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Effect of insulin on airway responsiveness in patients with type 2 diabetes mellitus: a cohort study
Claudio Terzano1, Susanna Morano, Daniela Ceccarelli
1Department of Cardiovascular and Respiratory Sciences, Respiratory Diseases Unit, Fondazione E. Lorillard Spencer Cenci, Sapienza University of Rome, Italy. cterzano@tin.it
Background:
The correlation between low insulin levels and a decreased sensitivity of the muscarinic receptor has been shown on induced-diabetes animal models. We designed a cohort study with the aim of evaluating the effects of insulin therapy on airway responsiveness (AR) in human patients with type 2 diabetes mellitus.
Methods:
We enrolled 92 patients with type 2 diabetes who had switched from oral anti-diabetic therapy to treatment by insulin subcutaneous injection. Patients were administered the methacholine challenge test (MCT) at time 0 (pre-insulin therapy) and at intervals of 15, 30, 90, 180, and 360 days after insulin treatment. The decline of forced expiratory volume in 1 second (FEV(1))% from baseline (Delta FEV(1)) in response to inhaled methacholine (MCH) was determined to assess airway hyper-responsiveness (AHR).
Results:
A total of 81 patients (18 women and 63 men) completed the study. Their mean age was 58 +/- 7 years and the mean duration of disease was 13.5 +/- 7.7 years. The mean decrease of FEV(1) at pre-insulin assessment was 2.96 +/- 2.6%. Compared with the pre-insulin value, a significant increase of Delta FEV(1) was observed at 15, 30, and 90 days after treatment (6.25%, CI 95% 5.4 to 7.2, p = 0.0005; 7.64%, CI 95% 6.6 to 8.1, p < 0.001; 6.45%, CI 95% 5.5 to 7.3, p = 0.0004, respectively), while after 180 and 360 days AR was similar to pre-insulin values (Delta FEV(1), 3.62%, CI 95% 2.7 to 3.5 and 3.11%, CI 95% 7.9 to 9.3, respectively).
Conclusions:
The finding of an increased AR in patients with type 2 diabetes during the first 3 months of insulin therapy may underline the importance of monitoring pulmonary function and respiratory symptoms in patients switching from oral anti-diabetic drugs to insulin therapy, especially in the subset of individuals with respiratory disorders.
Insights
Insulin therapy in type 2 diabetes patients temporarily increases airway responsiveness (AR) within the first 3 months. Monitoring pulmonary function is crucial for patients initiating insulin treatment, particularly those with existing respiratory conditions.
Area of Science:
- Pulmonary Medicine
- Endocrinology
- Clinical Research
Background:
- Animal models show a link between low insulin and reduced muscarinic receptor sensitivity.
- Type 2 diabetes mellitus (T2DM) is associated with potential airway changes.
- The impact of insulin therapy on airway responsiveness in T2DM patients requires investigation.
Purpose of the Study:
- To evaluate the effect of insulin therapy on airway responsiveness (AR) in human patients with type 2 diabetes.
- To assess changes in AR following the switch from oral anti-diabetic drugs to insulin treatment.
Main Methods:
- A cohort of 92 type 2 diabetes patients transitioning to insulin therapy was enrolled.
- Methacholine challenge tests (MCT) were performed pre-insulin and at multiple time points up to 360 days.
- Airway hyper-responsiveness (AHR) was assessed by measuring the decline in forced expiratory volume in 1 second (FEV(1)) after methacholine inhalation.
Main Results:
- 81 patients completed the study (mean age 58 years, mean disease duration 13.5 years).
- A significant increase in airway responsiveness (Delta FEV(1)) was observed at 15, 30, and 90 days post-insulin initiation compared to pre-treatment levels.
- Airway responsiveness returned to pre-insulin levels by 180 and 360 days of treatment.
Conclusions:
- Insulin therapy in type 2 diabetes patients is associated with a transient increase in airway responsiveness during the initial 3 months.
- Pulmonary function monitoring and assessment of respiratory symptoms are recommended for T2DM patients switching to insulin.
- Particular attention should be paid to individuals with pre-existing respiratory disorders during this transition period.
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