Trial Outcomes & Findings for Nitrite Supplementation in Long COVID Patients (NCT NCT05618574)

One participant in the Beet-It nitrate beverage group did not complete a baseline CPET test due to staff concerns about safety during the pre-test safety assessment.

Rating of Rate of Perceived Exertion (RPE) during the 5th minute of a 5-min of a 1.5 mile per hour steady-state treadmill walking test is used as an assessment of fatigability. RPE scale is from 6 (no physical exertion) - 20 (maximal exertion/very hard). This is assessed before and after approx. 14 days of supplementation with Beet-It nitrate beverage vs. placebo. The mean change from baseline to follow-up is used as the outcome measure.

Walking efficiency (VO2/kg) is assessed by incorporating VO2 assessments during the 5-min steady-state walking protocol. This is assessed using cardiopulmonary exercise testing (CPET) equipment. A lower VO2 for the same functional workload indicates improved efficiency. This is assessed before and after approx. 14 days of supplementation with Beet-It nitrate beverage vs. placebo. The mean change from baseline to follow-up is used as the outcome measure.

This test measures the amount of time it takes the participant to walk a 400-meter course to assess cardiovascular and pulmonary fitness or to predict adverse outcomes such as mobility disability. his is assessed before and after approx. 14 days of supplementation with Beet-It nitrate beverage vs. placebo. The mean change from baseline to follow-up is used as the outcome measure.

The SPPB is a test of balance, gait, strength, and endurance that combines gait speed, chair stand and balance tests. SPPB scaled score ranges from 0 - 12. Scores of 0 indicate that the participant is unable/barely able to perform the tasks, while 12 indicates they completed all tasks optimally. This is assessed before and after approx. 14 days of supplementation with Beet-It nitrate beverage vs. placebo. The mean change from baseline to follow-up is used as the outcome measure.

Peak VO2 (ml/min) non-normalized to weight will be collected using symptom-limited cardiopulmonary exercise testing (CPET). This is assessed before and after approx. 14 days of supplementation with Beet-It nitrate beverage vs. placebo. The mean change from baseline to follow-up is used as the outcome measure.

Peak VO2 will be collected using symptom-limited cardiopulmonary exercise testing (CPET). The average sedentary male will achieve a peak VO2 of approximately 35 to 40 mL/kg/min. The average sedentary female will score a VO2 max of between 27 and 30 mL/kg/min. This is assessed before and after approx. 14 days of supplementation with Beet-It nitrate beverage vs. placebo. The mean change from baseline to follow-up is used as the outcome measure.

VO2 (ml/min) non-normalized at AT will be assessed using symptom-limited CPET. The VO2 at AT for the general population occurs at approximately 50-60% of the peak VO2. This is assessed before and after approx. 14 days of supplementation with Beet-It nitrate beverage vs. placebo. The mean change from baseline to follow-up is used as the outcome measure.

VO2 (ml/kg/min) at AT will be assessed using symptom-limited CPET. The VO2 at AT for the general population occurs at approximately 50-60% of the peak VO2. This is assessed before and after approx. 14 days of supplementation with Beet-It nitrate beverage vs. placebo. The mean change from baseline to follow-up is used as the outcome measure.

To determine the impact of nitrite-rich juice supplementation on skeletal muscle mitochondrial respiration on patients with Long COVID, muscle biopsy of the vastus lateralis will be completed at baseline and following 2 weeks of supplementation. At each time point muscle respiratory capacity will be measured using the Oroboros-2k system. The main outcome will be change in state 3 respiration (maxOXPHOS, pmol/mg/min wet.wt.). Data will be reported as Mean +/- standard deviation.

5 ml of blood will be collected from participants and spun down using a centrifuge to separate the plasma from the rest of the blood. Serological sampling is completed at baseline and at final visit. Serum nitrite (µmol/L) and nitrate levels (µmol/L) will be measured at baseline and after the study intervention to evaluate the successful metabolism of nitrate (in beetroot juice) to nitrite.

5 ml of blood will be collected from participants and spun down using a centrifuge to separate the plasma from the rest of the blood. Serological sampling is completed at baseline and at final visit. Serum nitrite (µmol/L) and nitrate levels (µmol/L) will be measured at baseline and after the study intervention to evaluate the successful metabolism of nitrate (in beetroot juice) to nitrite.

The Veterans RAND-12 (VR-12) is a brief self-administered health survey comprised of 12 items used to measure health related quality of life, estimate disease burden, and evaluate disease-specific benchmarks using two score components: Physical Component Score (PCS) and Mental Component Score (MCS). Summary scores are standardized using a t-score transformation (normalized to US population with mean of 50 and standard deviation of 10). A higher PCS represents better self-reported overall physical function; a higher MCS represents better emotional well-being and fewer mental health limitations.