When comparing travel insurance plans to cover pre-existing conditions, check to see if there is a look back period.  A look back period means that going back on the calendar that much time from the policy effective date, if a pre-existing condition has not changed during that time, then it won’t be considered pre-existing.  A change can mean improvement or worsening of a condition, any change in diagnosis, treatment, or medication for that condition.  The look back period can be 60 days up to 3 years.  Always refer to the certificate of insurance for details.