CLINICAL EVIDENCE · UNIVERSITY OF PORTO · 2024
Rapport 244/CEFMUP/2024 · PI: Marina Dias Neto, MD PhD FEBVS · Ethics Approved May 2024 · Zero Adverse Effects
Quality of life was assessed using the CIVIQ-14 — the Chronic Venous Insufficiency Questionnaire, Portuguese translation. The CIVIQ-14 is internationally validated, widely used in vascular research, and specifically designed to detect meaningful changes in CVD patient status.
Scores range from 14 (no impact) to 70 (maximum impact). Lower scores indicate better quality of life.
Participants measured their own lower limb circumference twice daily — once in the morning immediately upon rising, and once before sleep — at three standardized anatomical levels: supramalleolar (ankle), middle third of the leg, and middle third of the thigh.
Measurements were taken using a Smart Tape Measure Body digital device (resolution 0.1cm, accuracy ±2%).
The presence or absence of back pain during limb elevation was specifically measured as a secondary outcome — directly addressing the compliance-limiting problem of every competing device.
All other adverse events or symptoms perceived during the intervention period were also recorded.
Lower limb elevation is the only therapeutic intervention recommended across every stage of chronic venous disease — from early-stage heaviness and varicose veins through to active venous ulcers. The European Society for Vascular Surgery 2022 Clinical Practice Guidelines cite it as universal.
Yet despite this universal recommendation, patient compliance with overnight elevation has remained chronically poor — for one consistent reason: every existing device causes back pain.
Wedge pillows and platform risers elevate only the lower limbs. When the user sleeps on their back, this creates lumbar flexion. On their front, lumbar extension. On their side, lateral flexion. In each case, spinal instability develops within days, and the patient abandons the device.
UZit addresses this at the mechanical level — an under-mattress full-body incline creates an even slope across the entire body, maintaining spinal neutrality regardless of sleep position. The clinical study was designed to determine whether this mechanical advantage translated into measurable clinical benefit.
"The existing solutions on the market only elevate the lower limbs and can induce persistent low back pain after a few days of regular use."
— Study Protocol, University of Porto, 2024
Study Design Visual Timeline
30 patients with symptomatic chronic venous disease, CEAP classifications C1, C2, or C3, recruited from the outpatient vascular surgery clinic at Casa de Saúde da Boavista, Porto.
Patients were randomly allocated to Group A or Group B.
UZit overnight elevation
Control (own resources: pillows, standard elevation methods)
No elevation intervention for either group — eliminates carryover effect from Phase 1.
Control elevation
UZit overnight elevation
Because every participant experienced both UZit and control conditions, each patient serves as their own control — dramatically strengthening the reliability of comparative findings.
Sample size was calculated to detect a clinically important difference of 10 points on the CIVIQ-14 scale, with 95% confidence interval and 80% statistical power (α = 0.05, two-tailed). 30 patients were enrolled to allow for up to 20% loss to follow-up.