Country of birth and mortality risk in hypertension with and without diabetes: the Swedish primary care cardiovascular database.

OBJECTIVES: Hypertension and diabetes are common and are both associated with high cardiovascular morbidity and mortality. We aimed to investigate associations between mortality risk and country of birth among hypertensive individuals in primary care with and without concomitant diabetes, which has not been studied previously. In addition, we aimed to study the corresponding risks of myocardial infarction and ischemic stroke.
METHODS: This observational cohort study of 62 557 individuals with hypertension diagnosed 2001-2008 in the Swedish Primary Care Cardiovascular Database assessed mortality by the Swedish Cause of Death Register, and myocardial infarction and ischemic stroke by the National Patient Register. Cox regression models were used to estimate study outcome hazard ratios by country of birth and time updated diabetes status, with adjustments for multiple confounders.
RESULTS: During follow-up time without diabetes using Swedish-born as reference, adjusted mortality hazard ratios per country of birth category were Finland: 1.26 (95% confidence interval 1.15-1.38), high-income European countries: 0.84 (0.74-0.95), low-income European countries: 0.84 (0.71-1.00) and non-European countries: 0.65 (0.56-0.76). The corresponding adjusted mortality hazard ratios during follow-up time with diabetes were high-income European countries: 0.78 (0.63-0.98), low-income European countries: 0.74 (0.57-0.96) and non-European countries: 0.56 (0.44-0.71). During follow-up without diabetes, the corresponding adjusted hazard ratio of myocardial infarction was increased for Finland: 1.16 (1.01-1.34), whereas the results for ischemic stroke were inconclusive.
CONCLUSION: In Sweden, hypertensive immigrants (with the exception for Finnish-born) with and without diabetes have a mortality advantage, as compared to Swedish-born.