Screening for Cardiovascular Risk and Diabetes in Primary Health Care : The Söderåkra Risk Factor Screening Study

Abstract: Background: Cardiovascular disease (CVD) has been the predominant cause of morbidity and mortality for many decades in Sweden. Preventive work in primary health care through individual approach and community-based programmes has shown some success. Still, we need better risk assessment tools and health strategies to lessen the burden of CVD in our population.Methods: This thesis is based on four studies that explore the cardiovascular risk factor pattern and its development to CVD morbidity and mortality in the middle-aged (40-59 years) population in Söderåkra, southern Sweden, 1989-2006. At a single physician consultation in 1989-1990 the participants provided information about lifestyle in a self-administered questionnaire, underwent a physical examination and received medical advice after a laboratory investigation. The laboratory tests consisted mainly of blood glucose, serum lipids and thyroid function tests. Blood samples were also frozen for later analyses. A telephone interview on self-reported lifestyle changes was conducted ten years later. In 2006, primary health care medical records were studied for incident diabetes and also for impaired glucose tolerance (IGT). Finally, national registers were studied for incident fatal or nonfatal cardiovascular disease until 2006. Cardiovascular risk assessments using three separate risk algorithms were applied on the population.Results: The participation rate was high with 90% attendance. The conclusion of this cross-sectional baseline analysis was that it is meaningful to check for a secondary cause of hyperlipidemia, hypothyroidism, in women with a cholesterol value above 7.0 mmol/L. After 10 years follow-up women reported significantly more lifestyle changes than men, odds ratio (OR) 1.56 (95% CI: 1.11- 2.18; p= 0.010). Men with a history of smoking or CVD at baseline and women with treated hypertension at baseline made successful lifestyle changes, OR 4.77 (95% CI: 2.18-10.5; p<0.001 and OR 1.84 (95% CI: 1.12-3.02; p= 0.016), respectively, than those without these characteristics. Until 2006, 38 participants had developed diabetes and four subjects IGT out of 664 participants, excluding 10 with diabetes at baseline. A low level of IGFBP-1 at baseline was associated with the development of type 2 diabetes/IGT, hazard ratio (HR) 3.54 (95% CI: 1.18-10.6, p=0.024). This was independent of abdominal obesity or inflammation (CRP). After excluding 16 participants with prevalent CVD at baseline, 71 first fatal or nonfatal CVD events in 689 men and women were registered. Several known risk factors and risk markers were applied on this population.Those that turned out to be significantly associated with development of incident CVD in univariate Cox´s regression proportional hazard analyses where used in three different risk assessment models: the consultation model, SCORE and the extensive model. A non-laboratory-based risk assessment model, including variables easily obtained during one consultation visit to a general practitioner (GP), predicted cardiovascular events as accurately, HR 2.72; (CI 95% 2.18-3.39, p<0.001), as the established SCORE algorithm, HR 2.73; (CI 95% 2.10-3.55, p<0.001), which requires laboratory testing. Furthermore, adding laboratory measurements covering lipids, inflammation and endothelial dysfunction, did not confer any additional value to the prediction of CVD risk, HR 2.72; (CI 95% 2.19-3.37, p<0.001). The c-statistics for the consultation model (0.794; CI 95% 0.762-0.823) was not significantly different from SCORE (0.767; CI 95% 0.733-0.798, p=0.12) or the extended model (0.806; CI 95% 0.774-0.835, p=0.55).Conclusions: Our study showed that it is worth searching for hypothyroidism, in women with a cholesterol value above 7 mmol/L. The study identified female gender, previous CVD, hypertension and smoking as predictors of positive lifestyle change during follow-up. A low level of IGFBP-1 predicted future diabetes/IGT in this population as did increased waist and CRP. Finally, data on nonlaboratory risk factors obtained during one GP visit predicted future cardiovascular risk as accurately as SCORE or a laboratory-based risk algorithm.