# Longterm efficacy of a patient focused intervention in patients with asplenia– a three year follow-up of the PrePPS trial

## TL;DR

A three-year follow-up shows that a tailored health intervention for asplenic patients significantly improves long-term adherence to preventive guidelines.

## Contribution

Demonstrates sustained efficacy of a HAPA-based telephonic intervention in asplenic patients over three years.

## Key findings

- PrePSS scores increased further at three years compared to six months post-intervention.
- Vaccination coverage and emergency antibiotic availability improved significantly.
- Only four patients experienced severe infections, none typical of post-splenectomy sepsis.

## Abstract

This study aimed to reassess the long-term impact of a Health Action Process Approach (HAPA)-informed intervention on guideline adherence among asplenic patients and their physicians, three years post-intervention.

This follow-up study was conducted within the framework of the interventional PrePSS (Prevention of Postsplenectomy Sepsis Score) study. Patients aged 18 or older with anatomical asplenia were in enrolled in a prospective controlled, two-armed historical control group design. The intervention group received tailored educational materials, medical alert cards, and a telephonic HAPA-based intervention. A telephonic follow-up assessment was conducted three years post-intervention, evaluating adherence to preventive measures using the PrePSS-score (range 0–10) and propensity-score based overlap weighting.

Out of 106 patients who had received the intervention, 79 (75%) completed the three-year follow-up. The PrePSS-scores further increased compared to six months post-intervention (median of 8.08 points vs 7.60 points), with notable improvements in vaccination coverage and availability of emergency antibiotics. Only four participants reported severe infections requiring hospitalization, none of which were typical of post-splenectomy sepsis. 47/79 (59%) of participants contracted SARS-CoV2 but clinical courses were mild with only one patient needing hospital and ICU treatment.

Patients who had received our novel telephonic intervention exhibited significant and sustained improvement in adherence to guideline-based preventive measures at three years post intervention. HAPA-based interventions may yield more sustained effects than traditional nudging strategies.