Tools for Practice


#58 COLD-FX® evidence: Consistently reported inconsistently


CLINICAL QUESTION
Does CVT-002 (COLD-FX®) reduce the chance of upper respiratory tract infections (URTI) or influenza?


BOTTOM LINE
Much of the COLD-FX® research is limited by trial design and reporting/analysis issues. The evidence is neither consistent nor convincing enough to recommend COLD-FX® to prevent viral URTI in seniors or adults. 



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EVIDENCE
Five industry-funded randomized controlled trials (RCTs), in four publications 
  • 783 patients ≥65 years old randomized to placebo or COLD-FX® at 400 mg or 800 mg per day for six months during influenza season:1  
    • Modified intention to treat analysis found no statistical difference in either clinical or laboratory confirmed URTI 
    • In per-protocol analysis (only subjects who completing the study), two of eight outcomes were statistically significantly improved and two borderline. 
  • Combination of two non-statistically significant RCTs on nursing home seniors (89 and 109 patients each)2 of placebo versus COLD-FX® 400 mg: 
    • Statistical difference in laboratory confirmed URTI and influenza (9% versus 1%, p=0.009) but not in clinical URTI or influenza. 
  • 323 patient (279 analyzed) RCT of 18-65 year olds (influenza vaccine naïve), demonstrated 0.25 fewer clinical URTI (0.93 reduced to 0.68) per person over four months in patients using COLD-FX® 400 mg/day.3  
  • 43 community patients ≥65 years old randomized to placebo versus COLD-FX® 400 mg:4 
    • Did not look at clinical URTI or laboratory URTI. 
    • Statistically significant differences in some symptoms only seen in the last of three follow-up visits and no overall comparison.   
Context:  
  • Viral URTI occur in adults approximately 2-4 x per year.5  
  • COLD-FX® trials suffer from many concerns: Drop-outs >10% before a single dose is taken,3 modifying analysis to achieve statistical significance (using per-protocol analysis,1 combining trials,2 or selecting certain time frames4), multiple analyses, laboratory not clinical values,2 and inconsistent results.  
  • Other reviews raise similar concerns with this research.6 
  • Hand washing7 and getting an influenza vaccination8 do appear to reduce the chance of influenza or an URTI (although this research, too, is potentially biased). 
may 26 2015 by adrienne


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Author(s):

  • James McCormack BSc (Pharm) Pharm D
  • Michael R Kolber BSc MD CCFP MSc

1. McElhaney JE, Simor AE, McNeil S, et al. Influenza Research and Treatment 2011; Article ID 759051.

2. McElhaney JE, Gravenstein S, Cole SK, et al. J Am Geriatr Soc. 2004; 52:13-9.

3. Predy GN, Goel V, Lovlin R, et al. CMAJ. 2005; 173(9):1043-8.

4. McElhaney JE, Goel V, Toane B, et al. J Altern Complement Med. 2006 Mar; 12(2):153-7.

5. Gwaltney JM. Am J Med. 2002; 112(Suppl 6A):13S–18S.

6. Nahas R, Balla A. Can Fam Physician. 2011; 57:31-6.

7. Jefferson T, Del Mar CB, Dooley L, et al. Cochrane Database Syst Rev. 2011; 7:CD006207.

8. Jefferson T, Di Pietrantonj C, Rivetti A, et al. Cochrane Database Syst Rev. 2010; 7:CD001269.

Authors do not have any conflicts of interest to declare.