Coverage of insulin delivery devices and basal insulin analogs by US managed care organizations

Abstract

Objective:

The perception in the US is that insulin formulations prescribed for type 1 and type 2 diabetes and delivered via insulin pens are more costly to patients than the same or similar products provided in vials, and that basal insulin analogs offered either in pens or vials are likewise more costly to patients than human insulin formulations. This study compares levels of coverage and copays by private and Medicare Part D plans for insulin pens and vials containing basal insulin analogs and for NPH formulations in vials.

Methods:

A commercially available formulary database (Access Point, Pinsonault Associates; updated quarterly) was analyzed as of January 2010 for private insurance plans and as of March 2010 for Medicare Part D plans. Analyses were performed for Tier-level coverage and copays per prescription for basal insulin analogs in pens and vials, and NPH in vials.

Results:

Basal insulin analogs in pens were covered by >91% of private and Part D plans. NPH coverage was reported by >92% of private plans and 69–95% of Part D plans, depending on brand. Irrespective of delivery mode, copays in the majority of private plans for basal insulin analogs and NPH were in the >$10–35 range. Copays were higher in Part D plans, with the majority of plans and subscribers in a >$35–50 range. Prior authorization was required by <10% of insurance plans for insulin analog pen prescriptions, and <3% of plans for insulin analog or NPH prescriptions in vials.

Limitations:

This analysis was descriptive, copay stratification was not based on a statistical model but on copay ranges typically used by the plans, and there were no direct correlations performed on the numbers of subscribers per plan vs copay or Tier level.

Conclusion:

These results counter the widely held perception that insurance coverage is less extensive for insulin pens vs vials. Medicare Part D plans often had higher copay requirements than private plans for the same product at the same copay Tier.

Key words::

• Insulin analogs
• Pen device
• Insulin vial
• Neutral Protamine Hagedorn
• Insurance coverage
• cost

Introduction

For all patients with type 1 diabetes, and for many patients with type 2 diabetes, good glycemic control requires insulin therapy. While numerous technological advances have improved the pharmacologic profiles of available insulin therapies and their delivery systems, many patients continue to rely on outdated regimens1.

Technological advances in insulin delivery systems have accompanied improvements in insulin profiles, including the development of insulin pumps and insulin pen devices, both of which provide numerous advantages over the vial and syringe. The first insulin pen device was introduced in 1985 by Novo Nordisk, and considerable improvements to design and ease of use of insulin pens have been made in the last 25 years2.

Studies have demonstrated that insulin pens are associated with higher quality of life scores3, greater glycemic control4, lower rates of hypoglycemia5, and greater adherence and persistence than vial and syringe5–7. Moreover, possibly due to higher adherence rates, the use of insulin pens has been associated with lower demands on healthcare services such as emergency visits, hospitalizations, and outpatient visits related to type 1 and type 2 diabetes management5,7–11. Consequently, in most areas in the developed world, insulin pens have replaced vial and syringe use, and more than 90% of patients with type 1 or type 2 diabetes in most industrialized countries use pens2. Worldwide, more than 60% of patients using insulin use insulin pen devices2. In contrast, ∼ 80% of patients receiving insulin therapy in the US continue to use vials and syringes2. A recent study reported that only ∼3% of patients in the US begin insulin therapy with pens1.

Because increased use of insulin pens in the US may ultimately improve patient acceptance of insulin, improve adherence, and reduce costs5,6,12, understanding the reasons for the poor uptake of these devices is important. Several factors have been proposed to explain the limited use of pens in the US, including suitability of the patient for pen use, therapeutic inertia, limited formularies offered by private and public insurance carriers, physician unawareness2, or absence of insurance. However, one of the most widely cited factors is the perception by healthcare practitioners that even for patients with insurance there is reduced access to, and poor insurance coverage for, pens, and therefore by extension, pens are thought to be more costly to patients2,13–15. A survey of insulin users reported that cost perception was the most common reason for not using insulin pens, cited by 23% of respondents16. Another common perception by healthcare practitioners is that the use of insulin pens requires prior authorization from most insurance companies. Together, these factors are likely to influence a physician’s propensity for recommending insulin pens, which in turn is the most important factor in determining their acceptance by patients13.

Although the perception that insulin pens are poorly covered is widely held, few data on insurance coverage of insulin pens for basal insulin therapies are available in the literature. To determine insurance coverage for these therapies and devices, we examined the extent of insurance coverage offered by private and basic Medicare Part D plans for insulin pens and vials containing basal insulin analogs or Neutral Protamine Hagedorn (NPH).

Methods

Insurance coverage and formulary status of the two basal insulin analogs, insulin glargine (Lantus, sanofi-aventis, Bridgewater, NJ) and insulin detemir (Levemir, Novo Nordisk, Princeton, NJ) in vials and in their associated disposable pen devices (SoloSTAR and FlexPen, respectively), and Neutral Protamine Hagedorn formulations in vials, abbreviated here as NPH-H (Humulin N, Eli Lilly, Indianapolis, IN) and NPH-N (Novolin N, Novo Nordisk) were examined, using a commercially available formulary database (Access Point, Pinsonault Associates, Mount Olive, NJ) of medications covered by private/non-Medicare and Medicare Part D insurance plans. This formulary database is updated on a quarterly basis from insurance plans’ publicly accessible preferred drug listings, which were confirmed with each insurance plan.

Data were analyzed for basal insulin analogs as of January 2010 for private plans and as of March 2010 for Part D plans. A total of 425 private insurance and 644 Medicare Part D plans provided data for this analysis of basal insulin coverage. The private plans covered a total of 226 million members, which was ∼96% of the privately insured market. Pharmacy benefits were included for 168.9 million of these subscribers. Medicare Part D data for basal insulin analogs were captured for 21.5 million out of a total of ∼24 million Medicare subscribers.

Formulary data for NPH formulations only in vials (as of August 2010) were separately summarized from a total of 396 private plans that covered 223.5 million members, of whom 167.4 million were included for pharmacy benefits. There were 611 Medicare Part D plans that covered 22.8 million subscribers for NPH.

The data discussed herein were analyzed by comparing coverage for each insulin formulation by device or vial, by numbers of plans and subscribers with pharmacy benefits (henceforth, simply termed, subscribers), by insurance Tier levels, and by insurance copay ranges. Insurance Tier (ranging from 1–4), is based on a scale of increasing copays required of the subscriber, and reflects lower preference on the part of the insurance carrier. Tier 1 is reserved for generic drugs and other low-priced drugs. Tier 2 is the most commonly used insurance Tier and consists of most preferred drugs, with less preferred, more expensive drugs listed in Tier 3, and the most expensive and often newer drugs listed in Tier 4. Copays are per prescription, per fill. When individual plans listed a copay range, only the highest dollar amount copay was noted. The copay was then grouped into one of five categories of copay ranges ($0, ≤$10, >$10–35, >$35–$50, >$50) that corresponded to the ranges typically reported by the plans.

These data included plans with as few as 29 subscribers and those covering as many as 3 million in a single state. All data were summarized and are presented anonymously, and were irrespective of subscribers’ health status, or presence or absence of diabetes.

Contextual information included in the introduction and discussion sections was collected from articles published in English identified using a search of the MEDLINE databases between January 1990 and May 2011. The following search terms were used: insulin pen, insulin delivery device, diabetes, analog, pen device, copay, coverage, and reimbursement. A manual search of the reference lists from the identified articles and recent reviews was also conducted to find additional articles.

Results

Basal insulin analog and NPH insulin coverage

The majority of private insurance subscribers (i.e., those with pharmacy benefits) were covered at Tier 2 for basal insulin analogs in pens and vials (Table 1). Out of the ∼169 million subscribers covered for basal insulin analogs in pens or vials, 108 million (64%) had Tier 2 coverage for insulin glargine compared to 120 million patients (71%) for insulin detemir, both in pens. Tier 2 coverage for vials included 164 million (97%) and 154 million (91%) subscribers for insulin glargine and insulin detemir, respectively.

Table 1.  Number of subscribers (×10⁶) covered by private and Medicare insurance plans.

Tier	Basal analogs – Private plans				Basal analogs – Part D				NPH – Private plans		NPH – Part D
	Glargine pen	Detemir pen	Glargine vial	Detemir vial	Glargine pen	Detemir pen	Glargine vial	Detemir vial	NPH-H vial	NPH-N vial	NPH-H vial	NPH-N vial
T1	0.58	0.58	1.56	1.56	0.15	0.11	0.19	0.15	3.0	25.7	0.11	0.2
T2	108.0	119.8	163.6	154.4	17.9	18.3	19.3	18.9	117.5	113.1	15.8	19.5
T3	47.7	35.2	1.9	8.3	1.5	2.0	1.3	2.2	30.8	26.6	2.37	1.75
T4	–	0.06	–	0.06	0.7	0.04	0.7	0.05	–	–	0.03	0.01
FB	0.3	0.3	0.07	0.3	–	–	–	–	–	–	–	–
NC	12.4	12.9	1.8	4.4	1.2	1.1	0.01	0.17	16.1	1.97	4.5	1.34
Sum	168.9	168.9	168.9	168.9	21.5	21.5	21.5	21.5	167.4	167.4	22.8	22.8

FB, flat benefit; NC, not covered; NPH-H, Humulin N; NPH-N, Novolin N.

Smaller numbers of subscribers were covered for the two basal insulin analogs at Tier 3 in pens (48 million, 28%), and (35 million, 21%), with even fewer covered for vials (1.9 million and 8.3 million, for insulin glargine and insulin detemir, respectively). Only 577,000 (0.3%) patients were covered at Tier 1 for either basal insulin analog in pens, compared to 1.6 million (0.9%) covered at Tier 1 for either analog in vials.

The majority of private insurance plans offered Tier 2 coverage for insulin glargine (293/425 plans, 69%) and insulin detemir (285/425, 67%) in pens, and 96% (408/425) and 88% (375/425) of plans, respectively, covered these basal analogs in vials (Table 2).

Table 2.  Number of private and Medicare Part D insurance plans covering basal insulin analogs and intermediate-acting human insulin formulations.

Tier	Basal analogs – Private plans				Basal analogs – Part D				NPH – Private plans		NPH – Part D
	Glargine pen	Detemir pen	Glargine vial	Detemir vial	Glargine pen	Detemir pen	Glargine vial	Detemir vial	NPH-H vial	NPH-N vial	NPH-H vial	NPH-N vial
T1	2	2	3	3	5	4	6	5	10	62	4	8
T2	293	285	408	375	472	487	525	525	295	242	367	488
T3	92	95	5	23	63	97	58	104	59	84	81	130
T4	–	1	–	1	52	1	51	1	–	–	2	1
FB	3	3	2	3	–	–	–	–	–	–	–	–
NC	35	39	7	20	52	55	4	9	32	8	207	34
Sum	425	425	425	425	644	644	644	644	396	396	661	661

FB, flat benefit; NC, not covered; NPH-H, Humulin N; NPH-N, Novolin N.

Under Medicare Part D, out of 21.5 million covered subscribers, ∼18 million were covered at Tier 2 for the basal insulin analogs in pens (insulin glargine, 83%; insulin detemir, 85%) (Table 1). Coverage of basal analogs in vials by Medicare Part D was slightly higher: Of 21.5 million patients, ∼19 million (90% and 88%) were covered at Tier 2. At Tier 3, 1.5 and 2.0 million (7% and 9%) were covered for the basal insulin analogs in pens, compared to 1.3 and 2.2 million (6.5% and 10%) for the same products in vials.

The proportions of Part D plans offering Tier 2 coverage of pens were 73% (472/644) and 76% (487/644) for insulin glargine and insulin detemir, which is slightly higher than found for their private coverage (Table 2). Compared to the private plans, a slightly smaller proportion of Part D plans (525/644 plans for both analogs, 82%) offered Tier 2 vial coverage, and a higher proportion of plans (insulin glargine, 9%; insulin detemir, 16%) provide Tier 3 coverage for vials.

As shown in Table 2, 8% and 9% of private plans (35/425 for insulin glargine and 39/425 for insulin detemir) do not cover basal insulin analogs in pens, with a similar proportion of Part D plans, 8% and 8.5% (52/644 insulin glargine and 55/644 insulin detemir), not offering coverage.

The majority of plans cover the two NPH formulations. Approximately 70% (118 and 113 million) of the 167 million subscribers were covered at Tier 2 by private plans for NPH-H and NPH-N, respectively (Table 1), which is essentially not very different to the proportions seen for Tier 2 coverage of the basal insulin analogs in pens. NPH-N can be obtained by 15.4% (25.7 million) of subscribers at Tier 1, a higher proportion compared to Tier 1 access to NPH-H (1.8%; 3.0 million), for either basal insulin analog (0.3% and 0.9%) offered in pens and vials, respectively.

Coverage of vials under Tier 2 for the two NPH formulations, NPH-H (295/396 plans, 74%) and NPH-N (242/396 plans, 61%), among private plans was lower than coverage for the basal insulin analogs in vials (Table 2). Part D coverage of NPH is offered to 22.8 million subscribers at all Tiers (Table 1). NPH-H is offered to 15.8 million (69%) and NPH-N to 19.5 million (86%) of the 22.8 million subscribers at Tier 2. Under Part D, a higher proportion of subscribers are covered for basal insulin analogs, both in pens or vials, than for either of the NPH formulations in vials.

The proportions of Part D plans covering NPH under Tier 2 were lower for NPH-H (367/661 plans, 56%), compared with NPH-N (488/661 plans, 74%), with similar preferences for each formulation being offered at Tier 3 (Table 2). Over all Tiers, a lower proportion of Part D plans (454/661 plans, 69%) cover NPH-H compared to NPH-N (627/661 plans, 95%).

Copays for basal insulin analogs and NPH insulin

Table 3 shows the distribution of copays for basal insulin analogs under private and Medicare Part D plans. The large majority of private insurance plans (Table 3) covered both basal insulin analogs in pens at Tier 2 (74% [277/374, insulin detemir] to 76% [287/378, insulin glargine]). Fifty percent of plans’ copays (190/378, insulin glargine; 187/374, insulin detemir) covered 78 million (insulin glargine) to 94 million (insulin detemir) subscribers in the copay range of >$10–35 per pen prescription. Up to 67% of private plans (256/393, insulin detemir; 271/407, insulin glargine) covered 125 million (insulin detemir) to 128 million (insulin glargine) subscribers at this copay range for vials. From 17–20% of private plans require copays in the >$35–50 range for basal analogs in pens or vials for 20–35 million subscribers, over 60% of which are in Tier 2. At Tier 3, most copays for pens in private plans were >$50, and typically ranged from $55–60, with some plans higher.

Table 3.  Copay ranges for basal insulin analogs: private and Part D plans.

Insulin	Copay ranges
	Tier	$0	≤$10	>$10–35	>$35–50	>$50	Total plans
Numbers of private plans
Pens
Detemir	T1	–	2	–	–	–	2
	T2	7	19	178	60	13	277
	T3	–	1	9	9	76	95
	Total %	1.9	5.9	50.0	18.4	23.8
	Total n	1.3	4.7	94.4	20.1	36.6
Glargine	T1	–	2	–	–	–	2
	T2	8	20	184	62	13	287
	T3	–	1	6	12	70	89
	Total %	2.1	6.1	50.3	19.6	22.0
	Total n	1.5	4.9	78.1	35.2	48.8
Vials
Detemir	T1	–	2	1	–	–	3
	T2	12	27	252	68	8	367
	T3	–	1	3	12	7	23
	Total %	3.1	7.6	65.1	20.4	3.8
	Total n	2.0	5.8	124.7	23.2	12.6
Glargine	T1	–	2	1	–	–	3
	T2	16	32	269	69	13	399
	T3	–	1	1	1	2	5
	Total %	3.9	8.6	66.6	17.2	3.7
	Total n	2.8	6.5	128.0	24.6	3.0
Numbers of Part D plans
Pens
Detemir	T1	–	3	–	1	–	4
	T2	3	1	63	420	–	487
	T3	–	2	–	15	80	97
	T4	–	–	1	–	–	1
	Total %	0.5	1.0	10.9	74.0	13.6
	Total n	0.015	0.14	3.0	15.4	1.5
Glargine	T1	1	3	–	1	–	5
	T2	3	1	79	389	–	472
	T3	–	1	6	12	44	63
	T4	–	1	–	–	51	52
	Total %	0.7	1.0	14.4	67.9	16.0
	Total n	0.054	0.14	2.3	16.1	1.6
Vials
Detemir	T1	–	4	1	–	–	5
	T2	3	2	177	343	–	525
	T3	–	–	5	17	82	104
	T4	–	–	1	–	–	1
	Total %	0.5	0.9	29.0	56.7	12.9
	Total n	0.015	0.19	3.3	16.0	1.5
Glargine	T1	1	4	1	–	–	6
	T2	3	2	146	374	–	525
	T3	–	6	16	35	1	58
	T4	–	–	–	–	51	51
	Total %	0.6	1.9	25.5	63.9	8.1
	Total n	0.054	0.16	2.8	16.7	1.4

Total % = total % of plans at indicated copay range; total N = millions of subscribers with pharmacy benefits. Excludes subscribers not covered.

Copays are per prescription, per fill.

Copays for pens were >$50 in 22% (83/378, insulin glargine) to 24% (89/374, insulin detemir) of private plans (covering 37–49 million subscribers) compared to fewer than 4% of plans requiring this copay for either analog in vials. A larger number of subscribers with private insurance had copays in the >$10–35 range for vials than pens, possibly due to the low number of plans requiring copays >$50 for vials compared to pens. Distribution of copays for the two basal insulin analogs in vials were similar to one another.

The majority of basal insulin analogs, pen or vial, were covered under Part D (Table 3) at Tier 2. However, under Medicare Part D, the distribution of copays for basal insulin analogs, by plan and by number of subscribers, are shifted to higher ranges compared to the private plans, with the shift occurring mainly within Tier 2 and increasing from the >$10–35 range to the >$35–50 range.

Thus, with private plans, 50% and 67% of plans required copays for basal analogs (in pens and vials, respectively) in the >$10–35 range, whereas under Part D only 10% and 25% of plans required copays for basal analogs (in pens and vials, respectively) in the >$10–35 range, but a larger proportion of Part D plans required copays at >$35–50. This accounts for 2–3 million Part D subscribers at a copay range >$10–35 for pens and vials, and up to 66–75% of plans, covering ∼15–17 million subscribers for pens and vials in the higher >$35–50 copay range out of the nearly 22 million total Part D members in this survey. Under Part D, there was a larger proportion of plans at the >$10–35 copay range for vials than pens, but the numbers of subscribers who were eligible for pens and vials were the same in this copay range. Also under Part D, there were approximately equal numbers of eligible subscribers for pens and vials within the >$35–50 copay range.

The distribution of copays for NPH formulations in vials is shown in Table 4. There are differences in copay ranges for NPH-H vs NPH-N, with a greater number of private plans covering NPH-H at Tier 2 than covering NPH-N at Tier 2. Both formulations are covered at Tier 2 with a copay range of >$10–35 in the majority of private plans, however. Under Medicare Part D the majority of plans cover these products at Tier 2 as well, but typically at the higher copay range of >$35–50. Tier 3 coverage provided by 46 Part D plans required a $95 copay for NPH-H (data not shown). This demonstrates that copays for NPH formulations in vials under Part D or private plans were generally no less expensive than basal insulin analogs in pens or vials.

Table 4.  Copay ranges for intermediate-acting human insulin (NPH).

Insulin	Copay ranges
	Tier	$0	≤$10	>$10–35	>$35–50	>$50	Total plans
Private plans
NPH-H	T1	2	5	3	–	–	10
	T2	20	30	234	8	3	295
	T3	–	–	2	13	44	59
	Total %	6.0	9.6	65.7	5.8	12.9
	Total n	3.3	3.4	93.8	30.4	25.0
NPH-N	T1	6	7	49	–	–	62
	T2	22	18	135	65	2	242
	T3	–	1	4	62	17	84
	Total %	7.2	6.7	48.5	32.7	4.9
	Total n	4.4	5.7	106.7	37.6	5.1
Part D plans
NPH-H	T1	1	3	–	–	–	4
	T2	3	3	50	311	–	367
	T3	–	–	6	52	22	80
	T4	–	–	–	–	2	2
	Total %	0.9	1.3	12.4	80.5	5.3
	Total n	0.06	0.1	1.9	17.3	0.83
NPH-N	T1	1	7	–	–	–	8
	T2	3	1	158	326	–	488
	T3	–	–	10	60	60	130
	T4	–	–	–	–	1	1
	Total %	0.6	1.3	26.8	61.6	9.7
	Total n	0.06	0.2	3.5	16.3	1.9

NPH-H, Humulin N; NPH-N, Novolin N; total %, total % of plans at indicated copay range; total n, millions of subscribers with pharmacy benefits. Excludes subjects not covered.

Copays are per prescription, per fill.

Prior authorization for basal insulin analogs

Of 425 private plans, 29 (6.8%), covering 8.4 million people, required prior authorization (PA) for insulin detemir in pens, while 39 plans (9.2%), covering 6.1 million people, required PA for insulin glargine in pens. PA was required by 8.5% of Part D plans for the same products. Prior authorization was not required by Medicare Part D plans for insulin analogs in vials, while up to 2.6% of private plans required it (Table 5).

Table 5.  Numbers of plans requiring prior authorization.

	Analog pens		Analog vials		NPH vials
	Glargine	Detemir	Glargine	Detemir	NPH-H	NPH-N
Private plans, n (%)	39/425 (9.2)	29/425 (6.8)	9/425 (2.1)	9/425 (2.1)	10/396 (2.5)	4/396 (1.0)
Plan subscribers* (%)	8.4 (5)	6.1 (3.6)	2.2 (1.3)	1.0 (0.6)	3.9 (25.3)	3.2 (1.9)
Part D plans, n (%)	55/644 (8.5)	55/644 (8.5)	0/644 (0)	0/644 (0)	18/661 (2.7)	0 (0)
Plan subscribers* (%)	1.7 (7.7)	1.7 (7.7)	0 (0)	0 (0)	0.6 (2.8)	0 (0)

Data are number of plans requiring prior authorization/total plans available.

*millions of subscribers with pharmacy benefits requiring prior authorization.

NPH-H, Humulin N; NPH-N, Novolin N.

For the NPH formulations, 2.5% (10/396) of private plans and 2.7% (18/661) of Part D plans required PA for NPH-H, while 1% (4/396) of private plans required PA for NPH-N. No Part D plans required PA for NPH-N.

Discussion

This study characterizes managed care coverage of insulin delivery pens and vials for basal insulin analogs in the US. For perspective, we also compared coverage of NPH formulations in vials. The formulary database used was unbiased, independent, and commercially available, and is updated quarterly. The data demonstrate that the majority of insured subscribers with pharmacy benefits were offered good Tier 2 coverage for the two basal insulin analogs in pens and vials or for the two basal insulin analogs themselves. Furthermore, the results show that coverage of insulin detemir or insulin glargine was offered to similar proportions, and, in some cases, higher proportions of subscribers, than who were offered coverage for the two human intermediate-acting formulations.

Both pens and vials for basal insulin analogs were covered at Tier 2 in the majority of plans and for the majority of subscribers in both private and Medicare Part D plans. In the private plans, the most common copay range for all basal insulins, regardless of the delivery system or type of insulin, was >$10–35. Approximately 23% of private plans, and 23--29% of private plan subscribers, had a >$50 copay for pens compared to fewer than 4% at this copay level for vials. Copays did not differ between pens and vials for the same product within the same Tier in most private plans, and most plans did not switch Tier levels for basal analog coverage of vials vs pens (not shown). Although there were some copay preferences for vials over pens by a minority of private plans, copays for the same branded product were often shifted to higher cost ranges by Part D plans compared to private plans, irrespective of vial or pen and while staying within the same Tier.

Under Part D, there was a larger proportion of plans at the >$10–35 copay range for vials than pens, but the number of subscribers who were eligible for pens and vials were the same in this copay range. Also under Part D, there were approximately equal numbers of subscribers eligible for pens and vials within the >$35–50 copay range. The majority of private and Part D insurance plans covered NPH to the same extent as basal insulin analogs. Moreover, less than 10% of both private and Medicare Part D plans required PA for any type of insulin, in either pens or vials.

These findings contradict widely held perceptions by physicians that managed care provides substantially greater coverage for vials compared to insulin pens, or provides greater coverage for NPH than for basal insulin analogs, or typically requires PA for insulin analogs in pens. These perceptions by healthcare providers have been shown to influence the use of insulin pens in the US13.

A small US survey of 108 primary care physicians, 192 internal medicine specialists, and 225 endocrinologists highlights the inconsistent attitudes among healthcare practitioners toward insulin pens13. This survey evaluated physicians’ perceptions of insulin pens and factors that influence physician treatment recommendations. The participants estimated that ∼50% of their patients used pens and, separately, that ∼60% of their patients initiated insulin pens if recommended by the physician. Most of the survey participants perceived pens to be more convenient (77–81%) and more effective than vial and syringe administration (61–65%), and between 54–65% of the respondents presented pens to their patients. However, only 32% of the primary care practitioners, 39% of the internal medicine specialists, and 44% of the endocrinologists recommended pens to their patients. These discrepancies suggest that this smaller proportion of the healthcare practitioners in the survey might have been responsible for the ∼60% of patients initiating insulin pens.

In this population of physicians who would not recommend pens, these devices were perceived to be more costly than vials and syringes for their patients. Physician perception of insurance coverage for pens and their cost to the patient were significant factors that influenced the determination of suitability of insulin pens for a patient13. Perception by the physician of existing insurance coverage was associated with an increased frequency of presenting the pen as an option, or recommending and initiating insulin pens. These data are borne out in a separate survey of patient attitudes where cost perception was the most common reason given by 23% of patients for not using a pen, although most patients were likely to use a pen if presented and recommended by the physician16. A survey of over 15,000 patients from 100 self-insured plans revealed that while 88% used insulin analogs, only 3% initiated insulin use with pens1. It is not clear if pens were covered to the same extent as vials were by these 100 self-insured plans. Consequently, equivalent copays for insulin pens and vials, offered by a majority of both private and Part D insurance plans, coupled with a greater awareness by both prescribers and insured patients of the availability of pen coverage, likely will affect the frequency of insulin pen use in the US, which lags far behind the frequency of pen use in most other industrialized countries2.

Several studies have reported that insulin pen users have higher adherence rates than vial and syringe users5,7–9. Higher adherence rates have been associated with improved glycemic control and improved outcomes17–19, lower rates of microvascular complications20, a reduced risk of hypoglycemia5,8, and decreases in hypoglycemia-attributable emergency department visits5,8, lower overall diabetes-related healthcare costs5,8, and all-cause treatment costs5,8,9 that may include lower inpatient and outpatient hospital costs9.

A perception by prescribers that insulin pens require PA may be another factor that may limit their use in the US. However, this survey demonstrates that only a small minority of private or Part D plans require PA before insulin therapy with pen devices is initiated. Improved awareness that PA for insulin pens is not required by the majority of plans may also improve their acceptance by physicians.

The cost of copays affects treatment acceptance and adherence. A retrospective cross-sectional study of patients with type 2 diabetes on oral anti-diabetic medications, with or without insulin, reported that a $10 increase in cost sharing (i.e., copayment, coinsurance) was associated with a 6.2% reduction in adherence. In the same study, it was reported that adherence was associated with reduced risk of a number of diabetes-related complications; for example, among patients treated with oral anti-diabetes medications and/or insulin the risk of experiencing an acute myocardial infarction was 58% lower among adherent patients21. Another study of medical and pharmacy claims data for patients with type 2 diabetes reported that a $5 increase in patient costs resulted in a 15% decrease in the odds of being adherent and an increase in A1C of 0.1 percentage points22. In a literature review analyzing the link between adherence and A1C, it was found that better adherence is associated with improved glycemic control and decreased healthcare utilization for patients with type 1 or type 2 diabetes23. Consequently, the costs of copays significantly affect adherence and glycemic control, and may affect longer-term patient health outcomes. If insulin pens had higher copays than vials, any improvement in adherence due to potential device use could be mitigated. However, copays for insulin pens and vials in many plans were not substantially different according to this survey.

Copays were typically higher, though, in the majority of Part D plans compared to private plans for a given product at a given Tier level. Thus, the higher costs associated with shifts towards higher Medicare Part D copays might be counterproductive in terms of patient health outcomes and overall costs of diabetes-related care. A recent study demonstrated that insurance type influenced insulin management plans in children with type 1 diabetes15. Children with private insurance were more likely to receive two or more injections per day compared to children using public insurance (77% vs 40%). According to the authors of the study, insurance type was the most significant factor in overall glycemic control. Children with public insurance had a mean A1C of 9.8% compared to a mean A1C of 8.6% in children with private insurance (p < 0.0001). Differences in pen use and limitations on test strip usage were cited as factors that contributed to a lower emphasis on progressing to intensive therapy with multiple daily injections and thus to differences in glycemic control15. Societal, school, and family support systems were considered to play a role, but no data were collected to rigorously evaluate these factors.

Several limitations of this study must be acknowledged. First, the analysis was descriptive. Copay stratification was not based on a statistical model, but was chosen based on copay ranges that corresponded with ranges typically used by the plans. Some insurance plans used a copay range instead of a single copay. The highest cost figure in a plan’s copay range was then used to describe the copay in order to simplify the analysis. There were no direct correlations performed on the numbers of subscribers per plan vs copay or Tier level. Since some plans contained as few as 29 subscribers, while a small number of plans contained as many as 3 million subscribers, this may have skewed some of the analysis. This did not change the overall direction or interpretation of the results, since the data showed that relative proportions of plans and subscribers in any Tier level were comparable.

Conclusions

Basal insulin analogs delivered by pens are well covered by both public and private insurance. The majority of plans offered Tier 2 pen coverage of basal insulin analogs to a majority of subscribers, with some preferences in coverage compared to NPH. There are some preferences for vials over pens by a minority of plans, but the majority of plans covering the majority of subscribers cover pens and vials to the same extent. These results refute the widely held perception that insurance coverage is superior for NPH compared to basal insulin analogs, or that overall coverage and copays are less generous for the basal insulin analogs, or if delivered by pens compared to vials. Copay ranges were typically higher for the same product under Part D than under private insurance. A greater awareness by prescribers of insurance coverage of insulin pens over vials, of the similarity in overall insurance coverage between delivery systems and insulin formulations, and greater attentiveness to coverage differences among plans in the prescribing area, may help to increase acceptance and use of insulin pen devices in the US, ultimately improving glycemic control and contributing to improved health outcomes.

Transparency

Declaration of funding

Funding to support this study and the preparation of this manuscript was provided by Novo Nordisk Inc. The manuscript was prepared according to the ICMJE’s Uniform Requirements for Manuscripts Submitted to Biomedical Journals and the International Society for Medical Publication Professionals’ “Good Publication Practice for Communicating Company-Sponsored Medical Research: The GPP2 Guidelines”.

Declaration of financial/other relationships

EK and MA are employees of Novo Nordisk and own Novo Nordisk stock.

Acknowledgments

The authors would like to thank Nicole Cooper of MedVal Scientific Information Services, LLC for providing medical writing assistance and editorial assistance, and Efe Ighodaro for assistance with data analyses.