Association of comorbid schizophrenia with cancer stage at admission, treatments, length of stay, and 30-day in-hospital mortality in patients with pancreatic cancer: A retrospective matched-pair cohort study in Japan

Background

Previous studies have suggested an association between comorbid schizophrenia and various outcomes in patients with cancer, including cancer stage at admission, treatment, and in-hospital mortality. However, studies focusing specifically on patients with pancreatic cancer are limited.

Aims

This study aimed to elucidate the association between comorbid schizophrenia and cancer stage at admission, treatment, length of stay, and 30-day in-hospital mortality in patients with pancreatic cancer, while considering patient background factors, medical facilities, and year of treatment.

Method

We conducted a retrospective matched-pair cohort study using data from the Japanese Diagnosis Procedure Combination database. Patients with pancreatic cancer and comorbid schizophrenia were matched to those without psychiatric disorders at a maximum ratio of 1:4 according to sex, age group, year of admission, and admission facility. Each matched pair was treated as a cluster, and multivariable regression analyses using generalised estimating equations were performed to evaluate the association between psychiatric comorbidities and cancer-related outcomes.

Results

After adjusting for patient background factors, medical facilities, and the year of treatment, patients with comorbid schizophrenia were significantly more likely to be admitted with stage IV cancer, less likely to undergo chemotherapy, and more likely to have longer hospital stays and higher 30-day in-hospital mortality than those without psychiatric disorders. Although not statistically significant, patients with schizophrenia were less likely to undergo cancer-directed surgery.

Conclusions

Patients with pancreatic cancer and comorbid schizophrenia were significantly more likely to present with advanced cancer at admission, were less likely to receive chemotherapy, had longer hospital stays, and experienced higher 30-day in-hospital mortality than those without psychiatric disorders. Although not statistically significant, patients with schizophrenia were less likely to undergo cancer-directed surgery.