Basal Insulin Initiation and Maintenance in Adults with Type 2 Diabetes Mellitus in the United States

Figures & data

Table 1 Baseline Patient Characteristics

	Overall		Continuers [A]		Interrupters [B]		Discontinuers [C]		p-value [A vs B]	p-value [A vs C]	p-value [B vs C]
	(n = 154)		(n = 52)		(n = 52)		(n = 50)
Age
Mean (SD)	51.4	(16.4)	63.8	(12.5)	43.2	(14.0)	47.2	(14.8)	<0.01	<0.01	0.16
Male, n (%)	80	(51.9%)	28	(53.8%)	32	(61.5%)	20	(40.0%)	0.43	0.16	0.03
Race/ethnicity, n (%)*
White	124	(80.5%)	47	(90.4%)	37	(71.2%)	40	(80.0%)	0.01	0.14	0.30
Black or African American	23	(14.9%)	6	(11.5%)	10	(19.2%)	7	(14.0%)	0.28	0.71	0.48
Hispanic	9	(5.8%)	1	(1.9%)	3	(5.8%)	5	(10.0%)	0.31	0.08	0.43
American Indian or Alaska Native	3	(1.9%)	0	(0.0%)	0	(0.0%)	3	(6.0%)	–	0.07	0.07
Asian	5	(3.2%)	0	(0.0%)	4	(7.7%)	1	(2.0%)	0.04	0.31	0.18
Education level, n (%)									0.01	0.12	0.61
Less than high school	1	(0.6%)	0	(0.0%)	1	(1.9%)	0	(0.0%)
High school or equivalent	25	(16.2%)	13	(25.0%)	5	(9.6%)	7	(14.0%)
Some college	44	(28.6%)	17	(32.7%)	12	(23.1%)	15	(30.0%)
Associate’s degree or equivalent	20	(13.0%)	4	(7.7%)	7	(13.5%)	9	(18.0%)
College degree	64	(41.6%)	18	(34.6%)	27	(51.9%)	19	(38.0%)
Bachelor’s degree or equivalent	47	(30.5%)	9	(17.3%)	23	(44.2%)	15	(30.0%)
Graduate degree	17	(11.0%)	9	(17.3%)	4	(7.7%)	4	(8.0%)
Employment status, n (%)									<0.01	<0.01	0.03
Working full-time	64	(41.6%)	11	(21.2%)	32	(61.5%)	21	(42.0%)
Working part-time	15	(9.7%)	2	(3.8%)	6	(11.5%)	7	(14.0%)
Not employed	5	(3.2%)	1	(1.9%)	2	(3.8%)	2	(4.0%)
Disabled	14	(9.1%)	2	(3.8%)	2	(3.8%)	10	(20.0%)
Retired	41	(26.6%)	29	(55.8%)	4	(7.7%)	8	(16.0%)
Student	5	(3.2%)	0	(0.0%)	5	(9.6%)	0	(0.0%)
Homemaker	10	(6.5%)	7	(13.5%)	1	(1.9%)	2	(4.0%)
Living with a spouse/partner, n (%)	105	(68.2%)	35	(67.3%)	37	(71.2%)	33	(66.0%)	0.67	0.89	0.58
Health insurance coverage when initiating basal insulin, n (%)
Medical care	137	(89.0%)	51	(98.1%)	44	(84.6%)	42	(84.0%)	0.02	0.01	0.93
Prescription drugs	138	(89.6%)	50	(96.2%)	47	(90.4%)	41	(82.0%)	0.24	0.02	0.22
Years since first T2DM diagnosis
Mean (SD)	8.6	(9.3)	9.9	(7.0)	8.1	(11.2)	7.8	(9.5)	0.32	0.21	0.89
Median [IQR]	6.0	[3.0–12.0]	10.0	[4.0–14.5]	6.0	[3.0–10.0]	4.5	[2.0–10.0]
Mode of delivery of basal insulin initiated, n (%)									0.57	0.15	0.50
Pen (prefilled/disposable)	97	(63.0%)	37	(71.2%)	32	(61.5%)	28	(56.0%)
Pen (reusable) & cartridge	20	(13.0%)	4	(7.7%)	6	(11.5%)	10	(20.0%)
Vial and syringe	37	(24.0%)	11	(21.2%)	14	(26.9%)	12	(24.0%)
Prior use of antidiabetic medications to treat T2DM, n (%)
Any prior use of antidiabetic medication	118	(76.6%)	43	(82.7%)	45	(86.5%)	30	(60.0%)	0.59	0.01	<0.01
Oral antidiabetics	105	(68.2%)	41	(78.8%)	37	(71.2%)	27	(54.0%)	0.37	<0.01	0.07
Injectables other than insulin	30	(19.5%)	8	(15.4%)	15	(28.8%)	7	(14.0%)	0.10	0.84	0.07

Notes: Continuers had no gaps of ≥7 days in basal insulin treatment. Interrupters stopped basal insulin for ≥7 days within the first 6 months after initiation and since restarted basal insulin. Discontinuers stopped using basal insulin for ≥7 days within the first 6 months after initiation and had not restarted basal insulin by the time of the survey. *One respondent declined to answer this question. Categories not listed in the table had 0 respondents (“Native Hawaiian or other Pacific Islander”, “Other”). P-values were calculated using t-tests for continuous variables and chi-square tests or Fisher’s exact tests for categorical variables. P<0.05 was considered statistically significant.

Table 2 Perceptions About Insulin Use and Experience Across Persistence Groups

	Overall		Continuers [A]		Interrupters [B]		Discontinuers [C]		p-value [A vs B]	p-value [A vs C]	p-value [B vs C]
	(n = 154)		(n = 52)		(n = 52)		(n = 50)
Respondent’s motivations for starting insulin, n (%) responding “Yes”
Encouragement from physician/healthcare provider	101	(65.6%)	40	(76.9%)	30	(57.7%)	31	(62.0%)	0.04	0.10	0.66
Improved glycemic control	92	(59.7%)	26	(50.0%)	36	(69.2%)	30	(60.0%)	<0.05	0.31	0.33
Concern about developing other complications of diabetes	42	(27.3%)	16	(30.8%)	13	(25.0%)	13	(26.0%)	0.51	0.59	0.91
Preference for injections over pills	10	(6.5%)	1	(1.9%)	4	(7.7%)	5	(10.0%)	0.17	0.08	0.68
Inability to tolerate other antidiabetic medications	4	(2.6%)	2	(3.8%)	1	(1.9%)	1	(2.0%)	0.56	0.58	0.98
Other	3	(1.9%)	2	(3.8%)	0	(0.0%)	1	(2.0%)	0.15	0.58	0.31
Degree to which respondent felt views were considered, n (%)									0.06	0.33	0.30
Not at all/slightly	27	(17.5%)	5	(9.6%)	12	(23.1%)	10	(20.0%)
Somewhat	38	(24.7%)	16	(30.8%)	8	(15.4%)	14	(28.0%)
Very/fully	89	(57.8%)	31	(59.6%)	32	(61.5%)	26	(52.0%)
Converted to 0–100, mean (SD)	63.5	(27.3)	68.8	(26.6)	61.1	(28.6)	60.5	(26.3)	0.03	0.24	0.54
Feelings when considering insulin, n (%) who agree/strongly agree
Reassurance that insulin would help manage diabetes	122	(79.2%)	41	(78.8%)	45	(86.5%)	36	(72.0%)	0.30	0.42	0.07
Fear of developing other complications of diabetes	115	(74.7%)	40	(76.9%)	43	(82.7%)	32	(64.0%)	0.46	0.15	0.03
Feeling that insulin indicated that diabetes was worsening	108	(70.1%)	35	(67.3%)	39	(75.0%)	34	(68.0%)	0.39	0.94	0.43
Sense of failure	72	(46.8%)	21	(40.4%)	33	(63.5%)	18	(36.0%)	0.02	0.65	<0.01
Belief that insulin was not necessary	46	(29.9%)	6	(11.5%)	23	(44.2%)	17	(34.0%)	<0.01	<0.01	0.29
Concerns before starting insulin, n (%) who agree/strongly agree
Concern about becoming insulin-dependent	99	(64.3%)	25	(48.1%)	38	(73.1%)	36	(72.0%)	<0.01	0.01	0.90
Concern that he/she would need to monitor blood glucose more often	85	(55.2%)	21	(40.4%)	38	(73.1%)	26	(52.0%)	<0.01	0.24	0.03
Concern about ability to pay for insulin therapy	83	(53.9%)	22	(42.3%)	38	(73.1%)	23	(46.0%)	<0.01	0.71	<0.01
Fear of self-injection	81	(52.6%)	17	(32.7%)	36	(69.2%)	28	(56.0%)	<0.01	0.02	0.17
Fear of making mistakes during self-injection	81	(52.6%)	16	(30.8%)	38	(73.1%)	27	(54.0%)	<0.01	0.02	<0.05
Worry about potential weight gain	81	(52.6%)	20	(38.5%)	36	(69.2%)	25	(50.0%)	<0.01	0.24	<0.05
Concern about carrying insulin around	72	(46.8%)	20	(38.5%)	32	(61.5%)	20	(40.0%)	0.02	0.87	0.03
Concern that he/she would need to visit physician/nurse more often	71	(46.1%)	16	(30.8%)	34	(65.4%)	21	(42.0%)	<0.01	0.24	0.02
Worry about injecting insulin in front of other people	69	(44.8%)	15	(28.8%)	31	(59.6%)	23	(46.0%)	<0.01	0.07	0.17
Worry about proper insulin storage	64	(41.6%)	13	(25.0%)	31	(59.6%)	20	(40.0%)	<0.01	0.11	<0.05
Worry that regular insulin use would interfere with daily activities	64	(41.6%)	12	(23.1%)	32	(61.5%)	20	(40.0%)	<0.01	0.07	0.03
Worry that insulin would not provide glycemic control	63	(40.9%)	12	(23.1%)	28	(53.8%)	23	(46.0%)	<0.01	0.01	0.43
Concern about potentially frequent hypoglycemia	60	(39.0%)	9	(17.3%)	27	(51.9%)	24	(48.0%)	<0.01	<0.01	0.69
Worry that scarring or bruising would result from injections	55	(35.7%)	9	(17.3%)	29	(55.8%)	17	(34.0%)	<0.01	0.05	0.03

Notes: Continuers had no gaps of ≥7 days in basal insulin treatment. Interrupters stopped basal insulin for ≥7 days within the first 6 months after initiation and since restarted basal insulin. Discontinuers stopped using basal insulin for ≥7 days within the first 6 months after initiation and had not restarted basal insulin by the time of the survey. P-values were calculated using t-tests for continuous variables and chi-square tests or Fisher’s exact tests for categorical variables. P<0.05 was considered statistically significant. Feelings when considering insulin were assessed on a 1–5 scale (1=“Not at all”, 2=“Slightly”, 3=“Somewhat”, 4=“Very”, 5=“Fully”). Concerns before starting insulin were assessed on a 1–5 level of agreement scale (1=“Strongly disagree”, 2=“Disagree”, 3=“Neither agree nor disagree”, 4=“Agree”, 5=“Strongly agree”).

Figure 1 Patients’ feelings, worries, and concerns when initiating basal insulin (combined across continuers, interrupters, discontinuers; N=154). Numbers reflect the percentage of patients who agree/strongly agree with a particular feeling, worry, or concern.

Figure 2 Insulin use experience after first week of initiation. All differences (continuers vs. interrupters or vs. discontinuers) are statistically significant at p<0.05.

Table 3 Self-Reported Reasons for Different Persistence Patterns

	Total N = 154
Continuation (n=52)
Motivations for continuation of basal insulin, n (%)
Improved glycemic control	41	78.8%
Belief that insulin is best for reducing risk of complications of diabetes	33	63.5%
Instruction by physician/healthcare provider to continue	28	53.8%
Improved physical feeling	23	44.2%
Improved emotional wellbeing	13	25.0%
Convenience of insulin relative to other diabetes treatments	12	23.1%
Interruption (n=52)
More than one interruption, n (%)	40	76.9%
Factors contributing to interruption, n (%)
Weight gain	18	34.6%
Fear of potential side effects of insulin use	16	30.8%
Hypoglycemia	12	23.1%
Inconvenience of using insulin	12	23.1%
Instruction by physician/healthcare provider to stop	11	21.2%
Assessing whether diabetes could be managed without insulin	11	21.2%
Cost of insulin therapy	10	19.2%
Pain from injections	9	17.3%
Preference for oral antidiabetic medications	8	15.4%
Dislike/fear of needles	7	13.5%
Insufficient glycemic control with insulin	6	11.5%
Other	2	3.8%
Factors contributing to restarting basal insulin, n (%)
Persuasion by physician/healthcare provider to restart	36	69.2%
Persuasion by friends/family to restart	19	36.5%
Insufficient glycemic control without insulin	18	34.6%
Resolution of the issue that led to interruption	8	15.4%
Other	2	3.8%
Discontinuation (n=50)
Factors contributing to discontinuation, n (%)
Instruction by physician/healthcare provider to stop	23	46.0%
Weight gain	15	30.0%
Hypoglycemia	12	24.0%
Dislike/fear of needles	10	20.0%
Preference for oral antidiabetic medications	10	20.0%
Cost of insulin therapy	10	20.0%
Insufficient glycemic control with insulin	8	16.0%
Sense that diabetes could be managed without insulin	7	14.0%
Pain from injections	6	12.0%
Inconvenience of using insulin	5	10.0%
Fear of potential side effects of insulin use	3	6.0%
Perception of insulin use by others	1	2.0%
Other	6	12.0%
Factors that could contribute to restarting basal insulin, n (%)
Persuasion by physician/healthcare provider to restart	27	54.0%
Insufficient glycemic control without insulin	22	44.0%
Persuasion by friends/family to restart	12	24.0%
Nothing	6	12.0%
Other	2	4.0%

Notes: Continuers had no gaps of ≥7 days in basal insulin treatment. Interrupters stopped basal insulin for ≥7 days within the first 6 months after initiation and since restarted basal insulin. Discontinuers stopped using basal insulin for ≥7 days within the first 6 months after initiation and had not restarted basal insulin by the time of the survey.