Send the second message; do not bother changing the channel

Design

pragmatic health-system-embedded PROBE trial with a 2-stage sequential multiple assignment randomised (SMART) design

Population

20,604 adults with established ASCVD or high ASCVD risk and recent statin non-adherence, mean age 54.8 years, 40.9% female

Primary outcome

statin refill within 14 days of each randomisation

Effect

14.4% vs 12.0% (adjusted risk difference 2.3 points, 95% CI 1.3-3.4); second outreach 13.0% vs 10.4%; switching channel adjusted RR 1.06 (0.94-1.17)

ADHERE-ASCVD embedded a two-stage randomised trial in Kaiser Permanente Northern California, enrolling 20,604 adults with established atherosclerotic disease or high risk and recent statin non-adherence. Patients were randomised to secure portal message, SMS, non-secure email or usual communication; those who had not refilled within 14 days were randomised again to repeat the same channel, switch channel, or usual communication.

Initial digital outreach raised 14-day refill from 12.0% to 14.4% (adjusted risk difference 2.3 percentage points, 95% CI 1.3-3.4). Among non-responders, a second contact raised refill from 10.4% to 13.0% (adjusted risk difference 2.5 points, 1.3-3.7). Switching modality gave nothing over repeating the same one (13.2% vs 12.5%, adjusted RR 1.06, 0.94-1.17). Cumulative refill at 28 days was 24.9% against 21.2%.

The design is the finding. Most adherence programmes send one message and then escalate to a different channel on the assumption that the first one was not seen. This trial tested that assumption head-on and it was wrong: persistence pays, channel-switching does not. The effect per message is small, but it applies to a population defined by an automated query, costs almost nothing per patient, and compounds — which is the opposite of most adherence interventions, where the effect is large and the population unreachable.

• Build a second automated contact into any refill-reminder pathway — that is where the extra yield is
• Do not spend effort switching channel between contacts; repeat the one you have
• Judge these programmes on absolute percentage points, not relative risk — 2.3 points is the real number
• Refill is not adherence; pair the outreach with an LDL recheck to see whether anything changed

Why it matters

It replaces the standard assumption behind adherence outreach — that a non-responder needs a different channel — with evidence that they just need asking again.

Don't overread it

The outcome is a pharmacy refill within 14 days, not sustained adherence and not cholesterol lowered.

The statistics, in plain English

An adjusted risk ratio of 1.20 sounds substantial but the absolute gain is 2.3 patients refilling per 100 contacted, because the baseline is low. At population scale that is worthwhile; at the level of one patient in front of you it is not a reason to expect much. The confidence interval on switching channels (0.94-1.17) includes 1.0, so the trial found no benefit rather than a small one.

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