Insulin leakage value in relation to pen needle length and administered dose after subcutaneous injection

SubQ-Sim: A Subcutaneous Physiologically Based Biopharmaceutics Model. Part 1: The Injection and System Parameters

PURPOSE

To construct a detailed mechanistic and physiologically based biopharmaceutics model capable of predicting 1) device-formulation-tissue interaction during the injection process and 2) binding, degradation, local distribution, diffusion, and drug absorption, following subcutaneous injection. This paper is part of a series and focusses on the first aspect.

METHODS

A mathematical model, SubQ-Sim, was developed incorporating the details of the various substructures within the subcutaneous environment together with the calculation of dynamic drug disposition towards the lymph ducts and venous capillaries. Literature was searched to derive key model parameters in healthy and diseased subjects. External factors such as body temperature, exercise, body position, food or stress provide a means to calculate the impact of "life events" on the pharmacokinetics of subcutaneously administered drugs.

RESULTS

The model predicts the tissue backpressure time profile during the injection as a function of injection rate, volume injected, solution viscosity, and interstitial fluid viscosity. The shape of the depot and the concentrations of the formulation and proteins in the depot are described. The model enables prediction of formulation backflow following premature needle removal and the resulting formulation losses. Finally, the effect of disease (type 2 diabetes) or the presence of recombinant human hyaluronidase in the formulation on the injection pressure, are explored.

CONCLUSIONS

This novel model can successfully predict tissue back pressure, depot dimensions, drug and protein concentration and formulation losses due to incorrect injection, which are all important starting conditions for predicting drug absorption from a subcutaneous dose. The next article will describe the absorption model and validation against clinical data.

Optimizing autoinjector devices using physics-based simulations and Gaussian processes

Autoinjectors are becoming a primary drug delivery option to the subcutaneous space. These devices need to work robustly and autonomously to maximize drug bio-availability. However, current designs ignore the coupling between autoinjector dynamics and tissue biomechanics. Here we present a Bayesian framework for optimization of autoinjector devices that can account for the coupled autoinjector-tissue biomechanics and uncertainty in tissue mechanical behavior. The framework relies on replacing the high fidelity model of tissue insertion with a Gaussian process (GP). The GP model is accurate yet computationally affordable, enabling a thorough sensitivity analysis that identified tissue properties, which are not part of the autoinjector design space, as important variables for the injection process. Higher fracture toughness decreases the crack depth, while tissue shear modulus has the opposite effect. The sensitivity analysis also shows that drug viscosity and spring force, which are part of the design space, affect the location and timing of drug delivery. Low viscosity could lead to premature delivery, but can be prevented with smaller spring forces, while higher viscosity could prevent premature delivery while demanding larger spring forces and increasing the time of injection. Increasing the spring force guarantees penetration to the desired depth, but it can result in undesirably high accelerations. The Bayesian optimization framework tackles the challenge of designing devices with performance metrics coupled to uncertain tissue properties. This work is important for the design of other medical devices for which optimization in the presence of material behavior uncertainty is needed.

Needle-free injection of basal insulin improves fasting glucose variability as assessed by continuous glucose monitoring in T2DM: a prospective randomized multicenter open-label crossover study

BACKGROUND

Fasting glucose variability (FGV) extensively promotes the onset and development of diabetic complications. This study aimed to evaluate the FGV in type 2 diabetes mellitus (T2DM) patients administered basal insulin using a needle-free insulin injector (NFII).

RESEARCH DESIGN AND METHODS

This was a prospective randomized multicenter open-label crossover study. We randomly assigned 48 T2DM patients to receive basal insulin by NFII or conventional insulin pen (CIP) for 7-14 days and were then crossed over after washout. We conducted continuous glucose monitoring to investigate the FGV, our primary outcome was a composite parameter of the FGV with a fasting blood glucose target between 4.4 and 6.1 mmol/L.

RESULTS

The coefficient of variation for sensor glucose at 6 a.m. with CIP was 11.67 (8.70,14.81)% vs. 9.48 (6.48,12.24)% with NFII (p = 0.003), and the coefficient of variation for mean sensor glucose at 5-6 a.m. with CIP was 12.70 (9.17,16.56)% vs. 9.23 (7.01,11.98)% with NFII (p < 0.001). The overall basal insulin dosage with CIP injection was 18.00 (16.00, 20.00) IU vs. 16.00 (12.00, 19.00) IU during NFII (p < 0.003).

CONCLUSION

Compared with CIP, the use of the NFII to inject basal insulin improved FGV in T2DM.

CLINICAL TRIAL REGISTRATION

https://www.chictr.org.cn Identifier is ChiCTR2000034674.

Insulin Injection Practice and Injection Complications - Results from the Bangladesh Insulin Injection Technique Survey

INTRODUCTION

Diabetes mellitus is highly prevalent in Bangladesh and insulin is often needed for diabetes control. We lack sufficient data on the insulin injection technique and injection-related complications.

METHODS

The Bangladesh Insulin Injection Technique Survey (BIITS) was conducted in 2018 in 18 centres throughout Bangladesh, involving 847 patients taking insulin for at least 6 months. All of the study subjects were interviewed using a structured questionnaire focusing on key insulin injection parameters.

RESULTS

The mean duration of insulin use by the study subjects was 3.84 (± 4.05) years and the mean daily dose of insulin was 41 (± 25) units. A total of 71.6% participants performed ≤2 injections/day and premixed insulins were the most commonly used insulins. Mean glycated haemoglobin (HbA1c) was 9.5% (± 2%). The proportion of syringe users and pen-device users was 68.1% and 31.9%, respectively. Most of the participants injected in the abdomen and rotated the injection site(s). The majority lifted the skinfold correctly and inserted the needle at a 90-degree angle, but their dwell times after injections were not adequate. A total of 9.2% of the subjects had injection-site lipohypertrophy (LH) and among them, 38.5% injected into the lesion. Patients with LH had higher HbA1c. Higher duration of insulin use (≥5 years), reusing needles more often (>10 times), and injecting at angles other than 90 degrees were independent predictors of LH. The incidences of hypoglycaemia (36.7%) and hyperglycaemia (67.4%) were very high, and subjects with LH had higher chances of both hypoglycaemia and hyperglycaemia. Though most (92.1%) of the patients received education about insulin injection initially, it was not repeated in the recent follow-up and was found to be ineffective.

CONCLUSION

A huge gap between the insulin administration guidelines and current practice was observed in this study. Complications of insulin injections were also common. Healthcare providers should pay more attention to insulin education and re-evaluate injection practices from time to time.

Efficacy, safety and acceptability of the new pen needle 34G × 3.5 mm: a crossover randomized non-inferiority trial; AGO 02 study

OBJECTIVE

Insulin injection aspects, such as fear of injection and pain, directly affect glycemic control, patient adherence and quality of life. Use of thinner and shorter needles could increase acceptance of injections. The aim of the study is to evaluate the non-inferiority of the new 34G × 3.5 mm needle compared to a 32G × 4 mm in patients with diabetes treated with insulin.

METHODS

This is an open, randomized, two-period crossover, non-inferiority trial. Every treatment period lasted 3 weeks. Patients with type 1 or type 2 diabetes, treated with multiple daily insulin injections, were randomly assigned to receive a 34G × 3.5 mm or a 32G × 4 mm pen needle. The primary endpoint was the non-inferiority of the 34G × 3.5 mm in comparison with the 32G × 4 mm pen needle in terms of percentage absolute change of blood fructosamine (% |ΔFru|), using a non-inferiority margin of 20%.

RESULTS

Overall 77 patients were randomized and 73 completed the study. Patients characteristics were: 52% male, 80.5% affected by type 1 diabetes, mean age 52 years (±14.6), mean BMI 24.5 kg/m² (±5.6), HbA1c 8% (±1.1) and baseline fructosamine level 350 µmol/l (±84). Mean fructosamine levels increased by 0.56 µmol/l with the 34G needle, while a reduction of 7.29 μmol/l was documented with the 32G needle. The difference between the two groups (7.84 μmol/l) was not statistically significant (p = .27). The % |ΔFru| between the two groups was 7.55% (95% CI 5.67-9.44), meeting the non-inferiority criterion. Glycemic variability, expressed as standard deviation of fasting blood glucose and post-prandial glucose, was not different between the two treatment groups (p = .63 and p = .77, respectively).

CONCLUSIONS

The 34G × 3.5 mm needle was non-inferior to the 32G × 4 mm needle regarding fructosamine levels and glycemic variability supporting the suitability of the 34G × 3.5 mm needle for insulin injection in patients with diabetes.

CLINICAL TRIAL REGISTRATION

NCT02690467.

Impact of Injection Speed, Volume, and Site on Pain Sensation

BACKGROUND

Painful subcutaneous insulin injections may decrease treatment compliance. Improving injection comfort therefore represents a particular area of technological research in which steady progress has been made since the introduction of the insulin pen in 1985. Injection pain can be influenced by many variables, but relatively little is known about their impact. This study investigated the impact of injection volume (range 0-2250 µL), speed (range 0-800 µL/sec), and site (abdomen vs thigh) on pain sensation.

METHOD

In random order, patients (n = 80) with type 1 or type 2 diabetes received 24 saline injections subcutaneously through a 27G ultra-thin-wall needle. Injections were performed in the abdomen (n = 19) and thigh (n = 5) with predefined speed-volume combinations. For each injected speed-volume combination, patients scored their pain sensation on a 100 mm visual analog scale (VAS).

RESULTS

The mean pain scores for speed-volume combinations were all in the lower part (<20 mm) of the VAS, indicating zero to mild pain. Pain sensation was statistically higher ( P < .05) with the 2250 µL volume compared to other injection volumes (range 4.3-5.1 mm) and with thigh compared to abdomen injections (2.1 mm). Pain sensation did not change with increasing injection speed. Patient acceptance of the injection pain was high for all injections (range 93.7-98.7%).

CONCLUSIONS

In summary, large volume and thigh injections are rated more painful, but the clinical impact of these findings is likely marginal considering the low absolute pain levels and high patient acceptance rates. Injection speed does not influence pain sensation.

Forum for Injection Technique and Therapy Expert Recommendations, India: The Indian Recommendations for Best Practice in Insulin Injection Technique, 2017

Health-care professionals in India frequently manage injection or infusion therapies in persons with diabetes (PWD). Patients taking insulin should know the importance of proper needle size, correct injection process, complication avoidance, and all other aspects of injection technique from the first visit onward. To assist health-care practitioners in their clinical practice, Forum for Injection Technique and Therapy Expert Recommendations, India, has updated the practical advice and made it more comprehensive evidence-based best practice information. Adherence to these updated recommendations, learning, and translating them into clinical practice should lead to effective therapies, improved outcomes, and lower costs for PWD.

New Insulin Delivery Recommendations

Many primary care professionals manage injection or infusion therapies in patients with diabetes. Few published guidelines have been available to help such professionals and their patients manage these therapies. Herein, we present new, practical, and comprehensive recommendations for diabetes injections and infusions. These recommendations were informed by a large international survey of current practice and were written and vetted by 183 diabetes experts from 54 countries at the Forum for Injection Technique and Therapy: Expert Recommendations (FITTER) workshop held in Rome, Italy, in 2015. Recommendations are organized around the themes of anatomy, physiology, pathology, psychology, and technology. Key among the recommendations are that the shortest needles (currently the 4-mm pen and 6-mm syringe needles) are safe, effective, and less painful and should be the first-line choice in all patient categories; intramuscular injections should be avoided, especially with long-acting insulins, because severe hypoglycemia may result; lipohypertrophy is a frequent complication of therapy that distorts insulin absorption, and, therefore, injections and infusions should not be given into these lesions and correct site rotation will help prevent them; effective long-term therapy with insulin is critically dependent on addressing psychological hurdles upstream, even before insulin has been started; inappropriate disposal of used sharps poses a risk of infection with blood-borne pathogens; and mitigation is possible with proper training, effective disposal strategies, and the use of safety devices. Adherence to these new recommendations should lead to more effective therapies, improved outcomes, and lower costs for patients with diabetes.

Injection Technique and Pen Needle Design Affect Leakage From Skin After Subcutaneous Injections

BACKGROUND

After a subcutaneous injection fluid might leak out of the skin, commonly referred to as leakage or backflow. The objective was to examine the influence of needle design and injection technique on leakage after injections in the subcutaneous tissue of humans and pigs.

METHOD

Leakage data were obtained from a post hoc analysis of clinical trial data and from a pig study. Data from the clinical study were used to determine leakage as a function of injection volume, speed and region. Data from the pig study were used to determine leakage as a function of needle wall thickness, needle taper, injection angle, and wait time from end of injection to withdrawal of needle from skin.

RESULTS

Leakage volume was positively related to injection volume. Injections in the abdomen caused less leakage than thigh injections. A 32G needle caused less leakage than a 31G and a 32G tip (tapered) needle, and a "straight in" 90° needle insertion angle caused less leakage than an angled (~45°) insertion. Wait times of minimum 3 seconds caused less leakage than immediate withdrawal of the needle after injection. Needle wall thickness and injection speed did not influence leakage.

CONCLUSIONS

Leakage will be minimized using a thin needle, using 90° needle insertion in the abdomen, injecting maximum 800 µL at a time, and waiting at least 3 seconds after the injection until the needle is withdrawn from the skin.

Improvement of Insulin Injection Technique: Examination of Current Issues and Recommendations

PURPOSE

Correct insulin injection technique is a crucial aspect of diabetes management. The purpose of this article is (1) to outline the medical literature, including patient-based studies and surveys, surrounding the type of issues and problems that patients encounter with injectable insulin therapy and the degree to which correct insulin technique is being applied and (2) to review the latest recommendations for insulin injection technique and discuss the key aspects that diabetes educators and other health care professionals should be communicating to their patients to ensure that injection technique is optimized.

CONCLUSIONS

Examination of the literature and multiple patient surveys demonstrates that patients continue to have many issues with insulin injection technique, highlighting the pressing need for effective patient education. In addition, many patients are not using insulin pen devices correctly. Widespread lack of injection site rotation and reuse of needles have resulted in high rates of lipohypertrophy. Lipohypertrophy has in turn been associated with significantly increased levels of unexplained hypoglycemia and glycemic variability and significantly increased insulin costs. By providing clear, evidence-based consensus recommendations, initiatives such as the Forum for Injection Technique are helping to address these issues but will be successful only if concerted efforts in patient education and reeducation are made to ensure that these recommendations are implemented consistently. This should involve all stakeholders in insulin therapy-particularly diabetes educators, who are at the forefront of patient education.

Nontraditional Considerations With Insulin Needle Length Selection

Ensuring the correct delivery of insulin is essential in the treatment of diabetes. Both proper injection technique and needle length are important considerations for adequate insulin delivery. There have been several studies demonstrating that BMI does not affect efficacy or insulin leakage with shorter pen needles (e.g., 4 or 5 mm vs. 12.7 mm). Additionally, the International Scientific Advisory Board for the Third Injection Technique Workshop released recommendations in 2010 on best practices for injection technique for patients with diabetes, which, with regard to needle length, concluded that 4-mm pen needles were efficacious in all patients regardless of BMI. However, regardless of patients' BMI, insulin injection technique should always be assessed and physically disabling comorbid conditions taken into consideration when choosing a needle length that will be manageable for patients. The purpose of this article is to raise awareness of unique patient circumstances that may warrant the use of the longer 12.7-mm needle.

Safety and efficacy of insulin therapy delivered via a 4mm pen needle in obese patients with diabetes

OBJECTIVE

To determine whether insulin delivered via a 4-mm × 32-gauge pen needle (PN) provides equivalent glycemic control as 8-mm × 31-gauge and 12.7-mm × 29-gauge PNs in obese (body mass index ≥30) patients with diabetes.

PATIENTS AND METHODS

This prospective, multicenter, randomized, open-label, 2-period, crossover, equivalence, home-based study was conducted from October 26, 2010, through May 31, 2012. After a 3-week wash-in period, eligible patients aged 18 to 80 years with a hemoglobin A1c (HbA1c) level of 5.5% to 9.5% (37-80 mmol/mol) were randomized to compare either 4- vs 8-mm PNs or 4- vs 12.7-mm PNs, using each of the 2 assigned PNs for 12 weeks in random order. The primary outcome was change in HbA1c level, with equivalence limits of ±0.4%.

RESULTS

The 274 patients randomized (mean ± SD age, 56.7±11.0 years) had a mean ± SD body mass index of 37.0±6.1 (range, 29.1-59.9) and took up to 350 U of insulin daily; 226 patients were included in the modified intention-to-treat analysis. Mean (95% CI) changes in HbA1c levels with the 4-mm PN were -0.08% (-0.21 to 0.06) and -0.10% (-0.19 to 0.00) vs the 8- and 12.7-mm PNs, respectively, within equivalence margins. The 4-mm PN was less painful than the larger PNs (P<.05), with similar leakage rates reported (4.1%-4.3%). Patients preferred the 4-mm PN over the 12.7-mm PN (P<.05) but not significantly vs the 8-mm PN. There were no differences between PNs in insulin doses and hypoglycemic or hyperglycemic adverse event rates.

CONCLUSION

The 4-mm × 32-gauge PN provides equivalent glycemic control as 8- and 12.7-mm PNs in obese patients with diabetes, with less pain and no increase in leakage. Shorter PNs should be considered in all insulin-requiring patients with diabetes, including those who are obese.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01231984.

Intramuscular risk at insulin injection sites--measurement of the distance from skin to muscle and rationale for shorter-length needles for subcutaneous insulin therapy

BACKGROUND

Intramuscular (IM) injection can increase insulin absorption, causing hypoglycemia. Available needle lengths today are 4-12.7 mm for pens and 6-12.7 mm for syringes. We describe the distance (D) from skin surface to muscle fascia at injection sites for subcutaneous (SC) insulin therapy and recommend needle lengths to reduce IM injection risk.

MATERIALS AND METHODS

At two locations in the United States, skin and SC fat thicknesses were measured by ultrasound at the abdomen, arm, thigh, and buttock in diverse adults (body mass index [BMI] range, approximately 19-65 kg/m²) with diabetes (n=341 with one or more paired skin and SC measurement, permitting calculation of D). The natural log of D by body site, BMI, and gender were analyzed using a mixed model to estimate IM risk.

RESULTS

D varied significantly by body site, BMI, and gender (each P<0.001), increasing with higher BMI and in women. Median D ranged from 10.9 mm (95% confidence interval, 10.3, 11.6) at the thigh to 16.9 mm (15.9, 18.1) at the buttock. Minimum D was <3 mm at the thigh and <5 mm elsewhere. When inserted 90° without pinch-up, the most commonly used needle worldwide (8 mm) has estimated IM risks of 25% and 9.7%, respectively, in the thigh and abdomen, versus 1.6% and 0.1%, respectively, with a 4 mm needle. A 45° insertion reduces, but does not eliminate, IM risk with longer needles.

CONCLUSIONS

Gender, BMI, and body site affect D; when combined with needle length and insertion angle, these factors permit detailed estimates of IM insulin injection risk. Such risk varies across sites, appears greatest at the thigh, is unnecessarily increased with 8 mm and 12.7 mm needles, and is greatly reduced with shorter-length needles and good injection technique.

Mucocutaneous blood contact: blood release behavior of safety peripheral intravenous catheters

BACKGROUND

Protection against needlestick injuries has significantly improved in recent years thanks to so-called "safety devices." However, a potential drawback occasionally reported by users is a risk of blood splashing. If this blood comes in contact with the mucous membranes, it could lead to an infection.

METHODS

Five safety peripheral intravenous catheter brands were examined in a laboratory test. To simulate the extreme situations, which may arise through human use, the introducer needle was withdrawn from the catheter at 2 different angles whereby an industrial robot was used to simulate the sequence of this movement. Each brand was tested 30 times. The experiment was carried out using radioactively labeled human whole blood. The measurements for the transmitted volume of blood was taken both from an artificial head and from a surface measuring 18.5 cm by 26.5 cm at a height of 30 cm above the catheter; scintigraphy was used to take the measurements.

RESULTS

The volume of blood droplets potentially splashing into the mucous membranes was in the range of 1 nL.

CONCLUSION

For normal virus concentrations in the blood of sick patients, this dose is too small to cause hepatitis C and HIV.

Comparison of the effects of a new 32-gauge × 4-mm pen needle and a 32-gauge × 6-mm pen needle on glycemic control, safety, and patient ratings in Japanese adults with diabetes

BACKGROUND

This study was designed to evaluate two pen needles (PNs) with the same diameter but different lengths (4 mm and 6 mm) and different needle tip shapes (straight and tapered) to compare their effects on glycemic control, perceived pain, safety, patients' ease of use and preferences, and visual impression.

SUBJECTS AND METHODS

In this prospective, open-label, controlled crossover study, 41 insulin-treated patients with type 1 or type 2 diabetes were randomized into either Group 1 (the 32-gauge × 4-mm PN was used during Study Period 1, then the 32-gauge × 6-mm PN was used during Study Period 2) or Group 2 (the order for using the PNs was reversed).

RESULTS

The 32-gauge × 4-mm PN provided an equivalent glycemic control in diabetes patients as the 32-gauge × 6-mm PN, with an equivalent occurrence rate of adverse events. The 32-gauge × 4-mm PN was perceived as significantly less painful and rated as significantly more favorable than the 32-gauge × 6-mm PN according to the survey results on patients' ease of use and preferences and on their visual impressions.

CONCLUSIONS

The 32-gauge × 4-mm PN was not only as safe and efficacious as the 32-gauge × 6-mm PN, but also was perceived as less painful, easier to use, and more favorable to Japanese adult patients with diabetes.

Translating the research in insulin injection technique: implications for practice

PURPOSE

Glucose variability leading to suboptimal glycemic control is common among people using injection therapies. Advanced technology and new studies have identified important issues related to injection technique: needle length and gauge, body mass index, skin and subcutaneous tissue thickness, adequate resuspension of cloudy insulins, leakage, choice of injection site and rotation, pinching a skinfold, and lipohypertrophy. All these issues can affect pain and bruising, insulin absorption, and blood glucose levels. The purpose of this article is to review current and past research regarding insulin injection therapy and to provide practical, translational information regarding injection technique, teaching/learning techniques specific to insulin administration, and implications for diabetes self-management education and support.

CONCLUSION

International injection recommendations for patients with diabetes have recently been published and have identified specific recommendations for health care professionals. This article provides an evidence-based translational and practical review of the research regarding injection technique and teaching/learning theory. Diabetes educators need to reevaluate how they provide instruction for the administration of insulin and other injectable medications. Research regarding skin and subcutaneous thickness reveals that shorter needles may be appropriate for the majority of patients regardless of body mass index. Periodic reassessment of injection technique, including suspension of cloudy insulins and inspection of injection sites for lipohypertrophy, is a critical aspect of the role of the diabetes educator. An injection checklist is provided as a guide for diabetes educators.

Glycemic control, reported pain and leakage with a 4 mm × 32 G pen needle in obese and non-obese adults with diabetes: a post hoc analysis

OBJECTIVE

The shortest pen needle (PN) for subcutaneous insulin therapy is 4 mm. Clinicians may hesitate to use it in obese patients. We report a post hoc analysis of a previously published study of the 4 mm × 32 G PN, evaluating responses in obese (≥30 kg/m(2)) and non-obese (<30 kg/m(2)).

METHODS

Subjects (BMI 20 to 49 kg/m(2), 52% obese) with diabetes used 4 mm × 32 G PNs and either 5 mm or 8 mm PNs (both 31 G) in two, 3-week treatment periods in a randomized noninferiority cross-over trial. Percentage absolute change in fructosamine (%│Δ Fru│) was the primary endpoint. Equivalent glycemic control was defined as %│Δ Fru│ within 20% (including 95% CI). The impact of obesity on change in fructosamine, pain and reported insulin leakage from the skin is described.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov - identifier: NCT00928057.

LIMITATIONS

This report is a post hoc analysis of two BMI subgroups resulting in smaller sample sizes.

RESULTS

Of 168 who completed the study, 163 were included in the fructosamine analyses - 83 and 80 in the 4/5 mm and 4/8 mm groups, respectively. For the 4/5 mm group, mean BMI ± SD in non-obese and obese groups were 25.9 ± 2.3 and 35.0 ± 4.9 kg/m(2), respectively; 4/8 mm group 25.2 ± 2.6 and 35.6 ± 4.2 kg/m(2). BMI group was not significant for %│Δ Fru│ for either 4/5 mm or 4/8 mm. Between BMI groups, the difference of the means in %│Δ Fru│ was 0.4% (4/5 mm) and 0.3% (4/8 mm). The 4 mm PN was significantly less painful in all subject groups, except non-obese in 4/5 mm. Regardless of needle size, obese subjects reported more leakage events. For both BMI groups, there were fewer total reported leakage events when using the 4 mm vs 5 mm and 8 mm needles.

CONCLUSIONS

The 4 mm pen needle provided equivalent glycemic control in both obese and non-obese patients compared to 5 mm and 8 mm needles with no increase in reports of skin leakage, in this post-hoc analysis. These findings should be confirmed in a prospective randomized controlled trial.

Analysis and perspective: comparison of insulin diluent leakage post-injection using two different needle lengths and injection volumes in obese patients with type 1 or type 2 diabetes mellitus

The effects of needle gauge and length on the efficacy and tolerability of insulin injection therapy are becoming better understood. This analysis discusses some of these effects and comments on a new study by Ignaut and Fu in this issue of Journal of Diabetes Science and Technology on the effects of needle length on insulin diluent leakage from injection sites.

Insulin administration: selecting the appropriate needle and individualizing the injection technique

INTRODUCTION

Patients with diabetes who receive insulin therapy often fail to meet their targets for metabolic control with insulin injections. Their inadequate glycemic control may be related to incorrect injection procedure.

AREAS COVERED

This review examines the latest data related to insulin injection and needle characteristics, which play an integral role in patient satisfaction. Searches of Medline and Cumulative Index to Nursing and Allied Health Literature databases were conducted. Results show that optimal insulin injection can facilitate glycemic control in pediatric and adult patients. In general, needles shorter than 8 mm are appropriate for normal weight, obese pediatric and adult patients. However, body mass index, gender, race, age and injection site can influence the depth of subcutaneous tissue and thus, the desired needle size and injection technique. Although the abdomen, thighs and buttocks are all recommended injection sites, abdominal injections disperse insulin slightly more rapidly than thigh injections.

EXPERT OPINION

Wider acceptance of needles shorter than 6 mm will occur with more evidence of their safety and efficacy, particularly in children. Development of shorter and thinner needles to make injections even easier and less burdensome may be expected in the future.