Research suggests asthmatics at increased risk of cancer

11th May 2023

Asthmatics have a higher risk of developing cancer, though use of inhaled steroids may have a slight protective effect, according to a US study.

Globally, cancer is the leading cause of mortality, with nearly 10 million recorded deaths in 2020. Data suggests that infection and inflammation contribute to a quarter of all cancers. In fact, the inflammatory milieu within a tumour seems to be an indispensable participant in tumour progression. In asthmatics, the inflammatory nature of their condition increases the risk of lung cancer. Nevertheless, other data either demonstrate a positive association or no association with the risk of other cancers.

In the current study, researchers sought to better understand the relationship between asthma and cancer risk. They analysed electronic health records in a US claims database. The team developed a matching cohort of those with and without asthma which served as the control group. Using regression models, researchers searched for any relationship between asthma and the subsequent development of cancer. The primary outcome was the time to a cancer diagnosis after the date of an asthma diagnosis. 

Asthmatics and risk of cancer

The asthma cohort included 90,021 individuals matched to 270,063 without the disease. In multivariable analysis, asthmatics were more likely to develop cancer (hazard ratio, HR = 1.36, 95% CI 1.29 – 1.44). For example, significantly higher risks were observed for melanoma, blood, kidney and lung cancers. However, in contrast, risks were non-significant for bladder, colorectal and prostate cancers.

In a separate analysis examining the effect of inhaled steroid use, the overall cancer risk was slightly lower among steroid users (HR = 1.60 vs 1.11, inhaled steroid vs no steroid). Taken together, cancer risk was higher for nine of 13 cancers in asthmatics not using inhaled steroids but in only two cancers among steroid users. These findings suggest a possible protective effect of inhaled steroid use on cancer risk that requires further evaluation.

Intermittent oral steroid use in asthmatics linked to higher risk of adverse outcomes

20th January 2023

Intermittent oral steroid use among asthmatic patients is associated with an elevated risk of several steroid-related adverse outcomes

Intermittent oral corticosteroid (OCS) use in asthmatics, even as a one-off course, is associated with a higher risk of OCS-related adverse outcomes according to the findings from an observational study by an international research group.

Significant adverse effects have been associated with continuous exposure to oral corticosteroids and a 2021 Delphi study has offered expert consensus on OCS use, tapering, adverse-effect screening, recommending a dose of 0.5 mg/kg/day for a short course of OCS. Nevertheless, intermittent oral corticosteroid use is widespread across European countries, with one study revealing how the annual prevalence of high OCS use across all countries was approximately 3% and that of 702 685 patients with asthma, 14-44% were OCS users and 6-9% were high OCS users at some point. Even short-term use of OCS is linked to the development of adverse outcomes, with one US study showing that one in five American adults were given prescriptions for short-term use of oral corticosteroids during a three year period, with an associated increased risk of adverse events.

Despite the above findings, no previous studies have focused exclusively on intermittent oral corticosteroid use. In the present study, researchers used data derived from two anonymised, real-life databases and included asthmatic patients aged ≥ 4 years with at least 12 months’ clinical data prior to OCS use. The subsequent use of OCS was then categorised into three patterns: one-off (single), less frequent (≥ 90 day gap) and frequent (< 90 day gap) and individuals were matched with a non-oral corticosteroid control group, based on age and gender. The subsequent risk of developing an adverse outcome (AO) was then examined using survival analysis.

Intermittent oral corticosteroid use and adverse outcomes

A total of 476,167 OCS individuals with a mean age of 38.1 years (55.7% female) were matched and followed for a median of 8.3 years. Among the cohort, 41.7% had a one-off prescription whereas 26.8% and 31.6% had less frequent and frequent intermittent OCS prescribing patterns, respectively.

When compared to non-OCS patients, the risk of experiencing any adverse outcomes was elevated, even for one-off OCS individuals and was higher with increasing frequent pattern of intermittent OCS prescribing. For example, the hazard ratio (HR) of experiencing any adverse outcomes versus non-OCS patients was 1.19 (95% CI 1.18 – 1.20) for one-off OCS users, 1.35 (95% CI 1.34 – 1.36) for less frequent OCS users and 1.42 (95% CI 1.42 – 1.43) for frequent pattern of OCS prescriptions. Moreover, this risk was consistently elevated across all subgroups, based on age and other used treatments. Interestingly, the risk of each of the individual OCS-related adverse outcomes, with the exception of behavioural disorders, renal impairment and peptic ulcer was apparent even in one-off OCS users.

The authors concluded that a considerable proportion of patients with asthma who are prescribed OCS intermittently have a frequent pattern of use at some point, and which was associated with a higher risk of individual OCS-related adverse outcomes.

Citation
Heatley H et al. Observational UK cohort study to describe intermittent oral corticosteroid prescribing patterns and their association with adverse outcomes in asthma. Thorax 2022