General and cancer specific mortality of a population basedcohort of patients with inflammatory bowel disease: the Florencestudy

Background—A population basedepidemiological study identified all the patients diagnosed withulcerative colitis (UC) or Crohn's disease (CD) resident in theFlorence area in the period 1978-1992.
Aims—To assess the mortality of unselectedpatients with inflammatory bowel disease (IBD) in a Mediterranean country.
Methods—Overall, 920 patients (689 UC and 231 CD)were followed until death or end of follow up (31 December 1996).Information on vital status was available for all except eight patients(0.9%); 70 deaths were identified (23 in patients with CD and 47 inpatients with UC). Expected deaths were estimated on the basis of five year age group, gender, and calendar year national mortality rates. Standardised mortality ratios (SMR) and 95% confidence intervals were calculated.
Results—General mortality was significantly lowerthan expected in UC (SMR 0.6; 95% confidence interval 0.4 to 0.8), dueto a reduced number of cardiovascular and, possibly, smoking related deaths. Cancers of the respiratory tract were significantly reduced inUC but tended to be increased in patients with CD. These latter patients had not only an increased cancer mortality but also a 40%increased risk of dying for all causes already evident in the firstfive year follow up period and persisting thereafter. In contrast, inpatients with UC, SMRs were initially very low but tended to increasesteadily over the follow up period. Gastrointestinal deaths wereparticularly increased in patients with CD, but only moderately inthose with UC. Overall, there was some evidence of a twofold increasedmortality for colorectal cancer, the risk being highest for rectalcancers in patients with UC. A non-significant excess of deaths due tohaemolymphopoietic malignancies and suicides was also observed.
Conclusions—This study, the first in aMediterranean country, supports the existence of two divergentmortality patterns for patients with UC and CD, possibly explained bydifferences in smoking habits and by a greater severity of CD.