Explaining structural change in cardiovascular mortality in Ireland 1995-2005: a time series analysis.

BACKGROUND Deaths from diseases of the circulatory system and the seasonality of deaths from these causes fell sharply between 1995 and 2005 among older age groups in Ireland. We examine whether a structural break occurred in deaths from circulatory causes in Ireland between 1995 and 2005 and test whether this can be statistically accounted for by cardiovascular prescribing during the same period controlling for weather trends. METHODS Grouped logit time series models were used to identify if and at which quarter a structural break occurred in Irish circulatory deaths between 1995 and 2005. Data on cardiovascular prescribing and temperature within the quarter were entered into the trend-break model to account for the structural break. RESULTS Controlling for temperature, β-blocker, ace-inhibitor and aspirin medications rendered the structural break indicator insignificant among all age groups for men. Diuretic, statin and calcium channel blocker medications could not account for the break point for men aged 75-84 years. β-Blocker, aspirin and calcium channel blocker medications account for mortality trends among all age groups among women. Ace inhibitor and statin could not account for trends amongst women aged 65-74 years and nitrates and diuretics did not account for trends for any age group. CONCLUSIONS Cardiovascular prescribing accounts for the trend break in circulatory mortality among men and women aged ≥65 years after 1999 in Ireland but the effect of prescribing is lower for women. β-Blocker, ace inhibitor and aspirin medications were more successful than statin, diuretic and nitrates in accounting for the trends.