Life-Style
Flu Watch: May 2009
Monday, May 18, 2009
PTINR.com Staff
May shows the flu lingering in many states and making a comeback.
The flu season runs from the beginning of October through the end of May. Variant strains of the flu virus affect thousands of people during this season, ranging from young children to the most senior of citizens. The US Centers for Disease Control and Prevention (CDC) estimate that roughly 5-20% of the population is infected with the flu each year.1 Symptoms of the flu include, but are not limited to:
| Flu Symptoms |
| fever (usually high) |
| runny or stuffy nose |
| headache |
| muscle ache |
| extreme tiredness |
| stomach, nausea, vomiting |
| dry cough |
| sore throat |
| 1 |
Importantly, the symptoms of the flu can directly impact the results of international normalized ratio (INR) testing. Fever, vomiting, and diarrhea have been associated with increased INR values, placing patients at increased risk of bleeding. The higher the INR result above a patient’s target range, the greater the risk is of a major bleeding event. Not all patients with elevated INR test results will experience such a bleeding event, but the risk to each patient does increase.2
May shows the flu lingering in many states and making a comeback to wide spread reporting levels in 6 states. Specifically, California went from no reports of flu the week ending April 25th to widespread reporting the week ending May 2nd 2009.3
You should continue to get plenty of rest, eat healthy meals and wash your hands to prevent the spread of viruses and bacteria.
The flu kills an estimated 36,000 Americans each year and hospitalizes an additional 200,000 according to the CDC.1 Warfarin patients with the flu should be especially careful when choosing over-the-counter products to combat flu symptoms. Many over-the-counter medications interact with warfarin and can increase or decrease INR values. Patients are encouraged to obtain a list of cold and flu products with minimal warfarin (Coumadin ®) interactions from their health care professional.4
More frequent INR testing is also recommended for patients suffering from the cold or flu, who are potentially at increased risk because their INR values can rise or fall more rapidly.4 Weekly home INR monitoring allows for accurate testing between office visits, a strategy that has been shown to improve time in target range and significantly decrease the risk of bleeding and stroke.5
References:
Influenza: The Disease (2007). Retrieved January 28, 2009, from Centers for Disease Control and Prevention Web site: http://www.cdc.gov/flu/about/disease/index.htm
Hylek, E.M. et al. (1996). An Analysis of the Lowest Intensity of Prophylactic Anticoagulation for Patients with Nonrheumatic Atrial Fibrillation. NEJM, 335 (8), 540-6.
Weekly US Map: Influenza Summary Update. (2008). Retrieved March 3, 2008, from Centers for Disease Control and Prevention Web site: http://www.cdc.gov/flu/weekly/usmap.htm
Bristol-Myers Squibb Company. (2007). Medication Guide for Coumadin Tablets and Coumadin for Injection [Package Insert]. Princeton, NJ: Bristol-Myers Squibb Company.
Heneghan C., et al. (2006). Self-monitoring of oral anticoagulation: a systematic review and meta-analysis. The Lancet, 367, 404-11