Differences in cardiovascular mortality between Australia and New Zealand according to socioeconomic status: findings from the Long-Term Intervention with Pravastatin in Ischaemic Disease (LIPID) Study.

BACKGROUND: Cardiovascular mortality is higher in New Zealand compared to Australia, but reasons for this difference are uncertain. This study describes differences in cardiovascular risk factors and cardiovascular mortality in Australians and New Zealanders with stable coronary artery disease stratified by socioeconomic status. METHODS: Socioeconomic status was estimated from the residential area of 5949 Australians and 2784 New Zealanders with a history of myocardial infarction or unstable angina who participated in the Long-Term Intervention with Pravastatin in Ischaemic Disease (LIPID) Study. Socioeconomic and international differences in cardiovascular risk factors, medical treatments, and cardiovascular mortality during a median follow-up period of 7.8 years were evaluated. RESULTS: Cardiovascular mortality increased as the median residential-area income decreased in both Australia (hazard ratio [HR]/income tertile 1.20, 95% confidence interval [CI] 1.08-1.32) and New Zealand (HR 1.16, 95%CI 1.02-1.31), but was higher in New Zealand across all socioeconomic groups (HR 1.42, 95%CI 1.25-1.61). Obesity, smoking, and a high white blood cell count at baseline were associated with higher cardiovascular mortality and were more common in lower-income areas in both countries. The total:HDL cholesterol ratio was higher in New Zealand, but similar across all socioeconomic groups. In both countries there were socioeconomic gradients in open-label usage of cholesterol-lowering medication, percutaneous coronary intervention, and coronary artery bypass surgery. However, Australians in all socioeconomic groups were more likely than New Zealanders to receive these treatments. CONCLUSIONS: Although there is an important socioeconomic gradient in cardiovascular mortality in both Australia and New Zealand, cardiovascular mortality is higher in New Zealanders than Australians with stable coronary disease from all socioeconomic groups.

Depression and cardiovascular morbidity and mortality: cause or consequence?

BACKGROUND: Depression after myocardial infarction has been associated with increased cardiovascular mortality. This study assessed whether depressive symptoms were associated with adverse outcomes in people with a history of an acute coronary syndrome, and evaluated possible explanations for such an association. METHODS AND RESULTS: Depressive symptoms were assessed using the General Health Questionnaire at least 5 months after hospital admission for acute myocardial infarction or unstable angina in 1130 participants of the Long-Term Intervention with Pravastatin in Ischaemic Disease (LIPID) Study, a multicentre, placebo-controlled, clinical trial of cholesterol-lowering treatment. Cardiovascular symptoms, self-rated general health, cardiovascular risk factors, employment status, social support and life events were also assessed at the baseline visit. Cardiovascular death (n=114), non-fatal myocardial infarction (n=108), non-fatal stroke (n=53) and unstable angina (n=274) were documented during a median follow-up period of 8.1 years. Individuals with depressive symptoms (General Health Questionnaire score >/=5; 22% of participants) were more likely to report angina, dyspnoea, claudication, poorer general health, not being in paid employment, few social contacts and/or adverse life events (P<0.05 for all). There was a modest association between depressive symptoms and cardiovascular events (hazard ratio [HR] 1.42, 95% confidence interval [CI] 1.13-1.77), but not cardiovascular death (HR 1.12. 95% CI 0.71-1.77). After adjustment for symptoms related to cardiovascular disease, the HR for cardiovascular events was 1.22 (95% CI 0.97-1.53). After further adjustment for employment status, social support and life events, the HR was 1.13 (95% confidence interval 0.87-1.47). CONCLUSIONS: There was no significant association between depressive symptoms and fatal or non-fatal cardiovascular events after adjustment for cardiovascular symptoms associated with poorer prognosis. Previously observed associations between depression and cardiovascular mortality may not be causal.