Inhaled insulin is associated with positive outcomes in patients with type 1 diabetes. Various studies, discussed in this paper aim at showing that the benefits from using inhaled insulin to manage diabetes type 1 and 2 are similar to those from using subcutaneous insulin. The study by Garg et al. (2006) was the first study that compared the use of inhaled insulin to subcutaneous insulin in type 1 diabetic patients. Findings revealed that inhaled insulin and insulin glargine did not produce inferior effects to standard treatment and insulin glargine with HbA1c as the outcome. Both modes of treatment had a similar effect on glycemic control with regard to HbA1c. Fasting blood glucose values were shown to be lower while using the human inhaled insulin powder (HIIP) compared with the conventional injectable insulin. The study does not indicate differences in dosage in relation to the attained outcomes; hence, health care practitioners should endorse the use of inhaled insulin in the management of diabetes in general. This study showed that similar rates of hypoglycemia were achieved after the treatment periods (LSM±SE: 8.9±0.7 and 8.2±0.8 events per 30 days), but significant differences were noted at the early time points and for nocturnal hypoglycemia.
The study by Quattrin, Belanger, Bohannon & Schwartz (2004) shows that there was a significantly greater improvement in the overall satisfaction summary score in patients using inhaled insulin and a significant decrease in patients given injectable insulin. Patients using inhaled insulin had greater “quality-of-life scales and subscales of health perceptions, symptom interference, depression, positive affect, life satisfaction, psychological well-being, and cognitive function” in contrast to the group using subcutaneous insulin (p. 2626). There was a reduced risk of hypoglycemia in the inhaled insulin group as opposed to the subcutaneous insulin group (8.6 vs. 9.0 events/subject month; risk ratio 0.96 [95% CI 0.93– 0.99]) (p. 2625). Hypoglycemia was the main adverse effect of treatment, and as the results indicate, those in the subcutaneous group were more but not statistically significant. Patients in the inhaled insulin group had a cough as an effect of treatment, but this gradually reduced over time. In conclusion, the use of inhaled insulin resulted in similar effects of glycemic control as subcutaneous insulin.
Skyler et al. (2005) aimed at comparing the effect of pre-meal inhaled and subcutaneous insulin in type 1 diabetic patients. The study showed that there were comparable reductions in the levels of hemoglobin AIC (AIC). The baseline and end mean AIC values of the inhaled insulin group were “8.0 _ 1.0 and 7.7 _ 1.0%, respectively, while those in the subcutaneous group were 7.9 _ 1.0 and 7.8 _
1.2%” (Skyler et al., 2005, p. 1632). In addition, this inhaled insulin group experienced decrements in FPG irrespective of variation in dosage of NPH at bedtime. It is believed that the reductions are related to IAbs functioning, but there were no adverse effects as a result of these reductions. The general results of this study did not indicate significant differences between the use of inhaled insulin and subcutaneous insulin.
Injectable insulin is not a favorite to many clients who deem it inconvenient and burdensome (Skyler et al, 2001). The study by Skyler et al. (2001) showed that inhaled insulin was well tolerated, unlike oral, nasal, and transdermal insulin. Inhaled insulin was well tolerated because the alveoli are permeable points of entry for the insulin macromolecules. As a result, inhaled insulin was an ideal replacement for injectable insulin in patients with diabetes type 1. In addition, the benefits of inhaled insulin were not significantly different from those of injectable insulin in various parameters. To begin with, HbA1c concentrations were the same for the two treatments, “7.9% in the inhaled insulin group and 7.7% in the injectable insulin group at 12 weeks” (p. 334). The same effects were observed for hypoglycemia, pulmonary function, and hypoglycemia. All these benefits were achieved without significant variation in dosage. The mean daily dose of inhaled insulin was 12.2 mg compared with 15.9 mg for subcutaneous insulin, while the dosage for long-acting inhaled insulin was 24.8 units compared with 31.0 units of subcutaneous insulin (p. 334).
The study by Moses et al. (2009) to assess the long-term effects of inhaled insulin via the AERx IDMS by comparing it with subcutaneous insulin showed auspicious results. Pulmonary function tests were the same for patients in both inhaled and subcutaneous insulin groups, though there was a reduction in the percentage of prevailing “carbon monoxide diffusing capacity” of the lungs after 3 months which eventually stabilized (p. 265). These results are similar to those of Garg et al. (2006) which showed comparable rates of hypoglycemia in both groups, but higher risks of nocturnal hypoglycemia presented in the inhaled insulin group (RR 1.58, P = 0.001). Fasting plasma glucose was lower in the inhaled insulin group as opposed to the subcutaneous insulin group (p. 264-5). After 12 months, there was an insignificant difference between the efficacy of inhaled insulin compared with subcutaneous insulin (0.18% (CI 95% -0.04; 0.39).
Similar beneficial effects of inhaled insulin have been realized with type 2 diabetes as seen from the following studies. The study by Hermansen, Ronnemaa, Petersen, Bellaire & Adamson (2004) indicates that the effectiveness of preprandial inhaled insulin through AERx items is similar to that of preprandial subcutaneous insulin about glycemic control among patients with type 2 diabetes (8.9 ± 3.8 vs. 10.8 ± 3.7 mmol/l, P = 0.01). According to Hermansen, Ronnemaa, Petersen, Bellaire & Adamson (2004), reference to a blood glucose profile of nine-point, fasting blood glucose was not statistically different in both the AERx and the SC groups (7.04 ± 2.0 vs. 7.78 ± 2.1, P = 0.08) (p. 164). The study showed that inhaled insulin administered a few seconds before eating through the AERx iDMS is associated with metabolic control in the long term. The benefits received are similar to those derived from SC human insulin given 30 minutes before eating when following an intensive insulin regimen. Significant lower levels of fasting serum/plasma glucose (FSG/FPG) manifested in the AERx group (8.9 ± 3.8 vs. 10.8 ± 3.7 mmol/l, P = 0.01) in contrast to the SC group. These findings are a basis for evidence-based care practice of using inhaled insulin through AERx iDMS.
The study by Hollander et al. (2004) also showed a positive correlation between inhaled insulin and glycemic control in comparison to the usual insulin regimen among patients with type 2 diabetes. The study aimed at showing that inhaled insulin produced similar benefits to the conventional insulin regimen, but results showed more benefits of inhaled insulin. Hollander et al. (2004) indicate that more patients under the inhaled insulin regimen attained the goal of HbA1c, as recommended by the American Diabetes Association of <7%. In addition, there was a reduction in FPG and PPG levels in patients using inhaled insulin. FPG reduced from 152 mg/dl (8.44 mmol/l) to 132 mg/dl (7.33 mmol/l) after 24 weeks in patients in the inhaled insulin group. This reduction is in comparison to the reduction from 158 mg/dl (8.77mmol/l) to 149 mg/dl (8.27mmol/l) in the subcutaneous group (p. 2359).
The study by Gross et al. (2009), as well, showed that type 2 diabetic patients received similar benefits from AIR inhaled insulin and insulin lispro. This study confirmed what other previous studies had discovered; the benefits derived from inhaled insulin are similar to those derived from conventional subcutaneous insulin injection. Gross et al. (2009) showed that AIR insulin is not inferior to insulin lispro because both produced similar glycemic control outcomes after 6 months of treatment (7.36_0.09 and 7.31_0.09) in relation to their comparable hemoglobin AIC (AIC) values at baseline (8.18% vs. 8.21%, respectively). This study also showed that patients in the AIR group had a greater anti-insulin antibody response that was not associated with any adverse effects. As a result, it was concluded that AIR insulin is equally effective to injectable insulin; hence, a basal-bolus therapy is not necessary as a prerequisite for the attainment of AIC values of less than 7%.
There is sufficient evidence to show that inhaled insulin yields beneficial results as the standard treatment regimen for diabetes type 1 and 2 in as far as glycemic control is concerned. Just like subcutaneous insulin, inhaled insulin is associated with improved FBG, FPG/FSG, PPG, and AIC values, which are indicators for glycemic control. The studies discussed here showed no statistically significant differences in the efficacy of inhaled insulin in comparison to subcutaneous insulin. Inhaled insulin, therefore, can be used as an alternative treatment of subcutaneous insulin.
References
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