Researchers have found in a new study that inhaled insulin showed no increased risk of lung cancer compared with regular human insulin (RAA). However, it was associated with a threefold higher risk of COPD, though the absolute risk remained small. Due to study design limitations, including potential bias and lack of strong biological plausibility, a causal relationship cannot be established. These findings highlight the need for further long-term studies to better assess the pulmonary safety of inhaled insulin. The study was published in the Diabetes Technology & Therapeutics journal by Kevin C. and colleagues.Inhaled insulin has been developed as an alternative to subcutaneously administered rapid-acting insulin for patients with diabetes. However, pulmonary safety has been a major concern because insulin is directly administered to the lungs. The objective of this study is to determine the real-world pulmonary safety of inhaled insulin compared to RAA insulin, particularly in terms of the risk of lung malignancy and COPD among patients with type 1 and type 2 diabetes.This retrospective cohort study utilized data from the TriNetX Network, which is a large federated health research network. Adults with diabetes who were treated with either inhaled insulin or RAA insulin were included in the study. To minimize confounding, propensity score matching was conducted, resulting in well-balanced groups for comparison. The outcomes of interest were the incidence of any lung cancer and a composite outcome for COPD.Key findingsAfter matching, the number of patients with lung cancer was 2530 in the inhaled insulin group and 2531 in the RAA insulin group. The number of patients with COPD was 2493 in the inhaled insulin group and 2514 in the RAA insulin group. All patients were adults with type 1 or type 2 diabetes receiving care in real-world clinical practice. In the matched analysis, there was no difference in the risk of lung cancer between inhaled insulin and RAA insulin users. The number of cases of lung malignancy was low in both groups (≤10 events in both groups), with a risk ratio (RR) of 1.00 (95% confidence interval [CI], 0.42-2.40; P = 0.999).However, the risk of COPD was increased in patients who received inhaled insulin.The composite outcome of COPD was observed in 41 of 2493 patients (1.6%) in the inhaled insulin group compared with 12 of 2514 patients (0.5%) in the RAA insulin group. This was associated with a risk ratio of 3.45 (95% CI, 1.82-6.54; P < 0.001), indicating that the risk of COPD was increased by more than threefold.This real-world study suggests that inhaled insulin is not associated with an increased risk of lung cancer, but it is associated with a threefold increased risk of COPD than rapid-acting analogue insulin, although the absolute risk is low. This study emphasizes the importance of continued post-marketing surveillance studies of inhaled insulin to assess its pulmonary safety for a longer period of time.Reference:Cowart K, Everich H, Flores F, et al. Real-World Incidence of Lung Malignancy and Chronic Obstructive Pulmonary Disease with Inhaled Insulin in People with Diabetes. Diabetes Technology & Therapeutics. 2026;0(0). doi:10.1177/15209156251387102