#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 a 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.
- 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).
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