Cancer risk and mortality in asthma patients: A Swedish national cohort study

In addition, we used Cox proportional hazards regression to estimate hazard ratios (HRs) for mortality in patients with both asthma and cancer. Results. A total of 10 649 cancers were diagnosed in patients with previous asthma, with a SIR of 1.19 (95% CI 1.17–1.21).

A total of 15 cancer sites showed an increased incidence, whereas two cancer sites showed a decreased risk. Non-allergic asthma showed the highest risk of cancer (SIR = 1.25, 95% CI 1.18–1.32), followed by unspecified asthma (SIR = 1.22, 95% CI 1.19–1.25), status asthmaticus (SIR = 1.19, 95% CI 1.02–1.39), and allergic asthma (SIR = 1.14, 95% CI 1.06–1.22). The risk of cancer was similarly increased in asthma patients diagnosed in primary health care and those diagnosed in hospitals.

Cancer patients with previous asthma had increased mortality, with a HR of 1.55 (95% CI 1.50–1.60). HRs ranged from 1.09 to 1.94 for different sites/types of cancer. Conclusions.

Patients with asthma, irrespective of whether they were treated in primary health care or hospitals, had an increased risk of cancer. In addition, cancer patients with previous asthma had a worse prognosis compared with those without asthma, suggesting that these patients may require a multidisciplinary approach to manage the comorbidity.