Incidence and prevalence of hypercholesterolemia in Portugal: a systematic review. Part I.
BACKGROUND
Over 50% of the mortality and disability caused by ischemic heart disease and stroke could be avoided by controlling individual risk factors (hypertension, hypercholesterolemia, smoking and obesity). The ignorance of the extent and impact of hypercholesterolemia (HC) in Portugal prompted us to undertake this systematic review of the prevalence and incidence of hyperlipidemia in Portugal, based exclusively on work published nationally.


METHODS
We included every study published in the country that could provide data on the prevalence or incidence of hypercholesterolemia. The search strategy included an electronic search of national and international biomedical databases (Medline, Index Revistas Médicas Portuguesas, the Portuguese Directorate-General for Health and the Portuguese National School of Public Health), screening of reference lists from the individual studies, and personal contacts with institutions, groups and authors (such as the Portuguese Foundation of Cardiology). The data--recorded in electronic format--was collected independently by two of the authors (JC and MB), with consensus achieved with a third (AVC) when there were differences in the study coding.


RESULTS
We could only identify one paper on the incidence of HC in Portugal, which gave an incidence of 559 new cases per 100,000 inhabitants, increasing with age up to 54 years for men and 64 years for women. There was a higher incidence in men than in women up to the age of 54, but at more advanced ages this relationship was reversed. Prevalence studies on HC included 53,445 individuals overall, with sample size lower than 1000 in most of the individual studies. The most frequently used criterion for HC was > 200 mg/dL, with the mean level being higher in most studies. We calculated the mean prevalence for several cut-off points (190 mg/dL: 63.8%; 200 mg/dL: 56.7%; 240 mg/dL: 31.7%; 250 mg/dL: 21%). Due to the heterogeneity of the data, these results are to be interpreted with caution, even though they are consistent across individual studies. The prevalence of hypertriglyceridemia (HTG) was highly variable across studies. Most of them used a baseline criterion of 150 mg/dL (11-26%) or 200 mg/dL (8.9-33.9%).


CONCLUSIONS
Despite the obvious heterogeneity and a certain paucity of studies, we found consistent results concerning the prevalence of hypercholesterolemia in Portugal, and we can state that this constitutes a serious health problem in our country. The prevalence of hypercholesterolemia was higher than that of arterial hypertension in our population. The results of this study should serve as a basis for a commitment to action from the health authorities and health professionals as well as patients.
Costa
João
J
Centro de Estudos de Medicina Baseada na Evidência da Faculdade de Medicina de Lisboa, Lisboa.
Borges
Margarida
M
Oliveira
Eduardo
E
Gouveia
Miguel
M
Carneiro
António Vaz
AV
D006801:Humans; D006937:Hypercholesterolemia / Q000453:epidemiology*; D015994:Incidence; D011174:Portugal / Q000453:epidemiology; D015995:Prevalence