Facial photoprotection in xeroderma pigmentosum (XP) patients: Validation of a new self-reported questionnaire of adherence

A personalized and systematically designed adherence intervention improves photoprotection in adults with xeroderma pigmentosum (XP): results of the XPAND randomized controlled trial

BACKGROUND

Poor adherence to photoprotection in xeroderma pigmentosum (XP) increases morbidity and shortens lifespan due to skin cancers.

OBJECTIVES

To test a highly personalized intervention (XPAND) to reduce the dose of ultraviolet radiation (UVR) reaching the face in adults with XP, designed using known psychosocial determinants of poor photoprotection.

METHODS

A two-arm parallel group randomized controlled trial, including patients with suboptimal photoprotection to receive XPAND or a delayed-intervention control arm that received XPAND the following year. XPAND comprises seven 1 : 1 sessions targeting photoprotection barriers (e.g. misconceptions about UVR) supported by personalized text messages, activity sheets and educational materials incorporating behaviour change techniques. The primary outcome, mean daily UVR dose to face across 21 days in June-July 2018, was calculated by combining UVR exposure at the wrist with a face photoprotection activity diary. Secondary outcomes were UVR dose to face across 21 days in August 2018, time spent outside, photoprotective measures used outside, mood, automaticity and confidence to photoprotect. Financial costs and quality-adjusted life years (QALYs) were calculated.

RESULTS

Sixteen patients were randomized; 13 provided sufficient data for primary outcome analysis. The XPAND group (n = 8) had lower mean daily UVR dose to face [0.03 standard error of difference (SED) (SD 0.02)] compared with controls (n = 7) [0.43 SED (SD 0.17)] (adjusted difference = -0.25, P < 0.001, Hedge's g = 2.21) at the June 2018 assessment. No significant between-group differences were observed in time spent outside, photoprotection outside, mood or confidence. The delayed-intervention control showed improvements in UVR dose to face (adjusted difference = -0.05; Hedge's g = -0.1), time outside (adjusted difference = -69.9; Hedge's g = -0.28) and photoprotection (adjusted difference = -0.23, Hedge's g = 0.45) after receiving XPAND (June 2019 assessment). XPAND was associated with lower treatment costs [-£2642; 95% confidence interval (CI) -£8715 to £3873] and fewer QALYs (-0.0141; 95% CI -0.0369 to 0.0028).

CONCLUSIONS

XPAND was associated with a lower UVR dose to face in patients with XP and was cost-effective.

Improving photoprotection in adults with xeroderma pigmentosum: personalisation and tailoring in the 'XPAND' intervention

BACKGROUND

Individualised behaviour change interventions can result in greater effects than one-size-fits-all approaches. Factors linked to success include dynamic (vs. static) tailoring, and tailoring on behaviour, multiple theoretical variables, and participant characteristics. XP is a very rare (∼100 UK patients) genetic disease, involving an inability to repair ultraviolet radiation (UVR)-induced damage, resulting in skin cancers and eye damage from an early age, and mean life expectancy of 32-years. Management involves rigorous UVR photoprotection, which is often inadequate, and no interventions have been published. UK-based care is personalised and delivered by a multidisciplinary team at the National XP Service in London. Following an intensive, mixed-methods formative phase with patients diagnosed with XP (n-of-1, qualitative interviews, objective UVR measurement, cross-sectional survey) and relevant stakeholder consultation (clinical and patient/public teams), the 'XPAND' intervention was developed. This paper describes the comprehensive and novel tailoring and personalisation processes used to deliver the intervention.

METHODS

XPAND consists of core and personalised modules targeting cue-based (time of day, weather, symptoms), belief-based (motivation, priority), self-regulatory (effort, barriers, planning), and emotional (stress, self-consciousness, mental exhaustion) factors, social support, disclosure, habit, and willingness, using appropriately-matched BCTs. A-priori, phase I data and a baseline profiling questionnaire (data sources) were used to allocate modules to participants ('personalisation') and to adapt module content ('tailoring'). Iterative decisions about delivery were based on patient response to feedback, identification of additional barriers (e.g. reasons for varying protection across contexts), and emergence of new barriers as improvements in protection were attempted or achieved (e.g. appearance concerns).

CONCLUSIONS

Dynamic multi-level personalisation and tailoring based on mixed-methods in XPAND allowed for insights and decision-making not possible with cross-sectional quantitative or qualitative methods alone. Data collection and allocation/adaptation methods may be of use in other rare conditions where small patient numbers mean that within-participant, individual-level delivery is well-suited and feasible.