“The Effect of Mail Order Pharmacy Outreach on Older Patients with Diabetes”

Background:

Diabetes is one of many chronic conditions that affects the geriatric population in which medication adherence plays an important role in preventing its complications¹. Observational studies investigating the effect of pharmacy options on medication adherence for chronic diseases, including diabetes, show that mail order pharmacy (MOP) use is associated with higher adherence for diabetes medications², better glycemic control, lower emergency department use, and fewer hospitalizations³. We also have seen that financial incentives to use MOP resulted in a greater uptake of this delivery model⁴. Studies which specifically investigate interventions used to optimize the health of the geriatric population are of significant interest, and their importance will increase in the coming years as the older patient population continues to grow⁵. This study uniquely contributes to the literature by examining whether the effects of direct-to-patient outreach on MOP use differ by age and improve medication adherence in the older population.

Methods:

The Encouraging Mail Order Pharmacy Use to Improve Outcomes and Reduce Disparities (EMPOWER) Study conducted through Kaiser Permanente Northern California (KPNC) was a randomized pragmatic trial to encourage the use of MOP with the aim of improving adherence of oral cardiovascular drugs (such as antihypertensives, lipid lowering drugs, and other oral diabetic medications) in patients with diabetes. Participants included adults with diabetes, poor medication adherence (proportion of days covered <80%), and no MOP use in the prior 12 months, who were randomized to receive no intervention (control) or MOP outreach (intervention). This outreach consisted of a mailed letter, secure email message, and automated phone call outlining benefits of MOP. Outcomes examined were initiation of MOP use and medication adherence during 12 months of follow up⁶. We further examined if the effect of direct-to-patient outreach on MOP use and medication adherence differed by age group by adding an interaction term between study arm and age, where age was a categorical variable with 2 levels (age <60 and ≥60 years).

Results:

Among 43,012 KPNC patients included in this study, 23,447 (54.5%) were aged ≥ 60 years. The prevalence of secure messaging was lower in the older age group. Benefits for the older aged group more frequently included a MOP incentive (defined as a discount in which the patient received 3 refills for the price of 2). The older age group had a significantly higher number of classes of oral cardiovascular drugs with p<.0001 for all comparisons.

10.7% of patients ≥60 years and 11.9% of patients <60 years initiated MOP use, and 54.9% of patients ≥60 years and 49.0% of patients <60 years became adherent to metformin. There was a positive effect of MOP outreach on MOP initiation in both age groups with a larger positive effect (p=0.025) in the age group ≥60 years as shown in Table 1 (age ≥60: OR 1.23 (CI 1.14, 1.34), age <60: OR 1.08 (CI 0.99, 1.17)).

Table 1:

Initiation of MOP Use and Adherent to Metformin by Age Group

	Initiation of MOP Use	Adherent to Metformin
Age <60 Odds Ratio (95% CI)	1.08 (0.99, 1.17)	1.05 (0.95, 1.16)
Age ≥60 Odds Ratio (95% CI)	1.23 (1.14, 1.34)	1.15 (1.03, 1.29)
Interaction Term between study arm and age p-value	0.025	0.235

Conclusion:

Geriatric patients are particularly susceptible to medication non-adherence and may benefit from the use of MOP. Factors which can influence medication adherence in the older adult population are numerous including both patient and medication factors such as logistics obtaining medications (transportation to pharmacy, cost), complexity of medication regimens, the patient-prescriber relationship, and social support⁷. This study examined whether the effects of direct-to-patient outreach on MOP use and subsequent impact on medication adherence are larger in the older population. Our study showed that reaching out to patients directly to encourage mail order pharmacy use can be an effective way to increase mail order pharmacy enrollment in the older population as we saw increased use of MOP in the intervention group, with a significantly larger effect observed in the older age group (≥60 years). Although the benefit observed seems small, it is statistically and, we believe, clinically significant because it demonstrates increased MOP use at a population level. It is important to keep in mind that this is a low-cost pragmatic intervention that can easily be implemented and may be more beneficial for older adults based on this analysis. Our study is one of the first to examine whether the effect of an MOP encouragement intervention differed by age. During the pandemic, when older patients with diabetes are particularly vulnerable, MOP use is encouraged by the CDC to combine convenience with safety; this study shows that older patients are responsive to outreach efforts to increase MOP use⁶.

Further studies could examine the effect of human contact reminders vs recordings for encouragement⁸, MOP enrollment opportunities in routine clinic visits, or preference for technology in older adults (mail vs email vs phone).