Objectives: The existence of comorbid diseases among men with newly diagnosed prostate cancer may affect prostate cancer prognosis.
Methods: We identified patients (n = 8114) with a first-time discharge diagnosis of prostate cancer from Danish hospitals between 1995 and 2006. We measured comorbidity using the Charlson Comorbidity Index.
Results: The number of patients doubled between 1995 and 2006. The proportion of patients with Charlson scores of 0 (no comorbidity) increased from 62% to 63% of total patients diagnosed, whereas the proportion of patients with Charlson scores of 1 to 2 (moderate comorbidity) decreased from 31% to 29%, and the proportion with Charlson scores of 3 or higher (severe comorbidity) increased from 106 to 227 (7% to 8%). Among patients with a Charlson score of 0, the 1-year survival rate improved from 79% to 94%; among patients with Charlson scores of 1 to 2, the 1-year survival rate increased from 68% to 83%; and in patients with a Charlson score of 3 or higher, this rate increased from 61% to 69%. Compared with patients with Charlson scores of 0, patients with scores of 1 to 2 had age-adjusted 1-year mortality rate ratios (MRRs) of 1.60 in 1995 to 1997, increasing to 2.67 in 2004 to 2006. For patients with Charlson scores of 3 or higher, the adjusted MRR increased from 3.11 in 1995 to 1997 to 5.08 in 2004 to 2006.
Conclusions: Comorbidity was present in more than one-third of prostate cancer patients and was a negative prognostic factor. Although prostate cancer survival generally has improved in Denmark in recent years, no improvement was found among those with high levels of comorbidity.