Insulin injection technique

A Risk-Based Assessment for Determining the Pharmacokinetic Comparability Requirements of Biologic-Device Combination Products Administered by Subcutaneous Injection

The development of new large molecule drug therapies along with the innovation of biologic-device combination products such as prefilled syringes, autoinjectors and pen injectors have significantly impacted the treatment of new diseases and has improved the process of administering parenteral medicines. To support the regulatory approval of a new biologic-device combination products or subsequent chemistry, manufacturing and control changes impacting a combination product, sponsor companies must thoroughly assess the potential impact to product quality, safety and efficacy. In this report, a risk-based process to determine the potential impact to product quality, safety, and efficacy as well as corresponding regulatory actions supporting a chemistry, manufacturing and control change is presented. The risk assessment includes the standardized assessment of a) chemistry, manufacturing and control risk factors, potential responses and appropriately weighted scoring; b) pharmacokinetic risk factors, potential responses and appropriately weighted scoring; and c) the use of a 2-dimensional risk grid to combine the chemistry, manufacturing and control risks and pharmacokinetic risks to provide a regulatory recommendation. Three case studies (two clinical case studies and a post-approval case study) are provided to demonstrate the assessment process and capabilities.

The Durability of an Intensive, Structured Education-Based Rehabilitation Protocol for Best Insulin Injection Practice: The ISTERP-2 Study

INTRODUCTION

Studies on the durability of an intensive, structured education protocol on best insulin injection practice are missing for people with type 2 diabetes mellitus (T2DM). The aim of this study was to assess the durability of an intensive, structured education-based rehabilitation protocol on best insulin injection practice in well-trained subjects from our previous intensive, multimedia intervention study registered as the ISTERP-1 study. A total of 158 subjects with T2DM from the well-trained group of the 6-month-long ISTERP-1 study, all of whom had successfully attained lower glucose levels compared to baseline levels with lower daily insulin doses and with less frequent and severe hypoglycemic episodes, participated in the present investigation involving an additional 6-month follow-up period, called the ISTERP-2 study.

METHODS

Participants were randomized into an intervention group and a control group, depending on whether they were provided or not provided with further education refresher courses for 6 months. At the end of the 6 months, the two groups were compared in terms of injection habits, daily insulin dose requirement, number of severe or symptomatic hypoglycemic events, and glycated hemoglobin (HbA1c) levels.

RESULTS

Despite being virtually superimposable at baseline, the two groups behaved quite differently during the follow-up. The within-group analysis of observed parameters showed that the subjects in the intervention group maintained and even improved the good behavioral results learned during the ISTERP-1 study by further reducing both the rate of injection technique errors (p < 0.001) and size of lipohypertrophic lesions at injection sites (p < 0.02). Conversely, those in the control group progressively abandoned best practice, except for the use of ice-cold insulin and, consequently, had significantly higher HbA1c levels and daily insulin dose requirements at the end of the follow-up than at baseline (p < 0.05). In addition, as expected from all the above, the rate of hypoglycemic episodes also decreased in the intervention group (p < 0.05), resulting in a significant difference between groups after 6 months (p < 0.02).

CONCLUSION

Our data provide evidence that intensive, structured education refresher courses have no outstanding durability, so that repeated refresher courses, at least at 6-month intervals, are needed to have positive effects on people with T2DM, contributing not only to prevention but also to long-term rehabilitation.

TRIAL REGISTRATION

Trial Registration no. 118 bis/15.04.2018.

Role of Structured Education in Reducing Lypodistrophy and its Metabolic Complications in Insulin-Treated People with Type 2 Diabetes: A Randomized Multicenter Case-Control Study

INTRODUCTION

It is essential to use the correct injection technique (IT) to avoid skin complications such as lipohypertrophy (LH), local inflammation, bruising, and consequent repeated unexplained hypoglycemia episodes (hypos) as well as high HbA1c (glycated hemoglobin) levels, glycemic variability (GV), and insulin doses. Structured education plays a prominent role in injection technique improvement. The aim was to assess the ability of structured education to reduce (i) GV and hypos, (ii) HbA1c levels, (iii) insulin daily doses, and (iv) overall healthcare-related costs in outpatients with T2DM who were erroneously injecting insulin into LH.

METHODS

318 patients aged 19-75 years who had been diagnosed with T2DM for at least 5 years, were being treated with insulin, were routinely followed by a private network of healthcare centers, and who had easily seen and palpable LH nodules were included in the study. At the beginning of the 6-month run-in period (T-6), all patients were trained to perform structured self-monitoring of blood glucose and to monitor symptomatic and severe hypos (SyHs and SeHs, respectively). After that (at T0), the patients were randomly and equally divided into an intervention group who received appropriate IT education (IG) and a control group (CG), and were followed up for six months (until T+6). Healthcare cost calculations (including resource utilization, loss of productivity, and more) were carried out based on the average NHS reimbursement price list.

RESULTS

Baseline characteristics were the same for both groups. During follow-up, the intra-LH injection rate for the CG progressively decreased to 59.9% (p < 0.001), a much smaller decrease than seen for the IG (1.9%, p < 0.001). Only the IG presented significant decreases in HbA1c (8.2 ± 1.2% vs. 6.2 ± 0.9%; p < 0.01), GV (247 ± 61 mg/dl vs. 142 ± 31 mg/dl; p < 0.01), insulin requirement (- 20.7%, p < 0.001), and SeH and SyH prevalence (which dropped dramatically from 16.4 to 0.6% and from 83.7 to 7.6%, respectively; p < 0.001). In the IG group only, costs-including those due to the reduced insulin requirement-decreased significantly, especially those relating to SeHs and SyHs, which dropped to €25.8 and €602.5, respectively (p < 0.001).

CONCLUSION

Within a 6-month observation period, intensive structured education yielded consistently improved metabolic results and led to sharp decreases in the hypo rate and the insulin requirement. These improvements resulted in a parallel drop in overall healthcare costs, representing a tremendous economic advantage for the NHS. These positive results should encourage institutions to resolve the apparently intractable problem of LH by financially incentivizing healthcare teams to provide patients with intensive structured education on proper injection technique.

TRIAL REGISTRATION

Trial registration no. 118/15.04.2018, approved by the Scientific and Ethics Committee of Campania University "Luigi Vanvitelli," Naples, Italy, and by the institutional review board (IRB Min. no. 9926 dated 05.05.2018).

Indian Injection Technique Study: Population Characteristics and Injection Practices

INTRODUCTION

It was estimated that 3.2 million Indians with diabetes injected insulin in 2010, but little is known about the techniques used.

METHODS

In 2015 we conducted an injection technique questionnaire (ITQ) survey throughout India involving 1011 patients. Indian values were compared with those from 41 other countries participating in the ITQ, known here as rest of world (ROW).

RESULTS

Mean HbA1c was 8.6. BMI values in India were 1.5-3 units lower than in ROW depending on patient group, meaning the risk of intramuscular (IM) injections is high in India. The mean total daily dose (TDD) of insulin was lower in every category of Indian patient than in ROW, perhaps reflecting the lower BMI. Needle reuse, whether with pens or syringes, is much higher in India than ROW and so is the number of times the needle is used. The majority (56.8%) of Indian insulin users performed only 2 injections/day as opposed to ROW where 45% of patients performed at least 4 injections/day. Indian patients inject insulin in the thighs more often than patients in ROW, a site where IM injections are more risky. Many patients do not have proper access to sharps containers or have other risk factors that could lead to blood-borne pathogen spread. More than 60% of used sharps in India go into the rubbish, with nearly 12% not even having the minimum protection of a cap.

DISCUSSION

The shortest needles are very common in India; however, the level of needle reuse is high. Multiple daily injections therapy is not as common in India as ROW. More focus needs to be given to dwell times under the skin, reconstitution of cloudy insulins, skinfolds, and safe sharps disposal.

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.

Worldwide Injection Technique Questionnaire Study: Population Parameters and Injection Practices

From February 1, 2014, through June 30, 2015, 13,289 insulin-injecting patients from 423 centers in 42 countries took part in one of the largest surveys ever performed in diabetes. The goal was to assess patient characteristics, as well as historical and practical aspects of their injection technique. Results show that 4- and 8-mm needle lengths are each used by nearly 30% of patients and 5- and 6-mm needles each by approximately 20%. Higher consumption of insulin (as measured by total daily dose) is associated with having lipohypertrophy (LH), injecting into LH, leakage from the injection site, and failing to reconstitute cloudy insulin. Glycated hemoglobin values are, on average, 0.5% higher in patients with LH and are significantly higher with incorrect rotation of sites and with needle reuse. Glycated hemoglobin values are lower in patients who distribute their injections over larger injection areas and whose sites are inspected routinely. The frequencies of unexpected hypoglycemia and glucose variability are significantly higher in those with LH, those injecting into LH, those who incorrectly rotate sites, and those who reuse needles. Needles associated with diabetes treatment are the most commonly used medical sharps in the world. However, correct disposal of sharps after use is critically suboptimal. Many used sharps end up in public trash and constitute a major accidental needlestick risk. Use of these data should stimulate renewed interest in and commitment to optimizing injection practices in patients with diabetes.

Subcutaneous Injection Depth Does Not Affect the Pharmacokinetics or Glucodynamics of Insulin Lispro in Normal Weight or Healthy Obese Subjects

BACKGROUND

An 8-mm needle length is commonly used for insulin injections; however, recent recommendations suggest shorter needles may help patients avoid intramuscular injections and reduce pain, while maintaining adequate glucose control. The goal of these analyses was to compare the pharmacokinetics (PK) and glucodynamics (GD) of insulin lispro after a 5-mm or an 8-mm injection depth administration in 2 populations: normal weight (study 1) or obese (study 2).

METHODS

In both open-label, randomized, 2-period crossover euglycemic clamp studies, subjects received single 0.25 U/kg insulin lispro doses on 2 occasions (at 5-mm and 8-mm injection depths); samples for PK and GD analyses were collected up to 6 hours postdose. Noncompartmental PK parameters AUC0-tlast, AUC0-∞, Cmax and GD parameters Gtot, Rmax, tRmax were log-transformed prior to analysis using a mixed effects model.

RESULTS

There were no apparent differences between PK profiles at the 5-mm or 8-mm injection depth in either study, demonstrated by the ratios of geometric means of AUC0-tlast, AUC0-∞, and Cmax being close to 1, with 90% confidence intervals (CI) within (0.80, 1.25). There were no apparent differences between GD profiles at either injection depth with the ratios of Gtot and Rmax near unity and 90% CIs that included 1. In both studies, the tRmax values were similar between injection depths, with a small median of pairwise differences and a 90% CI that included zero.

CONCLUSIONS

Injection depths in the 5-8 mm range did not affect the PK or GD of insulin lispro in normal weight or obese subjects.

Simplicity, safety, and acceptability of insulin pen use versus the conventional vial/syringe device in patients with type 1 and type 2 diabetes mellitus in Lebanon

BACKGROUND

The aim of the study was to evaluate the simplicity, safety, patients' preference, and convenience of the administration of insulin using the pen device versus the conventional vial/syringe in patients with diabetes.

METHODS

This observational study was conducted in multiple community pharmacies in Lebanon. The investigators interviewed patients with diabetes using an insulin pen or conventional vial/syringe. A total of 74 questionnaires were filled over a period of 6 months. Answers were entered into the Statistical Package for Social Sciences (SPSS) software and Excel spreadsheet. t-test, logistic regression analysis, and correlation analysis were used in order to analyze the results.

RESULTS

A higher percentage of patients from the insulin pen users group (95.2%) found the method easy to use as compared to only 46.7% of the insulin conventional users group (P 0.001, relative risk [RR]: 2.041, 95% confidence interval [CI]: 1.178-3.535). Moreover, 61.9% and 26.7% of pen users and conventional users, respectively, could read the scale easily (P 0.037, RR 2.321, 95% CI: 0.940-5.731), while 85.7% of pen users found it more convenient shifting to pen and 86.7% of the conventional users would want to shift to pen if it had the same cost. Pain perception was statistically different between the groups. A much higher percentage (76.2%) of pen users showed no pain during injection compared to only 26.7% of conventional users (P 0.003, RR 2.857, 95% CI: 1.194-6.838).

CONCLUSION

The insulin pen was significantly much easier to use and less painful than the conventional vial/syringe. Proper education on the methods of administration/storage and disposal of needles/syringes is needed in both groups.

Skin and subcutaneous thickness at injecting sites in children with diabetes: ultrasound findings and recommendations for giving injection

BACKGROUND

Children who inject insulin need clear guidelines as to the length of needle best for them. We studied the distance from surface to muscle in children in order to make needle choices which are evidence-based.

METHODS

One hundred one children with type 1 diabetes were divided into three groups according to age: 2-6, 7-13, and 14-17 yr. The thickness of skin and subcutaneous (SC) tissue was measured by ultrasound in all injection sites.

RESULTS

Skin thickness varied from 1.58 mm in the arm of the youngest children to 2.29 mm in the buttocks of the adolescents. Values decreased progressively based on age (2-6 < 7-13 < 14-17) and on body site (arm < thigh < abdomen < buttocks). Skin + SC thickness varied in a similar fashion. The skin surface to muscle distances were <4 mm in nearly 10% of children, especially in the 2-6 yr group. In this group, the rate of intramuscular (IM) injections using the 4-mm pen needle when a pinch-up is not used would be 20.2%. This rate of IM injections doubles when using the 5-mm needle, and when injections are given under similar conditions it triples using the 6-mm needle.

CONCLUSIONS

It seems medically appropriate for all children to use short needles where possible to minimize inadvertent IM injections which may increase glycemic variability. Currently, the safest needle for all children appears to be the 4-mm pen needle. However, when used in children aged 2-6 yr, it should be used with a pinched skin fold.

Subcutaneous adipose tissue thickness in adults - correlation with BMI and recommendations for pen needle lengths for subcutaneous self-injection

OBJECTIVE

One of the aims of a subcutaneous (SC) injection is to avoid intradermal or intramuscular injections. Pen systems are an alternative solution to single-use syringes and have become standard for example diabetes therapy. Shorter and smaller needles minimize pain and the risk of intramuscular injections. The thickness of subcutaneous adipose tissue (SCAT) varies with position and with body mass index (BMI). The aim of this study was the creation of a map of SCAT thickness at typical spots for SC self-injection.

MATERIALS AND METHODS

MRI scans of 116 prospectively enroled volunteers (56 men and 60 women) were analysed. SCAT thickness was determined at 17 spots over the abdominal wall, left thigh, buttocks and upper arm, typical sites for subcutaneous self-injection. SCAT thicknesses were correlated with BMI and waist-to-hip ratio (WHR), and a linear curve fit was performed. The best fitting linear functions for the prediction of the SCAT thickness dependent on BMI and WHR were derived.

RESULTS

Correlations between SCAT and BMI were higher (0·67-0·21) than with WHR (-0·67 to 0·09). In women, correlation coefficients between SCAT data at the abdomen and BMI/WHR were higher than in men. On the other hand, data showed better correlations at the extremities in men.

CONCLUSIONS

The data, with correlation between BMI and fat thickness at different injection sites in relation to gender, provide guidance in selecting an adequate pen needle length for deep and safe subcutaneous self-injection. WHR was a much weaker predictor when compared to BMI.

New injection recommendations for patients with diabetes

AIM

Injections administered by patients are one of the mainstays of diabetes management. Proper injection technique is vital to avoiding intramuscular injections, ensuring appropriate delivery to the subcutaneous tissues and avoiding common complications such as lipohypertrophy. Yet few formal guidelines have been published summarizing all that is known about best practice. We propose new injection guidelines which are thoroughly evidence-based, written and vetted by a large group of international injection experts.

METHODS

A systematic literature study was conducted for all peer-reviewed studies and publications which bear on injections in diabetes. An international group of experts met regularly over a two-year period to review this literature and draft the recommendations. These were then presented for review and revision to 127 experts from 27 countries at the TITAN workshop in September, 2009.

RESULTS

Of 292 articles reviewed, 157 were found to meet the criteria of relevance to the recommendations. Each recommendation was graded by the weight it should have in daily practice and by its degree of support in the medical literature. The topics covered include The Role of the Professional, Psychological Challenges, Education, Site Care, Storage, Suspension and Priming, Injecting Process, Proper Use of Pens and Syringes, Insulin analogues, Human and Pre-mixed Insulins, GLP-1 analogs, Needle Length, Skin Folds, Lipohypertrophy, Rotation, Bleeding and Bruising, Pregnancy, Safety and Disposal.

CONCLUSION

These injecting recommendations provide practical guidance and fill an important gap in diabetes management. If followed, they should help ensure comfortable, effective and largely complication-free injections.

Defining the ideal injection techniques when using 5-mm needles in children and adults

OBJECTIVE

We aimed to establish the ideal injection techniques using 5-mm needles to reliably inject insulin into the subcutaneous fat in both children and adults and to quantify the associated pain and leakage of the test medium.

RESEARCH DESIGN AND METHODS

A total of 259 subjects (122 children/adolescents and 137 adults) were injected with sterile air corresponding to 20 IU insulin (200 microl) with 32-G 5-mm needles at 90 degrees or 45 degrees , in the abdomen and thigh, and with or without a pinched skin fold. Injection depth was assessed via ultrasonography. Subjects rated pain on a visual analog scale. Test medium injections into the abdomen and thigh (0.2-0.6 ml) were also administered to assess injection leakage.

RESULTS

Among children, 5.5% of injections were intramuscular (IM) and 0.5% were intradermal, while in adults, the incidence was 1.3 and 0.6%, respectively. The frequency of IM injections was greater in boys and negligible among adult women. Subcutaneous fat thickness was the primary predictor of the likelihood of IM injections (P < 0.001). A third of all patients reported experiencing no pain during insulin injection, with children/adolescents experiencing considerably more discomfort than adults. Some leakage of medium was observed, but was unrelated to injection volume and was generally minimal.

CONCLUSIONS

5-mm needles are reliably inserted into subcutaneous fat in both adults and children. These needles were associated with reduced pain and minimal leakage. We recommend an angled injection with a pinched skin fold for children, while in adults, the technique should be left to patient preference.

Skin and subcutaneous adipose layer thickness in adults with diabetes at sites used for insulin injections: implications for needle length recommendations

OBJECTIVE

During subcutaneous insulin therapy, inadvertent intramuscular (IM) injections may increase pain and/or adversely affect glucose control. The most appropriate needle length for patients depends on skin thickness (ST) and the distance to muscle fascia. ST and subcutaneous adipose layer thickness (SCT) were measured in adults with diabetes.

RESEARCH DESIGN AND METHODS

A total of 388 US adults with diabetes (in three BMI subgroups: <25, 25-29.9, and >or=30 kg/m(2)) with diverse demographic features were evaluated. Each subject had ultrasound measurements of ST and SCT at four injection sites.

RESULTS

Subjects had BMI 19.4-64.5 kg/m(2), age 18-85 years; 40% Caucasian, 25% Asian, 16% Black, 14% Hispanic; 28% type 1 diabetes. Mean ST (+/-95% CI) was: arm 2.2 mm (2.2, 2.3), thigh 1.9 mm (1.8, 1.9), abdomen 2.2 mm (2.1, 2.2) and buttocks 2.4 mm (2.4, 2.5). Multivariate analyses showed body site, gender, BMI, and race are statistically significant factors for ST but effects were small. Thigh ST was <0.6 mm thinner than the buttocks. Differences of 10 kg/m(2) account for 0.2 mm ST variation. Mean SCT was: arm 10.8 mm (10.2, 11.3), thigh 10.4 mm (9.8, 10.9), abdomen 13.9 mm (13.2, 17.7) and buttocks 15.4 mm (14.7, 16.2). Females had 5.1 mm greater SCT. Differences of 10 kg/m(2) account for 4 mm SCT variation.

ADVERSE EVENTS

A few mild hypo- or hyperglycemia events, unrelated to study procedure, were detected and treated before subject discharge from study visits.

LIMITATIONS

Only adults in the US were studied; some measurements could not be obtained on every subject, at every injection site.

CONCLUSIONS

Injection site ST does not differ by clinically significant degrees in demographically diverse adults with diabetes; SCT has a wider range. Needles >or=8 mm, inserted perpendicularly, may frequently enter muscle in limbs of males and those with BMI <25 kg/m(2). With 90 degrees insertion, needles 4-5 mm enter the subcutaneous tissue with minimal risk of IM injection in virtually all adults. These data will assist recommending appropriate length needles for subcutaneous insulin injections in adults.

An angled insertion technique using 6-mm needles markedly reduces the risk of intramuscular injections in children and adolescents

AIMS

The aims of this study were (i) to establish which children with Type 1 diabetes are at risk of intramuscular or intradermal insulin injections and (ii) to determine a needle length and technique that reliably administers insulin into subcutaneous fat.

METHODS

Seventy-two healthy diabetic children (age 6.3-14.3 years, body mass index standard deviation score 1.0 +/- 1.4) were recruited for study 1 and 37 of this cohort participated in study 2. In study 1, 200 microl air was injected into the abdomen and anterior thigh by a pinched skin-fold technique using either a perpendicular insertion of NovoFine(R) 31G 6-mm or an angled insertion of NovoFine(R) 30G 8-mm needles. In study 2, subjects received injections into abdomen and anterior thigh via angled 6-mm needles with either an unpinched or pinched technique. The site of air injection was visualized by ultrasound scan and measurements taken of subcutaneous fat thickness.

RESULTS

In study 1, intramuscular injections were detected in 32% of subjects, and in a further 22% air was visualized at the muscle fascia. In study 2, intramuscular injections occurred in 3% of subjects and a further 11% had muscle fascia air detected. No intramuscular injections occurred in subjects injecting with a 6-mm needle and an angled pinched skin-fold technique. Pinching abdomen and thigh skin folds increased the subcutaneous fat thickness by 192 +/- 16% and 22 +/- 6%, respectively. In very lean subjects, pinching thighs actually reduced subcutaneous fat thickness.

CONCLUSIONS

While intramuscular injections were observed frequently using standard injection protocols, an angled 6-mm needle technique reliably injects into the subcutaneous fat.

Subcutaneous insulin: pharmacokinetic variability and glycemic variability

The therapeutic goal in insulin-treated diabetic patients is to maintain on the long-term a tight glucose control (HbA1, < 6.5-7% or less) through an insulin regimen which "mimic" the physiological insulin profile: a basal insulin secretion to maintain glucose homeostasis and an acute post-prandial secretion in response to meal intake. Such goal represents a challenge for the clinician as conventional human insulins have major drawbacks: slow absorption and too late peak with regular insulins, delayed peak and often occuring at an unwanted time with intermediate and long-acting insulins. Furthermore, these insulins are characterised by a large within- and between-subjects variability, which complicate patients' task to self-adapt their daily doses, even for those well educated and compliants. These limitations and unpredictable variations in insulin action are responsible for an increased risk of hypoglycemic events, between meals as well as during the night period. As a consequence, glucose control is frequently insufficient in type 1 diabetic patients, and these limitations may contribute also to the delayed initiation of insulin therapy in type 2 diabetics when oral antidiabetic agents fail. This variability and the non-reproducibility of the conventional insulin pharmacodynamics are explained by several exogenous and endogenous factors describe in this review. Availability of new short-acting (lispro, aspart and glulisine) and long-acting analogs (glargine, detemir) of human insulin, with improved pharmacokinetic characteristics, and a lesser variability and better reproducibility, should facilitate a tight glucose control in insulin-treated patients. The main pharmacokinetic and pharmacodynamic characteristics of these new insulin analogs are presented and discussed in the light of there intra- and inter-individual variability. Their reduced variability should permit to reinforce near "physiological" insulin regimen such as "basal-bolus" technique and to consider new approaches and therapeutic strategies in type 1 and type 2 diabetic patients.

Performing Subcutaneous Injections: A Literature Review

BACKGROUND

Persons using daily subcutaneous injections to administer medicine perform them in different ways and thereby increase the risk of skin complications related to the injection. It is often part of nurses' role to administer medicine and educate the patient in injection technique. Course literature in nursing education, commercial patient education pamphlets, and instructional leaflets do not give consistent advice regarding subcutaneous injection technique.

AIM

The aim of this review was to identify the scientific foundation for the technical performance of subcutaneous injections. The question to be answered was: How should a subcutaneous injection be administered to achieve the right dose in the right place with minimum complications?

METHOD

The review included a search in three databases, a screening process at abstract level, followed by a quality assessment of included articles. The quality assessment was done independently by two people and followed specific protocols.

RESULT

A total of 38 articles were assessed for quality and covered information on dose, location, and complications of subcutaneous injection. The assessed studies are heterogeneous in design and describe different aspects of the subcutaneous injection technique. Therefore, the scientific foundation for technical performance is weak. However, several studies indicate that the amount of subcutaneous fat and appropriate needle length are of high importance for the drug to reach the target tissue.

CONCLUSION

More research regarding effective subcutaneous injection technique needs to be done.

Role Of Injection Technique In Use Of Insulin Pens: Prospective Evaluation Of A 31-Gauge, 8-Mm Insulin Pen Needle

OBJECTIVE

To evaluate the effectiveness, comfort, and ease of use of insulin pen injections with a 31-gauge, 8-mm needle.

METHODS

In 50 study subjects (24 patients with type 1 insulin-dependent diabetes and 26 insulin-using patients with type 2 diabetes), we assessed the delivery of insulin, residual insulin leakage, glycemic control, plunger depression pressure, and perceived pain associated with the B-D 31-gauge, 8-mm pen needles in comparison with the B-D conventional 30-gauge, 8-mm pen needles, while the patient used their own insulin pens (Novo or B-D). The study subjects injected their usual dose of regular and NPH insulin using the 30-gauge, 8-mm needle during the first 3 weeks of the study. This period was followed by two 3-week crossover segments of the study with either needle assigned in random sequence.

RESULTS

No statistically significant differences were noted in glycemic control or perceived pain of injection between the two needles. The interaction between the two needles and the two insulin pen brands on glycemic control was not statistically significant. Plunger depression pressure increased with the increase in the gauge of the needle and with increases in size of dose of injected insulin (P<0.01). B-D pen users reported lower plunger pressure ratings in comparison with Novo pen users (P<0.01), regardless of the needle type and dose range. Both the insulin pen type and the needle type individually had statistically significant (P<0.01) effects on the residual insulin leakage from the needle tip after injection; however, their interaction was not statistically significant. Insulin doses greater than 30 units were associated with increased leakage (P<0.01). As needle retention time decreased, residual insulin leakage from the needle tip after injection increased (P<0.01), regardless of the needle used.

CONCLUSION

The 31-gauge insulin pen needles are safe and effective for the delivery of insulin. With both 30-gauge and 31-gauge needles, attention to injection technique is essential to ensure complete delivery of insulin, particularly with administration of large doses.

Subcutaneous treatment with recombinant human erythropoietin--the influence of injection frequency and skin-fold thickness

Subcutaneous treatment with erythropoietin (epoetin) in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) is convenient, but the optimal injection frequency is under discussion. Epoetin was given subcutaneously to 22 stable anaemic CAPD patients in doses that adjust haemoglobin to 7.2+/-0.3 mmol/l during a correction period. During the maintenance period the frequency of injections in four randomized groups of patients was changed randomly to once, twice or three times a week or daily. Each period lasted more than 8 weeks. During the maintenance period the epoetin dose was almost unchanged, whether the patients were treated once, twice or thrice weekly. In 15 patients treated with daily injections, the overall dose reduction was 22%. These 15 patients were grouped arbitrarily into 7 patients with a skin-fold of more than 20 mm at the injection site, and 8 patients with a skin-fold of less than 20 mm at the injection site. The dose reduction correlated with skin-fold thickness; the reduction was seen only in the patients with skin-folds of less than 20 mm. Seven of the eight patients experienced an average dose reduction of 36+/-8%.

Diabetologic in-service education for health professionals from non-diabetological departments

In order to test whether or not an in-service requalification course on diabetes care for health professionals (HP) of nondiabetological departments can enhance their level of knowledge about diabetes and the quality of care for diabetic inpatients admitted for reasons other than diabetes, we carried out a requalification course involving 171 HP (161 nurses and 10 midwives) from nondiabetological departments of our hospital. Areas of intervention were: general knowledge of diabetes (GKD), bedside monitoring of blood glucose (BMG), insulin preparation and administration (IPA), diagnosis and treatment of hypoglycemic crises (DTH), and hospitalization-related problems (HRP). HP, divided into groups of about 20 each, completed a basal evaluation by means of a 25-item multiple choice questionnaire, and then attended six separate educative sessions, each of focusing on one topic, consisting of a theory lesson and an interactive exercise of equivalent length. At the end of the course, HP were re-evaluated with the same questionnaire, and their skills in BMG, IPA and DTH were tested by means of specific operational checklists, which divided each complex operation into a sequence of single operations, and then compared them with those of a control group of untrained colleagues (CG). The global knowledge of diabetes after the courses significantly improved, as gathered from the percentages of correct answers in each questionnaire (61.82% +/- 23.64% vs 31.18% +/- 20.00%; P < 0.001); separate analysis of different areas evidenced improvements in GKD (72.28% +/- 12.47% vs 31.46% +/- 20.56%; P < 0.01), BMG (68.77% +/- 15.75% vs 37.50% +/- 27.75%; P < 0.01), IPA (72.02% +/- 11.72% vs 33.45% +/- 21.22%; P < 0.05), and DTH (90.76% +/- 6.86% vs 49.82% +/- 26.68%; P < 0.05), but not in HRP. Professional skills profiles of HP, evaluated by measuring the number of errors done performing each task, were significantly (P < 0.001) better than those of CG, for BMG (1.09 +/- 0.73 vs 4.91 +/- 2.01), IPA (2.36 +/- 1.64 vs 5.64 +/- 2.25), and DHT (1.27 +/- 0.94 vs 3.82 +/- 1.12). Linear regression showed a significant (P < 0.001) correlation of skills and knowledge after the course for BMG (r2 = .49), IPA (r2 = .53), and DTH (r2 = .61). Positive although nonspecific indicators of outcomes of the course were the increase (of about 100%) of requests to our metabolic unit for diabetological consultations from other departments as well as the mentioning of diabetes in the diagnosis of discharge, and the 20% increase in the consumption of sticks for BMG. The course produced a significant improvement of knowledge and skills on specific diabetological items among participants.

Systematic inspection of insulin injection sites for local complications related to incorrect injection technique

We systematically inspected insulin injection sites in 100 insulin-requiring patients attending the Diabetic Clinic of the Tikur Anbassa Hospital (TAH) in order to identify local complications related to incorrect injection technique: local complications were found in 53 cases: skin hyperpigmentation and/or indurations in 30 patients; and fat atrophy or hypertrophy in 31 patients. Illiteracy was significantly more common among those with local complications (18/53 versus 6/47, chi 2 5.03, P < 0.05). Mean fasting blood glucose on the day of the inspection was significantly higher (14.9 + 6.3 mmol/l versus 10.5 + 6.1 mmol/l, P < 0.001) and a fasting blood glucose > 10 mmol/l more common (41/53 versus 20/47, chi 2 14.1, P < 0.0005) in those with than in those without local complications. There was no significant difference between the two groups in mean duration of diabetes (6.9 + 5.6 years versus 6.6 + 5.8 years), frequency of hypoglycaemic episodes (12/53 versus 5/47, chi 2 1.76, P > 0.05) or mean daily insulin dose (44 + 18 units versus 44 + 22 units per day). Therefore, we concluded that local complications resulting from incorrect injection technique, a common finding in the group of patients studied, may be common among insulin requiring diabetic patients in general. Incorrect insulin injection causes local complications and disfigurement which may compromise compliance. Furthermore, insulin absorption tends to be erratic from intradermal and fat hypertrophy sites thus interfering with effective diabetic control. Insulin injection sites should be inspected routinely to detect and correct family technique promptly.

Comparison of metal versus Vialon subcutaneous catheters in a palliative care setting

In 63 evaluable palliative care patients requiring intermittent bolus subcutaneous administration of medication, who were randomly assigned either a standard metal subcutaneous needle or a PTFE (Vialon) catheter, there was a significantly greater incidence of local reactions at the insertion site with the metal needles (9/30) compared with the PTFE catheters (2/33). Despite this, there was no significant difference between the two in functional survival. Volume of medication injected per day was the best predictor of total time that the subcutaneous lines remained in situ.

Impact of injection sites for soluble insulin on glycaemic control in type 1 (insulin-dependent) diabetic patients treated with a multiple insulin injection regimen

The absorption rate of rapid acting (soluble) insulin is slow from the subcutaneous tissue of the thigh compared to intramuscular injection into the thigh and s.c. injection into the abdominal wall. The aim of the study was to evaluate the impact of soluble insulin injected either intramuscularly into the thigh (IMT), s.c. into the abdominal wall (SCA) or s.c. into the thigh (SCT) on glycaemic control in Type 1 (insulin-dependent) diabetic outpatients treated with the basal bolus insulin delivery regimen. Fifty-five, C-peptide negative Type 1 diabetic outpatients were included in a randomised 3-month intervention study. The insulin doses were adjusted frequently by blinded observers based on the patients' self-monitored blood glucose values and reported hypoglycaemic episodes. The serum fructosamine value was within normal limits in three patients in the IMT group, in six patients in the SCA group and in none of the patients in the SCT group following the intervention period (p < 0.01). However, the difference in mean serum fructosamine values did not reach statistical significance (IMT: 1.24 mmol/l (95% confidence interval; 1.17 to 1.31), SCA: 1.25 mmol/l (1.18 to 1.32), SCT: 1.34 mmol/l (1.26 to 1.41), (p = 0.09). Blood glucose excursions were larger in the SCT group than in the SCA and IMT group from post-lunch to pre-dinner measurements and from pre- to post-dinner measurements. A higher number of measured low nocturnal blood glucose values (less than 4 mmol/l) was observed in the SCT group (34 of 85) than in the IMT (14 of 64) and SCA (21 of 81) group (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Knowledge on diabetes and performance among health professionals in non-diabetological departments

We tested the level of knowledge on diabetes and professional skills in a group of 60 non-diabetological health care professionals at the Policlinic of Pisa regarding the recognition and treatment of hypoglycaemia, the storage, mixing and administration of insulin, blood glucose stick monitoring, and the prevention and treatment of diabetic foot. The evaluation was carried out using a multiple-choice questionnaire and observation of the subjects, performance by means of pre-defined observation schedules, during the preparation and administration of a blend of rapid-intermediate insulin, the use of blood glucose sticks and the management of a simulated hypoglycaemic crisis. As regards hypoglycaemia, 90% of subjects did not give a correct definition, 88.3% were unaware of the existence of asymptomatic hypoglycaemia, and 96.6% did not give a complete answer as to the treatment of hypoglycaemia. For insulin, 51.7% did not know the standards for correct storage of insulin, 88.3% did not know the difference between "clear" and "opaque" insulins, and 91.7% ignored the required interval between administration of regular insulin and meals. For foot care, 45% admitted that the problems with diabetics' feet were frequently not controlled, and between 21.7% and 63.3% did not known the hygiene rules for feet. Assessment of the performance of the subjects using schedules revealed incorrect use of sticks and administration of insulin (80.2% mixed and 92.4% injected the insulin incorrectly). There is clearly a need for education of non-diabetological health professionals regarding the disease. This is supported by the health professionals themselves, 94.5% of whom wished to participate in a course on diabetes.

Insulin injection site tissue depths and localization of a simulated insulin bolus using a novel air contrast ultrasonographic technique in insulin treated diabetic subjects

Subcutaneous adipose tissue depth was measured in 50 randomly selected Type 1 diabetic patients by real-time ultrasound at five standard sites commonly used for injection. Tissue depths were often less than the length of the standard insulin syringe needle (12-13 mm) at the arm and thigh injection sites, especially in men. Thus, if the currently recommended perpendicular injection technique were to be employed, there would, in theory, be an appreciable risk of intramuscular insulin deposition. In order to determine the true site of deposition in those at risk (injection site tissue depth of < 12 mm), a novel air-contrast ultrasound imaging technique was developed. A mixture of 0.1 ml of air and 0.2 ml of sterile 0.9% saline was self-injected into an anterior thigh site by 30 subjects using their usual technique. The site of the resultant tissue depot was located by ultrasound. Sixty-three percent of the depots were localized to true subcutaneous tissue and the remaining 37% to between the fascial planes overlying muscle. None of the subjects proved to be injecting into muscle. These results contrast with predictions of the risk of intramuscular injection made from the ultrasound measurement of subcutaneous tissue alone at the anterior and lateral thigh sites of, respectively, 100 and 97% for men and 42 and 37% for women. Although 11 of the 30 subjects claimed to be using a full-depth perpendicular injection technique, on direct observation only four proved to be injecting perpendicularly and none of these to the full depth of the needle.(ABSTRACT TRUNCATED AT 250 WORDS)

Subcutaneous or intramuscular insulin injections

To find out whether diabetic children may inject their insulin intramuscularly rather than subcutaneously, a random sample of 32 patients aged 4.3-17.9 (median 11.3) years was studied. Distance from skin to muscle fascia was measured by ultrasonography at standard injection sites on the outer arm, anterior and lateral thigh, abdomen, buttock, and calf. Distances were greater in girls (n = 15) than in boys (n = 17). Whereas in most boys the distances were less than the length of the needle (12.5 mm) at all sites except the buttock, in most girls, the distances were greater than 12.5 mm except over the calf. Over the fascial plane just lateral to the rectus muscle the distance from skin to peritoneum was less than 12.5 mm in 14 of the 17 boys and one of the 15 girls. Twenty five of the 32 children injected at an angle of 90 degrees, and 24 children raised a skinfold before injecting. By raising a skinfold over the anterior thigh, the distance from skin to muscle fascia was increased by 19% (range 0-38%). We conclude that most boys and some girls who use the perpendicular injection technique may often inject insulin into muscle, and perhaps on occasions into the peritoneal cavity.

Absorption of NPH (isophane) insulin in resting diabetic patients: evidence for subcutaneous injection in the thigh as the preferred site

The absorption kinetics of NPH (isophane) insulin injected subcutaneously into the abdominal wall and subcutaneously (SC) and intramuscularly (IM) into the thigh was studied in 11 Type 1 diabetic patients. The thickness of the subcutaneous adipose tissue layer was measured by ultrasound. NPH (isophane) insulin injected IM into the thigh was absorbed faster than NPH insulin injected SC into the thigh (T50%, IM 8.0 +/- 0.6 h and SC 10.3 +/- 0.7 h, p less than 0.05). No difference in T50% values was found for injection into the abdominal wall (9.7 +/- 1.2h) compared with the thigh. The mean absorption rate from 1.5 to 13.5 h after injection was higher after injection IM into the thigh (6.4 +/- 0.3% of initial dose injected absorbed per h) than after SC injection into the thigh (5.2 +/- 0.3% h-1) and SC into the abdominal wall (5.1 +/- 0.3% h-1) (p less than 0.01). The most constant absorption rate was obtained after SC injection into the thigh (within-study day CV of the mean absorption rate 19.9 +/- 3.2% vs 34.4 +/- 3.2% after IM injection into the thigh and 27.1 +/- 4.9% after SC injection into the abdominal wall (p less than 0.02]. The study provides further evidence that the subcutaneous tissue of the thigh is the preferred injection site for NPH insulin.

Influence of skinfold thickness on heparin absorption

The absorption of high and low molecular fractions of heparin from the subcutaneous compartment was evaluated in eight healthy males. They were given an intravenous infusion of 4000 U calcium heparin in 4 hours and on another occasion a subcutaneous injection of 12,500 U calcium heparin (washout period of 1 week). Anticoagulation was monitored by anti-Xa, antithrombin activity, and activated partial thromboplastin time. To evaluate factors that might influence absorption, body weight, body fat, and abdominal skinfold thickness were recorded. There was a pronounced inter-individual variability in absorption but the absorption of the two fractions of heparin was similar. The highly variable absorption was related to the abdominal skinfold thickness, and this could have implications for therapeutic and prophylactic heparin regimens.