electronic-Perak Medical Journal Vol 2 No 1 August 2022
ORIGINAL ARTICLE
Adherence of Type 2 Diabetes Mellitus (T2DM) Patients Towards Antidiabetic Medications (ADM) at Outpatient Department, Hospital Tapah: A cross-sectional study using Adherence to Refills and Medications Scale for Diabetes (ARMS-D)
Chee-Fai Sui1*, Teresa Wen-San Chong1, Kah-Yan Yip 1, Appalasamy M1, Subramaniam AN1, Mohan KV1, Adnan NA1
1Pharmacy Department, Hospital Tapah, Ministry of Health MALAYSIA
Glycaemic control plays a pivotal role in the management of diabetes and it largely depends on patient adherence to diabetes treatment. WHO defined adherence as “the extent to which the patient follows medical instructions”3. The pharmacological treatment of T2DM involves OHA such as biguanides, sulphonylureas, alpha glucosidase inhibitors, thiazolidinediones, dipeptidyl peptidase-4 (DPP-4) inhibitors, sodium-glucose co-transporter-2 (SGLT-2) inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists and insulin therapy4. The effectiveness of a treatment depends on both the efficacy of a medication and patient adherence to the therapeutic regimen. Patients, health care providers and health care systems, all have a role to improve medication adherence5.
The factors contributing to non-adherence to ADM include patient socio-demographic characteristics, therapy related factors and the healthcare system6. Patient sociodemographic
INTRODUCTION
Type 2 Diabetes Mellitus (T2DM) is a major health concern not only in Malaysia but globally. According to National Health and Morbidity Survey 20151, the exponential increase of T2DM prevalence is alarming. The overall prevalence of diabetes mellitus (known and undiagnosed) among adults of 18 years and above in this survey was 17.5%. Management in T2DM brings economic burden to the Malaysia healthcare system. T2DM disease management takes up to RM2.04 billion expenditure in both government and private sector for the year of 2011. Out of RM2.04 billion, 70% was incurred by the government. Follow up cost for each T2DM patient was about RM459 per year and total cost for treating complication was RM42,362, which covered stroke, heart failure, myocardial infarction, cataract, nephropathy and amputation.2 The high cost expenditure on T2DM management can be reduced if patients are able to achieve consistent optimal glycaemic control and are strictly adherent to their medications and lifestyle changes.
Keywords: adherence, diabetes mellitus, adherence to refills and medications scale for diabetes (ARMS- D), antidiabetic medication (ADM) Citation: Sui CF, Teresa CWS, et al.
Adherence of type 2 diabetes mellitus (T2DM) patients towards antidiabetic medications (ADM) at Outpatient Department, Hospital Tapah: A cross sectional study using adherence to refills and medications scale for diabetes (ARMS-D). e-PMJ, Volume 2(1), 2022
*Correspondence to:
Chee-Fai Sui, Mpharm, suicheefai@
moh.gov.my
Received: 01 March 2020 Accepted: 17 September 2020 Copyright: © 2022 Sui et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Competing interest: The authors have declared that no competing interest exists.
ABSTRACT
INTRODUCTION
Patient adherence to diabetes medication plays a vital role in diabetes management. However, patients often show poor adherence towards their medication. This study aims to compare the differences of adherence rate to Antidiabetic Medications (ADM) including Oral Hypoglycaemic Agent (OHA) with or without insulin therapy and the factors that could explain the levels of adherence among diabetic patients in Hospital Tapah.
METHODOLOGY
A cross-sectional study was conducted among diabetic patients who collected medications at Outpatient Pharmacy Department of Hospital Tapah from January to April 2018. The minimum sample size required was 50 patients treated with OHA with or without insulin therapy. Patients who were referred from other centres to collect medications at Hospital Tapah, but not under Hospital Tapah follow up were excluded. Patients’ adherence towards ADM were assessed by using a 11-items self- administered questionnaire on patient’s medication taking and refill patterns, namely Adherence to Refills and Medications Scale for Diabetes (ARMS-D).
RESULTS
A total of 103 subjects out of 180 T2DM patients refilling their prescription during the study period were recruited. The mean age was 58 years old (Sd: 12.96). The results showed the majority were female (53.4%), Malay ethnicity (53.4%), and with highest secondary educational (46.6%). A total of 75.7% of the patients were depending on OHA alone and 24.3% of the patients were prescribed with OHA with insulin therapy. This study showed that 93.6% of patients who were on OHA alone and 84% patients who were on OHA with insulin therapy did not adhere to ADM.
CONCLUSION
The level of non-adherence to ADM was high among T2DM patients but it was not significantly associated to their socio-demographics factors. Patients who were prescribed with OHA plus insulin therapy was found to have a higher rate of adherence as compared to patients who were on OHA alone.
A study with a larger sample size will be needed to further confirm our findings.
Figure 1: Conceptual Framework of the Methods A validated questionnaire of Adherence to Refills and Medications Scale for Diabetes (ARMS-D) which consists of 11 items was adopted in this study to evaluate the adherence of patients towards their ADM. ARMS-D was used as it is a reliable and valid measurement of diabetes medication adherence against the most widely used self- report measure of diabetes medication adherence, the Summary of Diabetes Self-Care Activities medications subscale (SDSCA-MS)10,11. The responses were in Likert scale where responses range from 1= ‘none of the time’, 2= ‘some of the time’, 3=’most of the time’ and 4= ‘all of the time’9. The total score of each patient were from 11 to 44, where score 11 was interpreted as perfect adherence and score 12 to 44 were interpreted as non-adherence. The data collected was coded and entered into Microsoft Excel and exported to Statistical Package for the Social Sciences (SPSS) version 23 for analysis. The association between demographic characteristics and adherence was analysed using Chi-square test.
RESULTS
A total of 103 out of 180 eligible patients who were approached during the study period had agreed to participate in the study. Twenty-seven patients who were excluded from the study were not from Hospital Tapah.
Another 15 patients were excluded as they were only on insulin while 35 patients refused to participate.
The mean age of the study population was 57.82±12.96 where the majority of them were female (53.4%), Malay (53.4%), unemployed (40.8%), married (84.5%) with secondary level of education (46.6%) and 59.2% of the respondents were with no known source of income (Table 1). Based on ARMS-D, 91.3% of the patients did not adhere to their diabetes medication.
characteristics include age, gender, educational level and marital status, while psychological factors include patient’s beliefs and motivation towards the therapy, patient- prescriber relationship, patient’s knowledge on health concerns. On the other hand, therapy related factors consist of duration of treatment, route of administration, complexity and side effects of the medications. The availability and accessibility of healthcare system is vital. For example, the government hospitals or rural health clinics should be made available especially in rural areas where the underserved communities are able to enjoy quality and modern healthcare access. One local study by Nur Sufiza et al.7, in a primary care health clinic Malaysia shows that the highest non-adherence was in the combination OHA therapy with insulin (59.5%), followed by combination oral OHA (53.1%) and OHA monotherapy (48.5%). The authors’
findings provide some insight on the extend of non- adherence in T2DM in primary care settings. We intended to further investigate non-adherence in a district hospital setting to link the gaps on the severity of this issue in different health care settings. The objective of this study was to compare the rate of adherence of adult T2DM patients towards OHA with or without the insulin therapy and to evaluate the factors contributing to non-adherence among diabetic patients in a district hospital setting.
METHODOLOGY
A cross-sectional study was conducted among diabetic patients who collected medications at Outpatient Pharmacy Department of Hospital Tapah from January to April 2018.
Patients treated with OHA with or without insulin therapy were recruited. Patients who were referred from other centres to collect medications at Hospital Tapah but not under Hospital Tapah follow up were excluded. Patients’
adherence towards ADM were assessed by using a self- administered questionnaire namely Adherence to Refills and Medications Scale for Diabetes (ARMS-D).
In order to compare the patients’ adherence rate towards OHA versus OHA plus insulin, a sample size of 25 was needed for both groups to detect the proportion difference of -0.36 with a power of 80% and an alpha of 0.05. The proportion difference of -0.36 was considered the smallest important difference to be detected. The adherence rate towards OHA plus insulin was estimated as 0.438. This calculation was done using ScalexProp version 1.0.29. However, it was then later decided that the study needed to approach all the eligible patients in the study period.
The respondents were identified at Outpatient Pharmacy counter during prescription screening as information such as the patient’s age and medications were readily available.
The eligible patients were approached using convenience sampling and were explained to about the study. Written consent was obtained from patients who agreed to participate before answering a self-administered questionnaire. The illiterate respondents were interviewed by data collectors using a standard format of interviewing material. Data collectors were briefed on the standard interviewing format for illiterate subjects before the study was initiated.
electronic-Perak Medical Journal Vol 2 No 1 August 2022
DISCUSSION
Medication adherence is an important component of self- management for patients with diabetes. Based on the result analysis from the ARMS-D questionnaire, it can be observed that a high percentage of patients forget to take their medication which has led to a high percentage of non- adherence. According to Diabetes UK, medication adherence plays a vital role and it has been a concern in diabetes management. Diabetes patients can enjoy and improve their quality of life through good self- management12. Thus, risk of developing health complications, hospital admissions or even length of stay can be reduced. Studies from India and Granada presented that the patient’s age, polypharmacy, patient’s negligence or poor memory could be the major reasons of medication non-adherence8,13.
In this study, it was found that the percentage of non- compliance with ADM was higher in our study compare to the earlier findings in Uganda14, Palestine15, Hong Kong16, Mexico17, Saudi Arabia18 and India19 where it was found to be 28.9%, 51.4%, 59%, 61%, 65% and 75% respectively. This study which used the ARMS-D questionnaire also included one of the criteria to assess patient’s adherence towards ADM and has shown an undesirable result where most of the patients fail to plan on refilling before running out of medications. Chronic patients need to be on long-term control medications. Thus, refilling medications is important. Basic services can be provided, for instance, delivering monthly medications supply straight to the patient’s location of choice. Meanwhile, pillbox, alarm reminder or diary could help patients to remember and track their medication use. Any concerns shall be discussed in order to support all patients to comply with their medications. All these criteria should be taken into account for better understanding of patients’ non-adherence.
Improving patient’s adherence should always be a major role of pharmacist, therefore proper initiative should be taken to reduce the barriers related to adherence of patients20.
There are numerous potential reasons for non-adherence towards diabetes medication, and these are more frequently multifactorial. Poor adherence was correlated with age factor. According to Benner et al.21 and Okuno et al.22, the study suggested that the compliance level decreases progressively with increasing age, which was comparable to our results. This shows that age is an important variable which may affect the medication compliance, where age-related functional declination including vision or cognitive complications could play a role in this. Patient compliance can be improved by avoiding polypharmacy and reducing medication regimen complexity such as the number of medications and doses prescribed by physicians. Pharmacists can try to use special methods, techniques and devices such as pill count method, medication calendar, special medication containers and drug reminder packaging to improve patient’s adherence.
Majority of the patients in this study answered, ‘none of the time’ for question 2 to question 10 in the ARMS-D questionnaire (Table 2). It was observed there were 5 (6.4%) patients with OHA had perfect adherence while only 4 (16.0%) patients with OHA and insulin had perfect adherence (Table 3). There were no significant association between demographic characteristics and the adherence outcome (Table 4).
Table 1: Sociodemography of the patients, n = 103
Sociodemography n (%)
Age (Mean ± SD) 57.82 (±12.96) Gender
Male 48.(46.6)
Female 55.(53.4)
Ethnicity
Malay 55.(53.4)
Chinese 13.(12.6)
Indian 30.(29.1)
Orang Asli 5.(4.9)
Occupation
Unemployed 42.(40.8)
Retiree 32.(31.1)
Healthcare professional 9.(8.7)
Employed 10.(9.7)
Self-employed 5.(4.9)
Professional 5.(4.9)
Marital Status
Single 8.(7.8)
Married 87.(84.5)
Divorced 2.(1.9)
Widowed 6.(5.8)
Education level
No formal education 9.(8.7)
Primary school 32.(31.1)
Secondary school 48.(46.6)
Form 6/STPM 2 (1.9)
Diploma 7 (6.8)
Bachelor 3 (2.9)
Master 1 (1.0)
Doctorate 1 (1.0)
Income status
No income 61 (59.2)
< RM 1000 13 (12.6)
RM 1000- RM 1999 9 (8.7) RM 2000- RM 3999 11 (10.7) RM 4000- RM 5999 7 (6.8)
≥RM 6000 2 (1.9)
Table 2: Adherence to Refills and Medications Scale for Diabetes (ARMS-D) Questions (How often do you ………..)
none of the time, n (%)
some of the time, n (%)
most of the time, n (%)
all of the time, n (%) 1 Forget to take your diabetes medicine(s)? 41 (39.8) 49 (47.6) 10 (9.7) 3 (2.9) 2 Decide not to take your diabetes medicine(s)? 73 (70.9) 19 (18.4) 7 (6.8) 4 (3.9) 3 Forget to get your diabetes prescription(s) filled? 70 (68.0) 29 (28.2) 4 (3.9) 0 (0.0)
4 Run out of your diabetes medicine(s)? 84 (81.6) 15 (14.6) 2 (1.9.) 2 (1.9)
5 Skip a dose of diabetes medicine(s) before you go to the doctor? 82 (79.6) 15 (14.6) 4 (3.9) 2 (1.9) 6 Miss taking your diabetes medicine(s) when you feel better? 83 (80.6) 13 (12.6) 6 (5.8) 1 (1.0) 7 Miss taking your diabetes medicine(s) when you feel sick? 75 (72.8) 19 (18.4) 8 (7.8) 1 (1.0) 8 Miss taking your diabetes medicine(s) when you feel careless? 74 (71.8) 22 (21.4) 6 (5.8) 1 (1.0) 9 Forget to take your diabetes medicine(s) when you are supposed to take
it more than once a day? 71 (68.9) 24 (23.3) 7 (6.8) 1 (1.0)
10 Put off refilling your diabetes medicine(s) because they cost too much
money? 99 (96.1) 1 (1.0) 1 (1.0) 2 (1.9)
11 Plan ahead and refill your medicine(s) before they run out? 35 (34.0) 36 (35.0) 16 (15.5) 16 (15.5) Table 3: ARMS-D of patients with OHA only and OHA plus insulin
Medication *Perfect Adherence, n (%) **Non-adherence, n (%) p-valuea
OHA only 5 (6.4) 73 (93.6) 0.215
OHA and insulin 4 (16.0) 21 (84.0)
*Perfect Adherence = score 11
** Non-adherence = score 12 to 44
aChi-square test was used
Table 4: Association testing between medication and sociodemographic characteristics with Adherence to Refills and Medications Scale for Diabetes
Variables Adherence, n (%) Non-Adherence, n (%) p-value*
Age (mean ± SD) 55.3 (12.4) 58.1 (13.1) 0.550
Gender
Male 3 (6.3) 45 (93.7)
0.498
Female 6 (10.9) 49 (89.1)
Ethnicity
Malay 4 (7.3) 51 (92.7)
0.730
Non-Malay 5 (10.4) 43 (89.6)
Education
No formal education 1 (11.1) 8 (88.9)
0.830
Primary to Secondary 7 (8.3) 75 (91.7)
Tertiary 1 (8.3) 11 (91.7)
Marital status
Single/Divorced/Widowed 2 (12.5) 14 (87.5)
0.627
Married 7 (8.0) 80 (92.0)
Occupation
Unemployed 5 (11.9) 37 (88.1)
0.558
Retiree 3 (9.4) 29 (90.6)
Employed 1 (3.4) 28 (96.6)
Income status
No income 7 (11.5) 54 (88.5)
0.827
< RM 1000 0 (0.0) 13 (100.0)
RM 1000- RM 1999 1 (11.1) 8 (88.9)
RM 2000-RM 3999 1 (9.1) 10 (90.9)
RM 4000-RM5999 0 (0.0) 7 (100.0)
>RM 6000 0 (0.0) 2 (100.0)
*Chi-Square test was used
electronic-Perak Medical Journal Vol 2 No 1 August 2022 awareness of diabetes complications and high rate of adherence to dietary advice26. This suggests that higher level of education probably gives the patients a higher awareness about the disease and the importance of adherence among patients. In contrast, studies done in United Kingdom have shown that patients with low educational level had better compliance27. It is presumed that patients with low educational level have more trust in the health care provider’s advice, therefore leading to better adherence.
Similarly, our study has observed a better adherence among patients with no formal education as compared to patients with formal education. However, results shown in our study were not significant.
The limitations of our study included the lack of ADM choices and it was only conducted in a single centre.
Therefore, the results may not represent the actual population. A multi-centre study that involves a larger sample size of patients would have been able to provide a better relationship on association between ADM adherence and the variables studied. Besides that, the respondents were identified through prescription screening rather than enquiring on the type of DM medications that they were taking. It is essential to conduct this study with a larger sample size to have a better observation and interpretation on the factors that contribute to adherence to ADM among diabetes patients. This study was based on a self- administered questionnaire that could have contributed to recall bias and overestimating patient’s adherence. In addition, we are unable to verify the actual income levels of the respondents in this study. Thus, it is necessary for a future research to consider other variables which correlate with adherence, including ethnicity and health beliefs such as a belief in self-efficacy after taking medication and a belief in self-control over one’s health.
CONCLUSION
The level of non-adherence to ADM was high and results showed that patients taking OHA with insulin has a higher rate of adherence as compared to patients on OHA monotherapy. Demographic factors have also shown to have an insignificant effect on the patient’s adherence towards diabetes management in this study.
ETHICAL APPROVAL
Ethical approval for this study was obtained from the Medical Research and Ethics Committee (MREC), Ministry of Health Malaysia. This research has been registered under National Malaysia Research Register with reference numbers NMRR-17-3030-39341. This study is not funded by any organization.
ACKNOWLEDGEMENT
We would like to thank:
i. The Director General of Health Malaysia for his permission to publish this article.
Based on our study, employed patients have the highest rate of non-adherence towards their medications, followed by retirees and unemployed patients. This data suggested that the unemployed patients have the best adherence. A study to identify factors contributing to non-adherence to ADM among ambulatory T2DM patients in Southwestern Nigeria, had postulated that having a busy workload and inconvenience of taking medication outside home might be an impediment to the patients' ability to adhere to ADM13. This is coherent in our study as employed patients demonstrated the highest rate of non-adherence to ADM, but results were not statistically different. Lorenc L. et al. has reported that being away from home contributed to poor timing of taking medications. This study has established that patients have difficulties in consuming medications in public and bringing their medications with them thereby adversely affecting their adherence23. To prevent “forgetfulness” from being a reason for lack of medication adherence for employed patients, phone application can be downloaded to track and as a reminder to take their medications.
This study presented that patients who are treated with OHA and insulin therapy are more likely to have a better adherence towards their medications as compared to the patients who are solely on OHA. However, there were no significant difference in this result. Based on a study conducted in Spain24, the proportion of good adherence was higher in patients treated in insulin than in those treated with OHA and much lower in those treated with a combination of OHA and insulin. OHA is the “backbone” of T2DM management and due to the progression of the disease, insulin will be added in after some period of time.
Insulin treatment may cause psychological effects on patients. Therefore, initiation of insulin treatment alerts patients to be more health-conscious and possibly trigger them to be more conscientious about taking their medications.
This study findings show that gender may influence patient’s adherence to ADM. Female patients tend to show better adherence towards medications as compared to male patients but the result was not statistically significant. On the contrary, there were studies conducted showing opposing results. According to Sundbom and Bingefors25, it was found that poor adherence appears to be closely associated to women than men although differing results have been described in our study. It was suggested that gender could have an influence on adherence due to women and men having their own health beliefs, behaviours and different attitudes toward drugs. But, type of medicine also may have differences effect on compliance, for example, drug used to treat behavioural condition tend to have more women than man adhering to the medication regimens26. These differences could possibly indicate a need for more personalized drug selection and therapeutic management to improve clinical outcomes.
Education is an inevitable factor that affects patient’s adherence towards ADM. However, medication adherence differs noticeably across countries. In Pakistan, high educational level was significantly associated with better
23. Lorenc, L. and Branthwaite, A., 1993. Are older adults less compliant with prescribed medication than younger adults?. British Journal of Clinical Psychology, 32(4), pp.485-492.
24. Yurgin NR, Kristina Secnik Boye, Tatiana Dilla, Núria Lara Suriñach, and Xavier Badia Llach. "Physician and patient management of type 2 diabetes and factors related to glycemic control in Spain." Patient preference and adherence. 2008;2:87.
25. Thunander Sundbom L, Bingefors K. Women and men report different behaviours in, and reasons for medication non-adherence: a nationwide Swedish survey. Pharm Pract (Granada). Oct 2012;10(4):207-221.
26. Jimmy, B. and Jose, J., 2011. Patient medication adherence: measures in daily practice. Oman medical journal, 26(3), p.155.Jimmy, B. and Jose, J., 2011. Patient medication adherence: measures in daily practice. Oman medical journal, 26(3), p.155.
27. Kyngas H, Lahdenpera T. Compliance of patients with hypertension and associated factors. J Adv Nurs. Apr 1999;29(4):832-839.
REFERENCES
1. NHMS. Institute for Public Health. National Health and Morbidity Survey.
Non-Communicable Diseases, Risk Factors & Other Health Problems.
2015;2.
2. Mustapha FI AS, Manaf MR, Hussein Z, Mahir JN, Ismail F, Aizuddin AN, Goh A. What are the direct medical costs of managing Type 2 Diabetes Mellitus in Malaysia. Med J Malaysia. 1-October 2017;72(5).
3. Sabaté E, and Eduardo Sabaté, eds. Adherence to long-term therapies:
evidence for action. World Health Organization, 2003.
4. Cefalu WT. Pharmacotherapy for the treatment of patients with type 2 diabetes mellitus: rationale and specific agents. Clin Pharmacol Ther.
May 2007;81(5):636-649.
5. Jimmy B, Jose J. Patient medication adherence: measures in daily practice. Oman Med J. May 2011;26(3):155-159.
6. CPG Malaysia, Clinical Practice Guidelines on Management of Type 2 Diabetes Mellitus 5th Edition. 2015
7. Ahmad NS, Ramli A, Islahudin F, Paraidathathu T. Medication adherence in patients with type 2 diabetes mellitus treated at primary health clinics in Malaysia. Patient Prefer Adherence. 2013;7:525-530.
8. Mukherjee S, Sharmasarkar B, Das KK, Bhattacharyya A, Deb A.
Compliance to anti-diabetic drugs: observations from the diabetic clinic of a medical college in kolkata, India. J Clin Diagn Res. Apr 2013;7(4):661- 665.
9. Naing, L., Than Winn, and BNordin Rusli. "Sample size calculator for prevalence studies. Version 1.0. 01." (2016).
10. Mayberry LS GJ, Wallston KA, Kripalani S, Osborn CY. The ARMS-D out performs the SDSCA, but both are reliable, valid, and predict glycemic control. Diabetes Research and Clinical Practice. Nov 2013;102(2):96–
104.
11. Kripalani S, Risser J, Gatti ME, Jacobson TA. Development and evaluation of the Adherence to Refills and Medications Scale (ARMS) among low- literacy patients with chronic disease. Value Health. Jan-Feb 2009;12(1):118-123.
12. Captieux M, Pearce G, Parke HL, et al. Supported self-management for people with type 2 diabetes: a meta-review of quantitative systematic reviews. BMJ Open. 2018;8(12):e024262.
13. Adisa R, Martins B. Alutundu, and Titilayo O. Fakeye. Factors contributing to nonadherence to oral hypoglycemic medications among ambulatory type 2 diabetes patients in Southwestern Nigeria. Pharmacy Practice 7. 2009;3:163.
14. Kalyango JN, Erisa Owino, and Agatha P. Nambuya. Non-adherence to diabetes treatment at Mulago Hospital in Uganda: prevalence and associated factors. African health sciences. 2008;8(2).
15. Sweileh W, Ola Aker, and Saed Hamooz. Rate of compliance among patients with diabetes mellitus and hypertension. An-Najah Univ J Res (N Sci) 2005;19(1).
16. Lee VW, Leung PY. Glycemic control and medication compliance in diabetic patients in a pharmacist-managed clinic in Hong Kong. Am J Health Syst Pharm. Dec 15 2003;60(24):2593-2596.
17. Hernandez-Ronquillo L, Tellez-Zenteno JF, Garduno-Espinosa J, Gonzalez-Acevez E. Factors associated with therapy noncompliance in type-2 diabetes patients. Salud Publica Mex. May-Jun 2003;45(3):191- 197.
18. Khattab MS, Aboifotouh MA, Khan MY, Humaidi MA, al-Kaldi YM.
Compliance and control of diabetes in a family practice setting, Saudi Arabia. East Mediterr Health J. Jul 1999;5(4):755-765.
19. Shobhana R, Begum R, Snehalatha C, Vijay V, Ramachandran A. Patients' adherence to diabetes treatment. J Assoc Physicians India. Dec 1999;47(12):1173-1175.
20. Andersson K, Melander A, Svensson C, Lind O, Nilsson JL. Repeat prescriptions: refill adherence in relation to patient and prescriber characteristics, reimbursement level and type of medication. Eur J Public Health. Dec 2005;15(6):621-626.
21. Benner JS, Robert J. Glynn, Helen Mogun, Peter J. Neumann, Milton C.
Weinstein, and Jerry Avorn. Long-term persistence in use of statin therapy in elderly patients. JAMA. 2002;288(4):455-461.
22. Okuno J, Yanagi, H., Tomura, S., Oka, M., Hara, S., Hirano, C. and Tsuchiya, S. Compliance and medication knowledge among elderly Japanese home-care recipients. European journal of clinical pharmacology. 1999;55(2):145-149.
23. Lorenc, L. and Branthwaite, A., 1993. Are older adults less compliant with prescribed medication than younger adults?. British Journal of Clinical Psychology, 32(4), pp.485-492.