Adherence, satisfaction, and experience with metformin 500 mg prolonged release formulation in Indian patients with type 2 diabetes mellitus: a postmarketing observational study

Figures & data

Table 1 Baseline characteristics

Parameter	Total number of patients (N=1,000)
Age (years), mean ± SD (range)	46.6±9.3 (19.0:67.0)
Men/women, n	548:452
Marital status, n	1,000
Married, n (%)	947 (94.7)
Single, n (%)	33 (3.3)
Divorced, n (%)	1 (0.1)
Widowed, n (%)	19 (1.9)
Weight (kg), n, mean ± SD (range)	999, 71.8±13.0 (39.0:171.0)
Height (m), n, mean ± SD (range)	999, 1.6±0.1 (1.4:1.9)
Body mass index (kg/m^2), n, mean ± SD (range)	999, 26.5±4.3 (14.6:52.7)
Waist circumference (cm), n, mean ± SD (range)	965, 90.2±11.0 (1.0:176.0)
Occupation, n	998
Profession, n (%)	164 (16.4)
Semi-profession, n (%)	310 (31.0)
Clerical, shop owner, farmer, n (%)	136 (13.6)
Skilled worker, n (%)	147 (14.7)
Semi-skilled worker, n (%)	64 (6.4)
Unskilled worker, n (%)	33 (3.3)
Unemployed, n (%)	144 (14.4)
Education, n	998
Profession or honors, n (%)	93 (9.3)
Graduate or postgraduate, n (%)	470 (47.0)
Intermediate or post-high school diploma, n (%)	213 (21.3)
High school certificate, n (%)	139 (13.9)
Middle school certificate, n (%)	52 (5.2)
Primary school certificate, n (%)	19 (1.9)
Illiterate	12 (1.2)
Monthly family income (Rs), n	998
≥36,997, n (%)	258 (25.8)
18,498–36,996, n (%)	391 (39.1)
13,874–18,497, n (%)	195 (19.5)
9,249–13,873, n (%)	92 (9.2)
5,547–9,248 n (%)	19 (1.9)
1,866–5,546, n (%)	13 (1.3)
≤1,865, n (%)	30 (3.0)
Socioeconomic status, n	998
Lower socioeconomic class (score <5), n (%)	22 (2.2)
Upper lower socioeconomic class (score 5–10), n (%)	73 (7.3)
Lower middle socioeconomic class (score 11–15), n (%)	185 (18.5)
Upper middle socioeconomic class (score 16–25), n (%)	564 (56.4)
Upper socioeconomic class (score 26–29), n (%)	154 (15.4)
Diabetes complications, n	985
Diabetic retinopathy, n (%)	3 (0.3)
Diabetic foot ulcer, n (%)	1 (0.1)
Diabetic ketoacidosis, n (%)	1 (0.1)
Peripheral vascular disease, n (%)	2 (0.2)
Diabetic nephropathy, n (%)	4 (0.4)
Diabetic neuropathy, n (%)	8 (0.8)
Erectile dysfunction, n (%)	5 (0.5)
Vital parameters, n	993
Pulse (beats/min), mean ± SD (range)	82.2±9 (60:115)
Respiratory rate (beats/min), mean ± SD (range)	17.9±2.3 (12:26)
Systolic blood pressure (mm/Hg), mean ± SD (range)	128.1±12.1 (100:190)
Diastolic blood pressure (mm/Hg), mean ± SD (range)	80.2±7.5 (40:120)

Note: n represents the number of patients analyzed in the study.

Table 2 Study outcomes

Parameters	Total number of patients (N=1,000)
Treatment adherence to metformin 500 mg PR tablet, n, mean ± SD (range)	999, 2.64±1.71 (0:7)
Low, n (%)	445 (44.50)
Medium, n (%)	540 (54.00)
High, n (%)	14 (1.40)
Details of any feeling of discomfort, for ease of swallowing because of its size and shape, for acceptability due to no aftertaste for metformin 500 mg PR tablet in comparison with metformin 500 mg ER tablet, n	999
I do not feel any discomfort while swallowing the metformin 500 mg PR tablet compared with metformin 500 mg ER tablet, n (%)
Strongly agree	228 (22.80)
Agree	662 (66.20)
Neither agree or disagree	109 (10.90)
Disagree	0
Strongly disagree	0
Compared with metformin 500 mg ER tablet, metformin 500 mg PR tablet appears easy to swallow because of its size, n (%)
Strongly agree	214 (21.40)
Agree	644 (64.40)
Neither agree or disagree	140 (14.00)
Disagree	1 (0.10)
Strongly disagree	0
Compared with metformin 500 mg ER tablet, metformin 500 mg PR tablet is easy to swallow because of its shape, n (%)
Strongly agree	178 (17.80)
Agree	634 (63.40)
Neither agree or disagree	184 (18.40)
Disagree	2 (0.20)
Strongly disagree	1 (0.10)
Metformin 500 mg PR tablet is acceptable compared with metformin 500 mg ER tablet as there is no aftertaste, n (%)
Strongly agree	186 (18.60)
Agree	630 (63.00)
Neither agree or disagree	183 (18.30)
Disagree	0
Strongly disagree	0
Details of each of the symptoms under abdominal discomfort for metformin 500 mg PR tablet, n	999
Nausea, n (%)
Did not suffer at all	997 (99.70)
Suffered 1–2 times in the past 2 weeks	1 (0.10)
Suffered 5–6 times in the past 2 weeks	0
Suffered 9–10 times in the past 2 weeks	0
Suffered most of the times	1 (0.10)
Vomiting, n (%)
Did not suffer at all	998 (99.80)
Suffered 1–2 times in the past 2 weeks	1 (0.10)
Suffered 5–6 times in the past 2 weeks	0
Suffered 9–10 times in the past 2 weeks	0
Suffered most of the times	0
Diarrhea, n (%)
Did not suffer at all	996 (99.60)
Suffered 1–2 times in the past 2 weeks	3 (0.30)
Suffered 5–6 times in the past 2 weeks	0
Suffered 9–10 times in the past 2 weeks	0
Suffered most of the times	0
Stomach pain, n (%)
Did not suffer at all	998 (99.80)
Suffered 1–2 times in the past 2 weeks	0
Suffered 5–6 times in the past 2 weeks	0
Suffered 9–10 times in the past 2 weeks	1 (0.1)
Suffered most of the times	0
Increased flatulence, n (%)
Did not suffer at all	998 (99.80)
Suffered 1–2 times in the past 2 weeks	1 (0.10)
Suffered 5–6 times in the past 2 weeks	0
Suffered 9–10 times in the past 2 weeks	0
Suffered most of the times	0
Loss of appetite, n (%)
Did not suffer at all	996 (99.60)
Suffered 1–2 times in the past 2 weeks	3 (0.30)
Suffered 5–6 times in the past 2 weeks	0
Suffered 9–10 times in the past 2 weeks	0
Suffered most of the times	0
Details of various symptoms of abdominal discomfort when on metformin 500 mg ER tablet, n	999
Nausea, n (%)	0
Vomiting, n (%)	0
Diarrhea, n (%)	1 (0.1)
Stomach pain, n (%)	0
Increased flatulence, n (%)	0
Loss of appetite, n (%)	0
Details of ghost pill effect with, n	993
Metformin 500 mg PR tablet, n (%)	7 (0.70)
Metformin 500 mg ER tablet, n (%)	85 (8.50)
Details of comfort with metformin 500 mg PR tablet as compared with metformin 500 mg ER, n	999
Compared with metformin 500 mg ER tablet, how comfortable are you with metformin 500 mg PR tablet? n (%)
Very comfortable	224 (22.40)
Comfortable	679 (67.90)
Neutral	95 (9.50)
Uncomfortable	1 (0.10)
Very uncomfortable	0
Details of metformin 500 mg PR tablet on well-being as compared to metformin 500 mg ER, n	999
What is the effect of metformin 500 mg PR tablet on your well-being compared with metformin 500 mg ER tablets? n (%)
A great deal	213 (21.30)
Much	618 (61.80)
Somewhat	146 (14.60)
Little	8 (0.80)
Not much	14 (1.40)
Details of satisfaction level with metformin 500 mg PR tablet as compared to metformin 500 mg ER tablet, n	999
How satisfied are you with metformin 500 mg PR tablet compared with metformin 500 mg ER tablet? n (%)
Very satisfied	217 (21.70)
Satisfied	690 (69.00)
Neutral	91 (9.10)
Dissatisfied	1 (0.10)
Very dissatisfied	0
Details of reasons for switching to metformin 500 mg PR tablet from metformin 500 mg ER tablet, n	999
How satisfied are you with metformin 500 mg PR tablet compared with metformin 500 mg ER tablets? n (%)
Patient had difficulty in swallowing because of the size of the earlier tablet	205 (20.50)
Patient had difficulty in swallowing due to the shape of the earlier tablet	233 (23.30)
Patient did not like the taste of the earlier medication	111 (11.10)
Ghost pill effect	83 (8.30)
Dissatisfaction with the earlier antidiabetic treatment	427 (42.70)
Patient had abdominal discomfort because of the earlier medication	70 (7.00)
Details of reasons cited by the patients for their noncompliance when on metformin 500 mg ER tablets, n	811
Size of the tablet, n (%)	214 (21.40)
Current medicine sticks in the throat (food pipe)	3 (0.30)
Generally find difficult to swallow medication	198 (19.80)
Very large and makes it uncomfortable to swallow	13 (1.30)
Do not like the taste of the medication, n (%)	249 (24.90)
Felt worse because of medication side effects, n (%)	1 (0.10)
Bloating	1 (0.10)
Dissatisfaction with antidiabetic medication, n (%)	109 (10.90)
Feeling tired of taking medicines daily	109 (10.90)
Other reasons, n (%)	238 (23.80)
Forgetfulness	131 (13.10)
Inconvenience or interference with daily activities	31 (3.10)
Lack of finance	2 (0.20)
Lack of time to comply with the medication regimen	13 (1.30)
Medicine not available with me during travel	35 (3.50)
Taking medicines upsets me as it reminds me of my disease	26 (2.60)

Abbreviations: ER, extended-release; PR, prolonged release.

Figure 1 Site distribution.

Note: The number of sites is represented in parentheses.

Table S1 Patient questionnaire

Adherence to metformin 500 mg PR tablet based on the past 2 weeks
Do you sometimes forget to take your pills?						□ Yes □ No
People sometimes miss taking their medications for reasons other than forgetting. Thinking over the past 2 weeks, were there any days when you did not take your medicine?						□ Yes □ No
Have you ever cut back or stopped taking your medicine without telling your doctor because you felt worse when you took it?						□ Yes □ No
When you travel or leave home, do you sometimes forget to bring along your medicine?						□ Yes □ No
Did you take all your medicines yesterday?						□ Yes □ No
When you feel like your symptoms are under control, do you sometimes stop taking your medicine?						□ Yes □ No
Taking medicine every day is a real inconvenience for some people. Do you ever feel hassled about sticking to your treatment plan?						□ Yes □ No
How often do you have difficulty remembering to take all your medicine?						□ A. Never/rarely □ B. Once in a while □ C. Sometimes □ D. Usually □ E. All the time
Reasons for noncompliance when on metformin 500 mg ER tablets (Multiple choices can be ticked, and tick circles for exact reason.)
□ Size of the tablet ○ Very large and makes it uncomfortable to swallow ○ Generally find difficult to swallow medication ○ Current medicine sticks in the throat (food pipe) □ Don’t like the taste of the medication □ Felt worse because of medication side effects ○ Bloating ○ Nausea ○ Diarrhea ○ Vomiting ○ Abdominal pain ○ Any other, specify:______________ □ Dissatisfaction with antidiabetic medication ○ Feeling tired of taking medicines daily Any other, specify: ____________________________________ □ Other reasons ○ Forgetfulness ○ Lack of time to comply with the medication regimen ○ Inconvenience or interference with daily activities ○ Lack of finance ○ Medicine not available with me during travel ○ Taking medicines upsets me as it reminds me of my disease ○ Any other, specify: ____________________________________
Experience with metformin 500 mg PR tablet compared with metformin 500 mg ER tablet (Tick only one option per question.)
I do not feel any discomfort while swallowing the metformin 500 mg PR tablet compared with metformin 500 mg ER tablet (Rate the medication based on the ease and comfort of swallowing.)					□ 0 = Strongly agree □ 1 = Agree □ 2 = Neither agree or disagree □ 3 = *Disagree □ 4 = *Strongly disagree
Compared with metformin 500 mg ER tablet, metformin 500 mg PR tablet appears easy to swallow because of its size					□ 0 = Strongly agree □ 1 = Agree □ 2 = Neither agree or disagree □ 3 = Disagree □ 4 = Strongly disagree
Compared with metformin 500 mg ER tablet, metformin 500 mg PR tablet is easy to swallow because of its shape					□ 0 = Strongly agree □ 1 = Agree □ 2 = Neither agree or disagree □ 3 = Disagree □ 4 = Strongly disagree
Metformin 500 mg PR tablet is acceptable compared with metformin 500 mg ER tablet as there is no aftertaste					□ 0 = Strongly agree □ 1 = Agree □ 2 = Neither agree or disagree □ 3 = Disagree □ 4 = Strongly disagree
Do you experience any of the below-mentioned symptoms of abdominal discomfort after taking the Metformin 500 mg tablet? Please tick appropriate option for each symptom.
Symptoms of abdominal discomfort	0 = Did not suffer at all		1 = Suffered 1–2 times in the past 2 weeks	2 = Suffered 5–6 times in the past 2 weeks			3 = Suffered 9–10 times in the past 2 weeks	4 = Suffered most of the times
Nausea	□		□	□			□	□
Vomiting	□		□	□			□	□
Diarrhea	□		□	□			□	□
Stomach pain	□		□	□			□	□
Increased flatulence	□		□	□			□	□
Loss of appetite	□		□	□			□	□
Did you experience any of the below-mentioned symptoms of abdominal discomfort while taking metformin 500 mg ER tablet?
○ Nausea		□ Yes □ No
○ Vomiting		□ Yes □ No
○ Diarrhea		□ Yes □ No
○ Stomach pain		□ Yes □ No
○ Increased flatulence		□ Yes □ No
○ Loss of appetite		□ Yes □ No
Do you see the tablet being excreted in the faeces/stools? ○ With metformin 500 mg PR tablet □ Yes □ No ○ With metformin 500 mg ER tablet □ Yes □ No
Satisfaction with metformin 500 mg PR tablet compared with metformin 500 mg ER formulation: (Tick only one option per question.)
Compared with metformin 500 mg ER tablet, how comfortable are you with metformin 500 mg PR tablet? What is the effect of metformin 500 mg PR tablet on your well-being compared with metformin 500 mg ER tablets?							□ 0 = Very comfortable □ 1 = Comfortable □ 2 = Neutral □ 3 = Uncomfortable □ 4 = Very uncomfortable □ 0 = A great deal □ 1 = Much □ 2 = Somewhat □ 3 = Little □ 4 = Not much
How satisfied are you with metformin 500 mg PR tablet compared with metformin 500 mg ER tablets? (based on how much your experience with the medication matches with your expectations)							□ 0 = Very satisfied □ 1 = Satisfied □ 2 = Neutral □ 3 = Dissatisfied □ 4 = Very dissatisfied
Preference of antidiabetic medication (Tick one.)
Metformin 500 mg PR tablet □ Metformin 500 mg ER tablet □

Note:

* To be reported to Abbott Pharmacovigilance within 24 hours via email as per protocol using the appropriate Orange form only for Abbott products.

Abbreviations: ER, extended-release; PR, prolonged release.