Risk factors for obstruction, perforation, or emergency admission at presentation in patients with colorectal cancer: a population-based study

Objectives — Previous studies have shown that patients newly diagnosed with colorectal cancer (CRC) requiring emergency admission to hospital or those presenting with obstruction or perforation (defined here as OPE) have advanced disease. The objective was to conduct a population-based study among persons with a new diagnosis of CRC to identify factors associated with OPE in Ontario.

Methods — We analyzed data from the following databases: Canadian Institute for Health Information (CIHI), the Ontario Health Insurance Plan (OHIP), and the Registered Persons Database (RPDB). We identified all individuals > or = 20 yr of age with a new diagnosis of CRC (ICD-9 codes 153.0-153.4, 153.6-154.1) during 1996-2001 and defined the first admission for CRC as the index admission. We excluded those who received chemotherapy, radiotherapy, or palliative care prior to the index admission. We identified those with concomitant obstruction (ICD-9 code 560.9), perforation (ICD-9 code 569.8), or who were classified as emergency admission (referred to as OPE). Adjusted risk of OPE was calculated using logistic regression analysis.

Results — Between 1996 and 2001, we identified 41,356 persons with CRC, of whom 53.5% were men. In logistic regression analysis, female sex and low income were significantly associated with OPE, after adjusting for differences in age, cancer site, previous large bowel evaluation, comorbidity, having a regular source of primary care, and year of diagnosis. For men the adjusted odds ratio (OR) for OPE was 0.93 (95% confidence interval (CI) 0.88-0.99), and for the highest-income quintile the adjusted OR was 0.78 (95% CI 0.72-0.85).

Conclusion — Among persons with a new diagnosis of CRC in Ontario, women and those who are poor are more likely to present with obstruction, perforation, or emergency admission to hospital. Population-based CRC screening is needed to address these adverse outcomes.