Although it is well recognized that women on hormone replacement therapy (HRT) have decreased plasma levels of lipoprotein(a) [Lp(a)], there is currently no evidence suggesting that HRT influences the relationship between Lp(a) and incident cardiovascular disease (CVD). Danik et al. therefore sought to test this hypothesis in 27,736 initially healthy women who participated in the Women’s Health Study. Of those women, 12,075 reported using HRT at the time of blood draw. The women were followed for approximately 10 years. In women who did not use HRT, those in the top Lp(a) quartile had an age-adjusted hazard ratio (HR) for future CVD of 1.67 (95% CI, 1.30-2.15). After further adjustment for the Framingham risk factors, body mass index, diabetes, C-reactive protein levels, and treatment arms, the HR for future CVD was 1.77 (95% CI, 1.36-2.30). In women using HRT, there was no relationship between Lp(a) and CVD incidence, as these respective HRs were 1.11 (95% CI, 0.83-1.49) and 1.13 (95% CI, 0.84-1.53). Based on these results, the authors suggested that clinicians should interpret Lp(a) levels with great caution, especially in women using HRT. This paper was accompanied by an editorial by Berglund and Anuurad who discussed the standardization issues regarding Lp(a) measurement. They also underlined the fact that the relationship between Lp(a) levels and incident CVD was not found to be linear and appeared to be observed in women with either very high Lp(a) levels or in women with other metabolic disturbances such as elevated LDL cholesterol levels. Berglund and Anuurad concluded that further studies are required to assess the possible benefits of reducing Lp(a) levels and whether intensification of Lp(a) lowering treatment is clinically relevant.
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