The Pilot of Zinc Acetate to Improve Chronic Cough (ZICO) is a study of 36 patients with chronic refractory cough that will be used to (1) assess if zinc acetate (150 mg/day) will improve patient reported measures of cough, (2) to establish if treatment with zinc acetate is well tolerated, and (3) to determine if the trial logistics are feasible.
Chronic refractory cough in adults is defined as a cough lasting more than 8 weeks that does not resolve with treatment for asthma/eosinophilic airway disease, gastroesophageal reflux disease (GERD), or rhinosinusitis/post-nasal drip; and is not caused by smoking, angiotensin-converting-enzyme (ACE) inhibitors, or parenchymal lung disease. This is one of the most common conditions leading to specialty referral accounting for about 20% of new pulmonary consultations. Chronic refractory cough leads to severe impairment of quality of life and social isolation as well as sleep deprivation and chronic fatigue. The few available treatments have limited benefit and substantial side effects or abuse potential. While there are validated tools to measure the health-impact of chronic cough which can provide feasible clinical trial outcome measures, there have been no academic multi-center trials of chronic cough, and guidelines for treatment continue to rely largely on opinion rather than evidence. ZICO is a small scale randomized proof-of-concept clinical trial to establish the safety and tolerability of zinc in this population. The primary outcome measure will be the Cough Specific Quality of Life Questionnaire (CQLQ). Participants will be 18 years or older, with chronic cough lasting at least 3 months, which has been unresponsive to treatments for asthma, GERD or other upper airway disease. Individuals that are current smokers, use an ACE inhibitor, currently take zinc supplements (or multivitamins with zinc), or whose medical history includes primary parenchymal lung disease, congestive heart failure, chronic kidney disease, or another medical condition that could interfere with the study or are pregnant or breast-feeding will be excluded. Participants will be randomized to receive 6 weeks of treatment with either zinc acetate or placebo. Follow-up assessments will occur at 1, 3, 6 and 8 weeks after randomization; the final assessment is after a two week washout to establish the duration of treatment effect. In addition to completing a daily cough diary, participants will complete cough specific and general quality of life measures, complete spirometry testing and have serum zinc and copper levels measured.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
34
* Day 0 (randomization) to day 3 Zinc acetate 50 mg per day (one capsule) * Day 4 to day 7 If well tolerated: Zinc acetate 100 mg per day (two capsules) * Day 8 to V5 (6 weeks) If well tolerated: Zinc acetate 150 mg per day (three capsules)
* Day 0 (randomization) to day 3 Placebo (one capsule per day) * Day 4 to day 7 If well tolerated: placebo (two capsules per day) * Day 8 to V5 (6 weeks) If well tolerated: placebo (three capsules per day)
National Jewish Medical and Research Center
Denver, Colorado, United States
St. Vincent Health
Indianapolis, Indiana, United States
Washington University School of Medicine
St Louis, Missouri, United States
Mount Sinai School of Medicine
New York, New York, United States
Change in Cough Quality of Life Questionnaire (CQLQ) Score by Treatment Group
Unadjusted comparison of change in CQLQ score between zinc acetate and placebo treatment groups. CQLQ scores range from 28 to 112, with lower scores indicating fewer adverse events. A minimum clinically importance difference of 5 has been proposed for this questionnaire.
Time frame: Baseline and 6 weeks
Change in Leicester Cough Questionnaire (LCQ) Score by Treatment Group
Unadjusted comparison of change in LCQ scores between zinc acetate and placebo treatment groups. LCQ scores range from 3 to 21, with lower scores indicating a greater impact of cough upon one's life. The minimum clinically importance difference for the LCQ for people with chronic cough is 1.3.
Time frame: Baseline and 6 weeks
Change in Cough Visual Assessment Scale (C-VAS) Scores by Treatment Group
Unadjusted comparison of change in overall severity of cough as measured by C-VAS between zinc acetate and placebo treatment groups. C-VAS scores cover four domains - severity of cough in daytime, nighttime, and overall, and severity of urge to cough. Scores range from 0 to 100 for each domain with overall scores ranging from 0 to 400. Lower scores indicate less severity. Overall severity of cough is the only domain reported here.
Time frame: Baseline and 6 weeks
Change in Global Assessment of Change in Cough (GACC) Score by Treatment Group
Unadjusted comparison of change in GACC scores between zinc acetate and placebo treatment groups. GACC scores measure change in quality of life related to cough in four domains - activity limitation, symptoms, emotions, and overall quality of life. GACC scores range from -3 (very much worse) to 3 (very much better).
Time frame: Baseline and 6 weeks
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Duke University Medical Center
Durham, North Carolina, United States