Attitudes of patients and physicians to insulin therapy in Japan: an analysis of the Global Attitude of Patients and Physicians in Insulin Therapy study

ABSTRACT

Background: The barriers to insulin therapy perceived by Japanese patients with diabetes and their physicians are unclear.

Research design and methods: We performed sub-analyses of the Global Attitude of Patients and Physicians in Insulin Therapy (GAPP™) study, which included 100 Japanese physicians (of 1250 participating physicians) and 150 Japanese patients (of 1530 patients) who participated in Internet surveys (physicians) or computer-assisted telephone surveys (patients) across eight countries in 2010. We compared the results of Japanese participants with those obtained for the other seven countries.

Results: Overall, 44% of the Japanese patients reported omission or non-adherence to insulin, a greater value than that reported in other countries. Japanese physicians reported that non-adherence to insulin was driven by their patients’ lifestyles. A greater proportion of patients had a history of hypoglycemia in Japan than in other countries. Most of the physicians (94%) and patients (84%) in Japan reported that the currently available insulin treatment regimens do not fit the diverse lifestyles of patients.

Conclusions: Many Japanese patients receiving insulin therapy omit or do not adhere to insulin, possibly because of fear of hypoglycemia, or for lifestyle reasons. Insulin regimens that reduce the risk of hypoglycemia without interfering with patients’ lifestyles are needed.

KEYWORDS:

• Insulin therapy
• Japan
• attitudes
• perceptions
• hypoglycemia
• lifestyle

1. Introduction

Insulin therapy is the most effective means of controlling glucose levels in patients with diabetes, and insulin should be used from an early stage if necessary [1]. However, patients with type 2 diabetes mellitus often cite concerns about their insulin therapy, particularly hypoglycemia and weight gain, and the fact that insulin therapy is time consuming compared with oral antidiabetic agents used as add-on therapy. These concerns may act as barriers, delaying the initiation of insulin therapy [2]. Many patients on insulin therapy show poor adherence to or do not persist with treatment, resulting in inadequate treatment intensification [3–5]. Therefore, glycemic control remains poor, and may lead to hospitalization for the treatment of diabetes-related complications [3,6,7].

A study of 1441 insulin-treated Japanese patients revealed that glycemic control became more difficult as treatment adherence decreased, particularly in patients aged <65 years [8]. Moreover, a study of US patients revealed that patients who missed >10% of their insulin injections were more likely to experience hyperglycemic relapse compared with patients who missed 0–5% of their insulin injections [9].

For insulin therapy to be effective, it must be initiated in an appropriate manner, maintain adherence and treatment persistence, and intensify treatment [10]. However, these factors may be difficult to achieve and maintain. Therefore, healthcare providers and patients may avoid insulin preparations and syringes. According to the Diabetes Attitudes Wishes and Needs (DAWN) study, healthcare provider barriers to the initiation of insulin therapy may include their inaccurate understanding of the efficacy of insulin [11], the HbA1c level at which insulin is initiated [12], and the belief of some physicians that insulin therapy interferes with patient satisfaction with treatment because it is painful and places a burden on the patients [13–15]. Successful insulin therapy may also depend on the physician’s level of specialization and experience of treating patients [11,16]. Differences in the physicians’ and patients’ attitudes toward insulin therapy may also interfere with treatment [17–19].

Psychological barriers to insulin initiation include its efficacy, safety, and weight gain, as well as its possible effects on lifestyle and social stigma [7,10,15,20,21]. Although many of these concerns may be valid, patients often hold inaccurate attitudes toward insulin therapy, including the misconception that insulin causes late-stage diabetes complications and is associated with imminent deterioration and death, or represents poor self-management of diabetes [11].

The Global Attitude of Patients and Physicians in Insulin Therapy (GAPP™) study [22], a cross-sectional survey of physicians and patients in eight countries, investigated the barriers and issues related to self-management of insulin therapy. The study revealed that many insulin-treated patients have inadequate glycemic control, mostly because of omission of or poor adherence to insulin, and the lack of dose adjustments. We conducted sub-analyses of Japanese data to examine whether these issues also exist in Japan by comparing the results for both Japanese patients and physicians with those obtained in the other seven countries. We assessed the barriers to insulin therapy in Japanese patients and sought to determine the desired features of insulin therapy.

2. Methods

The GAPP study was a cross-sectional survey of physicians and patients with diabetes in eight countries (UK, USA, China, Japan, France, Spain, Germany, and Turkey) performed in 2010 [22]. The target sample size was 1250 physicians, including ≥50 primary care physicians (internists, general practitioners, and family physicians) and ≥50 specialists (diabetologists and endocrinologists) in each country. Physicians were eligible if they met the following criteria: in practice for >1 year since completing residency; seeing ≥5 patients with diabetes per week for primary care physicians or ≥10 patients per week for specialists; and having prescribed insulin therapy to their patients. The target sample size of patients was 1500, including ≥135 patients with type 2 diabetes in each country. Patients were eligible if they were aged ≥18 years, were prescribed insulin therapy to control glycemia, and had type 1 or 2 diabetes mellitus.

Physicians and patients were recruited from panels of healthcare professionals and research consumers, respectively, maintained by WorldOne Healthcare Research. Participants were randomly selected from the pool of eligible patients and physicians using a random number list. The physician survey was conducted via the Internet, and the patient survey was conducted by computer-assisted telephone interviews. For each survey, the master questionnaire (Supplementary Materials) was translated into the primary language for use in each country. The questionnaires were collaboratively developed by Edelman, Strategy One, Novo Nordisk, and the lead investigators. The study was approved by the Human Subjects Committee at Loyola University, Maryland, and complies with the recommendations of the 1964 Declaration of Helsinki and relevant ethical standards.

The primary variable was the frequency of omission or non-adherence to insulin injection. Other variables included reasons for omission or non-adherence to insulin injection, dissatisfaction with insulin therapy, opinions regarding insulin therapy, and perceptions of the impact of insulin therapy on daily life.

Fisher’s exact test was used to compare the results obtained in Japanese participants with those of the other seven countries using unweighted data.

3. Results

3.1. Characteristics of the participants

The overall survey comprised 1250 physicians and 1530 patients (Supplementary Table 1). Of 150 Japanese patients, 63% were men, the mean ± standard deviation (SD) age was 57.8 ± 11.3 years, and 90% had type 2 diabetes mellitus (Table 1). The mean duration of diabetes was 14.3 ± 9.9 years and the mean duration of insulin therapy was 7.7 ± 7.1 years. Of 100 Japanese physicians, 50 were specialists (43 diabetologists and 7 endocrinologists) and 50 were primary care physicians (44 internists and 6 general practitioners/family physicians).

Table 1. Characteristics of the study population in Japan.

All patients (n)	150
Males	63%
Age (years, mean ± SD)	57.8 ± 11.3
Type 2 diabetes	90%
Duration of diabetes (years, mean ± SD)	14.3 ± 9.9
Duration of insulin treatment (years, mean ± SD)	7.7 ± 7.1
Insulin taken within 30 min of the same time every day, even  if the mealtimes vary	81%
Patient-reported insulin regimens^a
Basal bolus	33%
Bolus only	27%
Premix only	15%
Basal only	13%
Bolus and premix	7%
Other	5%
All physicians (n)	100
Males	93%
Specialty
Diabetology	43%
Internal medicine	44%
Endocrinology	7%
General practice	6%
Family practice	0%
Duration of clinical practice (years, mean ± SD)	19.1 ± 8.7
Number of patients treated weekly (mean ± SD)
Patients with type 1 diabetes	6.2 ± 8.2
Patients with type 2 diabetes	94.5 ± 77.3
Insulin-treated patients with type 2 diabetes	28.1 ± 27.6

^aThe responses were coded using the information provided by the patients in response to the question ‘What is the brand name(s) of insulin you are taking – please look on the box if you are unsure?’ Considering the known market for insulin in Japan, it is thought that some patients were using NovoMix.

3.2. Patient and physician perceptions to diabetes management

Overall, 25.3% of the Japanese patients reported that their diabetes was inadequately controlled (Table 2). This was significantly lower (P = 0.0286) than the proportion (34.5%) in the other seven countries. The blood glucose levels, hypoglycemic symptoms, and diet/exercise therapy were reported to be ‘not at all under control’ in 2.0% of patients, ‘somewhat under control’ in 23.3%, ‘mostly under control’ in 58.7%, and ‘completely under control’ in 16.0%. Meanwhile, 88.5% of the physicians reported that ‘a significant number of diabetes patients are still not reaching target HbA1c/adequate blood glucose levels with insulin treatment.’ This proportion was similar in the other seven countries (Table 2).

Table 2. Management of diabetes.

	Countries excluding Japan	Japan	P^a
Patients’ responses^b
Evaluable n	1380	150
Completely under control	20.7%	16.0%
Mostly under control	44.8%	58.7%
Somewhat under control	28.3%	23.3%
Not at all under control	6.2%	2.0%
Combined responses^c
Sum of Completely under control + Mostly under control	65.5%	74.7%	0.0286
Sum of Somewhat under control + Not at all under control	34.5%	25.3%
Physicians’ responses^d
Evaluable n	1139	96
Agree	1010 (88.7%)	85 (88.5%)	1.0000
Disagree	129 (11.3%)	11 (11.5%)

^aFisher’s exact test.

^b‘To what extent do you feel that your diabetes is under control in terms of you managing your blood sugar levels, any low blood sugar events (hypoglycemia), diet and exercise?’

^cThe four response categories were combined into a dichotomous variable for statistical analysis.

^d‘A significant number of diabetes patients are still not reaching target HbA1c/adequate blood glucose levels with insulin treatment.’

3.3. Omission or non-adherence to insulin therapy

A significantly greater proportion of Japanese patients than patients in the other countries (44.0% vs. 33.6%, P = 0.0145) reported that they sometimes forgot to take their insulin injections as prescribed or missed their insulin injections (omission or non-adherence) (Table 3). The mean number of insulin injections that were not taken as prescribed in these poorly adherent patients was 2.94 ± 3.30 injections per month. By contrast, a significantly smaller proportion of Japanese physicians than physicians in the other seven countries reported that their typical patients sometimes failed to take their insulin injections as prescribed (66.0% vs. 78.1%, P = 0.0087; Table 3). These findings indicate that Japanese patients more frequently omitted or did not adhere to insulin therapy than did patients in other countries, but fewer physicians in Japan were aware of this problem than were physicians in other countries.

Table 3. Omission/non-adherence to insulin therapy.

	Countries excluding Japan	Japan	P^a
Patients’ responses^b
Evaluable n	1380	150
Yes, n (%)	464 (33.6%)	66 (44.0%)	0.0145
No, n (%)	916 (66.4%)	84 (56.0%)
Frequency of omitting insulin (mean ± SD)	NA	2.94 ± 3.30
Physicians' responses^c
Evaluable n	1150	100
Yes, n (%)	898 (78.1%)	66 (66.0%)	0.0087
No, n (%)	252 (21.9%)	34 (34.0%)
Frequency of omitting insulin (mean ± SD)^d	NA	6.18 ± 4.43

^aFisher’s exact test.

^b‘Do you ever miss your insulin dose or fail to take your insulin exactly as prescribed by your healthcare professional?’

^c‘Do any of your typical patients fail to take their insulin as prescribed?’

^d‘How many days in the past month do you expect a typical patient to have missed their basal insulin dose, or not taken their basal insulin exactly as prescribed?’

NA: not asked.

3.4. Reasons for poor adherence

The authors next assessed possible reasons for omission or non-adherence to therapy, focusing on lifestyle factors. The most common reason was ‘too busy’ in 26% of patients, ‘forgot’ in 23%, and ‘challenging to take insulin at the same time every day’ in 14% (Table 4).

Table 4. Reasons for omission/non-adherence to insulin in the study population in Japan.

	Patients (n = 66)^a		Physicians (n = 66)^b
Reason	%	Rank	%	Rank
Too busy	26%	1	24%	1
Forgot	23%	2	2%	9
Challenging to take insulin at the same time everyday	14%	3	15%	4
Fell asleep	11%	4	NA	–
Skipped meal	8%	5	17%	3
Embarrassing to inject in public	6%	6	18%	2
Traveling or changing normal routine	3%	7	8%	5
Did not take insulin out/forgot to take it while traveling	3%	7	NA	–
Regimen is too complicated	3%	7	3%	7
Injections are painful	2%	10	2%	9
Stress or emotional problems	0%	–	8%	5
Too many injections	0%	–	3%	7
Avoid weight gain	0%	–	2%	9

^aRespondents were asked to state the top three reasons. The order of reasons was randomized. The response ‘Forgot’ was reported under the free-entry term ‘Other.’ Data are shown as the percentage of respondents who selected each reason as one of the three reported reasons.

^bThe percentages cannot be directly compared between patients and physicians because the physicians were asked to report whether they expected each reason for their ‘typical patient’ rather than the percentage of their patients who actually reported this reason. The rank order of reasons by patients and physicians can be compared.

The top three ranked reasons for each group are shown in bold font.

NA: not asked.

Like patients, 24% of physicians reported that the most common reason for omission or non-adherence to insulin therapy was that the patient was ‘too busy’ (Table 4). Other reasons for omission or non-adherence included ‘it is embarrassing to inject in public’ and ‘skipped meal,’ which were reported by 18% and 17% of physicians, respectively.

These results demonstrated that there were some important differences between the responses of patients and physicians in terms of the reasons for poor adherence.

Adherence to insulin therapy was not influenced by patient factors, such as sex, insulin regimen, number of daily insulin injections, self-monitoring of blood glucose, or cardiovascular risk factors (data not shown).

3.5. Difficulties associated with insulin therapy

The patients surveyed here considered that the tasks related to injecting insulin are easy, because 91% of patients reported that the preparation of insulin injections is straightforward. However, many patients reported difficulties related to the lack of freedom and flexibility of insulin therapy. For example, 33% of patients reported difficulty in injecting insulin at the prescribed time every day (Table 5), 28% reported difficulty with regularly measuring their blood glucose levels, and 19% had difficulty injecting insulin with every meal (9% preparing injections and 10% adjusting insulin doses), even when the mealtime was changed. In a free-entry question to elucidate the greatest barrier to effective insulin therapy, 17% of patients reported ‘difficulty in taking injections when traveling or going out’ and 13% reported difficulty of ‘managing their meals, or meals when working outside.’

Table 5. Patient and physician perceptions of insulin treatment in the study population in Japan.

	Patients	Physicians
Evaluable n	150	100
Patient difficulties^a
Taking insulin at the prescribed time or with meals every day	33%^b	49%
Number of daily injections	13%	14%^c
Following the physician’s instructions	9%	62%
Preparing injections	9%	76%
Adjusting insulin doses	10%	NA
Changing the time of insulin to meet daily needs	NA	24%
Measuring blood glucose routinely	28%	94%
Dissatisfaction^d
Choose the frequency of injections	19%	48%^e
Choose the time of injections	18%	54%^f
Blood glucose control	36%	25%
Simplicity of regimen	12%	46%
Safety regarding low blood glucose	19%	59%
Insulin treatment overall	21%	34%
Opinions^g
I would treat my patients’ diabetes more aggressively if there was no concern over hypoglycemic events	NA	88%
I feel like I have to make a choice between efficacy and safety when treating diabetes patients with insulin	NA	62%
Wish there was an insulin treatment that would cover patients in case they forget a dose	NA	88%
Wish for good control with insulin that does not need to be injected every day	97%	91%
Wish the insulin regimen would fit daily life changes	84%	94%^h
Experiencing low blood glucose events is one of the most fearful parts of having diabetes	61%	NA
Insulin-treated diabetes controls life	57%	55%^i
Insulin regimen can be restrictive	47%	47%
Hard to live a normal life while managing diabetes	49%	33%

^aVery difficult or somewhat difficult (vs. very easy, somewhat easy, not applicable, do not know).

^bThe averaged response for two items (‘insulin at prescribed times’ and ‘insulin with each meal’).

^c‘Taking insulin frequently.’

^dVery dissatisfied or somewhat dissatisfied (vs. very satisfied, somewhat satisfied, not applicable).

^e‘Total number of injections per week.’

^f‘Insulin regimens that better fit the patients’ dynamic lives.’

^gStrongly agree or somewhat agree (vs. strongly disagree, somewhat disagree, neither, do not know).

^h‘Which insulin treatments could be more flexible?’

ⁱ‘Do your patients feel diabetes controls their lives?’

NA: Not asked.

By contrast, 76% of the physicians reported that patients find it difficult to prepare insulin injections, and 62% of physicians reported that patients find it difficult to follow their physicians’ instructions (Table 5). Additionally, 49% of the physicians reported that patients find it difficult to inject insulin at the prescribed time or at mealtime every day (Table 5).

Thus, there were also important differences between the responses of patients and physicians in terms of their perceptions of insulin treatment.

3.6. Psychological barriers associated with hypoglycemic symptoms

Overall, 66.7% of the Japanese patients experienced hypoglycemic symptoms in the past 12 months, which was significantly greater than the proportion of patients in the other seven countries experiencing these symptoms (56.9%; P = 0.0234; Supplementary Table 2). Among Japanese patients who reported having hypoglycemic symptoms, the mean number of episodes was 15.1 ± 19.44 episodes per patient in the last 12 months (Supplementary Table 2). Overall, 50.7% of patients had concerns regarding future episodes of hypoglycemic symptoms. Moreover, 61% of patients reported that hypoglycemia was one of the most concerning issues (Table 5). When the patients were told they needed to start insulin, 27% reported that they were fearful of hypoglycemic symptoms and 49% were fearful of hypoglycemia-related symptoms. Additionally, 88.0% of physicians were concerned about significant hypoglycemic symptoms or nocturnal hypoglycemic symptoms (Supplementary Table 2).

Sixty percent of the physicians were dissatisfied with the effects of insulin therapy in terms of achieving optimal glycemic control without increasing the risk of hypoglycemia. Additionally, 88% of physicians reported that they were more aggressive in treating diabetes in patients who had no concerns about hypoglycemic symptoms (Table 5). In a free-entry question regarding the strongest barrier to insulin therapy, the most common response from physicians was ‘hypoglycemia.’ Additionally, 20% and 29% of physicians reported that hypoglycemia was the strongest barrier to the initiation and continuation, respectively, of insulin therapy. Notably, 50% of physicians reported that they delayed insulin therapy, even if therapy was necessary, because of the fear of hypoglycemic symptoms. Thus, hypoglycemia is a common barrier to insulin therapy in both patients and physicians.

3.7. Attitudes and demands for insulin therapy

The surveys also explored possible differences in the attitudes of patients and physicians regarding insulin therapy and assessed their views on the ideal insulin therapy. Fifty-seven percent of patients reported that diabetes has been controlling their lives since starting insulin therapy and 55% of physicians reported that their patients had these feelings (Table 5). Eighty-four percent of the patients wanted a ‘flexible insulin treatment that could be adapted to situational variations in daily activities.’ Forty-seven percent of patients reported that the current insulin regimens sometimes restricted their lives (Table 5). Moreover, 49% of patients reported that it is hard to live a normal life while properly managing their diabetes (Table 5). Meanwhile, 54% of physicians reported that the current insulin regimens do not fit the diverse lifestyles of patients. Ninety-seven percent of patients wanted an insulin regimen that can maintain good glycemic control without daily insulin injections. In addition, 91% of the physicians wanted an insulin regimen that can maintain optimal blood glucose levels without daily insulin injections (Table 5). The attitudes of patients toward insulin therapy were not influenced by their general characteristics, such as age, sex, duration of diabetes, or the type of insulin they were using (data not shown).

4. Discussion

The present study has revealed that 44% of Japanese patients with diabetes omit or do not adhere to their prescribed insulin therapy, and that this was significantly greater than the proportion in the other seven countries (33.6%). The three main reasons for poor adherence cited by Japanese patients were ‘too busy,’ ‘forgot,’ and ‘challenging to take insulin at the same time every day.’ Intriguingly, the latter two reasons were not commonly reported in the prior analysis of all eight countries combined [22]. These findings suggest that Japanese patients believe they have busy and diverse lifestyles and that it is a burden to inject insulin at the same time every day. Higher adherence to a daily insulin regimen was related to better glycemic control in Japanese type 2 diabetes patients [8]. Thus, for Japanese patients, further consideration is needed to select an insulin regimen appropriate for the type of diabetes, taking into account the patient’s lifestyle.

The present study also revealed that hypoglycemic symptoms are a significant concern for insulin-treated patients. Surprisingly, approximately two-thirds of the Japanese patients reported that they experienced hypoglycemic symptoms in the last 12 months; this proportion was significantly greater than that in the other seven countries (57%). The majority of physicians were also concerned about hypoglycemic symptoms and reported that they were more aggressive in treating diabetes in patients who had no concerns about hypoglycemic symptoms. Thus, hypoglycemic symptoms are still a major barrier to achieving adequate glycemic control, for both patients and physicians. Concern about hypoglycemic symptoms was also a major barrier to the initiation of insulin therapy at an appropriate time. For example, many patients were fearful of hypoglycemia-related symptoms at the start of insulin therapy and physicians frequently delayed insulin therapy for fear of hypoglycemic symptoms. These findings underscore the need to reassure patients about the safety of insulin therapy to reduce their anxiety about hypoglycemic symptoms, possibly by supporting patient education on insulin therapy.

There were some differences in the patients’ and physicians’ perceptions of insulin therapy. For example, 91% of patients reported that it is easy to prepare insulin injections, whereas 76% of physicians believed that patients found it difficult to prepare insulin injections (Table 5). Some of the difficulties encountered by patients relate to the poor flexibility and freedom of insulin therapy. Indeed, many patients reported difficulties in injecting insulin at the prescribed time every day, possibly because of diverse lifestyle factors, such as traveling and work. Therefore, there is a need for insulin regimens that do not affect the patients’ ability to continue their lifestyles unchanged from before starting insulin therapy. The present study also suggests that physicians also want simpler insulin regimens because 63% of the Japanese physicians reported that the ideal insulin therapy is one that requires less frequent or no monitoring of blood glucose. This proportion is higher than the mean value (33%) reported for all eight countries combined [22]. Differences in the patients’ and physicians’ perceptions of insulin therapy were also apparent in the DAWN Japan study of 148 patients with type 2 diabetes and 68 physicians [19]. In particular, physicians underestimated the impact associated with insulin use for several responses, including ‘I don’t want to be different from others’ (patients vs. physicians: 55% vs. 7%), ‘Injecting insulin in the presence of others is embarrassing’ (81% vs. 41%), ‘I’m afraid of hypoglycemia’ (73% vs. 34%), ‘I don’t understand why insulin is necessary for me’ (45% vs. 17%), and ‘I’m afraid of side effects’ (52% vs. 17%). However, physicians overestimated the response ‘Injections are painful,’ which was reported by 77% of physicians compared with 65% of patients.

Our findings also suggest that the timing of administration of insulin each day may be a problem for patients and physicians. Many insulins, particularly basal insulins, require administration at a fixed time each day, precluding flexibility of administration to account for variability in daily life. Although physicians are likely well aware of this inflexibility, they may not be fully aware of its impact on the patient. Physicians generally consider that patients with a ‘good attitude’ toward insulin therapy will self-administer insulin as scheduled, without missing injections or making errors in dosage. We believe that patients and physicians should discuss the timing of injections, and whether administration inflexibility is a barrier that needs to be addressed. Additionally, patients may require more education on how and when to self-adjust their insulin therapy in consideration of variable daily lifestyles. Future studies should focus on the flexibility of insulin therapy and how well patients can manage their injections.

The present study has identified some concerns over starting and adhering to insulin therapy in Japanese patients. These concerns may delay the start of insulin therapy. A recent study of Japanese patients with type 2 diabetes mellitus showed that lower HbA1c levels and a shorter duration of diabetes at the start of insulin therapy led to better glycemic control [23]. Additionally, the Diabetes Distress and Care Registry at Tenri showed that the frequency of insulin injection omission was associated with diabetes treatment-related quality-of-life scores, and that healthcare providers should discuss treatment-related problems in patients with low scores to prevent insulin injection omission [24]. Therefore, our findings support the need to start insulin in a timely manner and to provide appropriate education to address the concerns of patients, particularly hypoglycemia and managing insulin injections around the patients’ lifestyles.

There are some limitations of this study. First, the sample size was relatively small, with only 150 patients and 100 physicians. Second, the survey did not assess the impact of insulin therapy on glycemic control; patients with worse glycemic control may perceive greater barriers or concerns with treatment. Third, attitudes may differ between patients with type 1 or type 2 diabetes mellitus, or between specialist physicians or primary care physicians, but these differences were not assessed. Fourth, differences in the general behaviors, attitudes, and cultural beliefs between Japanese and non-Japanese individuals might contribute to differences in the way individuals from different countries interpreted the questions and responded to the surveys. Fifth, there might be differences in the types/brands of insulin available in each of the participating countries at the time of the survey, and such differences might lead to differences in the attitudes toward insulin therapy among countries. Sixth, the participants were selected from research panels maintained by a market research agency, which might introduce selection bias. Accordingly, the results might not reflect the wider population of patients and physicians in Japan. Finally, there are factors, other than those investigated here, that might influence the level of adherence to insulin therapy among patients with diabetes. For example, it was reported that patient co-payments introduced a financial burden to patients [25], and that reducing co-payments appeared to improve adherence. In Japan, 70% of the cost of insulin therapy is reimbursed to the patient (or in the case of elderly patients, up to 90%). Unfortunately, the cost of insulin was not assessed in this study, so we could not investigate this point.

5. Conclusion

The present study provides further insights into the attitudes of patients and physicians to insulin therapy. In particular, many Japanese patients omit or do not adhere to their prescribed insulin therapy, and the insulin dose is not adjusted in many patients, all of which attenuate the efficacy of insulin therapy. Busy lifestyles and concerns about hypoglycemic symptoms are the main barriers to insulin therapy. Educational interventions focusing on diabetes self-management, including insulin administration and self-monitoring of blood glucose, can improve self-care behaviors, blood glucose levels, and other patient-reported outcomes [26–28]. Improving patient education should address these concerns and support adherence to insulin therapy. Additionally, there is a need for insulin regimens that can reduce the risk of hypoglycemia, can adapt to changes in daily activities, and that place a lower burden on patients. Such advances might contribute to improvements in overall glycemic control and the long-term prognosis of patients with diabetes.

Declaration of interest

S Harashima has participated in scientific advisory committees for Novo Nordisk and Abbott, and has received research grant support from Sanofi. N Inagaki has received research grant support from Merck Sharp & Dohme, Mitsubishi Tanabe, Eli Lilly, Roche, Shiratori, Astellas, Sanofi, Daiichi Sankyo, Dainippon Sumitomo, Ono, and Taisho Toyama, and has received speaking fees from MSD, Sanofi, Novartis, Kyowa Kirin, Dainippon Sumitomo, Mitsubishi Tanabe, and Boehringer Ingelheim. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. Writing assistance, provided by Nicholas D. Smith, PhD (Edanz Group Japan KK), was utilized in the production of this manuscript and funded by Novo Nordisk Pharma Ltd.

Acknowledgments

The authors would like to acknowledge Doron Schneider and Ji Linong, who provided advice on project design.

Supplemental material

Supplemental data for this article can be accessed here.

Additional information

Funding

The study was funded by Novo Nordisk A/S and Novo Nordisk Pharma Ltd., which agreed to the overall study design, but had no other role in the present study.

Notes on contributors

Shin-ichi Harashima

All authors were involved in interpreting the data and drafting/critically revising the manuscript. All authors share the final responsibility for the content of the manuscript and the decision to submit it for publication.

Akiko Nishimura

All authors were involved in interpreting the data and drafting/critically revising the manuscript. All authors share the final responsibility for the content of the manuscript and the decision to submit it for publication.

Nobuya Inagaki

All authors were involved in interpreting the data and drafting/critically revising the manuscript. All authors share the final responsibility for the content of the manuscript and the decision to submit it for publication.