Background: In Lazio region (Italy), mortality data are currently available from the death cause registry (DCR), which reports only underlying causes. Mortality due to other causes, defined concurrent mortality, are need to appropriately estimate the health impact from chronic diseases. The aims of the study were to estimate concurrent mortality from chronic obstructive pulmonary disease (COPD), using hospital discharge registry (HDR), to discuss the validity and limits of this method, and to compare underlying and concurrent mortality from COPD in the Lazio region.
Methods: A mortality study was carried out for residents who died in 1996-2000 with COPD listed as the underlying cause of death and those who died in the hospital with a different underlying cause of death listed but with a discharge diagnosis of COPD. Age-standardized mortality rates were obtained for males and females separately, using the direct method. A random sample of death certificates was used to validate concurrent causes of death as defined from discharge diagnoses.
Results: Age-standardised mortality for COPD as underlying cause of death was 3.68/10,000 in male and 2.29/10,000 in female residents. Mortality increased slightly in the study period for women, but no trend was evident. Age-standardised mortality for COPD as concurrent cause of death was 2.39/10,000 in male and 1.31/10,000 in female residents. The positive predictive value for concurrent COPD mortality was 54.3%.
Conclusions: Concurrent COPD mortality contributed 62.3% to the whole mortality. The estimates of concurrent COPD mortality were comparable to those reported in other countries, though using hospital data may overestimate the real concurrent mortality as estimated from death certificates.