TOPLINE

Among adults with cystic fibrosis–related diabetes (CFRD), those administered ultrafast-acting insulin after meals achieved glycemic control similar to that achieved by those given standard mealtime fast-acting insulin, with no notable differences in several continuous glucose monitoring (CGM) metrics, A1c levels, or insulin dose.

METHODOLOGY

• Although guidelines recommend giving insulin before meals, premeal insulin administration is often impractical for patients with CFRD due to unpredictable eating patterns and the risk for delayed hypoglycemia, prompting researchers to test whether ultrafast-acting insulin given after meals could offer a more flexible, equally effective alternative.
• They conducted a phase 4 clinical trial in France from August 2020 to January 2024 to compare two insulin-timing strategies — mealtime and postprandial insulin — in 38 patients with CFRD (mean age, 33 years; 63% women; 21 on CFTR modulators); 34 participants with CGM recordings available at baseline and for at least one treatment period during follow-up were included in further analysis.
• Each participant switched between standard mealtime insulin and after-meal ultrafast insulin every 3 months over a full year — covering months 0-3, 3-6, 6-9, and 9-12 — following 1 of 2 randomly assigned orders.
• During mealtime dosing, insulin was given immediately before or at the start of a meal; during postprandial dosing, insulin was given 20-30 minutes after the meal began.
• The primary endpoint was the time in range, measured as the percentage of time with blood glucose levels of 70-180 mg/dL, over the final 2 weeks of each treatment period. Secondary outcomes included other CGM measures as well as A1c, fasting glucose, and C-peptide levels.

TAKEAWAY

• The time in range was 75.8% with mealtime insulin and 74.7% with postprandial insulin, representing a nonsignificant difference of 1.1 percentage points (P = .316).
• The secondary CGM metrics — the time above range, the time below range, and the Glycemia Risk Index — were also similar between the two strategies.
• A1c, fasting glucose, and C-peptide levels and total, basal, and prandial insulin doses did not differ between treatments.
• CFTR modulators did not change most blood sugar outcomes, but their use was linked to less time spent in hypoglycemia (blood glucose levels < 54 mg/dL).

IN PRACTICE

"The clinical implication of our study is not that patients with CFRD should routinely carry or use two different types of insulin, but rather that postprandial administration of ultra-rapid-acting insulin may provide greater flexibility in the timing of insulin administration without compromising glycemic control," the authors wrote.

SOURCE

The study was led by Luc Rakotoarisoa, Diabetes and Nutrition Department, University Hospital of Strasbourg, Strasbourg, France. It was published online in Diabetes Research and Clinical Practice.

LIMITATIONS

The sample size was small, reflecting the rarity of CFRD and recruitment challenges during the COVID pandemic. CFTR modulator use was not evenly balanced between the randomly assigned groups, which may have affected the results. The study population had relatively good glycemic control, with a mean time in range exceeding 70%, possibly limiting the generalizability of the findings to individuals with poorer glycemic control.

DISCLOSURES

This study was supported by the French patient association Vaincre la Mucoviscidose. The authors reported no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.