Introduction Geographical differences in coronary heart disease (CHD) mortality have been widely described, but little is known about the incidence of such disease.

Objective Examine the geographic distribution of CHD hospital admissions from 1997 to 2008, in Continental Portugal, identifying relevant peaks of the disease.

Methods Hospital admissions due CHD (ICD9-CM: 410–414×, 429.2×) were obtained from the National Hospital Discharge Register. Age-standardised hospitalisation rates (ASHR) were computed by triennium (excluding 1997–1999, because of losses in georeferencing) for ages 35–74 years, at municipality level. Spatial statistics methods were applied to smooth ASHR and identify spatial clusters. Results were overlaid with a map of climate regions.

Results There were 356 119 hospitalisations with CHD as primary or secondary diagnosis, more frequent (66.7%) and expensive in men but more fatal and longer in women (p<0.001). Rate ratio (highest: lowest) were 5.2, 5.5 and 4.1 (men) and 9.7, 6.5 and 5.5 (women), respectively in 2000–2002, 2003–2005 and 2006–2008. Moran index of spatial autocorrelation showed moderate degree of spatial dependency (+0.36, +0.33 and +0.43 for men, +0.35, +0.33 and +0.41 for women, in 2000–2002, 2003–2005 and 2006–2008) and spatial clusters were identified. A Northeast-Southwest trend (from lowest to highest values) in ASHR was revealed, coincident with the borderline of the two main climate regions.

Conclusions Accentuated geographic differences in ASHR were observed, although rates remained stable in the study period. Higher fatality and lower cost in hospitalisations of women may reflect gender inequalities in the treatment. Spatial patterns suggested environmental factors are also determinants of CHD.