Wednesday, February 16, 2005
Flu Shots
There is a new study out from the Archives of Internal Medicine suggesting that giving flu shots to the elderly has not saved lives.
The researches had this to say:
We attribute the decline in influenza-related mortality among people aged 65 to 74 years in the decade after the 1968 pandemic to the acquisition of immunity to the emerging A(H3N2) virus. We could not correlate increasing vaccination coverage after 1980 with declining mortality rates in any age group. Because fewer than 10% of all winter deaths were attributable to influenza in any season, we conclude that observational studies substantially overestimate vaccination benefit.
I have some observations regarding the researchers' conclusions
-There are more elderly people now. Along with more elderly, there are more elderly living with chronic diseases that affect the immune system (transplant recipients, Chronic renal failure, RA, DM etc.). Wouldn't this affect the mortality rates? If you took 10 elderly people 30 years ago maybe only two were living with chronic immunosuppresive diseases (because the morbidity/mortality rates were not as good then). The flu vaccines would likely have been more effective because the patient population was healthier.
If you took 10 patients now, five or six would likely be dealing with a chonic disease that affects the immune system so the vaccines would be less effective because your patient population is sicker as a whole.
-The turning point appears around 1980. This is the same time the DRG system of payment to hospitals by Medicare started (1982). It would seem possible that the two are linked. Medicare began to pay depending on the principle diagnosis carried by the physician. The hospital and physician would've started listing diagnoses more correctly since so much was riding on them. For example, a physician would've been more likely to have started listing, as the principle diagnosis, the reason for presentation to the hospital, and dropped the simple "Influenza" diagnosis. What one would see is a dehydration, pneumonia, or sepsis diagnosis instead. They might've been caused by the Influenza virus but they, not the influenza, caused admission and death.
Freaky!
Just follow the directions, press and hold down the left mouse button. Move the mouse up to go forward or down to go back, very cool stuff.
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The researches had this to say:
We attribute the decline in influenza-related mortality among people aged 65 to 74 years in the decade after the 1968 pandemic to the acquisition of immunity to the emerging A(H3N2) virus. We could not correlate increasing vaccination coverage after 1980 with declining mortality rates in any age group. Because fewer than 10% of all winter deaths were attributable to influenza in any season, we conclude that observational studies substantially overestimate vaccination benefit.
I have some observations regarding the researchers' conclusions
-There are more elderly people now. Along with more elderly, there are more elderly living with chronic diseases that affect the immune system (transplant recipients, Chronic renal failure, RA, DM etc.). Wouldn't this affect the mortality rates? If you took 10 elderly people 30 years ago maybe only two were living with chronic immunosuppresive diseases (because the morbidity/mortality rates were not as good then). The flu vaccines would likely have been more effective because the patient population was healthier.
If you took 10 patients now, five or six would likely be dealing with a chonic disease that affects the immune system so the vaccines would be less effective because your patient population is sicker as a whole.
-The turning point appears around 1980. This is the same time the DRG system of payment to hospitals by Medicare started (1982). It would seem possible that the two are linked. Medicare began to pay depending on the principle diagnosis carried by the physician. The hospital and physician would've started listing diagnoses more correctly since so much was riding on them. For example, a physician would've been more likely to have started listing, as the principle diagnosis, the reason for presentation to the hospital, and dropped the simple "Influenza" diagnosis. What one would see is a dehydration, pneumonia, or sepsis diagnosis instead. They might've been caused by the Influenza virus but they, not the influenza, caused admission and death.
Freaky!
Just follow the directions, press and hold down the left mouse button. Move the mouse up to go forward or down to go back, very cool stuff.
# posted by Joe Florida @ 11:10 AM 
