CHD)) risk for 14,772 adults from thirteen cross-sectional South African populations (data collected from 1987 to 2009). Risk characterization performance for the non-laboratory-based score was assessed by comparing rankings of risk with six laboratory-based scores (three versions of Framingham risk, SCORE for high- and low-risk countries, and CUORE) using Spearman rank correlation and percent of population equivalently characterized as 'high' or 'low' risk. Total 10-year non-laboratory-based risk of CVD death was also calculated for a representative cross-section from the 1998 South African Demographic Health Survey (DHS, n = 9,379) to estimate the national burden of CVD mortality risk.
  
  
  RESULTS
  Spearman correlation coefficients for the non-laboratory-based score with the laboratory-based scores ranged from 0.88 to 0.986. Using conventional thresholds for CVD risk (10% to 20% 10-year CVD risk), 90% to 92% of men and 94% to 97% of women were equivalently characterized as 'high' or 'low' risk using the non-laboratory-based and Framingham (2008) CVD risk score. These results were robust across the six risk scores evaluated and the thirteen cross-sectional datasets, with few exceptions (lower agreement between the non-laboratory-based and Framingham (1991) CHD risk scores). Approximately 18% of adults in the DHS population were characterized as 'high CVD risk' (10-year CVD death risk >20%) using the non-laboratory-based score.
  
  
  CONCLUSIONS
  We found a high level of correlation between a simple, non-laboratory-based CVD risk score and commonly-used laboratory-based risk scores. The burden of CVD mortality risk was high for men and women in South Africa. The policy and clinical implications are that fast, low-cost screening tools can lead to similar risk assessment results compared to time- and resource-intensive approaches. Until setting-specific cohort studies can derive and validate country-specific risk scores, non-laboratory-based CVD risk assessment could be an effective and efficient primary CVD screening approach in South Africa.
authors.affiliation: Divisions of Cardiovascular Medicine, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA. tgaziano@partners.org
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Gaziano
authors.forename: Ankur
authors.initials: A
authors.lastname: Pandya
authors.forename: Krisela
authors.initials: K
authors.lastname: Steyn
authors.forename: Naomi
authors.initials: N
authors.lastname: Levitt
authors.forename: Willie
authors.initials: W
authors.lastname: Mollentze
authors.forename: Gina
authors.initials: G
authors.lastname: Joubert
authors.forename: Corinna M
authors.initials: CM
authors.lastname: Walsh
authors.forename: Ayesha A
authors.initials: AA
authors.lastname: Motala
authors.forename: Annamarie
authors.initials: A
authors.lastname: Kruger
authors.forename: Aletta E
authors.initials: AE
authors.lastname: Schutte
authors.forename: Datshana P
authors.initials: DP
authors.lastname: Naidoo
authors.forename: Dorcas R
authors.initials: DR
authors.lastname: Prakaschandra
authors.forename: Ria
authors.initials: R
authors.lastname: Laubscher
mesh_terms: D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000208:ethnology* / Q000628:therapy; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods*; D018570:Risk Assessment; D013019:South Africa / Q000208:ethnology