About one-third of patients adhere to subcutaneous immunotherapy regardless of cost
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Key takeaways:
- Patients at military treatment facilities received their subcutaneous immunotherapy for allergies for free.
- 64% of male patients and 56% of female patients reached the maintenance phase.
Only about one-third of patients adhered to their course of maintenance doses in their subcutaneous immunotherapy even when there were no out-of-pocket expenses, according to a study published in Annals of Allergy, Asthma & Immunology.
The combined retrospective and prospective observational electronic medical record review examined subcutaneous immunotherapy (SCIT) at a military treatment facility (MTF) in San Antonio between 2005 and 2012, Jun Mendoza, MD, allergist-immunologist, 10th Medical Group Allergy Clinic, U.S. Air Force Academy, and colleagues wrote.
Annual premiums for care at MTFs range from $0 to $942 each year, depending on the type of military association. However, all care and medications at MTFs including all allergy services are free of charge with no copayments or deductibles. As a result, the researchers said, cost was not a factor in whether patients continued SCIT treatment.
The study involved 897 patients receiving SCIT, aged 1 to 74 years (mean age, 34.8 years). Also, 16% were children, 47% were male and 30% had asthma. Patients were treated with aeroallergen, venom, and/or imported fire ant immunotherapy, with recommended durations of 3 to 5 years.
Initial evaluations, extract prescriptions and allergy injections all occurred at a single center. Treatment began with a buildup phase of one or two injections a week including 37 venom rush buildups and then a maintenance phase of one injection per month.
Among these patients, 14% did not initiate therapy, 60% received at least one maintenance dose and 13% had a systemic reaction while they were in the maintenance phase. Also, 34% completed at least 3 or more years of maintenance doses, which the researchers called adherence.
The 34% who achieved adherence included 34% who completed 3 years, 27% who completed 4 years and 19% who completed 5 years or more. The mean total duration of the maintenance phase was 4.23 years, with a mean time of 3.17 years.
Additionally, the researchers said that 7% of patients who reached maintenance doses had rush immunotherapy for venom and/or imported fire ant immunotherapy (hymenoptera immunotherapy, or HIT). Further, 84% were on aeroallergen immunotherapy (AIT), 18% were on HIT, and 2% were on both AIT and HIT.
The researchers also found that 64% of males and 56% of females reached maintenance dosing (P = .01).
There were no significant associations between the type of SCIT (AIT vs. HIT), the presence of asthma, age, or history of systemic reactions and reaching maintenance dosing, the researchers said.
Also, whereas 61% of the patients who experienced a systemic reaction reached maintenance dosing, the researchers did not call this statistically different from the 60% of those who did not experience a systemic reaction who also reached maintenance dosing.
There were no significant associations between duration of SCIT and the type of SCIT, presence of asthma, age, history of systemic reactions or sex as well.
However, the researchers cautioned that they did not survey these patients about why they did or did not adhere to treatment and said this would be an important area to examine in future studies.
The researchers also noted that the study included members of a mobile military population who might not stay in one area for 3 years or more. Although continuity of care may be a challenge for this population, the researchers said, this mobility is common among nonmilitary populations as well.
Since out-of-pocket expenses were not a factor in adherence, the researchers said that providers should focus on other factors in improving adherence and that further studies surveying patients about their reasons may improve outcomes.
Perspective
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Michael S. Blaiss, MD, FACAAI, FAAAAI
I did not find the results surprising. Cost is just one of many possible reasons for poor adherence to subcutaneous immunotherapy. We know needle-phobia and anxiety due to getting an injection are issues, as are the inconvenience of getting regular injections and feeling better when the allergy season is over. (“So why should I continue treatment?” patients may ask.). In addition to what I already have mentioned, the time commitment of 3 years or more for allergen immunotherapy, side effects such as local reactions, and lack of quick efficacy for some patients are other obstacles to adherence. Of course, cost is an issue in my practice, too.
I do think it is important that an unknown number of patients in this study were transferred to other military stations and labeled as nonadherent if they had not done 3 years of immunotherapy, even though they may have continued immunotherapy at their new military station. Therefore, the nonadherence rate may be lower than what was published.
In my own experience, about 50% of patients stop SCIT in the first year, and another 25% stop in the second year. Thus, adherence for 3 years is around 25%.
One important way to increase adherence is using shared decision-making in the process of prescribing immunotherapy. Patients need to be clear about the benefits, risks, outcomes and costs to make an informed decision. Some of these patients may be candidates for sublingual immunotherapy tablets, and those patients should be given information on this treatment alongside SCIT in a shared decision-making approach. Studies show that patients who help choose their treatment have a higher adherence rate. One last way to improve adherence is more office hours when immunotherapy is given, making it more convenient.
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