The impact of using different mortality outcomes in COPD patients on risk factors analysis

¹ Dept of Epidemiology, Rome E Local Heath Unit

	Abstract

To analyse the role of potential selection processes and their impact when evaluating risk factors for 30-day mortality among patients hospitalized for chronic obstructive pulmonary disease (COPD).

A cohort of 26,039 patients, 35+ years old, hospitalised with a COPD was enrolled. A 30-day follow-up was carried out using both the cause mortality register (CMR) and the hospital discharge register (HDR). Individual and hospital factors associated with 30-day mortality were studied using both mortality outcomes.

The 30-day mortality rate was 1.21 per 1000 p-days (95%CI=1.14–1.29) using the CMR and 1.06 per 1000 p-days (95%CI=0.98–1.13) using the HDR. Male patients, the most poorly educated, those who reside outside Rome, and those who had more than one hospitalisation in the two previous years were more likely to die after discharge than when hospitalized. The most frequent cause of in-hospital death was respiratory disease, and after-discharge, heart disease. Older age, male gender, comorbidities, previous hospitalizations for respiratory failure, and admission to a ward not appropriate to treat respiratory diseases were the most important predictors of 30-day mortality.

Using in-hospital 30-day mortality gives a significantly different estimate of the role of specific risk factors.