Patients who administered insulin via pen experienced a higher reduction in hemoglobin A1c (HbA1c) over 24 weeks of follow-up compared with those who used a syringe, according to research results published in Diabetology and Metabolic Syndrome.

To compare the use of pen vs syringe for insulin administration in older patients with uncontrolled type 2 diabetes, researchers conducted a randomized, nonblinded clinical trial at 2 centers in southern Brazil (ClinicalTrials.gov Identifier: NCT02517242). The researchers sought to evaluate the role of insulin administration method on glycemic control, hypoglycemia risk, treatment adherence, and quality of life.

The study population included adults 60 years and older with type 2 diabetes with an HbA1c of 8.5% or higher for 3 months. These patients were randomly assigned to receive either syringes or pens to use for insulin administration over the study period. In the pen group, patients received Luxura® pens (Eli Lilly) and 8-mm needles. Patients in the syringe group received syringes and 8-mm needles for insulin administration.


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Patients in both groups received capillary glycemia monitors, lancets, and reagent tapes to facilitate glycemia measurements 3 times daily.

The researchers invited 161 consecutive patients to participate; the final cohort included 121 older adults with a mean age of 66.75 years who had had diabetes for a mean of 18.05 years (baseline HbA1c, 10.06%). In terms of complications, 27.35% had ischemic heart disease, 32.32% had retinopathy, 47.27% had nephropathy, and 33.34% had neuropathy.

The pen and syringe groups included 61 and 60 patients, respectively, and only 11 patients in the total cohort were insulin naive. At baseline, mean HbA1c was 10.34±1.66% and 9.90±1.25% in each group. At 12 weeks, mean HbA1c decreased to 8.80±1.37% and 9.09±1.91% in each group, respectively; by 24 weeks, HbA1c continued to decrease (8.39±1.28% and 8.85±174%).

No significant difference was seen in absolute HbA1c between groups, but the overall reduction was higher in the pen group compared with the syringe group vs baseline. Over the first 12 weeks, the reduction in each group was -1.53±1.71% and -0.81±1.64% in the pen and syringe groups, respectively.

Between weeks 12 and 24, the reduction “did not appear to be different” between the groups. In terms of the follow-up period as a whole, there was a more significant reduction seen in the pen group compared with the syringe group (-1.94±1.93% and -1.04±1.46%) and an 18.76% and 10.5% reduction from the initial HbA1c.

Although there was a trend toward a higher number of hypoglycemia episodes in the syringe group, there was no difference in relation to the pen group. The incidence of hypoglycemia remained less than 1 episode per week in both groups, which did not change compared with baseline. There was also no between-group difference in terms of incidence of severe, asymptomatic, or nocturnal hypoglycemia during follow-up.

There was also no statistically significant difference in between-group adherence to the prescribed insulin dose. However, those in the syringe group reached an “adequate adherence average (use of more than 80% of the prescribed dose)” only after the fifth visit; those in the pen group had a mean greater than 80% beginning at the third visit.

There was an increase in the prescribed dose of insulin in both groups during the study. This difference was more pronounced in the pen group, but there was no difference detected between groups. At baseline, the pen and syringe groups used 0.76±0.33 IU/kg and 0.63±0.39 IU/kg; by week 24, mean use was 0.91±0.47 IU/kg and 0.74±0.51 IU/kg in each group, respectively.

No significant increase in weight over the 24-week follow-up period was noted.

The investigators also saw no difference in the number of medications other than insulin used per group in terms of either drug class or daily pills ingested.

No between-group difference was seen in the number of patients who were using a basal-bolus insulin regimen. At baseline, 27.87% and 31.67% in the pen and syringe group, respectively, were using a basal-bolus insulin regimen. By week 24, use of this regimen was 42.62% and 36.67%, respectively.

Quality of life was evaluated through questionnaires administered during the first and final visits. Baseline points were 37.62±27.3 and 28.46±21.8 in the pen and syringe groups; at the final visit, points were 25.90±26.3 and 25.31±24.03. A higher score was representative of a worse influence of diabetes on quality of life.

Study limitations include the lack of blinding, potential influence on patient care and insulin doses, and challenges on the patient level in performing blood glucose self-monitoring due to visual or cognitive problems.

“We found no difference regarding the frequency of hypoglycemia [and] the need for higher doses of insulin or other medications. There was also no impact on quality of life,” the researchers concluded. “In both groups there was a reduction in HbA1c values in 24 weeks of follow-up, however with an absolute greater reduction in the group that used pens.”

Reference

Machry RV, Cipriani GF, Pedroso HU, et al. Pens versus syringes to deliver insulin among elderly patients with type 2 diabetes: a randomized controlled clinical trial. DIabetol Metab Syndr. 2021;13(1):64. doi:10.1186/s13098-021-00675-y